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06-26-2010, 03:14 PM   #16
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There are basically two kinds of cameras when it comes to low loght AF: those with AF assist lamps, and those without. Most Canon and Nikon cameras have these, most Pentax cameras do not. The K-7 is the only Pentax camera to have one.

BTW, in the situation describe above, I'd have recommended switching to MF right away and not worrying about it. Awards ceremonies and the like are perfect for MF, because all the action happens in one place, and you can just pre-focus and fire away. I'd say it's better than even the fastest AF system, because you don't have to worry about the camera deciding to focus on the podium instead of the person standing behind it, etc.


Last edited by Marc Sabatella; 06-27-2010 at 10:03 AM.
06-26-2010, 11:32 PM   #17
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Just tried this with K-7 and 16-50.
AF spot, camera takes advantage of the green beam, still needs some contrast in lit area for focus to work.
AF auto, camera looks for high contrast in the scene, seems to ignore the assist beam!. Maybe someone can confirm this?.
I was shooting at ISO 800, f 2.8 and 1 second = pretty dark.
Also, when using the lens hood, 2/3`s of the assist beam does not even get there.
I am very impressed with AF and higher ISO performance so far.
Hope this helps.

Cheers, Mike.
06-27-2010, 03:18 AM   #18
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First of all, I wouldn't hesitate to use manual focus if the distance to where you are shooting is pretty constant. The other thing is to use AF C, which would allow the camera to fire, even if it isn't positive that it has a lock. Finally, others have complained about their ability of the 16-50 to lock focus. I would hesitate to judge the camera based on that lens -- my 16-50 does pretty well, but it does need some good contrast to lock focus.
07-09-2010, 07:46 AM   #19
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When I do HDRs in extremely low light in very large spaces using a wide angle lens, even the green assist light won't work for me because my 10-20mm Sigma lens is in the way. I have time so what I end up doing is put my Pentax flash on and use the flash's assist light. Lock the focus in, shut the flash off and proceed as usual. Mind you this is an unusual case as what I am photographing doesn't move and I have as much time as I need.

07-09-2010, 11:52 AM   #20
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QuoteOriginally posted by bkpix Quote
I have a K20D and was ready to abandon Pentax because of its poor low light AF. I was missing shot after shot that would be a cinch with my old Canon 20D.

Based on reviews, I got a K7.

Night and day difference. I spent a week on vacation in Las Vegas taking casual shots on the strip in the evening with the K7. No trouble.

Problem solved.
Yes, same here. And when the light is really poor I have my 50 f1.4 lens on.
07-09-2010, 11:54 AM   #21
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QuoteOriginally posted by Marc Sabatella Quote
There are basically two kinds of cameras when it comes to low loght AF: those with AF assist lamps, and those without. Most Canon and Nikon cameras have these, most Pentax cameras do not. The K-7 is the only Pentax camera to have one.

BTW, in the situation describe above, I'd have recommended switching to MF right away and not worrying about it. Awards ceremonies and the like are perfect for MF, because all the action happens in one place, and you can just pre-focus and fire away. I'd say it's better than even the fastest AF system, because you don't have to worry about the camera deciding to focus on the podium instead of the person standing behind it, etc.
Good Point Marc.
07-09-2010, 12:52 PM   #22
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Having both the K20D and the K7, and formerly the K10D, I would definitely say that the K7 AF performs better in low light situations at the cost of a little more noise.
JP
07-11-2010, 06:39 AM   #23
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QuoteOriginally posted by Rondec Quote
First of all, I wouldn't hesitate to use manual focus if the distance to where you are shooting is pretty constant. The other thing is to use AF C, which would allow the camera to fire, even if it isn't positive that it has a lock. Finally, others have complained about their ability of the 16-50 to lock focus. I would hesitate to judge the camera based on that lens -- my 16-50 does pretty well, but it does need some good contrast to lock focus.

I'm not sure if the K7 is the same as the GX20 in terms of focus options, but I got so annoyed with the camera refusing to take a picture if it didn't think it was in focus until I stopped using the shutter release to focus. With the focus purely controlled by the AF button, it no longer cares if it thinks it's in focus or not, whether it is in AC-S or AF-C. It took a while to get used to using the camera like this, but it's made a huge difference to my enjoyment using it.

07-11-2010, 08:05 AM   #24
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The K7 amazes me

I simply shoot away in low light in TAv or M and end up with a lot of shots at ISO 2000 to 3200 that absolutely surprises me when I get home. I only peek now and again but mostly trust the settings....I get so many more shots I like and concentrate on whats haoppening than fiddling with the LCD etc.

I apologise in advance if the picture is too highly compressed but I print to A4 and love the results.

f3.5 1/80 ISO 2500
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07-11-2010, 09:22 AM   #25
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QuoteOriginally posted by georgecape Quote
I simply shoot away in low light in TAv or M and end up with a lot of shots at ISO 2000 to 3200 that absolutely surprises me when I get home. I only peek now and again but mostly trust the settings....I get so many more shots I like and concentrate on whats haoppening than fiddling with the LCD etc.

I apologise in advance if the picture is too highly compressed but I print to A4 and love the results.

f3.5 1/80 ISO 2500
There's several issues going on in this thread, and i'm learning from what others have said, here and there, so thanks for all the contributions.

My experience is from shooting live play productions on stage for promo shots.

Even with the K20, i've found there's a lot you can do to improve one's shooting-

1. I've quoted the above post, because it mirrors what i'm doing. When you allow your camera to go to 3200 and 4000, especially in TAV, i get more successful shots. Why? because shooting higher iso allows one to use smaller apertures, e.g. f3.5 or f4 vice f2.8. Shooting at f2.8 puts a lot more pressure to get focus exactly right. With f3.5, f4 or f5.6, you have way more depth of field than f2.8. In georgecape's pic above, no way would he have been able to get so many people in reasonable focus with f2.8, probably would have been able to choose only one person.

2. I use LR 3 to take the noise out of my 3200 or 4000 shots, gives me the assurance that if i shoot in that range, i can clean them up.

3. Use your AF button to focus with rather than the 1/2 shutter. 1/2 shutter requires the camera to focus for EVERY shot. If you are not changing position, and are able to use a greater DOF as mentioned in 1., focus every once in a awhile with the AF button, and shoot many times without focusing.

4. Humans move. you need some amount of shutter speed to freeze their action or they will still be blurry. Thats why i use SR less and less. It takes time to spool up and if i'm using 1/90, 1/125 or faster for freezing the shot, and use iso3200 in a dark theathre, then i can freeze that human motion, usually.

5. Your Pentax dslr, or any dslr, will use the lenses largest aperture to focus with, only stopping down to your chosen aperture to take the actual image. That's why an f2.8 or even better, an f1.4 lens will focus even in darker conditions. I was out taking pictures of tree branches one night, couldn't get my f2.8 50-135 DA to focus, not enough light to MF, put on my 50 f1.4 and presto, focus achieved.

I'm liking what i hear about the Kx, but my K20 is doing well enough that i'll wait till photokina to see what's around the corner as new models.

I do have one question, the assist light on the K7 doesn't really have much range, does it? I can see where it would help at close range, but in a stage production, i can't imagine that it would be that much more useful. Metz 48 and 58 do have assist lights built into the flashes to help with focusing, that much i know. One could always use the onboard flash as an assist for focusing, except that for my stage work, flashes are prohibited.

Good discussion,
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