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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Lou Jost
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Post by Lou Jost »

Some of those cine lenses have very short flange distances, which would make for short working distances. But their small format is a plus; all else being equal, small lenses have to made to higher tolerances to achieve a given image quality, and when reversed, this translates to more resolution per picture width.

Do remember to stop the combos down slightly with an aperture between the lenses....

ray_parkhurst
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Post by ray_parkhurst »

Robert...this may have already been addressed, but I'm looking at the center crops from the Xenon and Mitty5x shots, and wondering why there is such a big difference in color. Was lighting the same between the shots?

RobertOToole
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Post by RobertOToole »

Hi Ray,

I just tried a 25.5mm f/1.9 super 16 cine lens a week ago, it was terrible as a stacked lens but it makes an excellent loupe :D

One of the forum guys here is getting a SK 35mm f/1.8 APO Xenoplan to try as a reversed on a telephoto. It's not a cine lens but it is small format and fast. The SK APO Xeno is rated down to 3 micro sensor pitch. Might be a good one maybe?

Robert

RobertOToole
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Post by RobertOToole »

ray_parkhurst wrote:Robert...this may have already been addressed, but I'm looking at the center crops from the Xenon and Mitty5x shots, and wondering why there is such a big difference in color. Was lighting the same between the shots?
Hi Ray,

I was wondering why no one asked about this before!

All the lenses were shot one after another without any changes and I've done this so many times now that its possible for me to run the entire test without bumping into anything, throwing the set-up off.

I used to think the changes were false colors or even Moire but now I realize its the way the light hits the wafer, I can make that type of color change happen when move the flash angle slightly. It can go from black to reddish to yellow just by moving a light a few mm. In this case one lens is higher up on the stand with a longer WD.

Also FYI all the images were processed with identical settings in ACR.

Thanks

Robert

dolmadis
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Post by dolmadis »

RobertOToole wrote:One of the forum guys here is getting a SK 35mm f/1.8 APO Xenoplan to try as a reversed on a telephoto. It's not a cine lens but it is small format and fast. The SK APO Xeno is rated down to 3 micro sensor pitch. Might be a good one maybe?Robert
Did our colleague consider this one?

Too short at circa fl 23mm?

http://www.bockoptronics.ca/bockoptroni ... 1_4_23.pdf

BR


John

Lou Jost
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Post by Lou Jost »

That 23mm lens is rated as a 3 Mp lens, which makes me wonder if it would be any good for our purposes.

dolmadis
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Post by dolmadis »

SK 35mm f/1.8 APO Xenoplan
That lens looks like it is 5mp

https://schneiderkreuznach.com/applicat ... 1.8-35.pdf

John

dickb
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Post by dickb »

SK rates a few of the lenses I own as 12 MP, the 35/2.0 Apo Xenoplan and the 20/2.0 Apo Xenoplan, those may be good candidates. I also have the aforementioned 35/1.8 Apo and 23/1.4 non-apo. So I should start testing I suppose..

What would be a good telephoto lens to use these on a FF camera? I don't have any very high megapixel APS-C cameras at the moment.

ray_parkhurst
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Post by ray_parkhurst »

dickb wrote:SK rates a few of the lenses I own as 12 MP, the 35/2.0 Apo Xenoplan and the 20/2.0 Apo Xenoplan, those may be good candidates. I also have the aforementioned 35/1.8 Apo and 23/1.4 non-apo. So I should start testing I suppose..

What would be a good telephoto lens to use these on a FF camera? I don't have any very high megapixel APS-C cameras at the moment.
I see a lot of 4 and another lot of 2 of 35/1.8 Apo Xenoplans for sale. They are not cheap, but also not super expensive.

What will be the WD for these C-mount lenses?

I also see that the mount is removable. Maybe this will help with short WD, at least to have the lens be smaller diameter near subject.

Will be very interesting to see the results!

dickb
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Post by dickb »

ray_parkhurst wrote:I also see that the mount is removable. Maybe this will help with short WD, at least to have the lens be smaller diameter near subject.


The removable focussing mount has no effect on the WD, the underlying 22.5mm diameter thread is equally long, so unless you take a hacksaw to that (you could, it is a 12mm long tube without glass) removing the mount doesn't increase the WD. It does decrease weight and diameter near the subject and not having a chromed ring there may be practical. I use other lenses with this barrel type reversed without focussing mount all the time, those are so small that there is no excuse for not putting them in your camera bag, like the Xenoplan 28/2.0 and the Cinegon 8/1.4. The Apo lenses are a bit larger in size.

ray_parkhurst wrote:Will be very interesting to see the results!

I am very good at postponing such things, so it may take a while. I'm always thinking I'll do it when I get a new camera, or other better hardware.. Would you prefer to see tests with these lenses just reversed or reversed onto a telephoto lens. If the latter, which lens for a FF camera?

ray_parkhurst
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Post by ray_parkhurst »

dickb wrote: I am very good at postponing such things, so it may take a while. I'm always thinking I'll do it when I get a new camera, or other better hardware.. Would you prefer to see tests with these lenses just reversed or reversed onto a telephoto lens. If the latter, which lens for a FF camera?
I can't comment on which lens to use since I don't know what you own. A 120mm will give you ~3.4:1, while 180mm will give ~5.1:1. I guess it would be good to have a compo of the performance at same mags with extension vs tube lens, but probably most important is to find a tube lens that gives good performance.

Most likely the other forum member Robert mentioned is also working on this, so you may not need to check at all unless the result is ambiguous, or so good you feel compelled to check yourself!

RobertOToole
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Post by RobertOToole »

dolmadis wrote:
RobertOToole wrote:One of the forum guys here is getting a SK 35mm f/1.8 APO Xenoplan to try as a reversed on a telephoto. It's not a cine lens but it is small format and fast. The SK APO Xeno is rated down to 3 micro sensor pitch. Might be a good one maybe?Robert
Did our colleague consider this one?

Too short at circa fl 23mm?

http://www.bockoptronics.ca/bockoptroni ... 1_4_23.pdf

BR

John
Hi John, Not sure but in this case it was more about what was available used.
But I see what you mean, the lens you link to has really looking simulated MTFs at f/4, although the image circle is small. Thanks for sharing that.

Best,

Robert

RobertOToole
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Post by RobertOToole »

dickb wrote:SK rates a few of the lenses I own as 12 MP, the 35/2.0 Apo Xenoplan and the 20/2.0 Apo Xenoplan, those may be good candidates. I also have the aforementioned 35/1.8 Apo and 23/1.4 non-apo. So I should start testing I suppose..

What would be a good telephoto lens to use these on a FF camera? I don't have any very high megapixel APS-C cameras at the moment.
You have quite a nice collection of Xenoplans there Dick!

I tested a bunch of lenses and the Sigma 150 OS, Makro-symmar and Noritsu 115 performed best. Most I tried were ok in the center but had high CAs in the corners. Not sure why the 3 I found work so well but they are all APOs.

Be sure to update us when you take a look at the Xenoplans :D

dolmadis
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Post by dolmadis »

Robert

Yes, I can see how that suggestion arose now.

I mentioned the 23mm lens because I have seen some guys in Poland on the Facebook Groups using this Reversed stacked on a Takumar 200mm f/4.

BR

John


Edit to add "Reversed"

ChrisR
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Post by ChrisR »

What will be the WD for these C-mount lenses?
17.526mm apparently:


http://www.ikegami.com/cb/products/pdf/ ... smount.pdf
Chris R

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