Stacked Lens vs APO objectives at 4x with Surprising Results

RobertOToole · Post by **RobertOToole** » Thu Oct 04, 2018 6:32 pm

Thanks to Lou Jost I've been a little intrigued about stacked lenses and now with Mljenko's tests results have inspired me to spend a couple hours over the last weekends chasing a truly good pair of lenses to stack. After a dozen or two pairs, I really thought I had wasted all of my time, then I stumbled on a couple promising pairs. The Noritsu 115 printer lens + Xenon 35/2. The Sigma 150 + Xenon 28 and then I got lucky and hit something else. The Schneider Makro-Symmar 5.9/120 0.75x 0059 Line Scan Lens + Xenon 28mm f2 Line Scan Lens.

I was a little bit surprised on what I saw with the first test images and with all the recent testing I have been doing it takes a lot to surprise me.

So I pulled out some of my better objectives and see how the SK MS+Xenon compared. The results were really surprising so I decided to create a post about it on my site and make it an official test.

I decided on these lenses to compare the SK lens stack at 4x:

Canon MP-E 65mm f/2.8 1-5x Macro Photo lens

Mitutoyo M Plan Apo 5X/0.14 Objective

Nikon CF Plan Apochromat 4x/0.20 160/- Finite Objective

Nikon CFI Plan Fluor 4X/0.13 Objective

Nikon CFI Super Fluor 4X/0.20 Objective

https://www.closeuphotography.com/stacked-vs-objectives

The test results really surprised me!

Test setup

Camera: Sony a6300, model # ILCE-6300, also known as: A6300
Sensor size: APS-C. 23.5 × 15.6 mm. 28.21 mm diagonal. 3.92 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block

For this test a stack of images was made with 5 micron steps, and was repeated for each aperture. The sharpest frame was then chosen using Photoshop at 100% actual pixel view. Separate images were selected for center, edge, and corner if needed. Each image was processed in PS CC with identical settings with all noise reduction and lens correction turned off, all settings were zeroed out (true zero) and the same settings were used for all of the images. All of the images shown here are single files. None of the images are stacked.

The ITL-200 tube lens was used for the Mitutoyo and all the Nikon Objectives. The Thorlabs ITL200 is made by Nikon for Fluor objectives and is one of the best tube lenses that I have tested and much better than both the Mitutoyo MT-1 and Nikon MXA20696 tube lens.

Sharpening note: I wasn't able to run a sharpening pass after the Raw files were converted. The only sharpening applied to the test images was done in ACR using sharpening settings of amount: 50, Radius: 0.5, Detail: 100, Masking: 30. Any additional sharpening resulted in over-sharpening so no additional sharpening was applied to any of the images. The MP-E 65 and Plan Fluor images did not show any over-sharpening effects so keep in mind these files would benefit from an additional sharpening pass. You can always download any of these files and apply sharpening on your own.

I am only going to post the center and corner crops for the
MP-E, Mitutoyo M Plan and the SK Lens stack, if you want to see more you will have to visit my site: https://www.closeuphotography.com/stacked-vs-objectives

To post these crops here on the forum I had to compress them quite a bit so for a hopefully better, less compressed version you can click on any image to view the image from the site.

Center crops:

Canon MP-E 65

The sharpest images for this test out of the MP-E were at f/3.5.

Mitutoyo M Plan APO 5x

Schneider Makro-Symmar 120/5.6 + Xenon 28mm f2 line scan lens

The SK MS + Xenon lens stack was used for this test at f/2.8 with the front lens iris.

RobertOToole · Post by **RobertOToole** » Thu Oct 04, 2018 6:36 pm

Corners

Canon MP-E 65

For some reason the MP-E corner crop has better image quality than the center. I double checked and looked through the stack for a better frame to make sure I didn't make an error.

Mitutoyo M Plan APO 5x

Schneider Makro-Symmar 120/5.6 + Xenon 28mm f2 line scan lens

As I mentioned before for the full test with results with 3 other lenses and a CA test visit the test page.

My conclusion is that the Makro-Symmar 120/5.6 + Xenon 28mm f2 line scan lens beats the MP-E and all of the other objectives, including the 4x 0,20 APO Plan and S Fluor 4x 0.20 objective.

Effective apertures and NA for the lenses above:

Canon MP-E 65mm f/2.8 1-5x Macro Photo lens
NA: 0.11 at 4x
Nominal: f/3.5
Effective aperture: f/17.5, using the cameras light meter I measured closer to f/18.

Mitutoyo M Plan Apo 5X/0.14 ?/- Objective
NA: 0.14
Nominal: f/2.98
Effective aperture: f/15.44

Schneider Makro-Symmar 120mm f5.9 + Xenon 28mm f2
NA: 0.18
Nominal: f/2.8
Effective aperture: f/11.7

Questions, comments welcome.

Thanks.

Robert

RobertOToole · Post by **RobertOToole** » Thu Oct 04, 2018 6:41 pm

Just a heads up.

The Makro-Symmar 120/5.6 are $1300 new at Schneider Optics USA but they are $299 from one of my favorite seller location in S. Korea.

This is top seller that ships quickly via Fedex express for free and does the best packaging on the planet.

They show 2 units left in stock.

This is the same model that I own.

dmillard · Post by **dmillard** » Thu Oct 04, 2018 8:53 pm

Thank you for another noteworthy test! What was the working distance with the stacked pair?

RobertOToole · Post by **RobertOToole** » Thu Oct 04, 2018 10:55 pm

dmillard wrote:Thank you for another noteworthy test! What was the working distance with the stacked pair?

Of course the smart thing to do would have been to measure the WD when it was on the stand, but that would have been too easy

I'll check tomorrow.

Robert

ray_parkhurst · Post by **ray_parkhurst** » Fri Oct 05, 2018 7:26 am

I'll make a wild guess at ~30mm.

RobertOToole · Post by **RobertOToole** » Fri Oct 05, 2018 8:22 am

dmillard wrote:Thank you for another noteworthy test! What was the working distance with the stacked pair?

I measure right on the 20mm mark using a caliper from the rear of the Xenon.

Thanks.

Robert

ray_parkhurst · Post by **ray_parkhurst** » Fri Oct 05, 2018 6:34 pm

RobertOToole wrote:
dmillard wrote:Thank you for another noteworthy test! What was the working distance with the stacked pair?
I measure right on the 20mm mark using a caliper from the rear of the Xenon.

Thanks.

Robert

Pretty tight, but the front of the Xenon is not huge, so lighting should be OK. How did you light the shots? I suppose this is one thing about stacked lenses that ends up being a disadvantage, ie the WD is similar to the FL, even shorter in this case.

RobertOToole · Post by **RobertOToole** » Fri Oct 05, 2018 6:57 pm

ray_parkhurst wrote:Pretty tight, but the front of the Xenon is not huge, so lighting should be OK. How did you light the shots? I suppose this is one thing about stacked lenses that ends up being a disadvantage, ie the WD is similar to the FL, even shorter in this case.

I was able to shoot all the lenses with the same set-up without having to re-position anything due to clearance issues.

The images are lit with two godox TT350 flash at about a 45 deg angle diffused with a godox dome drilled with a large hole for the lens. The flash are arranged at at 10 and 2 on the clock.

Ray I wonder what great combinations you might have sitting on your shelf? Have you tried stacking any lenses lately just for fun?

Robert

ray_parkhurst · Post by **ray_parkhurst** » Fri Oct 05, 2018 7:15 pm

45-deg is not too bad for most subjects. For coins, even at higher mags, I try for 60+ deg, so I would need to create an alternative way to light the subject with such short WD. It isn't too difficult but typically ends up being setup-specific.

Lens stacking has been on my mind since Lou did his work around 1x, and brought to the fore again with Miljenko's latest test reports. Most of the lenses I use are "optimized" types that would not benefit from stacking. But I have boxes and boxes full of interesting stuff that might indeed work in stacked configs. I will need to think about what I might try.

I expect the Xenon works well because of its large max aperture, and optimization at higher enlarging ratios...a perfect combo for lens stacking.

RobertOToole · Post by **RobertOToole** » Sat Oct 06, 2018 11:08 am

People have reached out to ask which Xenon is used in the combination.

Detailed info can be found here on my site: https://www.closeuphotography.com/schne ... m-f2-lens/

The 35/2 is also a good lens, a comparison between the 28 and the 35:

Rudi · Post by **Rudi** » Sat Oct 06, 2018 2:47 pm

Hi Robert,

I wondered iff you tried other combinations with the SK macro-symmar ?

Thanks, Rudi

RobertOToole · Post by **RobertOToole** » Sat Oct 06, 2018 3:14 pm

Hi Rudi,

Yes, I just so happened to try some pairs last night actually, I tried some of the Noritsu APO lenses and some wider lenses on the Makro-symmar. This is what I tried without much to report about:

Makro-Symmar +

SK Componon 28/4
SK Componon 28/2.8
SK Componon 35/4
SK APO Componon 45/4
Rodenstock 25/4
Rodenstock 35/4
Noritsu 55/4 E36 (and some others of the same type)
Tominon 32mm
And some other scanner lenses.

Nothing as good as the Makro-Symmar + Xenon so far. Some were very sharp in the center but the corner sharpness was not consistent.

I really can't explain why that SKMS+Xenon combo is so good.

I'll keep looking for new combinations anyway.

If you have any ideas you think might work please feel free to share your thoughts.

ChrisR · Post by **ChrisR** » Sat Oct 06, 2018 4:02 pm

Do you happen to have any of the eg Pentax/Konica/Nikkor/Canon STM pancake lenses?
They'll be retrofocus (probably bad) but the WDs would be better.
There's a number of short wide aperture Sigma Art lenses of course..

RobertOToole · Post by **RobertOToole** » Sat Oct 06, 2018 5:27 pm

ChrisR wrote:Do you happen to have any of the eg Pentax/Konica/Nikkor/Canon STM pancake lenses?
They'll be retrofocus (probably bad) but the WDs would be better.
There's a number of short wide aperture Sigma Art lenses of course..

Thanks for the reminder Chris. I do have a Sigma 24/1.4 art that I need to try and I can borrow a STM lens. I will work on that next week when I get a chance.

Robert