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Reversed lenses on tele lenses as macro lenses
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PostPosted: Tue Jan 24, 2012 10:41 pm    Post subject: Reversed lenses on tele lenses as macro lenses Reply with quote
Hello,
sorry for the funny title
I added a Konica Hexanon 40mm F1.8 in retro position to my Minolta MD Macro Rokkor 100mm F4 and got a good ~2:1 to ~5:1 macro lens.

(Example pics are without extension tube)



And some handheld results






DOF is ultra thin



Only drawback is some slight vignetting.
Any idea how to remove the vignetting?
Do you know any good and small macro tripods which could be put on a table?

Are there other great combinations of lenses you tried?

Last edited by ForenSeil on Sat Mar 24, 2012 2:16 am; edited 4 times in total


PostPosted: Wed Jan 25, 2012 1:38 am    Post subject: Reply with quote
looks nice result.
vignete wih this way if you stoppedown. you have to full wide open. which make thinner dof
maybe gorilla tripod can help you
Look forward to see your next try


PostPosted: Wed Jan 25, 2012 7:10 am    Post subject: Reply with quote
vignetting in this case is because you use 100mm lens as base lens in this combo. it happened to me also while using oly 90mm/2 macro with oly 50mm/2 macro


PostPosted: Wed Jan 25, 2012 7:16 am    Post subject: Reply with quote
WolverineX wrote:
vignetting in this case is because you use 100mm lens as base lens in this combo. it happened to me also while using oly 90mm/2 macro with oly 50mm/2 macro

hmm... the longer lens more vignete?
I always use 200mm for this. so how much is the limit?


PostPosted: Thu Mar 22, 2012 1:12 pm    Post subject: Reply with quote
I think I have the solution to what causes vignetting...some experience from spectroscope design.

The exit aperature of the collimator lens should be the same or larger than the aperature of the objective lens. And this must be the physical size, not the f-stop. Also this is the case only when the lenses are both focused to infinity. If they are corrected to perform best at infinity then they should be focused like that (I would say that maybe it is not a good idea to use a macro lens in this setup, because it could be that it doesn't correct abberations well when focused to infinity)

In your case you had a 100mm f4, which has a 25mm aperture, and a 40mm f1.8 that has a 22.2mm aperture. So you have vignetting... To avoid it you'd have to stop down the 100mm lens.


PostPosted: Thu Mar 22, 2012 4:57 pm    Post subject: Reply with quote
To OP,
Very nice results.. Thanks for sharing


sammo wrote:
I think I have the solution to what causes vignetting...some experience from spectroscope design.

The exit aperature of the collimator lens should be the same or larger than the aperature of the objective lens. And this must be the physical size, not the f-stop. Also this is the case only when the lenses are both focused to infinity. If they are corrected to perform best at infinity then they should be focused like that (I would say that maybe it is not a good idea to use a macro lens in this setup, because it could be that it doesn't correct abberations well when focused to infinity)

In your case you had a 100mm f4, which has a 25mm aperture, and a 40mm f1.8 that has a 22.2mm aperture. So you have vignetting... To avoid it you'd have to stop down the 100mm lens.


- always have something to learn here! Very Happy

Thank you for such very good explanation Cool


PostPosted: Fri Mar 23, 2012 2:48 am    Post subject: Reply with quote
sammo wrote:
I think I have the solution to what causes vignetting...some experience from spectroscope design.

The exit aperature of the collimator lens should be the same or larger than the aperature of the objective lens. And this must be the physical size, not the f-stop. Also this is the case only when the lenses are both focused to infinity. If they are corrected to perform best at infinity then they should be focused like that (I would say that maybe it is not a good idea to use a macro lens in this setup, because it could be that it doesn't correct abberations well when focused to infinity)

In your case you had a 100mm f4, which has a 25mm aperture, and a 40mm f1.8 that has a 22.2mm aperture. So you have vignetting... To avoid it you'd have to stop down the 100mm lens.


Interesting but in practive when I tried to stop down the 100mm the vignetting got much stronger, the stop of the 40mm lens had no visible influence to that Smile One stop above wide open there were already very dark corners. Or did I understand something wrong? Laughing

I think that a slightly longer tele lens (~150mm) or a 1,4x teleconveter could dissolve the problem.


PostPosted: Fri Mar 23, 2012 5:21 am    Post subject: Reply with quote
The technique of stacking lenses to get good macro shots has been around for quite a while. I first read about it in John Shaw's excellent book, Nature Photographer's Complete Guide to Professional Field Techniques, which was published in 1984. He preferred to have the base lens to be the longer focal length and the reversed one the shorter. As I dimly recall, a favorite of his was a 200/100mm combination. He had quite a few photographic examples in his above book.

This is a technique I've always meant to try out, but one that I've just never gotten around to doing. ForenSeil's examples are so nice, though, that it has reawakened an interest in the technique. I've seen adapters for mating lenses on eBay, guess I need to get me a few.


PostPosted: Fri Mar 23, 2012 3:50 pm    Post subject: Reply with quote
ForenSeil wrote:

Interesting but in practive when I tried to stop down the 100mm the vignetting got much stronger, the stop of the 40mm lens had no visible influence to that Smile One stop above wide open there were already very dark corners. Or did I understand something wrong? Laughing


I see on your photos that you did not have the lenses focused to infinity. Than this theory does not work any more as the light beams are not parallel between both lenses.
Could be also that this theory does not apply to complex lenses, just simple doublet or triplet systems.


PostPosted: Sat Mar 24, 2012 1:17 am    Post subject: Reply with quote
For ultimate fun try reversing 24mm onto 200mm to get magnification > 8x. Better yet, do it on m4/3. This gets 2mm blown up to the whole picture. Madness.


PostPosted: Sat Mar 24, 2012 1:42 am    Post subject: Reply with quote
You could try a microfilm lens, I got high magnification with an Olympus one.



PostPosted: Sat Mar 24, 2012 2:11 am    Post subject: Reply with quote
Is the Olmypus an microfilm enlarger-, reproduction- or projection lens?

El-Nikkors are known to work very well up to ~3:1 or 4:1 bye the way - I guess (Apo-)Rodagon and Componon-S may also work fine.

fermy wrote:
For ultimate fun try reversing 24mm onto 200mm to get magnification > 8x. Better yet, do it on m4/3. This gets 2mm blown up to the whole picture. Madness.

Interesting idea... but I wonder how to determine effective aperture at such a high magnification. I guess the diffraction is a massive magnifacation limit with this technique.

Last edited by ForenSeil on Sat Mar 24, 2012 12:27 pm; edited 1 time in total


PostPosted: Sat Mar 24, 2012 3:14 am    Post subject: Reply with quote
No idea, I found it in a box of assorted junk, when I looked it up it's supposed to have a stupendously high resolution.
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