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06-22-2015, 08:17 PM   #1
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Help with Rokinnon 14mm F2.8

I bought a Rokinnon 14mm 2.8 for use on my K-50. I am going to Cherry Spring State Park this summer hoping to get some good night shots. I am not very good at shooting in manual mode. With this lens, I find that I can't see if what I'm shooting is in focus, because everything in the image is too far away. A non-Pentax friend suggested digitally zooming the Live View, but I can't figure out how to do that (or if it can be done.) How can I get the subject close enough to tell if the image is in focus?

06-22-2015, 08:23 PM   #2
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QuoteOriginally posted by agatchell Quote
I bought a Rokinnon 14mm 2.8 for use on my K-50. I am going to Cherry Spring State Park this summer hoping to get some good night shots. I am not very good at shooting in manual mode. With this lens, I find that I can't see if what I'm shooting is in focus, because everything in the image is too far away. A non-Pentax friend suggested digitally zooming the Live View, but I can't figure out how to do that (or if it can be done.) How can I get the subject close enough to tell if the image is in focus?
Go in live view and hold down the OK button. That will pull up the image magnification and should greatly help you focus. If not, then the only remaining option is trial-and-error, which is sometimes a requirement when shooting star photos.

The 14mm is an A-type lens, so you can leave the aperture ring set to "A" and use the e-dials to select your desired shutter speed and/or aperture.

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06-22-2015, 08:45 PM   #3
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Page 111 of the (English) manual

Further you might want to read up on DOF and more specifically on hyperfocal distance. Set the lens to a focus distance of around 1.75 meters, select f/5.6 and everything from about 1 meter to infinity will be in (perceived) focus.
06-23-2015, 05:28 AM   #4
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QuoteOriginally posted by Adam Quote
Go in live view and hold down the OK button. That will pull up the image magnification and should greatly help you focus. If not, then the only remaining option is trial-and-error, which is sometimes a requirement when shooting star photos.

The 14mm is an A-type lens, so you can leave the aperture ring set to "A" and use the e-dials to select your desired shutter speed and/or aperture.
Thanks, Adam. That was simple. Tonight, I'll have to try it outside.

---------- Post added 06-23-2015 at 08:29 AM ----------

QuoteOriginally posted by sterretje Quote
Page 111 of the (English) manual

Further you might want to read up on DOF and more specifically on hyperfocal distance. Set the lens to a focus distance of around 1.75 meters, select f/5.6 and everything from about 1 meter to infinity will be in (perceived) focus.
Thanks, Sterretje. I did look in the manual first. But the index listed Live View only on pages 26 and 67.

06-23-2015, 05:33 AM   #5
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QuoteOriginally posted by sterretje Quote
Set the lens to a focus distance of around 1.75 meters, select f/5.6 and everything from about 1 meter to infinity will be in (perceived) focus.
Trouble is, the focusing scale on this lens can be way off (it is on mine), so some testing would be needed first to ensure that the lens is actually focused at 1.75 metres. Once confirmed, you could put a mark on the barrel if it differs significantly from the distance scale. Probably also worth making a mark at true infinity focus.
06-23-2015, 07:41 AM   #6
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QuoteOriginally posted by agatchell Quote
Thanks, Sterretje. I did look in the manual first. But the index listed Live View only on pages 26 and 67.
Get a PDF version; easier to search the complete manual. Operation Manuals Download : Support & Service | RICOH IMAGING

PS It should have been page number 109; I accidentally used the 111 from the Adobe UI instead of the real number.
06-25-2015, 12:08 PM   #7
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these lenses are notorious for having the wrong hard infinity focus point setting, it could be short of the mark or past it, so be sure and check it.

you can adjust that infinity focus hard stop by peeling back one of the rubber grips on the barrel, loosening some screws, and turning the barrel slightly.
06-25-2015, 12:23 PM   #8
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The first one of those lenses I got would not focus at infinity at all. I just sent it back to Amazon and got a replacement. This new one infinity focuses juuust short of the infinity mark. But once you get it figured out, it really is a fine lens.

06-25-2015, 12:56 PM   #9
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You could try taking a set of pictures of something at least 100 yards/metres away with the lens wide open. The first at the infinity setting, second slightly less and so on, and then review each on the screen at the highest magnification. It should be obvious whether infinity is correct . A 14mm lens has such a great depth of focus that the guess the distance and set the scale and use of hyperfocal distance settings as already mentioned will work as well as autofocus.
06-25-2015, 07:07 PM   #10
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QuoteOriginally posted by osv Quote
you can adjust that infinity focus hard stop by peeling back one of the rubber grips on the barrel, loosening some screws, and turning the barrel slightly.
Does this shift the entire scale along or just the stop? I mean, if I make this adjustment, will it result in an accurate distance scale? If so I will do this as mine is around 1.5cm out. I had been wondering whether this could be achieved without opening up the lens, which I wouldn't want to do.
06-26-2015, 04:55 AM   #11
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There is a video on YouTube that shows how to "fix" the infinity focus. It's in Spanish with English subtitles.


I didn't want to mess with it, but for the more adventurous....
06-26-2015, 09:29 AM   #12
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QuoteOriginally posted by jonby Quote
Does this shift the entire scale along or just the stop? I mean, if I make this adjustment, will it result in an accurate distance scale? If so I will do this as mine is around 1.5cm out. I had been wondering whether this could be achieved without opening up the lens, which I wouldn't want to do.
the infinity hard stop has to be set correctly, because that's where most of the photos will be taken at, 14mm is so wide that there won't be much need for a distance scale.

if you have foreground in a landscape shot... at f/8 on crop, the near edge of dof is at three feet or so? then infinity focus from there out?
06-26-2015, 10:14 AM   #13
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I bought a YASHICA TL-ELECTRO film slr brand new in the 70's and the 50-1.7 lens was not focussing at infinity. It was repaired/ replaced under guarantee. Turned out that the multistart focussing threads were fitted together in the wrong position.
06-26-2015, 10:14 AM   #14
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Some good replies already. Viewfinder and Live view is almost useless with this lens, true. You can use live view with the digital zoom, this can be useful especially for close up subjects.
Anyway, what I do is simple. I just learned approximately where infinity focus is around f8. Now I know where to place the focus ring when I shoot at f8 to get almost everything and infinity into acceptable focus. You can try using higher apertures as well, up to around f14, for extra DoF to mask focusing errors.
But if you are focusing on nearby things, within 1m, then you should be able to find focus well enough.

Secondly, make sure your lens is not decentered. Take a photo of a newspaper at 45 degree angle to the sensor place, places somewhere near to the lens (35cm from camera?) and shoot at f2.8, then f4, then f8. Now you should be able to see the DoF and whether the photo is decently sharp across the sides. If one half of the frame is oddly blurred or if the DoF is sharply diagonal, then the lens might be decentered and should be replaced/repaired.

Oh, one more thing. Using a tripod with 2sec timer will improve sharpness even more. This lens can produce super sharp images, but it is fickle and takes some getting used to. We even have a couple threads about this. Good luck.
07-10-2015, 01:08 PM   #15
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I've always used live view magnified to about x6 to focus on objects that are around one third into the scene, for an approximate hyperfocal distance. I have found this works really well with the Samyang 14mm.



The magnified view can be moved around with the 4-way controller in order to get your chosen object right in the center and well focused. The Samyangs huge focus throw really helps with this and objects can be nailed perfectly. It does take a few seconds and some back and forth trying.



I'm not sure if the k50 has any different type of LV that makes this more difficult than with K7?
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