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Mineral PhotographyDesperate for help.
4th Jul 2014 14:50 UTCJay I. G. Roland
Being a recent convert to mineralogy and micro mounting in particular and having a basic understanding of photography I just upgraded my 3 month old Brunel 'scope to a nice new Meiji EMZ 13TR to marry up to my 2 month old Canon EOS 1100D with great expectations.
From what I have read around the web, with these two pieces of kit I ought be able to take some pretty decent images of my nascent mineral collection. Alas, though I have only been trying for two days I have yet to create an image that I can be proud of.
Below is a 16 image stack of a cluster of pyrolusite crystals circa 6mm across perched amongst a larger cluster. Lighting is via a Brunel high power LED box with a pair of flexible heads each with their own lamp.
First off, despite the mag setting on the 'scope being a mere 15x I just cannot seem to get a detailed image. At higher settings understandably my images deteriorate accordingly. Colourwise the crystals should be gunmetal grey yet appear tinged with green on the screen and on top of all that the DOF is pretty poor to say the least. I am rather hoping to be able to really get inside those lovely vugs I have on various specimens but I don't seem able to get the basics right.
The image down the eyetubes cannot be faulted, it is perfect in my eyes (pun intended) and I was rather hoping to replicate that view onto a photographic image. Am I asking too much?
As for camera settings I was advised to set the mode to A-Dep, change the ISO to 200 and all should be well. The connection twixt camera and 'scope is T2 ring, long tube, 2.5x relay lens then small tube, all plugged into the tri port with no cameral lens in the light train at all. I believe this is the correct setup.
As for stacking software I am using Helicon Focus (hence the annoying watermark) and I wonder if this is where the bogey lies. For some reason, all the functions don't seem to be available to me (this also applied when I first took on the trial) and perhaps there is a crucial one that I am missing.
After reading an old article here on Mindat I trotted off to town to obtain a 'daylight' bulb for my reading lamp to act as an auxiliary light source...at circa 100 Watt it made not one jot of difference so am not sure if lighting is the problem. Might a ringlight help at all?
Any advice, thoughts or comments will be thankfully taken on board.
Regards,
Jay in a very wet Cornwall.
4th Jul 2014 17:01 UTCEugene & Sharon Cisneros Expert
If you can respond to the following questions, it may shed some light onto the problem.
Are you focusing on screen with the camera tethered to the computer?
How do you mechanically increment the focus steps for the stack?
Do any of the single images from the stack have any in focus areas?
A good starting place to test the system would be to try taking a single image of a piece of paper with print on it. You should be able to get a sharp image. Make sure that the paper is held flat. If you can't get a sharp image, then something is not right in the optical train. Here is an example of a laser printed target that I use for this purpose.
Gene
4th Jul 2014 17:12 UTCOwen Melfyn Lewis
Welcome to Heartbreak Hotel! Learning to make decent photomicrographs has a steep learning curve. How steep depends on how much experience of photography in general - and of microscopy - you already have.
For the moment, I will say just this. Good eyes are superb optical instruments. They are extremely sensitive with a large dynamic range and the brain is selective in the way that it interprets information from them. The aim in photography is to incorporate in a camera's image as much as possible and is as fine detail as the eye can see without any camera. The brain does not interpret a camera's images in the same way as it does live views.
I think you are tackling several challenges all at once and are likely to obtain the greatest success in the least time by not tackling them all at once. Rather, tackle the learning curve one bit at a time. I'd recommend starting right at the bottom as follows:
1. Put your stacking software away for a few months. Until you can produce good single images, stacking will improve nothing and will only compound your present difficulties.
2. Start by concentrating on producing excellent quality 2-D images - like of a 1 cm cross drawn on a clean piece of white paper and taped down centrally to the stage of your scope. Produce the sharpest and most evenly lit images you can at max and min magnification levels. Experiment with extreme oblique incident light to bring into relief the fibres in the surface of the matt paper so they show well in your pics.
3. When the 2-D images are excellent - nothing less will do - progress to imaging a simple crystal forms. Start with opaque stones and progress to transparent stones. Learn how to deal with depth of field limitations and even make them work to your advantage.
If you would like to continue this discussion, I'm sure others will join in to help.
To start with, your scope and camera are good. Now, how do you mount your camera on the scope, via a trinocular port? If so, who makes and who sold you your camera adapter, Meiji? Is the adapter fitted with a relay lens - or is it just an empty tube? Are you getting approximately the same level of magnification for a given level of zoom setting when eye-balling through your eyepiece(s) and when viewing the image capture on the camera's sensor plate? If not, what's the difference, roughly?
4th Jul 2014 17:22 UTCJay I. G. Roland
'Are you focusing on screen with the camera tethered to the computer?'
I am focusing first via the eyetubes to frame the shot initially then I revert to the screen displaying the image via Canon Utility software and do all my subsequent focus steps via that route though I am mostly looking at my dial gauge (see below). Yes, they are tethered via a USB cable (Canon).
'How do you mechanically increment the focus steps for the stack?'
I am using one of the coarse focus knobs on the 'scope and am using your great idea of fitting a dial guage that rests on the top of the head to determine distance twixt shots.
'Do any of the single images from the stack have any in focus areas?'
Yes, they all have a portion in focus (those at the beginning and end that do not are skipped from the stack).
Yesterday I did a 104 image stack and was well disappointed!
I shall attempt the printed paper test tomorrow, though to be honest I'm not quite sure what I'm looking for. A sharp image on the screen? That shouldn't be too difficult I imagine.
I do think that there is a slight parfocality difference twixt eyepieces and photo-tube so do wonder if that might offer a clue?
One of the first things I did once I unpacked and 'built' the scope was to set the ocular dioptres to suit my eyesight so that shouldn't be an issue.
Regards,
Jay.
4th Jul 2014 18:15 UTCEugene & Sharon Cisneros Expert
The simple test of one image, as in my illustration image, is just to make sure that the optical system is working properly. You should see nice sharp specks across most of the field of view. Assuming that is OK, we can move on to other possible factors.
You said that each of the stack images does have a sharp area. What size steps are you taking, as they may not be small enough? I find that objectives with NA~0.1 require steps of 50um or less, depending upon how they overlap.
It would be difficult at best to have the eyepieces and the camera to be par focal. Your eyes can compensate for a certain amount of defocus, where as the camera sensor cannot. You will always need to depend upon the image on the computer monitor to do critical focusing.
Gene
4th Jul 2014 18:22 UTCJoe Mulvey
Sometime this works for me - try stacking only 2 images and see what happens. You may be surprised. I have experimented with reducing the number of images to stack and sometimes they come out much better.
I really like CombineZ (esp. the price) although I have much respect for many people and the work they've done with HF.
Joe
4th Jul 2014 18:32 UTCEugene & Sharon Cisneros Expert
To start with, your scope and camera are good. Now, how do you mount your camera on the scope, via a trinocular port? If so, who makes and who sold you your camera adapter, Meiji? Is the adapter fitted with a relay lens - or is it just an empty tube? Are you getting approximately the same level of magnification for a given level of zoom setting when eye-balling through your eyepiece(s) and when viewing the image capture on the camera's sensor plate? If not, what's the difference, roughly?
Good questions to bring up, Owen. Actually, Jay mentioned that he is using a 2.5X relay lens. That got me to thinking that may be too much magnification. So, another question for Jay. Try putting a measuring scale under the scope and see how the FOV compares for the eyepiece view and the image shown on the monitor. I use direct projection, with no relay lens, for my Canon 7D APS sensor size.
Gene
4th Jul 2014 20:18 UTCHenry Barwood
Is your camera set on "silent" mode (near vibrationless shutter release)?
Are you using a remote to trigger the shutter, either tethered or via your computer?
What kind of illumination are you using (stacking is very sensitive to directional illumination)?
All these thins will degrade your image beyond focusing
4th Jul 2014 21:52 UTCVolker Betz 🌟 Expert
Not new difficulties, you observe. Your microscope is fine for visual observations and your camera is OK. Before stacking you should try to get a sharp single shot picture. I test with an object micrometer something like this
http://www.mindat.org/photo-528019.html
Or use anything flat with fine structures.
An object micrometer gives you an idea of the resolution and you can calibrate FOV.
Your first test was made with an object which is very difficult to stack. Objects with this haystack structure (stacks of crystals in the depth) you fight against optical laws. If the focus ist set to a point in the deep then other crystals with less distance are unsharp and hide the crystals behind. If you stack such things you will get a mess. There is no way out, a camera does not accomodate like the human eye.
Which field of view you have tested ?
I have also taken a look at the adapters:
http://www.meijitechno.com/camera_adapters.htm
I am not very pleased with that kind of adapting.
You have a front lens, a pankrat (the zoom), a couple of prisms, a photo tube, a relay lens, distance tubes and a camera mounted only on the objective bajonet.
Take in consideration : only the front lens makes your picture and all others parts contribute to loss of picture quality.
So again we come to the reality:
A steromicroscope is fine for viewing and you can photograph with it, but dont expect very good pictures unless you have apochromatic optics.
With a bellows / lens solution you can only see monocular on the computer screen but you can take excellent pictures if you stack properly..
Volker
5th Jul 2014 02:10 UTCRolf Luetcke Expert
A couple of things that have been neglected are that some, as beautiful as they are with the eye do not photograph well with the microscope cameras. The metallics are one of them. I have found that some minerals will just not photograph at all. The second one is taking not hundreds but thousands of photos to perfect ones technique. The first photos I took were very poor but after years and years I have gotten better over time. Patience and taking the above advice will work but it doesn't always work out the first try.
One problem is that if you have a light that is on the same surface as your camera, the fan may interfere with the image by moving the surface. Elevating a light onto a different surface than the table you are working on is another must.
I have a few micro specimens I would love to get great photos of but have given up because some will just not photograph well.
Keep trying, a good success will keep those juices flowing. Try different minerals as well and see if that doesn't make a difference as well.
Good luck and it is great fun.
Rolf
5th Jul 2014 11:18 UTCJay I. G. Roland
My understanding was that I should be able to take very good images straight out of the box, pretty much as I am able to get perfect images via the eyetubes. It appears that I was mightily wrong!
Owen, what you had to say really made me think that my approach was the wrong one and subsequently I shall likely follow your advice. The camera by the way is attached to the trinoc tube of the 'scope via two plain tubes and one 2.5x projection lens all supplied by Meiji and all brand new. The only non Meiji component is the T2 ring.
Gene, for the life of me I cannot find the na of the 'scope objective, perhaps for some reason Meiji are somewhat reticent to reveal this info for whatever reason?
Joe, I have indeed tried taking fewer shots for stacking and depending on the specimen it certainly can work. It is just that I have read so many times that the more shots taken at reasonably constant distances apart the better the final outcome...hence my 104 shot attempt!
Henry, yes, by using the Canon utility software the camera operates with the mirror raised thereby minimizing vibration. The answer to your other two questions are in the original post.
Volker, I was saddened to read that you thought the adapter setup was a bad one. After reading much on this subject I came to the conclusion that to better my performance using the afocal method on my Brunel 'scope (which I was doing until the Meiji arrived) I did indeed need to take this route. I do hope that I haven't blown a whole load of money only to not get some decent results.
Rolf, 'The first photos I took were very poor but after years and years I have gotten better over time.' I really don't think I have that much time left to me! Seriously though, yes, I do now see that it going to be a long learning curve as Owen has said, so obviously I was expecting too much too soon. As for my illumination setup there is no fan in my LED equipment. The 'scope is sitting on a very large slab of polished marble and this sits on a steel framed office desk (NOT the sort from Argos or B&Q!) so is very stable indeed.
What I think I ought do is as Owen suggests, leave Helicon alone for a while and go over my entire collection (bought, donated and self collected) and take pictures of them all at minimum or just higher mag to try to master that aspect first. The EMZ 13TR ranges from 10x - 70x and I do accept that to attempt to take images at the higher end of the scale would be pretty fruitless though the image via the eyetubes is very acceptable to the eye.
Do any of you ever use LED ringlights for photomicrography and if so are you happy with them?
Thanks again to all who contributed, very kind of you all to take the time.
Regards,
Jay.
5th Jul 2014 13:39 UTCOwen Melfyn Lewis
-------------------------------------------------------
> Well folks, many thanks for all your input. First
> off I now realise that I was perhaps being a tad
> over ambitious in my first attempts by selecting
> the very complex pyrolusite crystals.
Like jumping in the deep end, man, and seeing if you can swim OK :-)
> My understanding was that I should be able to take
> very good images straight out of the box, pretty
> much as I am able to get perfect images via the
> eyetubes. It appears that I was mightily wrong!
Well there are a few things to sort out but it shouldn't take too long.
>
> Owen, what you had to say really made me think
> that my approach was the wrong one and
> subsequently I shall likely follow your advice.
> The camera by the way is attached to the trinoc
> tube of the 'scope via two plain tubes and one
> 2.5x projection lens all supplied by Meiji and all
> brand new. The only non Meiji component is the T2
> ring.
Thanks. Now can you make good clear images of a 1cm(exactly) cross on paper as suggested and lets see them. One at x1 zoom and another at maximum zoom. No post camera processing including no cropping. Let's see exactly what the camera's sensor plate captures.
At x1 Zoom setting, does the size of the cross seem about the same when you view it through the eyepieces as it does when you view it through the camera? If not, about how much larger is it when viewed through the camera?
This quick and simple little exercise will suggest/eliminate certain possible problems with your setup. We are looking for perfect, centralised, two-colour images, pin-sharp from edge to edge and with no colour aberration.
5th Jul 2014 15:06 UTCJay I. G. Roland
At 10x mag the image on the monitor is considerably larger than the image via the eyepieces. In the latter there is plenty of space beyong each 'arm' of the cross. At 70x I would say the size difference is the same though via the eyepieces I can clearly see the paper fibres (and beautiful they are too!).
No image processing as asked for but I did have to 'shrink' the file sizes down to enable them to make it to Mindat.
Thanks again,
Jay.
5th Jul 2014 15:16 UTCJay I. G. Roland
Am wondering if the sensor on my camera being only an APS-C is 'man enough' for this task?
Perhaps a different size relay lens might do the job? Thinking back to when I ordered all the kit I was never asked what camera I would be using, also, I never chose the 2.5x relay lens myself, it was chosen for me from the three Meiji have available. Not sure why that was.
A 'phonecall to Meiji/the supplier might have to be made on Monday!
5th Jul 2014 15:22 UTCJay I. G. Roland
5th Jul 2014 17:16 UTCOwen Melfyn Lewis
Wow! Lots is useful information and some conclusions.
1. Magnification, Increasing magification by increasing the objective lens system power is true magnification, in the sense that increasing of also increases the resolving power of the scope at the same time. Increasing the value of the eypiece magnification does not do this. Rather it giges to a larger imarge without any incrase in resolution. The result is that resolution (whatever that is) looks worse.
2. As you now know, your camera adapter with the relay lens in place is giving you a a magnification factor well above that of the standard x10 eyepieces and this is one root cause of your troubles. As you get 'bigger' through the camera, the resolution deteriorates.
3. You need to remove the unwanted magnigication power of your adapters relay. Your second shot, that should be at x70 is, I believe at about a system magnification of about x200 (maybe more) and that is above what your scope is designed to deliver with decent resolution.
If you are able, please remove the relay (projection) lens and make those zoom x1 and zoom x7 shots of the 1cm cross again and show them here. That will give further conclusive information.
We already have a baseline for the main system problem. We now need confirmation and begin to develop a cure.
Don't fret about your camera sensor for the moment, I'm sure its fine (I use an EOS 600D which I think has the same sensor plate) - and so is your scope fine. It's the optical mating of the two that is screwed up, I'm pretty sure. Been there and bought the T-shirt :-)
Let's see that second pair of pics?
5th Jul 2014 18:34 UTCJay I. G. Roland
I really do appreciate this, shame you don't live in Cornwall....
Regards,
Jay.
5th Jul 2014 18:48 UTCEugene & Sharon Cisneros Expert
What are the size of the minor divisions on your ruler image? We can calculate the image scale and magnification from that info.
Check the detail on your cross images against the one that I posted above. I don't think that yours are critically sharp. We can better assess the problems that you are having once we get more information. The ruler images do look pretty good though.
Most stereo scope manufacturers do not state the NA of their objectives. They seem to like lines per mm better. Most of the better scopes have NA = 0.1 and very high end scopes, with apochromatic objectives, are NA = 0.2. I'm fairly sure that yours is 0.1. This sets the resolution of your scope to around 3um (333 lines/mm). As Owen stated, increasing the magnification will make the image bigger, but will not increase the resolution. Your best images will always be the ones taken at the lower magnifications. The limiting factor, when imaging with a stereo scope, is the relatively low NA.
Gene
5th Jul 2014 21:59 UTCOwen Melfyn Lewis
I'm puzzled. You have removed a x2.5 mag colount lends from the system and yet the overall system magnification before and after removal remains approcimately the same. This does not compute. Forget the 'lens flre' for the present - we need t concentrate on the image resolution. As you know, what you are presently attaining is mediocre.
I can't explain why having removed a x2.5 relay lens you are still imaging (at poor resolution) a 1cm cross and at an incorrect sytem magnification. Let ne explain. At x10 system magnification, tour scope has a field of view (the diagonal of your camera image) that is 2.3cm. None of your cross images show the whole cross (1x1cm). Why? At x1 zoom, this should fully display - and then some - in your x10 images - unless additional magnification is being introduced. Any ideas why the cross magnification is roughly the same when you have removed a x2.5 lens?
P.S. I'm about 10 miles north of Southampton which is no great distance from Cornwall - and dryer too by the sounds of it ;-) Also the 'fount of all knowledge' for Meiji(UK) scope/camera mating is in Somerset that is sort of half way between us.....
6th Jul 2014 09:37 UTCJay I. G. Roland
Owen, you're puzzled! I'm totally baffled and I have to say pretty well miffed. I was of the impression that I was buying into a decent quality setup yet it appears that I may have been mistaken. Do I have a duffer here I wonder?
Looking at the info sheet that came with the MA150 camera attachment (two tube set plus relay lens) after all the setup instructions it states 'now it is ready for photomicrography' then states 'focusing should be made through the camera finder'. This I find strange in itself, how on earth does one focus a camera with effectively no focusable lens attached? Perhaps this is just a relic from the pre DSLR days when one had to use the view finder?
I have gone over all of the camera/'scope interface points looking for something that might be adjustable yet to no avail, unless of course I tinker with the height of the tubes in relation to each other/the photo tube. The relay lens by the way is I believe fitted correctly with the writing uppermost.
I have yet again setup and switched on and gone through all the modes available on the camera just to see if there is any noticable change in image size and as I guessed, nothing was found that made any difference. This was done with relay lens in the system so doubt anything would be found sans relay lens so never bothered going through that.
What I think I need is someone with a Canon 1100D & Meiji EMZ 13TR combination to talk me through all of this...a very unlikely event methinks.
Thanks folks for your time...
Regards,
A very miserable Jay on a glorious Cornish morning.
6th Jul 2014 12:29 UTCVolker Betz 🌟 Expert
don´t feel bad. You are going through the learning curve. A stereo microscope is fine for viewing. (in most cases).
Photography is a different story. Eye and camera are quite different and have different demands.
For that reason there is a photo macroscope.
If you ask a representative of a steromicroscope seller and ask : Can I make pictures with this stereo, they will answer:
Yes you can. Confocal ?? No, you have to focus on the camera viewer, but we have a confocal c-mount camera.
If you ask: It is the best way to use a stereo microscope to make pictures ?
Most will answer: Well, a stereo microscope is optimized for human use and optimized for the human eye.
Photography is a different story. I am not expert in that. I know our stereo microscopes are fine for viewing.
I am now experimenting with digital photography and stacking since 2004 and only tried once to use a stereomoicrocope: To demonstrate it is not a optimal way. It is a compromize, not a optimum. And in some cases its a worse compromize.
Volker
6th Jul 2014 12:47 UTCOwen Melfyn Lewis
My sense of it is that you have a camera adapter that is not of the correct specification for your camera body and scope model.
The aim of the adapter is three-fold:
- To give a secure and vibrationless mounting of the DSLR body to the trinoc port.
- To give a perfectly focused image of your subject at the image plane in the camera. The image plane is the face of your sensor array.
- When your scope zoom is at x1, a 2-D subject that is 2.3mm in length and perfectly focused, should just fill the diagonal dimension of you sensor plate.
The adapter has two parameters that can be set to mate perfectly any DSLR body with a given scope - but they must be set correctly.
- Length of the tube. This is set at the factory but your adapter may (or may not) have a fine focusing collar, by the turning of which you can make a fine focusing adjustment for your setup. This should be a 'once-only' adjustment..
- Introduction of a lens assembly into the tube. This may be necessary to be able to focus at the image plane for a given path length from the scope's internal optics to the camera sensor plate. A relay lens assembly can never improve image resolution above that afforded by empty tube of the correct length but if it is mis-specified, a relay lens can degrade performance considerably.
According to its specification, a relay lens will enlarge or shrink the image focused on the sensor plate. X1 specification will not alter the image size but, with some scopes, may be needed to correct for chromatic aberration caused in the scope (some scopes are/were designed so that CA is removed by the eyepiece lense assembly. A relay lens mag factor of
So far, so good. However, I do not understand why, when you remove your relay lens the image formed at your sensor plate is not radically reduced in size. We do know from the first test that with the relay lens in place, the image your adapter is causing to be created of a 1 cm cross is roughly 2-3 times too large to fill on your sensor plate and that this is the probable cause of your unsatisfactory image resolution.
The contact details for who you need to talk to at Meiji UK. Do come back and let us know how your problem is resolved - as I am sure it will easily be.
Two other quick points.
- The lens flare you are getting in your 'no relay lens' shots looks as though it is caused by some light spilling into the scope's lens barrel from an insufficiently controlled light source placed at an extreme oblique angle to the subject. This can be easily cured once the cause is proved (operator error, not equipment failure).
- Try the following for interest/education. Sit at your scope in a darkened room with the camera adapter removed from the trinoc port. Set up you cross image and place a sheet of thin white paper over your trinoc port. This is now your image plane . Try and focus the cross on the paper (which you can see through). Raise the paper off the port if you need to. You will find that to can adjust the size of a focused image by increasing/reducing the distance of the sheet of paper from the trinoc port. If you remove the paper entirely and with your eyes accustomed to the dark, you should be able to focus a very large cross on your ceiling. Look at how the resolution of the cross improves as the size at the image plane reduces as the image plane is brought closer to the scope.
Do let's here how you get on with that Meiji expert.
6th Jul 2014 16:49 UTCOwen Melfyn Lewis
-------------------------------------------------------
> Hey Jay,
>
> don´t feel bad. You are going through the
> learning curve. A stereo microscope is fine for
> viewing. (in most cases).
> Photography is a different story. Eye and camera
> are quite different and have different demands.
>
> For that reason there is a photo macroscope.
>
> If you ask a representative of a steromicroscope
> seller and ask : Can I make pictures with this
> stereo, they will answer:
>
> Yes you can. Confocal ?? No, you have to focus on
> the camera viewer, but we have a confocal c-mount
> camera.
>
> If you ask: It is the best way to use a stereo
> microscope to make pictures ?
>
> Most will answer: Well, a stereo microscope is
> optimized for human use and optimized for the
> human eye.
> Photography is a different story. I am not expert
> in that. I know our stereo microscopes are fine
> for viewing.
>
> I am now experimenting with digital photography
> and stacking since 2004 and only tried once to
> use a stereomoicrocope: To demonstrate it is not a
> optimal way. It is a compromize, not a optimum.
> And in some cases its a worse compromize.
>
> Volker
Volker,
Yes, you are right that any stereo microscope used for photomicrography is a compromise - unless combined with stereo photography. Yet many excellent - even award-winning - images can be created using a mono combination of DSLR and stereomicroscope.
I know also that this is not your preferred method - nor should it be for any who want and can afford to own optimal instrumentation (and have the talent and skill set to use all to maximum advantage) for each of their several requirements. I have seen some of your images and they are made with extraordinary care and attention to detail; I have not seen better. That said, I don't think it is reasonable to encourage, from where he presently is on the learning curve, Jay to abandon his present investment in instrumentation and to take another path. I'll guess he has a couple of years - probably more - before he appoaches the limits of what his present equipment can achieve.
Are you familiar with Guebelin and Koivola's 'PhotoAtlas of Inclusions in Gemstones'? This is a three-volume work of over 2,000 pages and with some 6,000 images made by the authors? It is *the* standard work on mineral and other inclusions within transparent crystalline mineral hosts and is compiled of images created with DSLR and stereomicroscope. Some of its photography benefits from stereo imagery, an area into which I don't think even you have ventured - indeed to which the photomacroscope is unsuited t:-)
Horses for courses. Let Jay develop confidence in his ability to create workmanlike images before even thinking that changing his equipment will make him,overnight, a better photographer.
6th Jul 2014 17:13 UTCVolker Betz 🌟 Expert
from this perspective you are right. On the other hand Jay still needs a steeromicroscope to see and a camera to photograph.
The industry sells adapters, because there is a demand from customers. Only their solution is sometimes so so.
You are right, that stereo pictures is very interesting addition. It may of interest for you that I did that - and published in 1990 - with a Macroscope.
See:
Betz V. (1990) High Magnification Mineral Stereophotography. - Mineralogical Record, 21,475-480.
Regerds
Volker
6th Jul 2014 17:31 UTCOwen Melfyn Lewis
-------------------------------------------------------
> The industry sells adapters, because there is a
> demand from customers. Only their solution is
> sometimes so so.
That is most certainly true. Some should be put up against a wall and shot. I have no reason to include Meiji in that curse, A tour of their web site suggests that they take care with their adapter design. Whether because it was incorrectly ordered or wrongly supplied, my guess is that Jay does not have the correct adapter from the Meiji range of adapters to work with his model of scope and camera body.
>
> You are right, that stereo pictures is very
> interesting addition. It may of interest for you
> that I did that - and published in 1990 - with a
> Macroscope.
>
> See:
> Betz V. (1990) High Magnification Mineral
> Stereophotography. - Mineralogical Record,
> 21,475-480.
My sincere apologies! :)-D
Best,
Owen
7th Jul 2014 10:25 UTCJay I. G. Roland
"I've sold loads of these and your problem is the first that I have heard of".
I described my setting up procedure and all was correct as far as he was concerned. I also described the various image tests I did for Owen & Gene on here and he was also puzzled with the results.
I asked if Meiji sell a lower mag relay lens and it appears I have the lowest (2.5x) so no solution there.
BTW Owen, 'Meiji offer relay lenses of a range of magnifications, up to x2.5 - the magnification you seem to have.' This is not correct, the 2.5x relay lens I have is the smallest, the other two offered are 3.3x & 5x mag both according to the brochure and Steve himself. Not sure where you read that info.
One thing I did point out that might be an issue is that my 1100D uses an APS-C sensor so he said he would Google the camera to get more details and get back to me if he sees a solution.
He tells me that he and his family are visiting this area for holidays in early August and has offered to call in and take a look at the setup. Very kind of him I'm sure but I would rather that he had a solution here and now but I suppose one has to take what one is offered.
So, it would seem that I have to wait a month until this issue might be resolved which is a pain to say the least. My emotions are a mixture of delight for the actual 'scope itself but absolute dismay at the lack of photography ability.
Watch this space!
Thanks all,
Regards,
Jay.
7th Jul 2014 12:32 UTCOwen Melfyn Lewis
-------------------------------------------------------
> I asked if Meiji sell a lower mag relay lens and
> it appears I have the lowest (2.5x) so no solution
> there.
>
> BTW Owen, 'Meiji offer relay lenses of a range of
> magnifications, up to x2.5 - the magnification you
> seem to have.' This is not correct, the 2.5x relay
> lens I have is the smallest, the other two offered
> are 3.3x & 5x mag both according to the brochure
> and Steve himself. Not sure where you read that
> info.
Sigh.... see here for the Meiji c-mount adapter range. http://www.meijitechno.co.uk/microscope-accessories/cmount-adaptors.htm
You may or may not have a warranty issue and, if you do have recourse, it will be to the dealer who sold to you. That said, you have been given the 'fount of all knowledge' for mating digital cameras to Meiji scopes. What is your hesitation in calling?
>
> One thing I did point out that might be an issue
> is that my 1100D uses an APS-C sensor so he said
> he would Google the camera to get more details and
> get back to me if he sees a solution.
If your guy needs to google for info on the APS-C sensor array, you should not waste more time discussing with him.Note that a Canon APS-C plate is differently specified to the APS-C specification used by the rest of the industry. http://en.wikipedia.org/wiki/APS-C
You need a camera adapter thet is correctly specified for the Canon APS-C sensor plate. But please accept that this *not* the root of your trouble. Apparently, uou presently have a mismatch of adapter to camera that crops away about 2/3rds of the full image FOV! In other words, your system 'as is' has about an undesirable x3 magnification without any accompanying improvement in resolution. This gives the same affect as would reducing your system resolution to 1/3rd of what it should be and the image all caprured on the sensor plate. It follows that your adapter was mis-specified and needs to be made correct for the camera body you have. You do not need to change your camera body which is perfectly satisfactory.
Only once this issue is cleared up can you begin to tackle the several other issues you will want to address.
Sorry if this all sounds a bit blunt but I sense I'm writing against a 'don't confuse me with facts, my mind's made up' mind-set. ;-) Never mind, I'm done. You'll get there in the end I'm sure.
7th Jul 2014 13:03 UTCJay I. G. Roland
Absolutely not Owen, I am open to all advice and will and have acted upon the advice given, it just seems that I am getting conflicting information from different quarters. As for the relay lens for example, it was data gleaned from the brochure and the word of the dealer himself that led me to make that statement. I was aware of the c-mount adapters listed on the link you posted but according to the brochure again, they were specifically for video work so I ignored them.
I shall now get back onto him and ask why these adapters were not mentioned.
In the meantime below is a couple of shots I just took of a possible cacoxenite crystal I found yesterday. Taken at 50x and 70x mag it's certainly an improvement over the stacked pyrolusite but far from perfect.
Regards,
Jay in a soaking wet Cornwall.
7th Jul 2014 18:31 UTCOwen Melfyn Lewis
Edit: and now re-appeard - gremlins....:)-D
7th Jul 2014 19:06 UTCOwen Melfyn Lewis
It seems that you chose the adapter supplied to your order. This probably means that you have no warranty claim and need to be gentle and see if you can wheedle an exchange of adapter' on the parish' - but first you need to know which is the proper one for you.. Either way, you'll have to get the right one.
How to get the right adapter? It is clear that, unlike some other scope manufacturers Meiji address thoroughly the matter of Meiji scope-DSLR compatibility. What you need to do is to ask Meiji to specifiy which of their adapters you should order to mate your scope model to a Canon EOS 1100D body. Do that and your resolution problem should simply vanish. If it does not, you can quantify the image deterioration fairly accurately with what is called a stage micrometer (I think Meiji may just call it a 'micrometer'. With the image deterioration between eyepiece view:camera view recorded, you then have the basis of a claim. My guess though is that, if you buy what Meiji recommend, you will be home and dry - as far as image resolution is concerned.
Unless its been weeded out, you will find in this topic in an extended thread between Gene and myself about 24 months ago as I was digging myself out of the same 'cr*p' camera image resolution problem. The difference between thee and me is that my scope is a private import from a 'no name' Chinese manufacturer with almost as little english as I have chinese and who is located near the Tibetan border, shipping stuff out by jet-assisted yak.
I got there in the end (by my own bootstraps and learning curve) and so will you, rather easier and quicker than I ::-)
8th Jul 2014 00:51 UTCEugene & Sharon Cisneros Expert
Sorry to be late in replying. Perhaps I can add some clarification to what Owen and Volker have submitted.
1. Your 2.5X objective is most likely the best one for your scope. The FOV, with your zoom dial set to 1X is 8.5mm, according to the image of the measuring scale that you posted earlier. To verify that the relay lens is providing the correct image scale: Mag = sensor width/FOV = 22.2/8.5 = 2.61X referred to the sensor. This is fairly close to the advertised 2.5X, but also dependent upon the length of the adapters, so OK in that respect.
2. At the above setting, you basically have a 2.6X objective lens with an NA~0.1. A very good compound microscope 5X objective has an NA~0.1. These can be pushed to around 7X with good results, but usually not higher. By comparison, your setup should perform well up to 7X on the sensor before severe image degradation occurs (that would be 3X on your zoom dial). This is exactly what I found with my high end Nikon stereo scopes. Beyond 3X, on the zoom dial, they became very poor. I believe this concurs with Volker’s comments regarding photographing with a stereo microscope to be a compromise.
3. The bottom line is that you can take some great images with your setup, but they will be limited in the maximum magnification, or FOV attainable. I would guess that the best results will be with FOVs of ~3mm or greater.
4. The images of the measuring scale labeled 10X and 30X look fairly sharp. May I suggest that you try photographing at 1X, on your zoom dial, and setting your stack increments to 50um. Try a simple subject that is not confused. A single opaque crystal would be a good subject. This will give Helicon the least trouble and you the best result from which to work from. The learning curve is fairly steep and you should obtain good results before increasing magnification and/or the complexity of the subject. You are already aware of vibration problems. If you see motion on the live view, you need to solve that problem.
5. To obtain excellent results at FOVs down to 1mm requires the use of compound microscope, or other specialized, objectives. This type of objective starts at 4X NA=0.1 up to 20X NA=0.4 and higher. The 20X gives a FOV of ~1.1mm.
Cheers,
Gene
8th Jul 2014 01:29 UTCOwen Melfyn Lewis
-------------------------------------------------------
> 1. Your 2.5X objective is most likely the best one
> for your scope. The FOV, with your zoom dial set
> to 1X is 8.5mm, according to the image of the
> measuring scale that you posted earlier.
Gene,
If you check the Meiji model spec, you will see that this model has an FOV of 23mm at x1 zoom. I think that is something we can be sure of.
8.3mm at x1 zoom is really to small to give a useful performance across an x1-x7 zoom range of a general purpose stereo microscope..
As you say, Jay's images suggest his system is delivering about an 8.3mm FOV at x1 zoom. I think this is due to his adapter producing an image approx 2.5 times too large to fit on the Canon APS-C sensor plate at x1, resulting in a severely cropped image capture that has approx x2.5 'empty magnification' without any associated improvement in resolution. And that results in camera-captured images at all zoom levels with very disappointing 'snap' in comparison t what can be seen through the eyepieces. It also causes ther problems. As said, I have been there and bought this T-shirt :-)
But we shall see what we shall see in due course..
Best,
Owen
8th Jul 2014 02:54 UTCEugene & Sharon Cisneros Expert
I understand your point. In fact, Meiji does offer a 1X relay lens. In my experience, I wouldn’t want a FOV greater than 8mm. Very few of the subjects that I photograph are in that range. So, for me, a maximum FOV of 8mm is extreme.
Assuming good optics, there should be no difference in what intermediate optic you use with an appropriate zoom dial setting to get a given overall magnification and FOV. I estimated that 3X on Jay’s zoom dial would give approximately a 3mm FOV. That’s what a good compound microscope objective of NA=0.1 gives, so that should be equivalent. Pushing any further will result in a loss in resolution.
So, maybe a 1X would be better in the sense that it gives a wider range of FOV, but resolution will be limited at around a 3mm FOV no matter how you arrange the optics to get it.
The bottom line is that an objective lens with an NA of 0.1 is somewhat limited in resolution for what we do. If you don’t try to push beyond that resolution, good images are possible. To get higher resolution, an objective with higher NA is required by the laws of optical physics.
Gene
8th Jul 2014 05:24 UTCDouglas Merson 🌟 Expert
8th Jul 2014 07:32 UTCJay I. G. Roland
E-mail sent to Meiji yesterday...awaiting a response. I deliberately ommited telling them what photo kit I was sent, though the actual whole package was sent from Meiji Techno UK so maybe they may well be able to find out.
Hello Meiji Techno. I have just purchased a new EMZ 13TR from a UK retailer and am having difficulty with the photography aspect of the device. As a microscope I cannot fault it but for taking photographs there are several issues I am experiencing.
Could you please tell me the correct relay lens and eyepiece tubes I should be using for my camera which is a new Canon EOS 1100D with APS-C size sensor.
Thank you,
Regards,
Jay I G Roland.
Edit: Owen, It seems that you chose the adapter supplied to your order. This probably means that you have no warranty claim and need to be gentle and see if you can wheedle an exchange of adapter' on the parish' - but first you need to know which is the proper one for you.. Either way, you'll have to get the right one.
As I mentioned in an earlier post, I never chose the adapter at all, the option wasn't offered to me, I just accepted what was sent to me would be the right kit.
8th Jul 2014 12:57 UTCOwen Melfyn Lewis
> --------------------------------------------------
> -----
> > Hello Meiji Techno. I have just purchased a new
> > EMZ 13TR from a UK retailer and am having
> > difficulty with the photography aspect of the
> > device. As a microscope I cannot fault it but
> for
> > taking photographs there are several issues I
> am
> > experiencing.
> >
> > Could you please tell me the correct relay lens
> > and eyepiece tubes I should be using for my
> camera
> > which is a new Canon EOS 1100D with APS-C size
> > sensor.
>
> *CANON* APS-C sensor . As explained, this has
> smaller dimensions that the APS-C plate that the
> rest of the industry specifies as APS-C. No
> matter. Meiji should pick this up since you give
> the camera make and model.
>
> > Edit: Owen, It seems that you chose the adapter
> > supplied to your order. This probably means
> that
> > you have no warranty claim and need to be
> gentle
> > and see if you can wheedle an exchange of
> adapter'
> > on the parish' - but first you need to know
> which
> > is the proper one for you.. Either way, you'll
> > have to get the right one.
> >
> > As I mentioned in an earlier post, I never
> chose
> > the adapter at all, the option wasn't offered
> to
> > me, I just accepted what was sent to me would
> be
> > the right kit.
>
> Good. If your dealer decided the adapter to send
> you and it proves to be the wrong one, you are in
> line for a free exchange (Sale of Goods Act if
> warranty does not cover}.
>
> Let's see what Meiji have to tell you. Did you
> notice that there is an adapter (not yours)
> specified for your scope model on that Meiji
> adapter page I linked her for you?
>
> Best,
> Owen
8th Jul 2014 13:30 UTCOwen Melfyn Lewis
-------------------------------------------------------
> ... I wouldn’t want a FOV greater than 8mm. Very few
> of the subjects that I photograph are in that
> range. So, for me, a maximum FOV of 8mm is
> extreme.
Horses for courses Gene, Depends where your fancy leads. For *most* of what I want to do I find a 23mm FOV at x1 perfectly fine. I find much of my time spent viewing at x20-x30 mag. The basic system gives me a minimum FOV of 3.6 mm. On occasion and where required, I can reduce this to a 1.8mm FOV with no significant loss of resolution by using the auxillary x2 objective lens. If and when I need a smaller FOV than1.8mm, I'll buy a second pod.,
Jay has a setup pretty much like mine. I think he needs help to get it to function well and telling of other ways (whether better or not) does not help him now. He has the equipment he has - and pretty good his present scope and camera are. He too can get an x2 auxillary oblective from Meiji to get his FOV down to about 1.8 or a little less in his case, as and when he feels the need to do this..
Your explanation of the importance of lens NA in the scheme of things is surely helpful to those who want to understand the optical theory behind it all. For the moment, I think what he first needs is a camera adapter with the correct length (and maybe optics) to produce a perfectly focussed image with a diametric FOV that perfectly matches the diagonal dimension of the Canon APS-C sensor array (OK, just a little spill over)
Best,
Owen.
.
8th Jul 2014 22:02 UTCOwen Melfyn Lewis
8th Jul 2014 22:33 UTCEugene & Sharon Cisneros Expert
Are normal stereo microscopes suitable for high-quality photographic documentation?
95% of all stereo microscopes are designed either according to the Greenough principle or the telescope principle (Abbe principle). They deliver good to very good results on visual inspection. If, however, digital camera equipment is mounted onto a conventional stereo microscope, more often than not the quality of the images is disappointing. Especially in the case of the Greenough principle, the difference between the visual perception of the image quality and the image itself is particularly pronounced. How does such a difference arise? Is the human eye superior to the camera?
You can read the whole story here.
Gene
8th Jul 2014 23:22 UTCOwen Melfyn Lewis
Fact is, for the purposes of most of us, a stereomicroscope + DSLR body is quite good enough - and better than a USB eyepiece camera solution.. In the hands of an expert, a good rig of that tyoe will deliver better results that any tyro will obtain from any rig under the sun. For those who have become expert and then feel the need to spread their wings, that's fine.
But we all have to start somewhere and the hard lessons we learn as we progress actually make us better at what we do - if we bother to recognise and benefit from the lessons as they arise.
There is nothing crippling about DSLR body plus stereo microscope. See 'PhotoAtlas of Gemstone Inclusions' (at a couple of thousand dollars the set) and with all images made with DSLR+stereomicroscope). And weep quietly ;-)
Those who can, do. Those who can't spend more money on equipment :)-D.
Best,
Owen
9th Jul 2014 00:05 UTCEugene & Sharon Cisneros Expert
Those who can, do. Those who can't spend more money on equipment
For some, that may be true.
For others, good enough is never good enough, so they strive to do better, regardless of cost. I take my hat off to people like Volker, Mateo and others on Mindat, because they push the very limits of what is possible.
Gene
9th Jul 2014 00:12 UTCEugene & Sharon Cisneros Expert
We have lost sight of the issue and turned this into a pissing contest, which is not conducive to helping Jay. I give up Owen, you win the keg! :)-D
My best,
Gene
9th Jul 2014 00:23 UTCOwen Melfyn Lewis
-------------------------------------------------------
> > Those who can, do. Those who can't spend more
> money on equipment
>
>
> For some, that may be true.
>
> For others, good enough is never good enough, so
> they strive to do better, regardless of cost. I
> take my hat off to people like Volker, Mateo and
> others on Mindat, because they push the very
> limits of what is possible.
>
> Gene
Amen.
My best,
Owen
9th Jul 2014 08:33 UTCJay I. G. Roland
I may well have to 'phone them to get some sort of response.
Many thanks for the link for Micro Tech Lab Gene, I shall now brew a strong coffee and try to absorb as much of the article my tiny brain will allow at this time of a morning.
Later on today I shall make an attempt at the suggestion of trying to make a shortish stack image of a simple crystal form. Alas all I have of reasonable size is a circa 8mm across (at the base) 'milky' quartz crystal sat on a cluster of others. I'll keep the zoom level low and see how I go. The image will be posted here if I think it is good enough not to open myself to ridicule at not being competent enough to create a simple stack :-(
Regards and thanks again all,
Jay.
9th Jul 2014 12:43 UTCOwen Melfyn Lewis
-------------------------------------------------------
> I may well have to 'phone them to get some sort of
> response.
I'd do that Jay. You should get more done in a 10 min chat than you will in a week of e-mail exchange.
9th Jul 2014 12:53 UTCJay I. G. Roland
22 images taken at focus points adjusted by viewing the monitor alone with no strict distance twixt any of them. Zoom was at approx 15x.
Yet another improvement methinks though far from perfect.
I shall 'phone Meiji UK after 1pm so as to make sure no one is at lunch!
9th Jul 2014 13:39 UTCJay I. G. Roland
He tells me that I can purchase a 1.9x relay lens albeit at a whopping £192 + vat, that will give me a closer FOV whilst marginally reducing the magnification. He also suggested buying a dedicated 'scope camera, prices starting at £1000. I feel that I have spent enough so that's out of the question.
Not sure if I mentioned this earlier, but on Monday I spoke to the bossman at the company that sold me the 'scope and it turns out that he is coming to Cornwall next month for his holidays and that he has offered to pop in here and give things the once over. Matey at Meiji suggested I ask him to bring along one of these 1.9x relay lenses and possibly an EMZ8 'scope for me to try. I think I might just ask him to post me the lens on approval and take it back with him should it not do the business.
Regards,
Jay.
9th Jul 2014 14:21 UTCOwen Melfyn Lewis
But you are stuck with the fundamental problem of unsatisfactory sharpness. Hopefully, your dealings with Meiji over your camera adapter will remove this concern at a single stroke.
Unwanted reflections off surfaces. This is another bug bear that plagues crystal photography - for gemmologists in particular, who are trying to peer inside transparant crystals that have been cut, faceted and polished. It's one important case where where knowledge and experience are more important than is more expensive equipment.
Careful and precise light positioning is one route. Light diffusion is another. I find light polarisation useful too. For study/photography of inclusions in crystals the use of an immersion bath with and immersion fluid of similar RI to that of the host crystal is also a great help. Here's an image of a faceted spinel (not immersed) with all 'glare' from unwanted reflection extinguished by light polarisation, so the the inclusions inside the crystal can be seen clearly.
These are cropped macroshots taken with my 600D and the Canon 60mm macro lens.The effective FOV in the first shot is around 10mm and about 5mm for the second shot. This pushes the resolution limit for that lens array but is good enough for the moment. When I'm properly set up following a recent house-move, I'll take some more shots using my microscope pod in a horizontal bed designed for immersion photography with and without polarised light.
Reflection is the photographer's friend, Without it we could see nothing that was not light-emitting.IMHO, the control and exploitation of reflectance is at the heart of still image photography.
9th Jul 2014 14:45 UTCJay I. G. Roland
Macrophotography of minerals, lichens etc is another facet of this game that I would really like to learn. I did invest a few quid on a set of close up lenses for the 1100D and was reasonably happy with the results. My next purchase in that department will be a set of macro tubes, that is when I can find a decent set that have contacts all the way through. Ideally a dedicated Canon macro lens would be on the list but prices new are now beyond my reach, so a secondhand one might have to be sought out.
On the subject of lighting, what opinions if any do you have on ring lights? Are you able to recommend any in particular?
I did read about one that was divided into quarters so one could light any or all quarters to suit ones requirements.
BTW, I did call the supplier to ask about the 1.9 relay lens but he was out and will call me back later....though I fear I shall have to make the very same call again tomorrow!
Regards,
Jay.
9th Jul 2014 15:43 UTCOwen Melfyn Lewis
-------------------------------------------------------
> Just spoken to a very nice chap at Meiji UK and
> described my problem. Long story short, it appears
> that the EMZ series of 'scopes were designed along
> with the relay lens & tube setup for film cameras,
> and that is simply that!
No it ain't. Film camera or digital sensor array makes no essential difference. It's the resolution at the image plane that is the critical issue and not the image recording method.
>
> He tells me that I can purchase a 1.9x relay lens
> albeit at a whopping £192 + vat, that will give
> me a closer FOV whilst marginally reducing the
> magnification. He also suggested buying a
> dedicated 'scope camera, prices starting at
> £1000. I feel that I have spent enough so that's
> out of the question.
He seems a smooth-falking sales person rather that someone (an engineer) who has deep understanding of what he is selling. This is not at all an uncommon experience.
I'm intrigued as to why he advises a .x1.9 relay lens rather then a x1. Ask why? Be good to know before you make any decisions.
The bottom line is that the (circular) FOV is determined by your scope's optical design and setting. The purpose of the camera adapter is to perfectly focus that FOV at the image plane (sensor plate) in your camera and with the diameter of the scope's FOV just exceeding the diagonal length of the camera's rectangular sensor plate.
If that perfect match of FOV to sensor plate size cannot be attained for your camera body with one of Meiji's range of camera adapters, the next best solution is to use an adapter that projects the scope's FOV at x1 zoom onto the sensor plate as too small for the image to cover the max dimension of the sensor plate. This will show as darkness in all the four corners of images from the rectangular sensor plate, an effect called 'vignetting'. This is easily rectified by a little cropping of your captured images in post-camera image processing. This is where quite a few - including me - end up as the optimal solution for their equipment without spending big bucks. Do press Meiji for more information on this.
>
> Not sure if I mentioned this earlier, but on
> Monday I spoke to the bossman at the company that
> sold me the 'scope and it turns out that he is
> coming to Cornwall next month for his holidays and
> that he has offered to pop in here and give things
> the once over. Matey at Meiji suggested I ask him
> to bring along one of these 1.9x relay lenses and
> possibly an EMZ8 'scope for me to try. I think I
> might just ask him to post me the lens on approval
> and take it back with him should it not do the
> business.
A x1.9 should give you a slight improvement in performance but I do expect that an x1 (or even a little less than x1) relay lens should give you a markedly better result, The higher the zoom setting used in any image capture, the more apprarent the improvement obtained will be. The apparent resolution of your images will keep on improving as the relay lens magnification is reduced to the point where you are getting vignetting in your images. Ask to speak with an engineer at Meiji?
Why do most folks choose to adapt a high quality DSLR body to image the views through their microscope rather than to buy a purpose made microscope camera? Its easy; value for money. DSLR bodies are relatively low priced because of their mass production scale for a large general consumer market. Microscope cameras are made for a small specialist market and have to be priced up accordingly. Truth is, also, that a properly setup DSLR body will give to more flexibility and generally better image quality than all but the very best (and hysterically expensive) microscope cameras.
Quite a few (me included) start with an 'economy' model of microscope camera and eventually move on to a DSLR body + adapter rig. 'Economy' is a relative word. the camera that I stepped up from has a UK price >GBP 500 plus 20% tax! That's considerably more than my 600D body and adapter cost me. The downside is that, without expert help and guidance, getting a proper adaptation of a DSLR body to scope is either blind luck or else a Via Dolorosa. Some give up along the road. Others get to where they want to go.
9th Jul 2014 16:09 UTCOwen Melfyn Lewis
I use a ringlight for a lot of my macro work but not at all for photomicrography. I have a whole family of lights I use, a couple or three of which are fitted to my microscope bases and the remainder of which are free-standing. They range from a xenon arc lamp, through quartz halogen + fibreoptic feeds, fluorescent flood lighting to hand-held mini Maglites. Since my ringlight (a colour temperature balanced mix of fluorescent ring and white LED's in circular array) is free standing I could use it with my long working distance microscope pod easily enogh - but I have never felt the need to try.
As a gemmologist, much of the time I want to get light in and out of a crystal to look at what is inside. That's a minority interest for many mineralogists who, most times, want to image exterior surfaces only.
A ringlight is a good lighting solution but has its limitations too. It is inflexible in application and is to be avoided at all costs when imaging convex polished surfaces!
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Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: May 14, 2024 00:28:54