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03-14-2017, 12:31 PM   #1
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Rokinon 14 Focus

Long-time lurker first time poster.
Recently acquired a K-1 and the 28-105(happy with that) and the Rokinon 14mm 2.8.

The Rokinon is nice and sharp close up, but I can't get anything like good focus out past about 20ft distant. The 28-105 is significantly better.
The issue seems to be that the Rokinon lens infinity focus stop is before the camera actually achieves focus at anything more than about 20ft, much less infinity.

There are numerous threads about this that I've read, as well as that Spanish video explaining how to manually calibrate the infinity focus. However, that only seems to correct the problem if you're getting into focus before the infinity mark, and you need to turn it back. If, as in my case, you hit the stop and still aren't in focus yet, can this be corrected? Or should I just send the lens back?

Thanks, and sorry to beat a dead horse on this topic.

03-14-2017, 01:03 PM   #2
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This is a great lens, but it can have some quality control issues, mainly some will have a de-centered lens. I have the Bower copy of this lens, here are two write ups I did about it:

Bower 14mm f/2.8 Ultra Wide Angle Lens . - PentaxForums.com
Bower 14mm f/2.8 - PentaxForums.com
03-14-2017, 01:13 PM   #3
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QuoteOriginally posted by SteveinSLC Quote
Rokinon lens infinity focus stop is before the camera actually achieves focus at anything more than about 20ft, much less infinity.
It is a know QC issue of the lens. If you don't want to return it (good optically performance), you can search online for calibrating the focusing scale and adjust infinity focusing. I remember there were a lot of such posts shortly after the lens was released.
03-14-2017, 02:51 PM   #4
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QuoteOriginally posted by SteveinSLC Quote
...There are numerous threads about this that I've read, as well as that Spanish video explaining how to manually calibrate the infinity focus. However, that only seems to correct the problem if you're getting into focus before the infinity mark, and you need to turn it back. If, as in my case, you hit the stop and still aren't in focus yet, can this be corrected?...
You can probably adjust it. Opening a new product voids the warranty so proceed with caution. If a return is easy, I recommend doing that, just in case there's a more serious problem.

A few years ago I noticed infinity softness with my Rokinon 14. The recalibration of the focus ring worked for me. I think the usual focus problem is that it focuses too far beyond infinity, but in your case and in mine the poor quality control was off in the other direction.

03-15-2017, 02:42 AM   #5
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I had a similar problem with my Samyang branded version, which I had replaced.
Just check it is definitely focus and not softness. At 2.8 this lens is very soft, make sure you are shooting at F4 and above.
03-15-2017, 06:50 AM   #6
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QuoteOriginally posted by Alnjpn Quote
I had a similar problem with my Samyang branded version, which I had replaced.
Just check it is definitely focus and not softness. At 2.8 this lens is very soft, make sure you are shooting at F4 and above.
A good copy of the 14/2.8 is sharp wide open.
03-15-2017, 03:19 PM   #7
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Thanks all. Yeah, at distance, mine's not as sharp as I'd like at any aperture. If the 28-105 is a lot better, something is off. Maybe I could adjust it, but I'm not going to take the chance. Back it goes.

Now have to decide between another copy, trying the 24mm/1.4 instead(which also seems to have the same QC issues), or spending a lot more for the Pentax 15-30.

Looking for something fast and sharp for landscapes and astrophotography. Any thoughts one whether it's worth trying more Samyang/Rokinons, going with the Pentax or waiting for Pentax or Sigma to come out with something? There is also the Irix, but the couple of early reviews I've seen have had quality issues with that too.
03-16-2017, 03:38 AM   #8
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Hello everyone:

I'm not sur my copy of this lense is a good one. I have even tried to recalibrate the infinity, but it is very subtile to do it. Event at x16 in LV + i'm not sure the lense can be sharp at f.2.8 when looked through x16 live view on a far object (building).

Here you'll find a capture i've done before my attempt to calibrate it, @f2.8


and here a 100% crop in the center of the frame:


Do you think the problem here is focusing or the lense suffer from other issue ?

03-16-2017, 06:02 AM   #9
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QuoteOriginally posted by SteveinSLC Quote
Thanks all. Yeah, at distance, mine's not as sharp as I'd like at any aperture. If the 28-105 is a lot better, something is off. Maybe I could adjust it, but I'm not going to take the chance. Back it goes.

Now have to decide between another copy, trying the 24mm/1.4 instead(which also seems to have the same QC issues), or spending a lot more for the Pentax 15-30.

Looking for something fast and sharp for landscapes and astrophotography. Any thoughts one whether it's worth trying more Samyang/Rokinons, going with the Pentax or waiting for Pentax or Sigma to come out with something? There is also the Irix, but the couple of early reviews I've seen have had quality issues with that too.
Try another Samyang/Rokinon provided returns are easy. The 14/2.8 works well if you don't get a bad copy. Or, if you prefer the 24/1.4 field of view, try that one.

The 15-30 is a good lens too but much heavier than the Samyang primes.

---------- Post added 03-16-17 at 09:11 AM ----------

QuoteOriginally posted by Meg4mi Quote
...Do you think the problem here is focusing or the lense suffer from other issue ?
The 100% crop seems reasonably sharp.

Flickr says it was at 30 seconds, ISO 3200. 30 seconds: If the astrotracer was off or miscalibrated, stars move a little bit. ISO 3200: The noise is not bad but smears details a little bit.

It looks like the bright stars have an off-center halo. Was the 100% crop from the center or a corner?

Try a similar shot, at 15 seconds, ISO 800. The image will be much darker but might be easier to assess sharpness and aberrations. Compare the center and all 4 corners.
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