Over the last few day I spent way too much time comparing two 5.6/120 APO Digitars and my old faithful 5.6/120 Makro Symmar. The first APO Digitar came from a friend, thanks Daniel, and the other a can't-pass-on-it price on eBay.
But I'm happy to report that the APO-Digitar 120 (AD120) is excellent and it does render slightly differently than the Makro Symmar (M-SR 120)but they are really very similar and both excellent as a macro and as a tube lens. The test images were so close I didn't bother to post the makro Symmar images, only the APO Digitar at 2500 px, to save time.
Full test can be found here on Closeuphotography.com: https://www.closeuphotography.com/schne ... igitar-120
A couple of interesting notes:
The AD120 maximum aperture measures at f/6.15 F&R (the lens is symmetrical). I also used a Raf center section adapter that was slightly faster at f/5.2. The iris is closed maybe 2mm even at the f5.6 setting. The Raf is wide open.
Schneider does not publish any information on whether the AD120 is optimized for sensor cover glass, Rodenstock publishes this info BTW, but I assume it is since the lens was designed for digital backs and they do have an IR sensor stack, also the AD120 has zero CA issues so the design seems to be fine with a digital camera stack.
Gaussian optic data from Schneider indicates the designs of the AD120 and M-SR120 are similar but slightly different.
After all the testing I've done, I can highly recommended the AD120 for macro work on extension at 1x and in a stacked setup. I was able to shoot the Componon 2.8/35 wide open at 3.4x without any issues with CAs. See the 2500px image below.
SHARPNESS TEST AT 1X
Front lens: Schneider APO Digitar 5.6/120 mounted normally and focused on extension
Nominal aperture: f5.6
Effective aperture: f/11.2
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 10 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, 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.
SHARPNESS TEST AT 3.4X MAGNIFICATION
TEST SET-UP
Front lens: Schneider Componon 35mm f/2.8 lens reverse mounted
Nominal aperture: f2.8
Effective aperture at 3.4x: f/9.5!
Rear lens: Schneider APO Digitar 5.6/120 mounted normally and focused at infinity
Aperture: f5.6
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 2 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, 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.
Questions and comments welcome.
Robert
Happy to help!
