50mm on Full Frame Test

This is a contrived test of center and corner sharpness of various 50mm lenses, SLR and rangefinder. I decided to compare the performance of my 1938 Leitz Summar before selling it. The test was fairly simple: I took two pictures of a Schneider wooden cuckoo clock, one at the center of the frame, and one at the edge (but not corner). All photos were taken on a Sony A7-II, with IBIS enabled, and manual focus using the zoom-in button. Distance was about 3 meters (typical portrait or half-body distance) and all lenses were wide-open to maximize aberrations.

Here's the clock face at the center of the image (rotated 90 degrees for convenience):

And here is the same clock face at the edge of the image (also rotated 90 degrees):

And here are the center images:

Canon 50mm f/1.8 LTM

Industar-61LZ 55mm f/2.8

Jupiter-3 50mm f/1.5 Sonnar copy

Jupiter-8 50mm f/2 Sonnar copy

Carl Zeiss Jena Pancolar 50mm f/1.8

Contax Carl Zeiss Planar 50mm f/1.7

Canon 50mm f/1.8 STM

Ernst Leitz Wetzlar 50mm f/2 Summar (1938)

Pentax Super-Takumar 55mm f/1.8

Pentax Super-Takumar 50mm f/1.4 (7-element)

And the edge images:
Canon 50mm f/1.8 LTM

Industar-61LZ 55mm f/2.8

Jupiter-3 50mm f/1.5 Sonnar copy

Jupiter-8 50mm f/2 Sonnar copy

Carl Zeiss Jena Pancolar 50mm f/1.8

Contax Carl Zeiss Planar 50mm f/1.7

Canon 50mm f/1.8 STM

Ernst Leitz Wetzlar 50mm f/2 Summar (1938)

Pentax Super-Takumar 55mm f/1.8

Pentax Super-Takumar 50mm f/1.4 (7-element)

3D-Printed Finder Guider

This is a 3D-printed finder guider that I built from a 60mm achromatic objective in a metal cell from Sheldon Faworski, a length of 2" cardboard mailing tube, and some parts 3D-printed from ABS.

The 3D-printed parts include:
  • an adapter to marry the lens in cell with the cardboard tube (with suitable tapering down that does not vignette the lens aperture)
  • an adapter with two tapped grub screws to allow a standard 1.25" nosepiece to be attached to the finder guider (an ASI120MM is attached)
  • two guide scope rings
The 2" mailing tube was cut to the exact length so that the ASI120MM only just reaches focus. The ABS parts were then epoxied to the cardboard tube.



Viltrox EF-NEX IV AF Adapter on Sony A7 II Brief Impressions

I have written about the Viltrox EF-FX1 before.

TL; DR - the EF-NEX IV performs pretty much the same way as the EF-FX1, is marginally better in some cases, and worse in other cases.

AF performance is by and large acceptable to mediocre, with two notable exceptions: the Canon 16-35mm f/4 L IS and 10-18mm f/4.5-5.6 IS STM will not AF. On the plus side, the A7 II actually manages to AF the Canon 180mm f/3.5L Macro, which the EF-FX1 was unable to. AF is quite slow and not very reliable however.

The EF-NEX IV also manages to report the focal length properly (which the EF-FX1 could not), and it can detect APS-C lenses and automatically crop (I was unable to get the "tunnel view" with the 10-18mm IS STM).