1x test; Stacking vs extension

L-R: Schneider Componon 80mm f5.6, Schneider Componon S 80mm f4, Schneider M-Componon 80mm f4, Tamron AF 90mm f/2.8 SP Di macro lens.

Stacking lenses for 1x macro photography

I’ve found that stacking lenses can deliver excellent results anywhere in the range of 2x to 5x magnification. I am curious to see if I could also get good results at 1x by stacking two lenses of the same focal length. The formula is really simple, magnification = focal length of the rear lens / focal length of the front lens, so a 100mm lens reversed in front of a 100 mm lens would give a magnification of 1x.

In testing a pile of enlarging lenses for stacking at 1x I found that the Schneider 80mm f4 Componon S lens was the shortest focal length I could find without any corner shading when used in a stacked setup. Lenses in the 50mm to 75mm range all had issues with vignetting when stacked. Enlarging lenses over 100mm in focal length tend to be slower and or more expensive.

Modern 1x macro lenses typically offer pretty decent image quality. Most newer lenses are designed with close focus correction and use a combination of internal focus and extension to focus at 1x. Is it possible to out-perform a typical 1x macro lens by stacking two low-cost enlarger lenses for a faster effective aperture? Stacking lenses, also called coupling lenses, is a technique where you mount a lens in reverse on a second lens, usually a telephoto lens. With the rear lens set to infinity focus and with the front lens reverse mounted there is no loss of light due to extension. Stacked lenses have the potential to resolve more than a macro lens focused at 1x with extension since a wider aperture = higher potential resolution.

So can two 4/80 lenses deliver better sharpness and image quality than a good quality 1x consumer macro lens for less cost?

lenses in this test

Schneider Componon S 80mm f4 enlarger lens
Plastic BKV-L barrel 6 element enlarger design with a 5 blade iris. These lenses are easy to find on the used market for less than $100 and if you are patient it can found for less than $50 (a CPN S 4/80 sold for only $12 in January 2019).

Schneider Componon 80mm f5.6 enlarger lens
This is the older 15 blade iris single coated design without the S designation. This version is plentiful on Ebay and cost anywhere from $10 to $50 but the condition of these lenses varies quite a bit.

Schneider M-Componon 80mm f4 macro lens
The M-Componon is a special large format macro lens designed for larger than life-size reproduction. Expect to pay $300 - $350 for this lens in excellent shape sometimes as new-old-stock condition. M-Componons are sometimes sold mis-labeled as a normal Componon and can sell for less than $100.

Tamron AF 90mm f/2.8 SP Di macro lens
10 element full frame consumer market 1x macro lens. This is a typical performer with very good to excellent image quality. Clean copies can be found used for around $150 sometimes. I have seen online test sites that rate this lens at a 9.5+ out of 10 for sharpness!


1x test: STACKING VS EXTENDING

For this test the 80mm Componon S, 80mm f5.6, and the M-Componon 80mm were mounted in a stacked configuration on a Schneider Componon S 80mm f4 rear lens. The Tamron macro lens was photographed using f5.6, which is the sharpest aperture at 1x. Opening the aperture resulted in worse CAs and stopping down resulted in a fall off in sharpness.

Un-cropped Silicon wafer test target with crop areas outlined in blue.

Componon S 4/80 vs Componon 5.6/80

COMPONON S Stacked SETUP INFORMATION

Front lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens reverse mounted
Rear lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens mounted normally focused at infinity
Nominal and effective aperture: f4

COMPONON 5.6 SETUP INFORMATION

Front lens: Schneider Kreuznach Componon 80mm f5.6 lens reverse mounted
Rear lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens mounted normally focused at infinity
Nominal and effective aperture: f5.6

CENTER CROP IMAGES AT 100% VIEW

Click on any image below to view a 1500 pixel version in a Lightbox viewer or better yet, to open an image in a new browser tab, right click, or two-finger press, and select Open in a New Tab or New Window from the menu. You can also right click, or two-finger press, and select  Save Image As and compare the images in any image viewer.  

The Componon S is very good in the center an the older f5.6 Componon on the right does is surprisingly sharp as well. The f5.6 image on the right has the black point adjusted increase contrast, without the adjustment the image is pretty flat. The f5.6 lens also has a warm cast. The 5.6/80 Componon lens doesn’t show any glass defects other than some fine dust particles but this is normal for an older lens like this. Older well-used enlarger lenses often suffer coating and glass damage from long term exposure to darkroom chemicals. I ordered another sample of the 5.6 lens but it didn’t arrive in time to include here.

The Componon S image is very good overall. The 5.6/80 is usable and better than I expected but there are some issues.

Componon S 4/80 vs M-Componon 4/80

COMPONON S SETUP INFORMATION

Front lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens reverse mounted
Rear lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens mounted normally focused at infinity
Nominal and effective aperture: f4

M-COMPONON Stacked SETUP INFORMATION

Front lens: Schneider Kreuznach M-Componon 80mm f4 lens mounted normally
Rear lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens mounted normally focused at infinity
Nominal and effective aperture: f4

CENTER CROP IMAGES AT 100% VIEW

Click on any image below to view a 1500 pixel version in a Lightbox viewer or better yet, to open an image in a new browser tab, right click, or two-finger press, and select Open in a New Tab or New Window from the menu. You can also right click, or two-finger press, and select  Save Image As and compare the images in any image viewer.  

Comparing sharpness both lenses are good but the M-Componon slightly ahead here mostly due to better CA control. Looking at the black and blue lines in the lower right the M-Componon image has pure black without any red fringing.

Componon S 4/80 vs Tamron 90 SP macro lens

COMPONON S Stacked SETUP INFORMATION

Front lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens reverse mounted
Rear lens: Schneider Kreuznach Componon S 80mm f/4 Componon lens mounted normally focused at infinity
Nominal and effective aperture: f4

Tamron 90 SETUP INFORMATION

Tamron AF 90mm f/2.8 SP Di macro lens was mounted normally for this test
Nominal aperture: f/5.6
Effective aperture: f11.2
The Tamron was sharpest at f5.6. The image quality was really poor at wider apertures due to big issues with chromatic aberrations.

CENTER CROP IMAGES AT 100% VIEW

Click on any image below to view a 1500 pixel version in a Lightbox viewer or better yet, to open an image in a new browser tab, right click, or two-finger press, and select Open in a New Tab or New Window from the menu. You can also right click, or two-finger press, and select  Save Image As and compare the images in any image viewer.  

The sharpness advantage in the Componon S crop image is not a surprise since the Tamron is shooting at an effective f11 vs f4 for the Componon S. The difference in chromatic aberration is pretty noticeably. If you are having a problem seeing the difference in CAs look at the black areas between the blue lines in the lower right corner.

Outer CROP area AT 100% VIEW: Componon S 4/80 vs Componon 5.6/80

The results here are similar to the center. The sharpness level is similar between the two lenses but the contrast is much better in the Componon S image.

Outer CROP area AT 100% VIEW: Componon S 4/80 vs M-Componon

Both lenses perform very well here with a slight edge in sharpness and resolution going to the M-Componon.

Outer CROP area AT 100% VIEW: Componon S 4/80 vs Tamron 90 SP macro lens

The Componon S image on the left is sharper and cleaner than the Tamron. The biggest issue with the Tamron is excessive lateral CAs.

Edge CROP area AT 100% VIEW: Componon S 4/80 vs Componon 5.6/80

The 5.6 Componon image shows less contrast than the f4 lens, but the sharpness is surprisingly close between the two lenses. This seems to indicate the optical designs are very close if not identical.

Edge CROP area AT 100% VIEW: Componon S 4/80 vs M-Componon

Both the S and M Componon lenses are very sharp at the edge but the M-Componon is just noticeably sharper with less lateral CAs. The M-Componon is a better performer at the edge.

Edge CROP area AT 100% VIEW: Componon S 4/80 vs Tamron 90 SP macro lens

This should be an interesting comparison since enlarger lenses typically experience a drop-off in sharpness in the corners where the Tamron lens is designed to cover a full frame sensor so it should have an advantage here. The Componon S lens is sharper and cleaner than the Tamron SP Di macro lens at the edge.

Chromatic Aberrations

At 200% the differences in chromatic aberrations between the lenses are easy to see. The M-Componon is clearly best with the Componon S in second place. The Tamron is easily the worst.

One of the advantages of the stacking the 80mm lenses is that the some of the lens aberrations seem to cancel out when stacking lenses of the same type.

TEST RESULTS

Schneider Componon S 80mm f4

The S-Componon is the winner of this test when you consider the price, I paid about $30 for my plastic BKV-L barrel 4/80 lens. You can pick one of these up for anywhere from $10-100+.

Schneider Componon 80mm f5.6

The f5.6 Componon sharpness is very good but the single coating seemed to cause an issue with contrast. Also there was a color cast issue with this sample, I did order a second sample to compare but it did not arrive in time to include in this test.

Schneider M-Componon 80mm f4

The Schneider M-Componon 80mm f4 performance is the best in the test but the M-CPN is also the most expensive lens in this test. Looking at the test results here its obvious that there is more difference in image quality between the the Componon S and the M-Componon than there is between the f4 Componon-S and the f5.6 Componon. The optical design of the f4 and f5.6 lenses is most likely similar. The chromatic aberration correction of the M-Componon is quite a bit better than both the Componon and Componon S so it’s most likely a different design.

Tamron AF 90mm f/2.8 SP Di macro lens

This lens is a good performer and not a bad value for only around $200 but the sharpness of this lens is not at the same high level as the stacked as the Componon-S or M-Componon lenses. The performance advantage is not just due to the faster effective aperture since the chromatic aberrations are a lot higher with the Tamron even at a much smaller aperture.

TEST SET-UP 

Camera: Sony α6300, 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 4 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.

LINKS FOR MORE INFORMATION ON the lenses in this test

The Schneider Componon S BKV-L barrel mount 4/80 PDF on the Schneider Optics US site:

https://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=176&IID=1978

Schneider Componon S 4/80 tech sheet PDF from the Scheider Optics US site:

https://www.schneideroptics.com/pdfs/photo/datasheets/componon-s/componon-s_40_80_1.pdf

Schneider Componon S 4/80 MTF curve PDF from the Scheider Optics US site:

https://www.schneideroptics.com/pdfs/photo/datasheets/componon-s/componon-s_40_80_2.pdf

The Schneider Componon S Makro-Iris mount 4/80 PDF from the european SK site:

https://schneiderkreuznach.com/application/files/4215/1902/8433/2018-02-19_09-20_668.pdf

Details on the M-Componon 4/28 with lots of general M-Componon information:

https://www.closeuphotography.com/schneider-kreuznach-28mm-f4-m-componon/

SP AF 90mm F/2.8 Di Macro 1:1 (Model 272E) info on the Tamron site:
http://www.tamron-usa.com/assets/pdfs/272E.pdf

Review of the SP AF 90mm F/2.8 Di Macro on the Photozone, now Optical Limits site:

https://www.opticallimits.com/Reviews/282-tamron-af-90mm-f28-di-sp-macro-test-report--review