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11-14-2014, 04:31 AM   #1
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samyang 16mm f2 lens calibration

Hi,
I received Samyang (Rokinon, Vivitar) 16mm f/2 yesterday. I set focus to infinity and took six shots of palm tree which is about 20 m from me.
When I compared these pictures I noticed that on the right side palm tree looks little bit softer/blur than in the middle and left side. Do you think I should send it back for calibration?

https://drive.google.com/folderview?id=0ByeW6kWG57WwX19YblU2eE1nSWs&usp=sharing

Thank you.

11-14-2014, 06:29 AM   #2
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Yes. Definitely.

Personally, however, I'd get it exchanged for a new replacement (presuming it is new?) as I don't see why you should have a brand new item repaired when it's a manufacturing fault.
11-14-2014, 07:47 AM   #3
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Yeah it doesn't sound like it's a calibration issue, this is a de-centering issue. Which means, as John said, a manufacturing defect. Return it for a new one.
11-14-2014, 07:57 AM   #4
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You're right. It's de-centering issue.

01-14-2015, 06:04 AM   #5
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You won't believe what are the final results.
After two months of waiting, I've got reply:

"We got the info from the service that your lens is correct and, therefore, substitute is not approved. Deviations in terms of sharpness does not fall within the
regulatory failure because the manufacturer states that the sharpness of the lens may vary.
In any case, the entire procedure lasted this much, because we were in "fight" with the service/manufacturer and elaborated to them that it
should be replaced because it's under warranty. But unfortunately, they did not agreed with that."

I really don't know what to do. Whom should I contact?
01-14-2015, 10:54 AM   #6
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I have this one and initially had similar concerns. Part of the reason you can own this for $300 is that by design it focuses past infinity, much like all modern AF lenses. There doesn't seem to be any QC for focus adjustment. It is what it is and you learn to live with it or can QC and fine adjust an infinity dead stop on your own! (something I have yet to do this on mine, but would really like!).
Another thing to consider is that at f/2.0 there is limited depth of field, even at 16mm. So the lens may not always get you razor sharp corners. On my copy I use it almost exclusively wide open and have been really impressed with the sharpness. However under certain conditions, I get blurry edges, sometimes not. I think this has to do with geometry and lens design. Stopping down doesn't seem to have much effect on this.I suggest you try more "testing", i.e. go out and shoot!
04-21-2015, 02:25 AM   #7
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I just want to say that local store gave me new lens (it was two months ago) and now sharpness is equal on the left and the right side of the image.
04-21-2015, 07:35 AM   #8
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Cool....You like the 16mm ? I am in love with my 14 after adjusting infinity....

04-21-2015, 08:19 AM   #9
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Yes. It really is a wonderful lens. I didn't adjust infinity because at mine copy, infinity is exactly where it must be - at the vertical line. Of course, I still have few mm of empty space after infinity, but since I have this visible mark for infinity, I didn't want to bother with adjusting.
04-21-2015, 08:40 AM   #10
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QuoteOriginally posted by malenisjaj Quote
Yes. It really is a wonderful lens. I didn't adjust infinity because at mine copy, infinity is exactly where it must be - at the vertical line. Of course, I still have few mm of empty space after infinity, but since I have this visible mark for infinity, I didn't want to bother with adjusting.
Right....and the 16mm is probably a bit easier to shoot with than the 14mm.....I wouldn't bother either if that's the case.
04-22-2015, 06:59 AM   #11
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How did you get them to exchange your lens for a new one after they had already told you that they wouldn't do it?
04-22-2015, 10:49 AM   #12
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No, the Samyang repair service in Poland told them that they think it's nothing wrong with that lens and they were the ones who didn't want to repair it/change it. I was persistent in my plan to get the new lens (and so was the local store) because with this lens, there were problems with de-centring which is factory fault; I even contacted with some guy in Samyang Korea who told me that he'll help me, but after few emails, he disappeared.

The bottom line: at the end, the local store bought the new lens which they gave to me and they continued the "battle" with Samyang repair service in Poland.
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