This lens just covers full format, it was built for 24x24mm
square format.
Focal length: 75mm
Mount: Robot M26
Aperture: F 3.8 - F 22
Min focus distance: 1m
Length (from flange): 44/50mm [+ 13mm for 2 adapters]
Diameter: 46mm
Weight: 200gr.
Some pictures:
A7 and the lens.
Sample pictures: You may click
on the sample image (except closest focus) for full resolution. The
full resolution image opens in a new window, so you can keep it open
for comparison. Focus is on infinity (except
closest focus). These pictures are hand-held out of the window of my
holiday home, so there might be blur by shake, especially at F22.
F 3.8.
F 8.
F 22.
Closest focus (F8) is 78cm from
outermost
edge of the lens. Focus on
the program wheel of the camera.
This
lens just covers full format, it was built for the 24x24mm square
format of the Robot cameras. The adaption to the A7 is easy, the focal
flange distance of the Robots is 31mm. That's not far from the M39
which
is 28.8mm. So you add a 2.2mm adapter to a M39 one and you are there.
M26 to M39 adapters a readily available on the web and they can be
cheap. The Robot lenses are relatively small and they are fine for
APS-C.
This lens is relatively small for a 75mm lens and has a multi-blade iris, perfectly round. According
to the serial number, this is an old lens, made in late 1952. As
you can see on the sample pictures, with wider apertures there is a bit
vignetting in full format, not visible on the 24x24mm Robot
cameras. Although the glass of the lens is fine, there is low contrast
with a digital camera. On film it's fine. Maybe the lens design, old
coating and/or the small M26 diameter on longer lenses are not good for
digital cameras.
