Stacked Lens vs APO objectives at 4x with Surprising Results

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

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ChrisR
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Post by ChrisR »

Dolmadis wrote:The Retro or reversed magnification is 1.14 to 1.60.
Yup, so it's centered on ~ 3/4 one way round, and 4/3 the other, +/- 20%.
dmillard wrote:SR 5.6/120-0060 optimized for 0.5X, ..... indistinguishable to me. Both lenses were focused at infinity,
+/- 20% strikes me as a narrow range, particularly for a lens with a modest aperture. It makes one wonder which optimization SK care about most. Perhaps it's distortion? I guess it would be necessary to look very critically, at the rated mag.
Chris R

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Post by ChrisR »

rjlittlefield wrote:
ChrisR wrote:They do all tend not to have deeply recessed front elements which helps to get the lens physically close, though being retrofocus makes them more likely to vignette..
I'm still confused. Would we not be using these short lenses on the front of the combo, reversed, with their normal rear elements facing the subject? In that case, and with the other lens focused at infinity, I'm thinking the working distance should be equal to the flange focal distance minus however much the lens normally protrudes into the mirror box, regardless of the focal length of the lens. Lenses that don't protrude much would have a weak advantage, but no lens can protrude very far because of the mirror.

What am I missing here?

--Rik
I don't see much confusion! Yes I know they'd be used reversed in this application.
As I wrote, the fact that the front lens elements tend not to be recessed much makes it possible to locate them very close to the "tube" lens.

Add that to
1) they can be quite wide apertures - one I have is a f/1.9
2) They're Prime lenses with FLs in a useful range, around 24-45mm
3) retrofocus means the WD is at least reasonably good -
A SK 40mm enlarger lens reversed has 27.8mm WD, not as good as a reversed Canon 40mm STM at 37mm WD.
A SK 28mm f/4 WD (rear) is about 21mm
The 24mm STM reversed gives about 34mm WD.
Robert's Xenon 28mm gives 20mm WD.
(Even a Canon MP35 (front) is about 27mm)
4) Some of them eg the Canons are good, lightweight, optically modern designs and not comparatively expensive.
5) several of us probably have one or two.

I reckon that's enough to suggest "consider it if you have one"?
Chris R

dmillard
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Post by dmillard »

ChrisR wrote: +/- 20% strikes me as a narrow range, particularly for a lens with a modest aperture. It makes one wonder which optimization SK care about most. Perhaps it's distortion? I guess it would be necessary to look very critically, at the rated mag.
Qioptiq's Inspec.x L 5.6/105 line-scan lenses have similarly close optima of 0.33X, 0.5X, 0.76X, and 1X in the forward position.

These narrow ranges contrast with film era versions of the same and similar lenses. The SK Makro-Symmar 120 in shutter was described as being useful from 0.5X to 2X, as was Nikon's equivalent 120mm AMED lens. Rodenstock's original 180mm Apo Makro-Sironar in shutter had interchangeable front and rear units, for use at reproduction scales between 1:3 and 1:1 forward, and between 1:1 and 3:1 reversed. The more recent 120mm Apo-Macro Sironar was optimized at 0.5X, but could be used from 1X to 0.25X.
Last edited by dmillard on Tue Oct 09, 2018 5:11 pm, edited 1 time in total.

dmillard
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Post by dmillard »

ChrisR wrote: 3) retrofocus means the WD is at least reasonably good -
...................................................................................................
4) Some of them eg the Canons are good, lightweight, optically modern designs and not comparatively expensive.
5) several of us probably have one or two.

I reckon that's enough to suggest "consider it if you have one"?
For what it's worth, the inexpensive, lightweight Minolta 35mm f/2.8 that I just tried had a working distance of 32mm. I'll go through my lens drawer, and just possibly find a hidden gem. :wink:

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Post by rjlittlefield »

ChrisR wrote:I don't see much confusion!
The confusion was mine. I was missing the point that the pancake lenses, being physically thin, may allow the pupils of the front and rear lenses to be closer together, which could reduce vignetting. I had thought you were saying that the pancake lenses would have more WD than a non-pancake lens of the same FL, and I think that idea is not true. But yes, I do agree they'll have more WD than a non-retrofocus lens of the same FL.

I also agree that it's a good idea to test such lenses if they're conveniently available. Sometimes you get lucky!

--Rik

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Post by RobertOToole »

dmillard wrote:
ChrisR wrote: +/- 20% strikes me as a narrow range, particularly for a lens with a modest aperture. It makes one wonder which optimization SK care about most. Perhaps it's distortion? I guess it would be necessary to look very critically, at the rated mag.
Qioptiq's Inspec.x L 5.6/105 line-scan lenses have similarly close optima of 0.33X, 0.5X, 0.76X, and 1X in the forward position.

These narrow ranges contrast with film era versions of the same and similar lenses. The SK Makro-Symmar 120 in shutter was described as being useful from 0.5X to 2X, as was Nikon's equivalent 120mm AMED lens. Rodenstock's original 180mm Apo Makro-Sironar in shutter had interchangeable front and rear units, for use at reproduction scales between 1:3 and 1:1 forward, and between 1:1 and 3:1 reversed. The more recent 120mm Apo-Macro Sironar was optimized at 0.5X, but could be used from 1X to 0.25X.
This old S-K brochure for the HM 120/5.6 is more extreme, 1:4 - 4:1.

Image

RobertOToole
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Post by RobertOToole »

dmillard wrote:
ChrisR wrote: 3) retrofocus means the WD is at least reasonably good -
...................................................................................................
4) Some of them eg the Canons are good, lightweight, optically modern designs and not comparatively expensive.
5) several of us probably have one or two.

I reckon that's enough to suggest "consider it if you have one"?
For what it's worth, the inexpensive, lightweight Minolta 35mm f/2.8 that I just tried had a working distance of 32mm. I'll go through my lens drawer, and just possibly find a hidden gem. :wink:
Thats the WA 35mm I assume, not the 30mm enlarger lens?

The enlarger lens had serious CA issues.

Robert

typestar
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hidden gem...

Post by typestar »

dmillard wrote: For what it's worth, the inexpensive, lightweight Minolta 35mm f/2.8 that I just tried had a working distance of 32mm. I'll go through my lens drawer, and just possibly find a hidden gem. :wink:
RobertOToole wrote: Thats the WA 35mm I assume, not the 30mm enlarger lens? The enlarger lens had serious CA issues.
@dmillard:

I think you use(d) this Minolta MD 2.8/35 mm SLR lens, latest Series MD-III (??)

http://www.artaphot.ch/minolta-sr/objek ... a-35mm-f28

http://artaphot.ch/images/Technik/Sony_ ... ony_A7.jpg

https://phillipreeve.net/blog/manual-mi ... s-ratings/

https://www.flickr.com/photos/96189377@ ... 7024230073

What a fun to find hidden gems and bring them back to the sun...

All the best,

christian
Last edited by typestar on Wed Oct 10, 2018 10:29 am, edited 5 times in total.

ray_parkhurst
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Post by ray_parkhurst »

People have been using this stacked lens technique for quite a long time. It seems like folks would have tried "everything" at this point, but I guess what's new is willingness to try a range of tube lenses that may not have been tried before to get just the right pairing to compensate both objective and tube lens to create a standout stacked combo.

You guys have me searching my drawers and boxes for stuff I had relegated to being "uninteresting" under normal use conditions which might be the next Xenon. Curse you all! :lol:

Lou Jost
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Post by Lou Jost »

The number of possible permutations is daunting. I think flat field lenses are more likely to be good than curved-field lenses.

Also I think that it is important to use an aperture between the lenses to stop the combo down a bit, unless the front lens has a focal length much shorter than the rear lens. In that case the aperture of the front lens can be used.

dmillard
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Re: hidden gem...

Post by dmillard »

typestar wrote:
RobertOToole wrote: Thats the WA 35mm I assume, not the 30mm enlarger lens? The enlarger lens had serious CA issues.
@dmillard:

I think you use(d) this Minolta MD 2.8/35 mm SLR lens, latest Series is MD-III

http://www.artaphot.ch/minolta-sr/objek ... a-35mm-f28

http://artaphot.ch/images/Technik/Sony_ ... ony_A7.jpg

https://phillipreeve.net/blog/manual-mi ... s-ratings/

https://www.flickr.com/photos/96189377@ ... 7024230073

What a fun to find hidden gems and bring them back to the sun...

All the best,

christian
You are right Robert and Christian, it is the 35mm MD Minolta with the 49mm filter thread. Please note that this was not an endorsement of this particular lens, just a preliminary test that showed it gave uniform coverage of the field (on an APS-C format NEX 7) with minimal CA on a scale bar when using the Makro-Symmar.
Last edited by dmillard on Wed Oct 10, 2018 12:18 pm, edited 1 time in total.

dolmadis
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Post by dolmadis »

Lou Jost wrote:The number of possible permutations is daunting. I think flat field lenses are more likely to be good than curved-field lenses.
What candidates would you have in mind Lou?

BR

John

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Post by Lou Jost »

One of my favorite tube lenses is the Sigma 135mm f/1.8 Art lens. But because I am starting to do more full-frame work, I am now experimenting with a whole new set of tube lenses, of longer focal lengths than I've tried in the past. I hope I can test them systematically soon.

RobertOToole
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Post by RobertOToole »

ray_parkhurst wrote:
You guys have me searching my drawers and boxes for stuff I had relegated to being "uninteresting" under normal use conditions which might be the next Xenon. Curse you all! :lol:
Keep looking Ray, I can't wait to see what you come up with, I think you are more well stocked in optics than anyone here :shock:

I just got lucky.

Robert

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Post by ray_parkhurst »

RobertOToole wrote: Keep looking Ray, I can't wait to see what you come up with, I think you are more well stocked in optics than anyone here :shock:

I just got lucky.

Robert
I do have literally hundreds of lenses laying about, but I have a feeling few will be usable stacked. Only the enlarger lenses seem suitable, and those have been well-researched (most of them anyway).

One area that has potential, which I don't have examples of, are short FL Cine lenses. Reversed Cine lenses seem to be a stable for many macro photographers, but most of what I've seen has them used with extension in reverse, not stacked. Unlike enlarger lenses, which tend to have smaller apertures, many Cine lenses have big apertures and this big potential for working well stacked.

Does anyone on the forum have a selection of short FL Cine lenses with wide apertures to test this theory? I would not know where to start!

Edited to add: some of the "TV" lenses may be good for this purpose. C-mount lenses should have enough coverage in reverse. I see some Fujian 35/1.7 lenses available cheap. Anyone own one of these?

Edit 2: or maybe a 25/1.4:

https://www.ebay.com/itm/Fujian-25mm-f- ... SwQFhbWBmA

Edit 3: these Cine or TV lenses, in C-mount, will of course have shorter WD...

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