7D won't focus and fire.
Jan 22, 2013 09:53:24 #
shutterbug64
Loc: Colorado
It won't focus most of the time when I'm in the studio testing, no shots taken, focusing on background & it won't fire. I don't know if it's the background, low light, low contrast, ?, I point it at background light and it fires. When my subject is there, it fires. Have had it do it in critical situations, usually low light.?? Almost like it needs good contrast to focus on or I don't have a setting correct. Any help.
Jan 22, 2013 10:31:15 #
shutterbug64 wrote:
It won't focus most of the time when I'm in the studio testing, no shots taken, focusing on background & it won't fire. I don't know if it's the background, low light, low contrast, ?, I point it at background light and it fires. When my subject is there, it fires. Have had it do it in critical situations, usually low light.?? Almost like it needs good contrast to focus on or I don't have a setting correct. Any help.
Every current auto-focus camera I know of requires a reasonably contrasty target upon which to focus. The focusing mechanism is essentially measuring contrast. When the camera is in focus, the contrast is maximum. Your camera simply cannot find enough contrast in any part of your plain background. Do not blame the camera for your bad technique.
I tend to use manual focus more often, but when I use auto, I try to focus on something with good contrast, like a door frame or window edge.
Jan 22, 2013 10:37:17 #
Jan 22, 2013 12:21:12 #
When testing, use a foam head, chair, etc in front of the background.
This will also help with general positioning of the lights, etc also.
This will also help with general positioning of the lights, etc also.
Jan 22, 2013 12:44:08 #
shutterbug64 wrote:
It won't focus most of the time when I'm in the studio testing, no shots taken, focusing on background & it won't fire. I don't know if it's the background, low light, low contrast, ?, I point it at background light and it fires. When my subject is there, it fires. Have had it do it in critical situations, usually low light.?? Almost like it needs good contrast to focus on or I don't have a setting correct. Any help.
Modern cameras use contrast to autofocus. To prove this, aim your camera at a piece of plain white paper and fill the screen. The lens will hunt and if you achieve focus you are lucky. Now take a marker and make a single line across the paper then try again. Your lens will snap to and focus every time. Contrast and light...
Jan 22, 2013 14:10:05 #
shutterbug64
Loc: Colorado
Thanks everyone. This all helped. I have one of those pop out fabric disc with white/bullseye on one side and grey on the other and was having trouble with even that focusing on the crosshairs on the material. My 5D works great on it. The videos site really helped. 45 years of professional photography and still learning.
Jan 23, 2013 08:04:29 #
shutterbug64 wrote:
It won't focus most of the time when I'm in the studio testing, no shots taken, focusing on background & it won't fire. I don't know if it's the background, low light, low contrast, ?, I point it at background light and it fires. When my subject is there, it fires. Have had it do it in critical situations, usually low light.?? Almost like it needs good contrast to focus on or I don't have a setting correct. Any help.
This isn't related to the focusing, but most cameras have the option of shooting when you push the shutter button, even if it's not in focus. Otherwise, if it can't get good focus, you can't shoot. I prefer to get the shot, even if the focus isn't perfect, depending on the situation.
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