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07-16-2010, 01:51 PM   #16
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From Popular Photography AF speed tests:

07-17-2010, 08:53 AM   #17
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QuoteOriginally posted by Pentaxoid Quote
The lack of AF assist lamp is a MAJOR annoyance. I looked really stupid last week, when my $1000 equipment was incapable of taking pictures in the dark. The cheap P&S cams did the job, them
Were they shooting without flash? I rather doubt it. And if so, did you see the results? They almost certainly would have looked *terrible*, as shooting in the dark without flash means high ISO.

Had you given yourself the same advantage they had - use of flash - you'd have done as well or better, since the flash would have served as the focus assist.
07-17-2010, 09:25 AM   #18
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The K-7 should have the better AF system. It also depends on the lens u use. I saw the K-7 with the new sigma 70-200mm HSM and it was increadable fast compared to my Pentax 50-135mm lens. So lensdesign does a lot. Accuracy of the K-7 I think is great.

With the K-x you can use the internal flash as a lightassist for AF.
07-17-2010, 10:15 AM   #19
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I often shoot in pretty dark venues - a lot of my shots are about ISO5000, f/3.5, 1/4 sec I think that's about -1 to 0 EV - ie: near the low limit to the Pentax K-x focusing ability.

Just to put this into context - if we took ISO100 and f/4 pretty standard settings - then my shutter speed would be about 15 secs. Or for ISO400 that's still about 4 secs

So if it wasn't for the K-x I would not be able to take photos at all without flash.

I sometimes have difficulties focusing in such low light and I mean so seriously that I am unable to do it manually the image is so dark in the viewfinder - although one might argue that a real penta-prism viewfinder would be brighter - which it is - I have some older film SLRs that have reputation of really good bright viewfinders - and I still would not be able to focus on the plain ground glass areas (that includes the Minolta Acu-Matte screens as well as Olympus OM-2 and 4 which were reputed to have really big bright screens) and if I could focus with the split image finder then there would be enough for the K-x AF to work..... it's not just low light - but under such lighting it's hard to find anything with enough contrast to focus on.

Under those conditions I often look for another part of the subject that might have enough contrast to focus on -

eg: original as-is no PP other than resize and standard sharpening -

EXIF attached - ISO5000, f/3.5, 1/4sec, 18mm

I didn't know it at the time but trying to focus on the face was futile -
as can be seen in the original photo -
I had to focus on the junction between the outer shirt and the T-shirt.

For me it was worth the effort as the shot looks like this after pp -


See posts #103, #105 - for discussion details in Kx in Use


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