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01-07-2015, 11:58 PM   #16
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It's a very good lens - a favourite walkaround of mine. But at the long end do close it down to f4! :-)

01-08-2015, 01:34 PM   #17
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Have you tried shooting with Live View, on a tripod, with a 2s timer? You may discover that your shots are front focused due to you moving/shaking back a little after focusing or the camera's AF is a little off.
01-08-2015, 04:23 PM   #18
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Mines very close in sharpness to my A50mm f1.4 in comparable apertures. Stronger at the Tele end than wider. I also suggest checking focus adjustment. Mine needed it on both the K-x and k5.
01-08-2015, 04:37 PM   #19
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Question when you determine the focus adjustment will the K-3 remember your settings?

01-08-2015, 06:05 PM   #20
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The Tammy was back focusing and it seems much better with a AF micro adjustment value of -2 on my K3. Infact I repeated the same shots as yesterday (f/2.8 , 1/100s , ISO 200) and I got pictures which almost matched the FA43 in sharpness. I tried numerous times and noticed they were not very consistent. It focused fine when I refocused freshly each time after focusing on another subject at a different distance. Also I felt Live View focusing performs slightly sharper/consistent than the view finder. Is this theoretically possible?
Also is AF performance inferior under low/indoor lighting? Will try outdoor tomorrow during daytime.
01-08-2015, 08:31 PM - 1 Like   #21
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QuoteOriginally posted by nithin Quote
Also I felt Live View focusing performs slightly sharper/consistent than the view finder. Is this theoretically possible? Also is AF performance inferior under low/indoor lighting?
Yes this is possible. One method uses contrast detection, the other phase detection (CDAF vs PDAF) . Lots of thread on this topic, including

https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/202226-normal-cd...than-pdaf.html
https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/228507-c...than-pdaf.html

and here is one from outside the Forums

Deron Chang's Fujifilm X System Photo Blog: Understanding CDAF and PDAF

and a general search on CDAF vs PDAF will bring you a lot more results.

QuoteOriginally posted by nithin Quote
Also is AF performance inferior under low/indoor lighting?
Yes. I'm finding that too. I also found my shots at 2.8 with flash were far superior to without flash. Mixture of better focusing and shorter shutter times. I'm getting a sense for this lens that under low light you need to use a minimum shutter speed more like 1/2FL or at least as fast a 1/75 no matter what FL you are using.
01-08-2015, 10:08 PM   #22
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Thanks for sharing those PD/CD links, real useful! One of those times where my anecdotal observations turn out to have a scientific proof ;-)
Will read more to understand how the Phase detection actually works.
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