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09-11-2018, 07:45 AM   #61
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QuoteOriginally posted by matroxication Quote
Thank you for the valuable info. I will test the lens and will let you know
Some more tips: Find your background first, then find interesting objects and leading lines in the foreground (rivers, creeks, rock formations, etc.). Get lower to the ground than usual with your other lenses. Use a tripod and stop down to f9.5 f11to f13 for best results., if you are shooting in low light. If you shoot people, try to keep them in more in the center and out of the sides. Also, stay lower than usual with people so you are not shooting above them too much, which makes them look squished. Ignore the distance markers on the Samyang. Every sample I have seen is wrong (another reason why Irix is better, but more costly!). Lastly, make sure you know how to test for decentering, which my sample had in terrible abundance. Best to shoot a large brick or prominently textured wall from medium distance, all in the same plane and on a tripod... Note, no ultra-wide is going to be quite as sharp as normal and telephoto primes - except the very best, but should about equal the the resolution of your kit zoom lens (28-105). Remember to almost always sharpen images in LR and/or PS. Have fun and have a great trip!

09-11-2018, 09:38 PM   #62
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Thanks mtgmansf.

Took the lens out for a quick spin and apologies for the composition since I really hate it. Using ultra wide lens is a whole different league which I need to start to master. All the pics were taken hand held since I have to head back to work fast. Am not sure if this lens has decentering issue since this is the first time am using UWA lens. But I can see on few pictures that the right edges were really soft compared to the left.
Would require some feedback/assistance on these images to see if there is any issue with the lens.

Last edited by matroxication; 09-19-2018 at 10:04 PM.
09-11-2018, 11:11 PM   #63
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QuoteOriginally posted by matroxication Quote
Thanks mtgmansf.

Took the lens out for a quick spin and apologies for the composition since I really hate it. Using ultra wide lens is a whole different league which I need to start to master. All the pics were taken hand held since I have to head back to work fast. Am not sure if this lens has decentering issue since this is the first time am using UWA lens. But I can see on few pictures that the right edges were really soft compared to the left.
Would require some feedback/assistance on these images to see if there is any issue with the lens.
I completely agree that the sharpness wise it cannot match to any of my primes. Also getting focus lock on the ultra wide lens is very challenging. I would probably have it at infinity at all times and keep my subjects over a meter so that everything is focused.
09-12-2018, 07:04 AM   #64
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QuoteOriginally posted by matroxication Quote
I completely agree that the sharpness wise it cannot match to any of my primes. Also getting focus lock on the ultra wide lens is very challenging. I would probably have it at infinity at all times and keep my subjects over a meter so that everything is focused.
Not sure what F stop you are using on these photos - this does make a difference. On some of the photos - three and six, I see some unsharpness and possible decentering, maybe on the top and bottom left and bottom right of the pictures, but you really need a level plane with consistent lighting to know for sure! Other photos you include - maybe mostly stopped down - look fine all over. I think you know what to look for, based on your observations. Textured wall at medium and far distances is the way to go, if you are level and plane when you take the shot. Of course, decentering is worse when wide open and with more limited depth of field. Frankly, I never shoot less than f8 and usually at f11 or f13.5, and almost always on a tripod. (my 14mm copy had decentering even noticable at f8 on the top right side!) However, if you plan on night photography, you may need to test wide open thoroughly, since smearing of stars and corners can be a big no-no, if they are out of focus. Lastly, infinity of the Samyang may or may not be accurate. Most people, including some in this forum, say it is usually not, so you should find your own infinity and maybe two or three other accurate distances that you commonly use, and mark them on a white or light piece of tape on the lens with a sharpie, if you plan on zone focusing, and if you have limited depth of field. Cheers and good luck...

P.S. Suggest as another mentioned , to find the Samyang 14mm distortion profile in LR or PS and use that, especially if you have buildings or people in the picture. For landscapes, I usually adjust my own images manually, but that is my preference.


Last edited by mtgmansf; 09-12-2018 at 07:06 AM. Reason: addition.
09-12-2018, 12:01 PM   #65
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Don't focus in the center and look at the corners. Keep square to the wall target but focus in the corners (one at a time) and get them as sharp as you can and compare. It is usually pretty obvious -- decentering will cause some smearing which you cannot avoid.
09-12-2018, 12:31 PM   #66
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QuoteOriginally posted by vonBaloney Quote
Don't focus in the center and look at the corners. Keep square to the wall target but focus in the corners (one at a time) and get them as sharp as you can and compare. It is usually pretty obvious -- decentering will cause some smearing which you cannot avoid.
Good advice! Try at a couple of distances and, if present, also try a few different apertures- ones you are most likely to use- to see how that affects or reduces any smearing due to decentering - present. Again, key to this test is to be fairly square to a square surface, especially testing with wide apertures.
09-12-2018, 01:50 PM   #67
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Thanks everyone. Yeah, I tried to keep the camera parallel to the subject while taking the picture of the wall. Regarding the infinity, I kept the focus ring at the maximum and still find that far subjects are not sharp. I primarily bought this lens for the trip and will be using it primarily for sceneries with people.

Also focus peaking is challenging with wide angle especially and am still not getting used to it.
09-19-2018, 10:01 PM   #68
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Finally returned my lens to the distributor to swap with another copy. Currently they don't have stock and hopefully should be getting it by end of this month before my travel. I asked the distributor to test before shipping it out due to time constraints. Unfortunately with Pentax, the distributor cant guarantee a working copy since they don't have any Pentax camera for testing. They can only confirm for Canon or Nikon. Keeping fingers crossed.

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