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Mineral PhotographyZeiss Luminar's light problems
4th Jan 2008 21:40 UTCMatteo Chinellato Expert
4th Jan 2008 21:53 UTCdominik schlaefli
kind regards,
Dominik.
4th Jan 2008 22:04 UTCMatteo Chinellato Expert
http://img174.imageshack.us/img174/7851/testue2.jpg
4th Jan 2008 22:29 UTCdominik schlaefli
kind regards,
Dominik
5th Jan 2008 05:21 UTCMatteo Chinellato Expert
I use the Zeiss mounted in a Nikon bellow. I know he have the dust on the camera, but in the micro minerals the photo does not appear clear, it is like out of focus
5th Jan 2008 12:31 UTCdominik schlaefli
5th Jan 2008 12:38 UTCMatteo Chinellato Expert
6th Jan 2008 13:24 UTCdominik schlaefli
kind regards,
Dominik
6th Jan 2008 22:43 UTCDon Saathoff Expert
Don S.
7th Jan 2008 18:21 UTCdominik schlaefli
7th Jan 2008 19:12 UTCMatteo Chinellato Expert
7th Jan 2008 19:23 UTCJean-Marc Johannet Manager
7th Jan 2008 21:06 UTCMatteo Chinellato Expert
http://img403.imageshack.us/img403/3020/testam4.jpg
8th Jan 2008 05:34 UTCDouglas Merson 🌟 Expert
Doug
8th Jan 2008 06:15 UTCMatteo Chinellato Expert
8th Jan 2008 20:20 UTCDon Saathoff Expert
If no movement, the problem is focus or lens. Some basic questions: do you focus w/ your glases on or off....does your camera have a diopter adjustment for individual eyesight anomolies....has the lens been dropped (loose elements)
.....are you shooting at the lens' optimum aperture (the old rule was "one stop down from the middle")
8th Jan 2008 20:27 UTCJean-Marc Johannet Manager
8th Jan 2008 20:29 UTCMatteo Chinellato Expert
8th Jan 2008 20:32 UTCMatteo Chinellato Expert
no any lens. You seen my set here
http://www.mindat.org/mesg-13-51471.html
last photos
8th Jan 2008 20:52 UTCdominik schlaefli
8th Jan 2008 20:56 UTCMatteo Chinellato Expert
8th Jan 2008 21:13 UTCJean-Marc Johannet Manager
I think there is not fx stops on Luminars but only numbers: 1,2,4,8 & 15.
First number (1) is for fully opened aperture.
Between two numbers 50% more of time is need to have the same result.
If you use it at 8, it is nearly fully closed and your will need very long expossure time, subject to unfocus if your set is not stable enough!!
Did you make your tries with long extension on you bellows or short one?
Luminar 16 mm is given for very high magnifications, you have to use it at his optimum ratio, 14:1.
Jean-Marc.
8th Jan 2008 21:14 UTCDon Saathoff Expert
I see nothing in your set-up out of the ordinary. Does your camera view-finder use a ground-glass focusing screen w/ the image projected directly to the ground-glass or are you focusing on an image produced by an LCD? If there is a true ground-glass, are there any grid marks or indexing lines in the ground-glass and, if so, do they appear sharp to your eye? Also, if using a ground-glass, is your reflex mirror re-seating all the way down?
If you are seeing the image as sharp in the viewfinder, then the relationship betweem the projected image on the film (CCD) and the relationship between the projected image on the focusing medium is different. If the image you see in the viewfinder is sharp then I would suspect a mechanical problem in the camera!
Don S.
Jean-Marc was posting while I was writing this book...he has a point...stopped all the way down is NOT the optimum aperture!....and I assume you set aperture AFTER you focus wide open.
8th Jan 2008 21:38 UTCMatteo Chinellato Expert
I think there is not fx stops on Luminars but only numbers: 1,2,4,8 & 15.
First number (1) is for fully opened aperture.
yes, and the photo is not complete focus
Between two numbers 50% more of time is need to have the same result.
If you use it at 8, it is nearly fully closed and your will need very long expossure time, subject to unfocus if your set is not stable enough!!
depend on mineral, normaly I have a 1 to 4 sec. of exposure if is put on 8, if I put on 4 I not have a image unfocus
Did you make your tries with long extension on you bellows or short one?
depend if i want have a high expansion or not, normaly I fix the front and I go on and down with the leaves back where I have the camera
Luminar 16 mm is given for very high magnifications, you have to use it at his optimum ratio, 14:1.
not like many the 16 mm, not give a well focus photo
8th Jan 2008 21:44 UTCMatteo Chinellato Expert
I see nothing in your set-up out of the ordinary. Does your camera view-finder use a ground-glass focusing screen w/ the image projected directly to the ground-glass or are you focusing on an image produced by an LCD?
direct from viewfinder of the camera, is for this I want change the camera for have a live view on the camera monitor
If there is a true ground-glass, are there any grid marks or indexing lines in the ground-glass and, if so, do they appear sharp to your eye? Also, if using a ground-glass, is your reflex mirror re-seating all the way down?
If you are seeing the image as sharp in the viewfinder, then the relationship betweem the projected image on the film (CCD) and the relationship between the projected image on the focusing medium is different. If the image you see in the viewfinder is sharp then I would suspect a mechanical problem in the camera!
The camera have reviewed 4 months ago and all is ok have say who have control,probably I have to change the camera seen in 1 year is go over the 50.000 clicks
Don S.
Jean-Marc was posting while I was writing this book...he has a point...stopped all the way down is NOT the optimum aperture!....and I assume you set aperture AFTER you focus wide open.
no, I set the aperure first to focus and it remains fixed for all photo session
9th Jan 2008 00:58 UTCDon Saathoff Expert
Don S.
WAIT!!!...try focusing wide open THEN stopping down....when you focus at a smaller aperture, the "circle of confusion" is smaller and depth of field will prevent a sharp focus (what you percieve as being acceptably sharp could actually lay anywhere within that depth of field distance)...focus wide-open THEN stop down for exposure!!!
30th Dec 2010 02:02 UTCRobert Simonoff
Thanks
Bob
9th Jan 2011 19:35 UTCFred Kruijen Expert
Some (top) lenses are made to use them with the aperture fully opened. I see no reason why you should stop down.
I suggest to focus wide-open, and don't stop down for exposure.
Distinti saluti,
Alfredo.
9th Jan 2011 20:51 UTCMatteo Chinellato Expert
normaly I use the zeiss 16 mm at the 4.5 close, if I use all open the image lost many on the borders
9th Jan 2011 22:12 UTCVolker Betz 🌟 Expert
I have seen this thread before, but as am working on that subject my answer is a little late.
I see some movements in your picture, coming from your setup with bellows on a tripod. I would recommend to mount your bellows on a more vibration free stand.
To avoid that you need a more compact and more stable installation. Your set up is fine with the 63 mm Luminar. I was running in the same problems with the 25 mm range lenses and a Canon 500 D. Even with mirror lookup the pictures with 25 mm Luminars suffered of sharpness compared to such I made with a 4500 Nikon ( and ocular adapter).
In the end now use a (very old) Ortholux Microscope with my Luminars and Photars in the 25 mm range. This is a 9 kg stand, very solid. Also the bellows are not perfect for the small fields of view, I would prefer fixed tubes.
Also the bajonet connection between camera and bellows has often to much room for movement. I saw significant improvements if the camera and the bellows are connected to the same base and not only the camera at the bellows. (not easy to to, by the way.)
Recent experiments showed me that any kind of shutter is not good for small fields of view. I am just making experiments with a Panasonic D2. It has no mirror and a different shutter: But even with that camera there is some loss of sharpness at short exposure time. But long exposure time helps. I could document that there is a significant difference between a 1/125 sec. and a 2 sec. exposure. 2 sec. a much sharper. I could measure a 1.5 micron resolution using a 15 mm Mikrotar of N/A 0.2.
A DSLR is not the best for small fields of view, the best would possibly be a cooled heigh resolution microscope camera (in theory) but this are horrible expensive. So the micro 4/3 cameras used with a about 2 sec. exposure seems to be the a reasonable solution at present, until we get a 12 Mpixel video camera which is very questionable.
Another point is that you close the aperture. This is not advisable for a 25 mm luminar. I made some experiments some years ago, which showed ( in practice) that with a 40 mm Luminar any closing of the aperture is suffering sharpmness, and much more with the 25 mm.
Regards
Volker
10th Jan 2011 03:13 UTCRalph S Bottrill 🌟 Manager
10th Jan 2011 07:24 UTCVolker Betz 🌟 Expert
a camera with the micro 4/3 standard like the Panasonic Lumix D2 and some others. One of their advantages is that there adapters available for many other lens connections.
Volker
10th Jan 2011 07:45 UTCMatteo Chinellato Expert
the moviment in subjects of at 1 mm or under its normaly, we speack of pieces normaly seen with a SEM. Under my tripod I have put a weight for telescope of 2.5 kg. for eliminate the moviment. The 63 mm I use only for crystals at the 5 to 10 mm or up, for the others I use the 16 mm. Another its use a FF camera, type my Canon 5D mark II, or the 7D, another its use a compact camera, its totaly different, for not speack if you use fixed tubes the grain on the photo its many visible, I have personaly used fixed tubes in the first times, and is well visible the problems. At few time my move problems probably end with a new system I am under to buy
10th Jan 2011 09:05 UTCStephan Wolfsried Expert
I can fully confirm what Volker wrote. Any stopping down of the Luminars costs sharpness. I use them fully open with good results.
My actual favorite is the Luminar 25 mm. The FOV ranges from 4,6 to 2,5 mm, which covers most of my specimens. With a stiff stand I get no artifacts like You showed in Your demo photo.
I fixed the bellows a second time beside the camera, which minimizes vibrations for sure. Se my thread on photgraphy. If I lengthen the bellows with distance rings the whole setup becomes easily affected from vibrations, and this with a 100 kg granite fozndation. So I found out the better way is to use the Luminar 16 mm without additional bellows extension (FOV min 1,5 mm).
instead of the Luminar 25 mm wth extended bellows and another 130 mm extension (several rings) with also FOV 1,5 mm.
With reduced light intensity I now work with 3 seconds exposure time and the shutter vibrations seem to be tolerable.
The resolution with the Luminar 16 mm is around one micron, even a bit less. Measured with a Wafer with test structures on it (0,30 ....1,5 microns). This is also a good method to evaluate the influence of vibrations and getting an optimum of the exposure time.
I did also experiments with 10...15 seconds, but this is a big challenge to my patience. And the improvement is not really a good trade off with time consumption.
Cheers Stephan
10th Jan 2011 09:33 UTCMatteo Chinellato Expert
yes but I work in orizontal not vertical with the bellow. Calculate the photo I have put in this post in the 2008 its pass 3 years, in 3 years many its change, now its this the result I have with crystals under the 1 mm
http://www.mindat.org/photo-345669.html
http://www.mindat.org/photo-274786.html
http://www.mindat.org/photo-355009.html
http://www.mindat.org/photo-355008.html
http://www.mindat.org/photo-348997.html
etc....
10th Jan 2011 09:40 UTCMatteo Chinellato Expert
10th Jan 2011 22:57 UTCOT. Ljøstad Expert
Your camera/mineral specimen (and mine) is not 100% aligned or moves sideways which is not a big problem since the stacking software aligns the photos and adds all the sharp areas of the different photos to form the finished, sharp photo. See one of my worms on the attached photo.
All dust grains on the sensor will always be sharp on all the photos, and because of the camera/specimen movements they form the unwanted worms. My worms dissapear when I clean the sensor. The worms on the finished photo are easy to remove with the retouching tools in Photoshop. It is also possible to retouch all the black dots from the different photos in batch mode if you have a lot of photos.
From time to time (but I never wait as long as 2 months) I clean the sensor of my camera with Sensor Swabs and Eclipse fluid. The only problem is the hight price of the Swabs and fluid.
One good way to see if you have any dust on your sensor is to remove the lens and take a photo without a lens towards a well-lt, white paper. It does not matter what shutterspeed you use. When you study the enlarged photo on your screen of your computor you will se the dots formed by dust partickles on sensor.
11th Jan 2011 05:36 UTCMatteo Chinellato Expert
1st Feb 2011 13:14 UTCPavel Skacha Expert
I bought Zeiss luminar 16 mm recently. I am in a "testing mode" right now, but I find something makes me unhappy. I noticed that when is a subject (crystal) in a deep cavity, so the objectiv is relatively close to the specimen, on the photos is good visible grey tarnish (place with lower contrast) roughly in the middle of the view. I will later try to place some photo of it, but have anyone some simillar experience?
Thanks, kind regards
1st Feb 2011 19:23 UTCVolker Betz 🌟 Expert
you face the typical "problem" of short focal lenght: working distance is small. So ist difficult to photograph crystals in a "deep " cavity. I am photographing now almost 40 years ( with breaks) with luminar lenes.
From the photrographers ponit of view ther are a few rules:
1. Use excellent lenses
2. Only photograph objects which are suitable for photography ! dont wast time !
3. See 2 and don´t photghraph objects which are unsuitable
4. Newer show bad pictures to anyone, just descard it.
5. and most important:Only a few pecentage of pictures are good.
If you take 100 pictures only expect 1 is good.
6 . Be happy.
Regards
Volker
2nd Feb 2011 07:51 UTCHarald Schillhammer Expert
-------------------------------------------------------
, on the photos is
> good visible grey tarnish (place with lower
> contrast) roughly in the middle of the view.
This sounds very much like an internal flare problem. In addition, the very flat light angle that is necessary with such a short working distance might further enhance the problem by producing some kind of veiling flare, but that is usually not showing up as a central spot. I experienced something similar with a Leitz Photar 12,5mm. I have long ago stopped using it. Nowadays, when I do not use a microscope, I only use the 25mm Photar and a reverse-mounted EL-Nikkor 75mm, both on bellows.
It would be good to know how you have attached the Luminar. Some adapters/tubes are prone to produce internal flare.
Volker Betz Wrote:
-------------------------------------------------------
> 2. Only photograph objects which are suitable for
> photography ! dont wast time !
> 3. See 2 and don´t photghraph objects which are
> unsuitable
> 4. Newer show bad pictures to anyone, just descard
> it.
That depends on. Not every image has to necessarily be a candidate for winning a photography award. In many cases the documentary purpose outweighs the need for top notch quality. Not everybody has access to high quality equipment, although expensive equipment is no guarantee for high quality pictures ;).
Anyway, one should always try to set minimum quality standards for himself that even documentary photographs should meet, at least within the available technical possibilities.
Cheers
4th Feb 2011 23:09 UTCMarko Burkhardt Expert
I would like to know which objective do you use for this photo:
Was this a Luminar 16mm, a Photar 12,5mm or a Macro Nikkor 19mm?
Marko
5th Feb 2011 05:39 UTCMatteo Chinellato Expert
9th Feb 2011 06:51 UTCPavel Skacha Expert
thanks for your messages.
Yes, maybe it is the problem in the adapter, bcs I have relatively long variant (about 5 cm, bought on ebay) and its inner side is not free of reflexions. I will try to fill the inner side by a velvet and test it again.
Thanks for your advices
Have a nice day
9th Feb 2011 07:06 UTCHarald Schillhammer Expert
Is that the cone shaped Beljan adaptor? If yes, then this is probably the culprit. Coating the inner side usually helps.
Cheers
9th Feb 2011 13:44 UTCPascal Chollet Expert
63mm : best results stopped down to 4
40 mm : best results stopped down to 2 & half
25mm : best results stopped down to 2
16mm : best results at full aperture.
What I do is using each lens at it's optimal aperture. I adjust the step between 2 photos according to the magnification and the resulting depth of field.
16mm luminar seems to be hard to use with digital cameras. I also have sharpening problems with this lens, and friends of mine, using this lens too, noticed the same thing.
I've got a (lucky) friend who owns both 16mm luminar & 19mm macro-nikkor. the results with the luminar can't stand no comparaison with the pics obtained with the macro-nikkor, really much sharper.
One suggested me that the problem could come from diffraction combined with digital CCD building, wich is not plane but made of photosites in the bottom of a honeycomb structure, after a lowpass filter. this structure really doesn't match fully stopped down lenses, producing more diffraction.
The notice of the Nikon D1x suggest not to stop down more than f/11 (with regular lenses) for best results. diffraction problems might happend really sooner with high magnification lenses.
Pascal
9th Feb 2011 13:58 UTCHarald Schillhammer Expert
> down more than f/11 (with regular lenses) for best
> results. diffraction problems might happend really
> sooner with high magnification lenses.
>
> Pascal
Do you use the Luminars on a bellows or other tube-like extension? You have to consider that each increase in tube/bellows extension results in a smaller effective aperture, meaning that even with fully open or weakly stopped down aperture you might get well beyond the diffraction limit when the extension exceeds a certain length.
Cheers
9th Feb 2011 13:59 UTCMatteo Chinellato Expert
10th Feb 2011 11:32 UTCPavel Skacha Expert
Thanks
10th Feb 2011 17:43 UTCDario Cericola Expert
-------------------------------------------------------
>
> Recent experiments showed me that any kind of
> shutter is not good for small fields of view. I am
> just making experiments with a Panasonic D2. It
> has no mirror and a different shutter: But even
> with that camera there is some loss of sharpness
> at short exposure time. But long exposure time
> helps. I could document that there is a
> significant difference between a 1/125 sec. and a
> 2 sec. exposure. 2 sec. a much sharper. I could
> measure a 1.5 micron resolution using a 15 mm
> Mikrotar of N/A 0.2.
>
Hallo Volker, just a curiosity... How do you measure the resolution?
Dario
10th Feb 2011 19:45 UTCVolker Betz 🌟 Expert
> shutter is not good for small fields of view. I am
> just making experiments with a Panasonic D2. It
> has no mirror and a different shutter: But even
> with that camera there is some loss of sharpness
> at short exposure time. But long exposure time
> helps. I could document that there is a
> significant difference between a 1/125 sec. and a
> 2 sec. exposure. 2 sec. a much sharper. I could
> measure a 1.5 micron resolution using a 15 mm
> Mikrotar of N/A 0.2.
>
Hallo Volker, just a curiosity... How do you measure the resolution?
Hello Dario, measuring ? ist a more a rule of thumb estimation, by photographing a object micrometer with marks in 10 µm distance and about 2 µm wide. I am looking for a better micro object. 2 µm is about near the calculated resolution for a aperture 0,2.
I am still working on the subject. My object micrometer is for transmitted light, photographed in relefected light and has a cover. This causes some effects.
In some time I well have a better answer.
Volker
10th Feb 2011 21:55 UTCDario Cericola Expert
Dario
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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: March 29, 2024 15:57:18