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Amscope...

Posted by Steve Sorrell  
avatar Amscope...
January 05, 2012 02:48AM
au    
Hi all

Today I received a package containing two items. A microscope adaptor for my Canon 600D (AmScope CA-CAN-SLR) and a 9Mp microscope digital camera (AmScope MU900).

I have just done a couple of comparison shots and there is (understandably) a huge difference in quality. I think that although I will use both, I will focus much more on the adaptor.

The Canon plus adaptor is far superior to the MU900 wrt:
  • Depth of field
  • General crispness
  • Colour balance (I use an LED ring light)

The MU900 will be useful seeing that I can connect directly to my laptop and has a slightly wider field of view.

Also, something that I found interesting, the MU900 gives you a mirror image. Not a real problem as it is easy to flip with software, but you wouldn't necessarily notice unless you had something like letters or numbers. I only noticed because I was comparing two photos taken using different methods. I suppose I would have eventually realised!

Anyway, here are two photos of a barite after alstonite from Nentsberry to show the differences. The first is the MU900 (after reversing the image!), the second using my Canon.




Regards
Steve
avatar Re: Amscope...
January 05, 2012 02:51AM
au    
And a second specimen, a Florence Mine fluorite (cubes to ~2.5mm). Again, MU900 first.




Regards
Steve
avatar Re: Amscope...
January 05, 2012 06:11AM
au    
Both will clearly take a bit of getting used to. I will most likely focus on the Canon adaptor.

Here's one after I've played around a bit...

Hemimorphite, Minera Mine, Wrexham, Wales© crocoite.com

Regards
Steve
Re: Amscope...
January 05, 2012 08:09AM
Steve,

I find that the most useful thing about attaching an SLR (I am using a Canon 7D) to a scope is that you can more easily control the aperture (and thus depth of field) and white balance. The numerical aperture of an SLR setup is usually better than for a dedicated camera too.

Downside of an SLR is that it's harder to see the image that you are going to get beforehand, at least without getting a crick in the neck, and it can be harder to adjust the mount so that the focal plane of the camera is coplanar with the focal plane of the microscope optics. If the two are not the same, the camera image is out of focus with respect to the microscope image, so it requires fiddling around, but also can introduce aberration of various kinds - I find that colour fringing (chromatic aberration) and intensity ringing are usually the most noticeable.

By comparison, I find that a dedicated scope mounted camera (I have a Lumenera Infinity 2) is better for taking sequences of images, so I use that for EDF work. It's also less likely to cause vibration (the mass at the top of the scope is much less than with an SLR) so is better suited for high magnification work - I have been imaging crystals down to about 10 microns in size with this setup quite successfully (some of these images are on Mindat - fornacite and mereheadite xls).

At the moment I am trying to find an e-mount adapter for a microscope - I have a Sony NEX-7 and want to try this out as a scope camera. If it works, it should be superb - better than an SLR in many ways. It has an APS-C sensor (so 24 MP) but is about 20% the size and weight, and has 'anti-vibration' and HDR capability in the body. It also has a tilt/swivel screen on so no more sore neck!

Regards

Rick
avatar Re: Amscope...
January 05, 2012 10:04AM
au    
Three things with this setup Rick (Canon and adaptor that is):
  1. 600D has a tilt/swivel screen with the ability to zoom in to focus - which is good
  2. No ability to set the apeture - it shows as F00 and I can't override - so stuck with what I get. Mind you the DoF is not bad.
  3. Canon camera body is not that heavy, so little strain - which is good

Regards
Steve
Re: Amscope...
March 11, 2012 07:05PM
I finally got a chance to mess around and get an APS-C sensor camera running on one of my scopes, and the results are quite good - I can get images around 3500*3500 pixels of an area about 1mm across - effectively ~1000x magnification at normal screen resolution (96 dpi). Depth of field is good, and the colour is good too.

I'll attach an image to this post as an example - the wulfenite xl is about 3mm square.

Rick
Attachments:
open | download - Wulfenite Sandiq Pakistan.jpg (827.7 KB)
Re: Amscope...
March 12, 2012 12:48AM
ca    
Hello Rick

Can the Sony NEX-7 feed a live image to a computer that can be captured by the computer?
avatar Re: Amscope...
March 12, 2012 02:47AM
us    
Hi Steve and Rick,

If you are not already aware of it, Cannon EOS Utility software gives you the ability to view the image live on your computer monitor. I use it with my D7 and find it to be the best way to focus and control the camera settings remotely. Also, you can lock up the mirror and use the electronic first curtain shutter to eliminate virtually all vibration.

Rick, I am wondering why you say that the aperture is easier to control. Are you using the camera lens in an afocal setup? In any case increasing depth of field by reducing NA always results in less resolution. Nice shot of the Wulfenite, no problem with resolution there! What combination of camera and microscope did you use?

I just got first light in my new setup, using the 7D, last week and am still sorting out problems. But, here is one of my first attempts. Neptunite at 2mm FOV.

Gene
Attachments:
open | download - Neptunite 02.jpg (880.1 KB)
Re: Amscope...
March 12, 2012 03:21AM
us    
Excellent image, Gene. Is it a stacked image, or just really good depth of field?

Henry Barwood
Troy University
Troy, Alabama USA
Re: Amscope...
March 12, 2012 05:56AM
Nice neptunite picture, Gene - and not a bad specimen either 8-)

The wulfenite picture is taken with a Sony NEX-7 fitted to a Wild M7A scope. There is no lens on the camera - I have (made) an adapter to fit the camera to a standard C mount thread, which allows me to fit it to any of my scopes using their standard phototubes etc. Simplest possible solution that I could think of, and means that I dont need to change any of my other gear.

I have tried with my Canon 7D as well but with less good results - actually, I prefer the Sony for lots of reasons.

Reiner: I have not tried to do live feed from the NEX-7 to a PC, sorry.

Rick
avatar Re: Amscope...
March 12, 2012 03:54PM
us    
Rick,

It looks like you have a winning combination, and I look forward to seeing more images.

Henry,

The image of the Neptunite is a stack of 26, processed with CombineZ. Unfortunately, the immutable laws of physics never provide for a free lunch. That image should have been more like a stack of 50, but for testing I have been keeping the stacks to a minimum.

Gene
Re: Amscope...
March 12, 2012 11:37PM
ca    
Hello Rick,

How did you make an adapter and where did you get the parts? I am thinking of getting a Sony NEX-7 and want to make sure I can adapt it to my scope.
Re: Amscope...
March 13, 2012 06:19AM
Reiner,

I literally made it - I have an industrial CNC lathe and a big CNC mill in my garage (I build 5 inch gauge live steam locomotives) - so I machined my own from a bit of aluminum bar that I had lying around.

Sony dont make a c-mount adapter.

Rick
avatar Re: Amscope...
March 13, 2012 05:12PM
us    
Here is a link to a C-Mount to NEX adapter. $5.95 including shipping!
Re: Amscope...
March 13, 2012 08:01PM
ca    
Great ! thank you Gene!
avatar Re: Amscope...
March 14, 2012 12:52AM
Steve,

Congrats on choosing the 600D. It's a great camera for both macro and micro work I think. As the swing-out, rotatable LCD view (with the option of x5 or x10 mag for critical focussing) makes for a comfy life and a less cluttered bench as one does not need to compose on a PC screen.

I bought mine around Xmas time and have spent most of the time since then finding how to wring the most out of it in macro work (with the 2.8 60mm EFS lens. Only in the last week have I bent myself seriously to finding out how to wring the most out of in in photomicrography. I seem to be battling with severeal issues but none are camera related,

The prime issue is that I can't get the same image crispness in the camera that I do when viewing through the eyepieces.The likely culprit here is the relay lens in the adapter, since that is the only piece of glass between the prisms in the pod and the CCD sensor. At the moment, having also first calibrated the 'scope, I'm running up a series of test images with a stage micrometer (0.01mm graduations with the division markers having an estimated width of about 0.002mm) before going into bat with the camera adapter supplier. Since the relay lens is an x1, to my simple thinking, it should be possible to have it taken out and attain an image in the camera of a quality determined by the microscope optics alone (i.e. equal to or better than that I ger when viewing through the eyepieces.

Other useful features in the 600D that are useful for micro work (if you haven't found them already) are:

- Make sure to set the camera to swing up the mirror when you start live view, so that at (remote) shutter release vibration is much reduced.

- Fix the dimensions of your images to 1:1 rather than the more usual 16:9 or 4:3. For photomicrography, I think that a square image is generally more useful (less post-camera cropping), making the best use of the microscope's circular field of view..

- Set the camera to show gridlines. (dividing your now squared frames into 16 smaller squares. This helps with composition and also gives one a crude graticule for assessing FOV and the size of objects in the image at any level of microscope zoom (if you've made up a calibration chart first).

Here's a series of pics that show the current state of play.

1. This is a cropped macro shot of a pink octahedral Spinel holding an 'alien' yellow octahedral Spinel about 1/10th its volume. The pink crystal is about 3.8mm 'on the square'.

2. The same specimen, imaged with a cheap-ish 2MB digital eyepiece camera adapted to shoot through the scope's trinoc port. Nominal x10 magnification

3. The same stone imaged with the 600 D using the adapter bought for it to fit on my pod. Magnification x62. Worked on with the unsharp mask and light source adjustment.

Edit:
Ooops! wrong shot for 3. Now corrected.


Glad to find another 600/600D user here smiling smiley



Edited 1 time(s). Last edit at 03/14/2012 10:50AM by Owen Lewis (2).
Attachments:
open | download - 118 IMG_0960test.JPG (379 KB)
open | download - PICT0001test.JPG (380.9 KB)
Re: Amscope...
March 14, 2012 06:20AM
Good to see that somebody is now manufacturing e-mount to c-mount adapters - when I first looked, there were none, so I ended up having to make my own.

Rick
avatar Re: Amscope...
March 26, 2012 10:09AM
au    
Thanks Gene. I hadn't tried connecting to my laptop until post-Tucson. It is good to have a large screen to focus.

Thanks Owen for the tips, so much I haven't even found, let alone tried yet.

Here's a close up shot that I did a couple of days ago...
Elbaite, Stak Nala© crocoite.com

Will get back to micros in the next day or so.

Regards
Steve
avatar Re: Amscope...
March 26, 2012 06:17PM
Steve,

That's very pretty - and a lovely specimen too smiling smiley

Yesterday. I decides to sit down and quantify properly my perception that my microscope + camera adapter does not deliver the same image resolution to my 600D sensor as the microscope alone does to my eye retina. The results were unexpected and a little humbling.

The test was made by taping a stage micrometer slide to the microscope's stage (designed for gemmological usage). The slide has on it a 1mm graticule subdivided into 10 divisions, each division being subdivided into ten smaller divisions of 0.01mm each (including the width of one of the dividing markers). By observation, the dividing markers and the spaces separating them when viewed most clearly at high magnification at approximaely equal, suggesting a marker width of about 0.005 mm (5 microns).

Images were viewed with the naked eyball in the usual way through an eye-piece and also imaged in the 600D body mounted via its adapter to the trinocular port. Viewing and imaging was done at every x5 magnification step from x10 to x62. Results and conclusions were as follows.

1. Resolution by the microscope's optics varies with the magnification level set. At x10, the limit of resolution of my instument is about twenty microns (0.02mm). At x20, the resolution is just about 10 microns. As magnification increases further so does the resolution. Interpolation indicates that at x65 the resolution is close to 1 micron.

2. These results hold true both for eyeballing and camera imaging. However, by 'naked' eyeballing the image being produced in the microscope at all mag levels is *perceived* to be sharper, though in truth the resolution is no better! How can this be? I reason as follows:
- The field of view of the microscope is 23mm at 10, reducing to 3.7mm at x65 (nom). These manufacturer's specs were earlier verified in another series of tests.
- However, through the camera adapter the sensor plate is presented (square view) with an FOV of just under 5mm at x10 reducing to about 0.75 mm at x62.
- This amounts to approximately x5 'empty magnification', i.e. looking x5 bigger but with no improvement in resolution to go along with it. Ergo, the fuzziness at sharp edges caused by the laws of optics and the microscopes design limits is simply multiplied up by x5, giving the appearance of worse resolution (by about a factor of 5! sad smiley This is the same effect as obtained by increasing the magnification range of a zoom microscope by doubling of tripling the magnification of the eyepieces.
- This is something I should take up with the adapter manufacturer. Assuming a square image capture (the most efficient match to the circular FOV of a microscope), ideally, image size in each should be the same at any microscope setting.
- Making the linear FOV presented to the camera about 1/5 of the microscope's FOV results in several disadvantages, an apparent loss of sharpness being but one!

3. Another and very unexpected result is that resolution is better when the target was (low level) brightfield illuminated (appearing dark on a light background) was much clearer (better resolution) then when illuminated with overhead lighting, which also creates some strange chromatic aberrations. I propose to re-run this second set of tests, varying the intensity of the ilumination to determing the optimum and then see if there is still any difference in the quality of the imaging.

Meantime, here's a pic of a part of the stage micrometer taken at x65 zoom. Original file is at 3456x3456 pixel definition, reduced here to 800x800



Not as pretty as yours, Steve - but I lead a sad life smiling smiley
avatar Re: Amscope...
March 27, 2012 10:19PM
us    
Hi Owen,

By calculation, at 62X, you should have a horizontal field of view of ~3.6mm on an APS-C sensor, if your relay lens is indeed 1X. If you measure 0.75mm, then something is definitely wrong. I am assuming that there are no other optics between the relay lens and the sensor. Have you tired removing the relay lens and projecting directly onto the sensor? Depending upon the microscope optics, the relay lens may be necessary to correct field curvature, or even chromatic
aberration. This is because, in some microscopes, the final correction is done in the eyepieces.

I look at the aspect ratio issue from a different perspective and always run at sensor’s native aspect ratio. My reasoning is this. Many objectives will fully illuminate an APS-C sensor (see attachment). So, the notion of best matching to a circular field doesn’t enter into my thinking. It is the circular field that is actually cropped by the sensor. I want to capture all of the information that is possible and then crop out what I don’t want later. This is especially important in stacking because of the spatial drift of each image in the stack with respect to the last. These artifacts have to be cropped out after processing, which further reduces effective sensor area.

Gene
Attachments:
open | download - sensor size.GIF (12.9 KB)
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