Originally posted by voicelit Why SV or Tav for action photos when manual recommends TV ? Also, it seems you can't just set ISO - say in the SV dial mode - then go to other dial mode like AV and keep the same ISO setting ?
Marty,
TAv (shutter AND aperture priority) mode is one of the K10D's peculiar excellences. I am extremely fond of this feature.
When should you use TAv rather than simply Tv (shutter priority) or Av (aperture priority)? When you want to set BOTH the shutter speed and the aperture -- and you want the camera to give you a technically correct exposure by adjusting only the ISO. And you would want to set both the aperture and the shutter speed manually when both of them matter to you.
If you're shooting action in bright sunlight, and your main concern simply is to freeze the action, you could use Tv mode and set the shutter speed to, say, 1/1000th sec. The camera will then adjust the aperture to give you a good exposure. The ISO in this case probably gets left alone, unless it's absolutely needed.
If you're shooting, say, a portrait, with your subject sitting still, and you care most about depth of field, you might use Av (shutter priority) mode to set a wide aperture like f/4, and let the camera calculate the right shutter speed for a correct exposure.
But sometimes, especially if the light isn't good, you want to manually set the aperture wide open AND you don't want the shutter speed to go below a certain speed, so you use TAv and set 'em both manually; and the K10D will do its best to give you a correct exposure by adjusting the ISO. Note that you can set the range within which the ISO is adjustable and if the camera can't get a good exposure in that range, well, you're out of luck. I use TAv quite a bit when shooting indoor school sports, because the lighting in the gyms is bad and quite variable. If it weren't variable, I'd just use M mode, which is where I shoot almost all the rest of the time. But if I'm shooting volleyball, simply changing the direction my camera is pointing from here to there may cause me to move from a relatively bright spot in the gym to a relatively dark spot (or vice versa). In TAv mode, the camera will instantly adjust the ISO for me.
NOTE: NOTHING solves the problem of shooting in the dark. You could try getting a faster lens (one with an aperture that goes to f/2.8 or f/2 or f/1.4). Or you could buy a Nikon D3 which seems to able to produce good captures at spectacularly high ISO settings like 30,000 (seriously) -- but note that the Nikon D3 goes for $5000 and there's a very long wait. ;-)
Quote: Auto focus seems to struggle at night even with flash ? Too dark to focus ? I'll learn.
How well do
you see in the dark? Auto-focus depends on contrast. As the scene gets darker and darker, contrast drops, and when contrast drops to a certain level, the camera's auto-focus starts to struggle -- or fails completely. Using flash doesn't automatically make auto-focus any easier, as the flash fires when the shutter is tripped, but the camera needs to focus before the shutter is tripped. Some flash units have a focus-assist lamp that shines a little bit of light before the actual exposure, to help enhance the contrast. I shoot so seldom with the K10D's built-in flash that I can't remember if it has this feature or not, and it's bright afternoon here so hard for me to test. My Pentax AF 540 FGZ detachable flash unit does have focus adjust that works tolerably well.
But as I said, cameras just don't work too well in the dark!
Will