when I use the Zeiss Luminar 16 mm and 25 mm in some photos of micro crystals the image appear with a visible grain. It is a problem of light? If I use optic fibers this problem vanishes? http://www.mindat.org/forum.php?read,13,84308,84308#msg-84308 Fri, 24 May 2013 13:08:29 +0000 Phorum 5.2.15a http://www.mindat.org/forum.php?read,13,84308,213345#msg-213345 http://www.mindat.org/forum.php?read,13,84308,213345#msg-213345
Dario]]> Dario Cericola Mineral Photography Thu, 10 Feb 2011 21:55:49 +0000 http://www.mindat.org/forum.php?read,13,84308,213338#msg-213338 http://www.mindat.org/forum.php?read,13,84308,213338#msg-213338 > 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]]> Volker Betz Mineral Photography Thu, 10 Feb 2011 19:45:39 +0000 http://www.mindat.org/forum.php?read,13,84308,213325#msg-213325 http://www.mindat.org/forum.php?read,13,84308,213325#msg-213325 -------------------------------------------------------



>
> 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]]> Dario Cericola Mineral Photography Thu, 10 Feb 2011 17:43:20 +0000 http://www.mindat.org/forum.php?read,13,84308,213304#msg-213304 http://www.mindat.org/forum.php?read,13,84308,213304#msg-213304
Thanks]]> Pavel Skacha Mineral Photography Thu, 10 Feb 2011 11:32:02 +0000 http://www.mindat.org/forum.php?read,13,84308,213248#msg-213248 http://www.mindat.org/forum.php?read,13,84308,213248#msg-213248 Matteo Chinellato Mineral Photography Wed, 09 Feb 2011 13:59:15 +0000 http://www.mindat.org/forum.php?read,13,84308,213247#msg-213247 http://www.mindat.org/forum.php?read,13,84308,213247#msg-213247 > 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]]> Harald Schillhammer Mineral Photography Wed, 09 Feb 2011 13:58:54 +0000 http://www.mindat.org/forum.php?read,13,84308,213246#msg-213246 http://www.mindat.org/forum.php?read,13,84308,213246#msg-213246
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]]> Pascal Chollet Mineral Photography Wed, 09 Feb 2011 13:44:52 +0000 http://www.mindat.org/forum.php?read,13,84308,213238#msg-213238 http://www.mindat.org/forum.php?read,13,84308,213238#msg-213238
Is that the cone shaped Beljan adaptor? If yes, then this is probably the culprit. Coating the inner side usually helps.

Cheers]]> Harald Schillhammer Mineral Photography Wed, 09 Feb 2011 07:06:34 +0000 http://www.mindat.org/forum.php?read,13,84308,213236#msg-213236 http://www.mindat.org/forum.php?read,13,84308,213236#msg-213236
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]]> Pavel Skacha Mineral Photography Wed, 09 Feb 2011 06:51:19 +0000 http://www.mindat.org/forum.php?read,13,84308,212974#msg-212974 http://www.mindat.org/forum.php?read,13,84308,212974#msg-212974 Matteo Chinellato Mineral Photography Sat, 05 Feb 2011 05:39:53 +0000 http://www.mindat.org/forum.php?read,13,84308,212961#msg-212961 http://www.mindat.org/forum.php?read,13,84308,212961#msg-212961
I would like to know which objective do you use for this photo:

© Chinellato Matteo

Was this a Luminar 16mm, a Photar 12,5mm or a Macro Nikkor 19mm?

Marko]]> Marko Burkhardt Mineral Photography Fri, 04 Feb 2011 23:09:07 +0000 http://www.mindat.org/forum.php?read,13,84308,212703#msg-212703 http://www.mindat.org/forum.php?read,13,84308,212703#msg-212703 -------------------------------------------------------
, 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]]> Harald Schillhammer Mineral Photography Wed, 02 Feb 2011 07:51:20 +0000 http://www.mindat.org/forum.php?read,13,84308,212613#msg-212613 http://www.mindat.org/forum.php?read,13,84308,212613#msg-212613
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]]> Volker Betz Mineral Photography Tue, 01 Feb 2011 19:23:05 +0000 http://www.mindat.org/forum.php?read,13,84308,212571#msg-212571 http://www.mindat.org/forum.php?read,13,84308,212571#msg-212571
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]]> Pavel Skacha Mineral Photography Tue, 01 Feb 2011 13:14:30 +0000 http://www.mindat.org/forum.php?read,13,84308,209814#msg-209814 http://www.mindat.org/forum.php?read,13,84308,209814#msg-209814 Matteo Chinellato Mineral Photography Tue, 11 Jan 2011 05:36:13 +0000 http://www.mindat.org/forum.php?read,13,84308,209773#msg-209773 http://www.mindat.org/forum.php?read,13,84308,209773#msg-209773
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.]]> Ot. Ljostad Mineral Photography Mon, 10 Jan 2011 22:57:41 +0000 http://www.mindat.org/forum.php?read,13,84308,209643#msg-209643 http://www.mindat.org/forum.php?read,13,84308,209643#msg-209643 Matteo Chinellato Mineral Photography Mon, 10 Jan 2011 09:40:51 +0000 http://www.mindat.org/forum.php?read,13,84308,209642#msg-209642 http://www.mindat.org/forum.php?read,13,84308,209642#msg-209642
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

[www.mindat.org]
[www.mindat.org]
[www.mindat.org]
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[www.mindat.org]

etc....]]> Matteo Chinellato Mineral Photography Mon, 10 Jan 2011 09:33:10 +0000 http://www.mindat.org/forum.php?read,13,84308,209641#msg-209641 http://www.mindat.org/forum.php?read,13,84308,209641#msg-209641
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]]> Stephan Wolfsried Mineral Photography Mon, 10 Jan 2011 09:05:05 +0000 http://www.mindat.org/forum.php?read,13,84308,209637#msg-209637 http://www.mindat.org/forum.php?read,13,84308,209637#msg-209637
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]]> Matteo Chinellato Mineral Photography Mon, 10 Jan 2011 07:45:34 +0000 http://www.mindat.org/forum.php?read,13,84308,209636#msg-209636 http://www.mindat.org/forum.php?read,13,84308,209636#msg-209636
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]]> Volker Betz Mineral Photography Mon, 10 Jan 2011 07:24:23 +0000 http://www.mindat.org/forum.php?read,13,84308,209606#msg-209606 http://www.mindat.org/forum.php?read,13,84308,209606#msg-209606 Ralph Bottrill Mineral Photography Mon, 10 Jan 2011 03:13:33 +0000 http://www.mindat.org/forum.php?read,13,84308,209583#msg-209583 http://www.mindat.org/forum.php?read,13,84308,209583#msg-209583
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]]> Volker Betz Mineral Photography Sun, 09 Jan 2011 22:12:21 +0000 http://www.mindat.org/forum.php?read,13,84308,209558#msg-209558 http://www.mindat.org/forum.php?read,13,84308,209558#msg-209558
normaly I use the zeiss 16 mm at the 4.5 close, if I use all open the image lost many on the borders]]> Matteo Chinellato Mineral Photography Sun, 09 Jan 2011 20:51:49 +0000 http://www.mindat.org/forum.php?read,13,84308,209545#msg-209545 http://www.mindat.org/forum.php?read,13,84308,209545#msg-209545
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.]]> Fred Kruijen Mineral Photography Sun, 09 Jan 2011 19:35:16 +0000 http://www.mindat.org/forum.php?read,13,84308,207978#msg-207978 http://www.mindat.org/forum.php?read,13,84308,207978#msg-207978
Thanks
Bob]]> Jessica and Robert Simonoff Mineral Photography Thu, 30 Dec 2010 02:02:02 +0000 http://www.mindat.org/forum.php?read,13,84308,84705#msg-84705 http://www.mindat.org/forum.php?read,13,84308,84705#msg-84705
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!!!]]> Don Saathoff Mineral Photography Wed, 09 Jan 2008 00:58:07 +0000 http://www.mindat.org/forum.php?read,13,84308,84696#msg-84696 http://www.mindat.org/forum.php?read,13,84308,84696#msg-84696
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]]> Matteo Chinellato Mineral Photography Tue, 08 Jan 2008 21:44:53 +0000 http://www.mindat.org/forum.php?read,13,84308,84694#msg-84694 http://www.mindat.org/forum.php?read,13,84308,84694#msg-84694 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]]> Matteo Chinellato Mineral Photography Tue, 08 Jan 2008 21:38:23 +0000 http://www.mindat.org/forum.php?read,13,84308,84688#msg-84688 http://www.mindat.org/forum.php?read,13,84308,84688#msg-84688
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.]]> Don Saathoff Mineral Photography Tue, 08 Jan 2008 21:14:09 +0000