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02-01-2012, 07:04 PM   #31
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QuoteOriginally posted by Marc Sabatella Quote
The difference is less than one stop. You can of course get the exact same shutter speed with either f/1.8 or f/2.4, it's just a question of how you want to pay for it. At f/2.4, you pay for it with increased noise (less than a full stop's worth) over what you would get shooting at f/1.8. At f/1.8, you pay for it with shallower DOF than you'd have at f/2.4. Either way, it's not a huge deal - again, less a full stop. But generally for a bill like that, I'd rather pay for it in noise, as I'm not likely to notice the difference except when viewing at 100% on my monitor, whereas the difference in DOF is likely to be noticeable even at web resolution. Of course, in situations where I *want* the shallower DOF, that's all well and good, but I find that's almost never the case shooting telephoto in low light. And to the extent it might be true for certain types of shots - portraits, et - it's going to be almost never true for sports. Shallow DOF will not be your friend.
Everything you said above is true. However in low light it's often that one stop, and also using 1,600 or 3,200 ISO (on the K5 - I'd never use that on the K7), that will make the difference between locking focus or not or having the shutter speed you require or not, especially so in fast moving sports it becomes a case of some sort of shot or no shot at all because the moment has passed.
I've always found f2.8 only really usable in half decent or better light .... as soon as the light dips below an acceptable level for the shutter speed I require then of course the penalty is the low DoF (whether it's sport or birding), fine at say up to 30 yds for a single player but not so good if you want e.g. two jumpers both in focus. I will add a caveat here that I have never shot basketball (though I have shot tennis where this technique works just fine - for a single player) and so my opinion may not be valid in that case since a deeper DoF may be required.

02-01-2012, 08:19 PM   #32
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Buy what you can afford? I personally haven't used a 77mm but love my 70mm!
02-02-2012, 08:44 AM   #33
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QuoteOriginally posted by 8540tomg Quote
It may be a personal thing with me Marc but here is my reasoning for seldom using the K10 beyond ISO 400. I do a lot of birding and tend to crop the images quite a bit. I use a 400mm lens and the depth of field (DOF) with this optic is razor thin. To get reasonable DOF I have to use ISO beyond 400. When I do this, combined with the crop, you really do notice the image degrading.
OK, but now you're talking about a very corner case situation.

As for shooting in the gym again I found the K10 to be wanting. To get resonable depth of field and freeze the action I had to use higher ISOs. Most gyms are quite dim and it is not uncommon to need ISOs of 1600 and higher to freeze the play and get satifactory DOF. Players be it volleyball or basketball are not stationary targets. I just never liked the results I got for indoor sports with the K10.
Of course, I'm not saying there is no difference whatsoever, but it could be instructive to post shots you've taken back to back with the same lens and same exposure settings but two different cameras, or at ISO 400 versus 800 versus 1600 on the same camera. What you see as a significant difference when you have the luxury (or curse) of pixel peeping at 100% is likely to not even be moticed by others. There is also the placebo effect to consider, and the act that you might just be a better photographer now than you once were.

As for the diffeence between concerts and sports, there i no relevant difference here. Either way, we are talking about shooting the same ISO levels, and ISO levels sre all we are talking about. Either it is feasible to shoot ISO 800-1600 or it isn't. I think most of our reluctance comes from excessive pixel peeping, not anything that actually matters.

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