Question about lens/sensor sharpness on K3

Question about lens/sensor sharpness on K3

Photo Information
Hi all, this is a photo of Kingswear from Dartmouth, while waiting for the Red Arrows at the Regatta. Any feedback regarding the SHARPNESS of the image would be greatly appreciated. I am not sure whether it is the camera or the lens or both which are to blame for the loss of fidelity of the image. Any ideas about how I should get better results as far as sharpness is concerned?
02/09/2014 - 01:00georGTi
CategoryLandscape / Travel
Shutter Speed1/400
Aperturef/6.3
LensN/A
ISO100
Focal Length137.5mm
Views/Likes63/0

alfpics

Link Posted 02/09/2014 - 09:42
Difficult to say, in part as file size limitations on uploading will reduce resolution - but a quick look to me implies a lens problem as the buildings in bottom and middle centre look fairly sharp, whereas the cream/ yellow ones to left of centre don't and it can't be caused by DOF as distance wise they are in between the other two!
Andy

georGTi

Link Posted 02/09/2014 - 11:14
Thank you Andy for that, it's exactly what I was seeing, and you can imagine how much more obvious the issue is at full resolution. If it's clear to see here, without me pointing out where the problem is, then it's not just me imagining problems I'll have a word with the chaps at the shop I got the kit from to see what they think too. The camera has already been to the Pentax repair labs, I'm still fairly sure mine is a Friday afternoon model...

alfpics

Link Posted 02/09/2014 - 12:41
Hope you can get it sorted. I guess it could be down to skew-wiff sensor
Andy

paulb531

Link Posted 02/09/2014 - 12:46
You have got a long focal length of 137.5mm did you use a tripod? You may have some camera shake if not. Also your lens will not be as sharp at F/6.3 as it would be at F/8. It is a matter of ruling things out until you isolate the problem I'm afraid. It could also a bit out of focus - not everything is going to be in focus at that F stop which will add to the lack of quality. Up the ISO to say 400 for a test and use 50mm or less at F8.

Best of luck

Regards

Paul
Last Edited by paulb531 on 02/09/2014 - 12:52

georGTi

Link Posted 02/09/2014 - 16:31
Thank you Paul for your input, at 1/400 of a second, ISO 100 there shouldn't be motion blur, also any motion blur would be all over the image, no? I'm afraid I would expect better results from a top of the range model. Focus again, another contested issue, I feel that in all the images I've taken, there's a softness present (Pentax service visit didn't make much of a difference), tried boosting contrast and sharpness in the camera (this image included), it's hit and miss at best of times... I think I need to make a 1:1 comparison with another K3, using my own lenses to get a better idea of where the fault, if any, lies. George

alfpics

Link Posted 02/09/2014 - 17:09
Which lens is this? And do you have other lenses? If so does it happen with them - if it does, that might point to the sensor not being aligned properly (ie exactly square on to the lens mount). My 55-300 does have a bit of an issue to the rhs of an image where it is softer/ exhibits aberration at the longer focal lengths.
Andy

georGTi

Link Posted 02/09/2014 - 19:17
Thank you for the tip! This is the 50-200 kit lens and actually I have another photo from the same day, taken with the 18-50 kit lens, with similar issues . I'll definitely take the two photos to discuss the issues with the shop crew. I'll keep you posted!

Teaka53

Link Posted 02/09/2014 - 21:49
Hi George, I have the K3 and use 50mm, 70-300mm & 18-135 lenses and do not experience any lack of sharpness that is not down to me.
Malc

georGTi

Link Posted 03/09/2014 - 12:31
Hi Malc,

Thank you for that, I suspected that much. There's certainly something wrong with my setup, it's going back to the shop next week, will keep people informed of what happens... (that is, if the people are curious )

George

georGTi

Link Posted 13/09/2014 - 12:43
The camera is now sent off for repair, the chaps at Devon Camera Centre agreed that there's indeed some sort of issue with the camera, remains to be seen if Pentax themselves agree too
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