Why a $50 enlarging lens?
After testing more than a dozen lens combinations unsuccessfully before I found a special pair of stacked lenses I can tell that its not easy to find the right combination. The mission here was to find great lens for a stacked pair using low cost enlarging lenses that are easy to find. On my search I stumbled on a set of Schneider Componon lenses in industrial cylinder mount barrels for only $50 each, which is a little high for a used Componon lens but these were new and still sealed in the box and the seller offered free shipping so I was a deal too good to pass on. As far as focal lengths go I picked up a 28, 40 and 50mm but the 28 and 35mm focal lengths are a little harder to find but the longer focal lengths around 50mm are common.
My first test with the Componons was made using the 50/3.5 as the rear lens and the 28/4 in reverse and the sharpness was excellent but the combination did not cover the entire frame so there was heavy vignetting. For this test against the Mitutoyo I decided to use a rear lens that I have used successfully before the Makro-Symmar 120, with the 28mm Componon mounted in reverse. This combination turned out to be very good.
STACKing VS EXTENDing
Stacking lenses, also called coupling lenses, is a technique where you mount a lens in reverse, or face-to-face, on a second lens, usually a telephoto lens. With the rear lens set to infinity focus, and the front lens reverse mounted, then effectively the front lens is still focused at infinity also, without the without any loss of light due to extension. Together the combination has the potential to resolve more than either of the lenses setup for close-focus with extension.
You can predict the maximum possible resolution from a certain lens by using the simple fact that a wider aperture = higher potential resolution. Lens aberrations can also increase at wider apertures, so there is a tradeoff between blurring due to diffraction by stopping down too much and aberration suppression for many lenses, so empirical testing is needed to find the sharpest aperture for each lens that is a good balance between sharpness and aberration control.
An f/4 lens focused at 2x magnification by extension only would have an effective aperture of f/12 using the simple formula, effective aperture = nominal aperture * ( Magnification + 1 ). With the same lens but this time using the stacked lens technique the effective aperture would be only f/8 using the formula effective aperture = nominal aperture * Magnification.
Componon setup information
Front lens: Schneider Kreuznach 28mm f/4 Componon lens reverse mounted
Rear lens: Schneider Kreuznach 120mm f/5.6 Makro-Symmar Line Scan Lens set to f.5.6 and normally mounted focused at infinity
Stacked lens NA: 0.217
Stacked lens nominal aperture: f/2.3 via a 8mm aperture disk placed between the two lenses.
Stacked lens effective aperture: f/9.89
Mitutoyo 5x M Plan APO setup information
Objective: Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective
Tube Lens: Thorlabs ITL200 reverse mounted and beyond infinity using 144 mm extension from sensor to lens with 75mm from tube lens to objective
Nominal aperture: f/2.9
Effective aperture: f/15.4
COMPARING 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.
4.3X TEST: 100% CENTER CROPS
Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens: This stacked enlarging lens does surprisingly well next to the Mitutoyo and a few grade marks better than if the lens was focused using extension. It’s important to note that the lack of chromatic aberrations which is very unlike a Componon, that fact is even more amazing when you consider we are looking at an image made at 4.3x magnification.
Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective: Excellent sharpness and contrast and a nice neutral colors. Typical performance from a Mitutoyo Plan APO.
4.3X TEST: 100% below CENTER CROPS
Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens: Away from the center the differences in the two optics are a lot harder to see. In some areas the enlarging lens looks a bit sharper.
The Makro-Componon stack has a touch more CAs but it is beyond amazing for an enlarging lens to produce such clean results especially away from the center of the frame.
Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective: Still better contrast and better neutral colors but the sharpness advantage is just about gone.
4.3x TEST: 100% EDGE CROPS
Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens: There are some CAs in this crop but the detail is excellent compared to the Mitutoyo. In my experience having owned maybe 12 Componon 28/4 lenses this type of image quality near the edge of the frame on a APS-C is impossible using extension at 4.3x.
Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective: The drop in sharpness here is due to the decreased image circle caused by pushing the lens down to 4.3x. Normally the 5x M Plan is sharp all the way to the very edge of the frame.
4.3X TEST: 100% CORNER CROPS
Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens: Fantastic image quality with better sharpness and contrast than the Mitutoyo.
Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective: Good performance here considering the objective has been pushed down to 4.3x for the test.
Best overall: Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens
This sounds almost unbelievable but the stacked lens does have better image quality over the entire frame at 4.3x. The performance was very close between the two in almost all of the crop areas. When you consider that I paid only $50 for the Componon this level of performance its almost unreal or too good to be true. This test shows that the 28/4 Componon can make a great lens for a stacked combination so you should be able to find a telephoto lens that you might already own to possibly get similar or maybe even superior results than you see here.
Center: Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective
Below Center: Mitutoyo M Plan Apo 5X/0.14 ∞/- Objective
Edge: Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens
Corner : Schneider Makro-Symmar 120mm f5.6 + Componon 28mm f4 lens
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.
The Schneider Componon
Componon lenses are marketed as a higher performance line of lenses but they suffer from the same issues as most enlarging lenses and that is limited resolution due to conservative maximum apertures and only average chromatic correction but they are really easy to find and you can easily find a good sample for less than $50 on Ebay.
Scheider has sold the same componon lenses in at least 5-6 different mounts. The Componons you see here use cylinder body industrial mounts and are harder to find than the plastic consumer mount Componons but all of the versions have similar performance. The center section of the industrial mount lenses incorporate an aperture disk so it takes maybe 5 seconds to unscrew the front and rear cells to swap out the section to change apertures.
other stacked lens combinations
Schneider Makro-symmar 120mm F5.6 And Xenon 28mm F2 Line Scan Lens Stack:
Sigma 150mm f2.8 os macro + xenon 28mm f2 line scan lens Stack:
LINKS FOR MORE INFORMATION on the Makro-symmar
The Makro-Symmar 120/5.9 Industrial 12K lens lineup on the Schneider Optics website (USA):
The Makro-Symmar 5.9/120MM-0059 model used here on the Schneider Optics website (USA) website:
Schneider’s V38-line Scan Lens lineup including the 120/5.9 lens:
Makro-Symmar 5.9/120MM Data Sheet PDF:
Makro-Symmar 5.9/120MM talk on Photomacrography.net:
Makro-Symmar HM 120 5.9 lens
A detailed test report on the Makro-Symmar 120 lens in the B-0 mount called the 120 Makro-Symmar HM including comparison images is available here on Closeuphotography.com:
More information on the Xenon Lens
A review of the Xenon is available here on Closeuphotography.com:
Xenon f/2 lens discussion on Photomacrography.net:
This is an older discussion but there is still lots of interesting info: