This post covers using this vintage lens, an Optomax 35mm f/3.5 preset, on a modern digital mirrorless camera. The lens is an M42 mount copy which I picked up from eBay for £5 a few weeks ago.
Optomax 35mm f/3.5 Images
Optomax 35mm f/3.5 Description
It's a lens of simple construction with a fairly slow max aperture of f/3.5 which is controlled with a pre-set aperture ring, and a very large focus adjustment range. The aperture has 6 blades, and the focal length of 35 mm equates to a 35 mm equivalent of 52.5 mm when the APS-C crop factor of 1.5 is taken into account. This makes it about the same as the normal focal length supplied as a standard lens. Its simple construction makes it pretty simple to get apart, so it should be easy to repair and clean - I certainly found it easy to unscrew the front retaining ring and remove the front element to blow some dust out.
Being pre-set would possibly make it useful for people wanting to take video, as the aperture can be adjusted whilst taking a clip without any 'clicking' and if it was adjusted slowly enough the camera could compensate without the brightness changing much. This could possibly lead to some interesting focal effects.
In use, I found it a difficult lens to easily judge focus with. Even using the focus peaking feature of the Sony NEX, the large adjustment range meant I was turning a large amount without any noticeable difference, so I was constantly moving it back and forth to try to pin the optimum point. The slow f/3.5 aperture also didn't help here as there is quite a large 'in focus' range.
The close focus abilities of this lens are almost non-existent. The closest I could get to focus was about 3 feet away, and the slow aperture and quite wide angle made it difficult to isolate flowers etc. I found the best use to put this lens to is as a snapshot lens by setting the aperture to about f/11 and aligning the f/11 mark on the depth of field scale with the infinity point on the focus ring. This gets everything from about 5 feet to infinity in focus.
My particular example had a small amount of dust which I removed as described above, and also has some oil on the aperture blades, but being pre-set this isn't really a problem as they don't stick when the pre-set ring is shifted.
Optomax 35mm Sample Pictures
The following sample pictures were taken using his lens over the course of a couple of days during lunchtime walks around Stevenage. They have all had some picture tweaks in Lightroom CC which involved enhancing the clarity, correcting the exposure slightly and boosting the colour saturation where applicable.
Overall I think this lens is a capable performer for the £5 I paid for it. Not up to the standard of the better Takumar 28 mm f/3.5 but in picture quality much better than another Optomax lens I tested which was the 200mm auto telephoto.
