Zeiss Luminar's light problems

no I have in the 25 mm the f15 max in others I arrive to F30, but up the f10 the image lose many quality.

Matteo,
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.



Edited 1 time(s). Last edit at 01/08/2008 09:17PM by Jean-Marc Johannet.

Matteo, I've been in photography for over 40 years, mostly as an engineer....but, I'm completely baffled by your problem. Digital is new to me but some aspects of photography are simply universal and subject to the same physical laws. In the anatase xl alone I simply see a sharpness or focus problem, but the "moving artifacts" are beyond me.

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.



Edited 2 time(s). Last edit at 01/08/2008 09:19PM by Don Saathoff.

Matteo,
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, I've been in photography for over 40 years, mostly as an engineer....but, I'm completely baffled by your problem. Digital is new to me but some aspects of photography are simply universal and subject to the same physical laws. In the anatase xl alone I simply see a sharpness or focus problem, but the "moving artifacts" are beyond me.

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....I give up....I surrender....I have no more ideas for you....I am really sorry!!!

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!!!

Matteo did you eve find a "resolution" to your problem. I have seen many fine micro photos from you, but are they using this setup?

Thanks
Bob

Ciao Matteo,

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.

hello

normaly I use the zeiss 16 mm at the 4.5 close, if I use all open the image lost many on the borders

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Hello Matteo,

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

What is a micro 4/3 camera Volker?

Regards,
Ralph

Hello Ralph,

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

hello Volker

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

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Matteo,

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

hello

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

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etc....

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Attrezzatura e tecnica sono solo l'inizio. È il fotografo che conta più di tutto. (John Hedgecoe)

A real problem I have now its find who polished the Zeiss lenses seen here in Italy I not find

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Attrezzatura e tecnica sono solo l'inizio. È il fotografo che conta più di tutto. (John Hedgecoe)

I have got the same "worms" of dots on some of my photos that I have taken with a Nikon D 700 DSLR and my Luminars. The worms originates from dust on the sensor. If I stack a photo from 15 different photos with a dust grain on the sensor, I got a worm consisting of 15 grey dots.

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.



Edited 1 time(s). Last edit at 01/10/2011 11:18PM by OT. Ljostad.

my sensors its polished, every some months I send all my camera to Canon for polishing the sensors. Its the lenses have dust into. The problem is find who polish this, seen its old lenses

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Attrezzatura e tecnica sono solo l'inizio. È il fotografo che conta più di tutto. (John Hedgecoe)

Hello,

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

Hello Pavel,

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