In search of a useable 20mm lens – Vivitar 20mm 1:3.8 by Kiron

For some time already I’m struggling to get a really good 20mm lens for my Sony A7. “OK, and so you buy an old Vivitar 20mm? What are you thinking?” Yeah, I know, just took a gamble with this one. It appeared on eBay, I set a maximum bid of some 50 euros on Auctionsniper and forgot about it. Lo and behold, I won it for 25 euros!

It’s made by Kiron, the serial number starting by 22 gives it away. The filter thread size is 82mm so it’s not exactly a compact lens. It focusses quite close, something like 15cm and as a consequence the maximum reproduction ratio is a nice 1:3.5 or so.

This morning it arrived from Austria and I almost immediately set out to test it. Problem! This one is in Canon FD mount and none of my 3 adapters would mount on the lens, not even the Novoflex one. There was a small protruding pin somewhere in the mount that prevented that; I say was because I have removed the pin in the meantime. I couldn’t imagine it would have any function when mounting the lens on an adapter so I started pinching, scraping and filing until the remains of the pin were flush with the rest of the mount. Gave the eBay seller his positive feedback, returning would be somewhat out of the question now, wouldn’t it? The yellow arrow points at the location where once a pin existed.

And finally it’s ready to mount on the Sony A7 and answer the burning question: is it any good?
The total scene, taken at f/8 tripod-mounted.

And here are the crops from center and right edge.

And there you have it. I’d say center sharpness is adequate but edge sharpness is simply bad. I must say that the picture as a whole has a nice tonal range and light fall-off isn’t an issue at this aperture. It looks like there’s a lot of distortion but the road is curved. Other test shots do not show it to an extreme degree, I guess a suitable profile for Lightroom will iron it out like it does for most of my other wide-angle lenses, but I don’t think I’ll go through the trouble of making one.

This certainly will not become my 20mm landscape lens, edge and corner sharpness is simply not there, end of story.

That brings me to the following results from my quest for a suitable 20mm or 21mm lens.

• Olympus OM Zuiko 21mm 1:3.5. The first one’s sharpness degraded gradually from center to corners, somewhere halfway it became unacceptable. The second one was mildly decentered. Both gone.
• Minolta MD W.Rokkor 20mm 1:2.8. Sold the first one a few years ago, still have the second one as part of my collection. Totally unuseable, there’s an unsharp ring around the center. Philip Reeve said it all in his comparison between this lens and the Canon FD 20mm 1:2.8, I have nothing to add to that.
• Panagor 21mm 1:4. Only tested it on the Panasonic GH2 and that didn’t look like it would be good enough for a full-frame camera by a long stretch. Gone.
• Nikon Nikkor 20mm 1:2.8 AIS. Marginally good enough on a D200. Don’t know how it would perform on an A7, I sold it years ago when I switched from Nikon DX to Panasonic Micro-FourThirds.