Smaller, anyone? Three more weird lens adaptations to the Sony A7R(II) (2015)
Olympus XA F-Zuiko 2,8/35
I always preferred the Rollei 35S Sonnar 2,8/40 over the Olympus XA F-Zuiko, which by no means is a bad lens. It is indeed a pretty remarkable lens, if you consider how small it is and how close to the film plane it sits, not more than one centimeter.
This unique lens means a very compact camera could be built around it, without the need to push or pull the lens before use, like on the Rollei 35 or the Minox 35.
Another special feature is the diameter of the rear lens, which is significantly larger that the front lens. The lens also has internal focusing, and the XA camera is a true rangefinder, something Rollei always wanted the 35 to be, but never got there.
From the dimensions of the lens it is obvious that the sensor–lens interaction cannot be ideal, as good as the lens may be ”as such”. I have nevertheless tried to mount the lens, because it was there (in a defect XA), and secondly because I still hope to learn more about the interaction between lens and this Sony sensor in particular.
Certainly, I can easily impress people by using phrases like “Telecentric lenses”, “off-center rays”, “micro lenses” and “sensor thickness”, but do I really understand the context – well, no.
But since the proof is in the pudding, I decided to just try and glue it on, again onto a M42 adapter filed to size. As the lens has internal focusing (not external, like the Sonnar) I took great care with the hacksaw and the grinding to arrive at the exact register – without a real grinding machine this is as accurate as it gets.
Another innocent E-mount adapter becomes the victim of my hacksaw:
After taking out the shutter segments the rest was a piece of cake, just add some external parts of the XA housing and there you go…
As I had already tested the optical quality when the thing was only half assembled, I decided to devote less time to outside appearance, because I doubt I will ever really use this lens.
Image quality is actually pretty abysmal. The lens is reasonably sharp in the center but this is about the only positive aspect. Contrast is generally low, and outside of center the image becomes ridiculously bad, with all kinds of defects, vignetting, lack of sharpness, color shifts, you name it.
In essence, as nicely as the XA camera works with film, its lens is a no-go on the Sony (neither on the A7R nor on the A7RII), even if the whole thing looks funny and almost makes the A7 pocketable.
Pentax 2,8/35 from a PC35AF
And then there was that old Pentax compact camera in the closet, with a lens that had a pretty good reputation on film. Not a stellar lens, for sure, just one of the early Autofocus era, but one of the better ones if I remember correctly. Here we see the shutter placed behind the lens and no separate aperture selection – the programmed shutter opens the shutter more or less, depending on the metering.
There is even a rather funny display of the autofocus setting in the finder:
The number of small springs, clips and levers to be found in this camera is pretty remarkable. I believe electronics (of which there also is a lot) were automatically assembled even back then, but the small parts were put together by human hands, I am sure.
What a lot of work for so little money…
A modern digital camera (e.g. a Sony NEX) contains a lot less parts….
Here again, image quality is
unfortunately bad, this time not because of vignetting or color shifts, but
because the corners are not sharp, to an extent that is beyond what can be
found „interesting“ or „full of character“.
The Rollei XF35 is like a step child in the Rollei family, because it is a purchased camera for the most part. The lens however bears the famous “Sonnar” name and offers more than standard with its 1:2,3 speed and its five elements layout. The back focal length is a little wider than that of the two aforementioned lenses, so there is some hope for better optical performance.
Mechanically, the lens has a nice focusing ring because it comes from a true rangefinder camera. It even has some kind of an aperture ring, meant to regulate the aperture depending on the distance, to provide some kind of automation with manual flashes, without the need for calculations. If this could be modified to work as a true aperture ring, the adapted lens might be quite practical in everyday use, maybe even nice to look at.
Unfortunately there is no proper iris again, only two low cost sectors, so we should not expect nice bokeh.
Modifying the aperture ring turned out to be pretty difficult and the throw of the ring is indeed less than ideal - but the manual focusing is.
Provided there is enough light, the optimal aperture is f=11, i.e. fully stopped down. . Focusing fully open (at the opposite stop) and then closed again is a fast way of working, and also makes sure the corners are sufficiently sharp. Then - but only then - this little thing is fun to use.
All in all, I have to admit that the appeal to adapt these lenses lies in the process itself. None of these old lenses comes even close to the levels of performance set by the Sony or Zeiss lenses originally designed for the Sony camera.
This may in part be attributed to the particular likings of these sensors, who don’t work together well with foreign glass, certainly also to the enormous resolution, which makes optical flaws so very obvious, but it looks as if there has also been progress….