Blurry images. Need your advice.

Started Sep 14, 2013 | Discussions thread
Gerry Winterbourne
Veteran MemberPosts: 8,013
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Re: without exif it's difficult to help...(nt)
In reply to JimBim, Sep 15, 2013

JimBim wrote:

The image without PP. 1/350 sec at f8, 29mm, ISO400, no crop, DA16-45, K20. Converted from DNG to JPG in LR4. The editor compared to Nikon D700, lens 50mm fixed.

As Alan says, you don't need f/8 for this shot. You could have used f/4 to give a narrower DOF, and that would have allowed ISO100 for the same shutter speed. Your lens has significantly better resolution at f/4 than it does at f/8 http://www.photozone.de/pentax/134-pentax-smc-da-16-45mm-f4-ed-al-review--test-report?start=1 so you've thrown away some sharpness (about 5%) because of that.  (The test is on K10 but the relative resolution at different apertures will be about the same on other bodies)

Also, as already pointed out, there's a fraction more noise at ISO400 than ISO100. That's not a major factor but just erodes a bit more sharpness.

This particular shot is badly front-focused. There's no way of knowing if that's because of mis-calibration of AF or because you got it wrong in MF. Either way, if the same thing has happened in your other shots the effect is worse than the other things I've mentioned. Put everything together, though, and it's not surprising the editor says the shots are sot.

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Gerry
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne
gerry.winterbourne@ntlworld.com

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