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03-09-2014, 02:13 PM   #1
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Sammy 16mm f/2.0 INF dead stop adjustment Rokinon Bower Samyang

Has anyone adjusted the infinity dead stop on their Samyang / Rokinon / Bower 16/2.0 ??

I found these instructions for the (similar) 14mm/2.8:

Como calibrar el enfoque del Samyang 14mm. How to fix focus of Samyang 14mm | | VideofyMe

photo-worX.de - Samyang 14mm Reparaturanleitung

The 16 looks to be a similar IF design, would really LOVE a dead stop at infinity, I'm sure not the only one!~

03-09-2014, 04:29 PM   #2
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I would try using the moon as a target for infinity focus. The focal length means looking for details in other targets is hard, but the moon in a dark sky has sharp edges that should work.
03-09-2014, 05:51 PM   #3
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Thanks Dave, this is why I'd like to have a dead stop at infinity - as nature intended!
03-10-2014, 02:22 AM   #4
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QuoteOriginally posted by digital029art Quote
Thanks Dave, this is why I'd like to have a dead stop at infinity - as nature intended!
I think there are two different things involved that we should try and keep apart. First, at least with older lenses, there were many reports about badly adjusted focusing scales that were obviously off. This could, and should, be adjusted. On my copy of the 16mm, however, this is not the case. There is an infinity mark that is (almost) exactly where infinity is (at normal temperatures). But the hard stop is a little further. This appears to be intentional. Maybe the infinity setting changes with temperature or other factors, as it does with long tele lenses, which have a similar "floating" infinity setting. The 16mm also has a complicated focusing mechanism with the front and back lens groups moving in opposite directions. I'm not sure if it is a good idea to meddle with these things.

03-10-2014, 01:04 PM   #5
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Thank you wkraus. Based on my experience with other Sammy lenses, infinity is always off. I think this is labor saving on Samyang's part - there seems to be no calibration done at the factory. They assemble the lens and let the end user find infinity! Some of their designs, like the 8mm/3.5, which is a real old-school focus helix - very easy to adjust (reset) properly. The 14mm is an IF design and is a little more complicated to set properly. Certainly allowance for temperature changes is only necessary for telephoto lenses, it's not needed on a 16mm!!

What I'd like to know is if anyone has already adjusted theirs - it's got to be very similar to the 14!
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