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05-16-2013, 07:16 PM   #16
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Here's a really unfair comparison: The same scene, shot with a Sigma DP2 Merrill, no sharpening, 100% crop:



It's unfair because the Sigma is 30mm, and it doesn't have a Bayer array to muddy things up at the pixel level. It beats the pants of the Samyang for sharpness, but I still lug the Samyang along on hikes because it's acceptably sharp, has a great focal length, and it renders colors extremely well.

05-16-2013, 07:25 PM - 1 Like   #17
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QuoteOriginally posted by thechumpen Quote
Interestingly I have just tried with my 18-55 set at 18 and this gives pretty much the same thing. Maybe I am just expecting too much
I don't own the lens, but I will add my $0.02 to the discussion. A common complaint with wide angles is that they are not sharp. A common problem is that the photos taken with them are simply out of focus. The short focal length does provide greater DOF, but in practice that means very little if you are going to pixel peep. After all, magnification of the final image is part of the DOF equation. Ultimately, there is only one true point of focus regardless of focal length and if you miss it...

Translation...focus accuracy still counts if you want the photo to be sharp.

Problem...it is very difficult to attain accurate focus with an ultra-wide. Everything is so "teeny" in the viewfinder that it is hard to tell what is and is not in focus. To make things worse, many wide angle lenses have very short focus throws.

Solution? If you are going to be picky about sharpness, use the focus aides on a decent aftermarket screen -or- use a focus loupe in live view. Focus on the near aspect of your subject and let the background take care of itself. In PP, make a careful assessment for lateral CA and correct if your tool is capable of doing that chore. Lateral CA causes global loss of sharpness and is often present.

One other thing...when doing tests for lens sharpness, use a flat target parallel to the plane of focus. The old rule of thumb is to do this at a distance 20X the focal length for 35mm film or 30X for APS-C. This may not be practical for 14mm, but I think you get the gist.


Steve
05-16-2013, 08:50 PM   #18
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QuoteOriginally posted by stevebrot Quote
I don't own the lens, but I will add my $0.02 to the discussion. A common complaint with wide angles is that they are not sharp. A common problem is that the photos taken with them are simply out of focus. The short focal length does provide greater DOF, but in practice that means very little if you are going to pixel peep. After all, magnification of the final image is part of the DOF equation. Ultimately, there is only one true point of focus regardless of focal length and if you miss it...

Translation...focus accuracy still counts if you want the photo to be sharp.

Problem...it is very difficult to attain accurate focus with an ultra-wide. Everything is so "teeny" in the viewfinder that it is hard to tell what is and is not in focus. To make things worse, many wide angle lenses have very short focus throws.

Solution? If you are going to be picky about sharpness, use the focus aides on a decent aftermarket screen -or- use a focus loupe in live view. Focus on the near aspect of your subject and let the background take care of itself. In PP, make a careful assessment for lateral CA and correct if your tool is capable of doing that chore. Lateral CA causes global loss of sharpness and is often present.

One other thing...when doing tests for lens sharpness, use a flat target parallel to the plane of focus. The old rule of thumb is to do this at a distance 20X the focal length for 35mm film or 30X for APS-C. This may not be practical for 14mm, but I think you get the gist.


Steve

+1 (and put your prices up)
05-16-2013, 08:52 PM   #19
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QuoteOriginally posted by SyncGuy Quote
Holy mother of goat! I would say it's a dud!

Well I dunno..... (and this is out of focus)
(I reckon some numpty at the factory put a Canon bezel on it)

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05-16-2013, 10:35 PM   #20
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QuoteOriginally posted by ak_kiwi Quote
Yes I totally agree. You have to calculate hyperfocal distances based on the crop factor.
I was referring to the focused distance (rather than DOF markings which I don't have on my copy) as marked on the lens barrel which I checked against a measuring tape after manually focusing in live view.
This is a common issue with the samyang lenses, and a common complaint.

I believe the focal distances are based upon perhaps canon regestry distance, and do not represent correctly the design for the longer regestry distance of Pentax.

Generally I do not bother with focus distance, but use the focus indication (green hexagon) in the view finder.i have had excellent results with this lens on both digital and film bodies. Perhaps I am lucky but with my "good copy" I have had a lot of fun, especially on my PZ1 shooting B&W film

14mm is relatively wide on digital, but considering I already have a sigma 10-20 it is not extreme. 14mm on film is really really wide
05-17-2013, 05:00 AM   #21
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QuoteOriginally posted by scratchpaddy Quote
Maybe I misunderstand you, but this test makes no sense. Is your tripod in the same place for the pictures you took for both lenses, or did you move back so that the paper occupied the same amount of the frame when you took the picture with the DA 35, as ak_kiwi is saying? If the tripod didn't move, it's a no-brainer that the DA 35 is sharper: the paper covers more pixels.
Your test shot looks perfectly fine to me. How sharp do you expect it to be? It's a lot more difficult to make a lens as wide as this than it is to make a 35mm. I'd say it's outstanding for the price it sells for.
That's great info. This is all learning for me as I don't know what to expect and from the sound of it my test was just plain unfair (I didn't move the camera between tests). I just thought that somewhere I would have hit the sweet spot of focus and with the small aperture would get enough DOF to get a sharper image than what I got. However, if it's normal that you would never get a sharp enough image to have clear text from 3 metres away with this lens then that's just my expectation that needs to be adjusted.

I followed Steve's advice and took a picture from around 30X focal length away and got the image below. That looks pretty sharp to me. Am I right in thinking that if it were a "bad" lens I would not get something this sharp even when close up?

http://www.flickr.com/photos/sjamesphotos/8747599230/in/photostream
05-17-2013, 07:03 AM   #22
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QuoteOriginally posted by Lowell Goudge Quote
This is a common issue with the samyang lenses, and a common complaint.
I believe the focal distances are based upon perhaps canon regestry distance, and do not represent correctly the design for the longer regestry distance of Pentax.
If the construction is the same as that of their 8mm fisheye, then it should be a simple matter of loosening the three grub screws hidden under the focus ring rubber band and resetting the ring so that the infinity mark actually corresponds to infinity focus (or that the infinity end stop is just a touch beyond infinity focus). Even then you'll probably find that the distance markings are largely just a decoration
05-17-2013, 09:49 AM   #23
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QuoteOriginally posted by thechumpen Quote
Am I right in thinking that if it were a "bad" lens I would not get something this sharp even when close up? 20130517-IMGP3502 | Flickr - Photo Sharing!
I think that's really sharp, not bad at all. The only thing now is if the focus is adjusted correctly, can you focus to infinity.

05-17-2013, 10:31 AM   #24
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QuoteOriginally posted by Na Horuk Quote
I think that's really sharp, not bad at all. The only thing now is if the focus is adjusted correctly, can you focus to infinity.
Not sure yet but when I get chance (and the right surroundings) I will be giving it a go and reporting back.
05-17-2013, 02:17 PM   #25
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There are also some tutorials online with a walk-through on how to adjust the focus ring and distance scales to be (more) accurate
05-17-2013, 06:02 PM - 1 Like   #26
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QuoteOriginally posted by Na Horuk Quote
There are also some tutorials online with a walk-through on how to adjust the focus ring and distance scales to be (more) accurate
How to fix focus of Samyang 14mm with English subs.
05-18-2013, 11:03 AM   #27
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QuoteOriginally posted by kh1234567890 Quote
How to fix focus of Samyang 14mm with English subs.
Thanks for posting that kh - very useful.
05-28-2013, 06:36 AM   #28
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Have taken a few pictures with the lens now and personally I am really happy with it. A few samples below. Note (disclaimer) that I am a complete amateur and these were taken with no real experience of focussing etc, and also messed around a bit in Lightroom. Therefore please take with a pinch of salt but to me they look OK, which implies the lens is pretty good and will be very capable once I have had some time to learn how to use it and check out the focussing etc.

Edit: Not sure how to post larger images but you can find them here: http://www.flickr.com/photos/sjamesphotos/







05-28-2013, 07:43 AM   #29
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Wow ! Those look sharp enough to me
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