08-11-2013 12:29 AM
When taking lacrosse and football photos, I prefer to set Canon 6D to TV mode using 1/500 or 1/640 with appropriate ISO for time of day or night. In the Spring in late afternoon / early evening games. After having no problems for say first 100 photos, the camera in TV mode starts setting aperture too high (say 9, when just before was 4.5 in identical light), thereby creating photos that are way too dark. I shoot with sun behind me, so the natural light is pretty consistent, while the aperture selected automatically in TV mode jumps around wildly.
To avoid missing too many shots when this occurs, I move to Manual mode, keep speed at 1/500 or 1/640, and set aperture to correct number. I'd prefer camera do the work while I zoom in and out. and as the sun begins to set.
I never had this problem with other Canon DSLR's. Also, the camera behaves once it's totally dark and I'm depending on stadium lights.
Am using Canon 6D with Canon 70-200 mm EF IS II USM.
08-11-2013 08:26 AM
2 thoughts come to mind. Are you acidently changing the exposure compensation & if not you might want to try a different metering mode.
08-11-2013 10:50 AM
My guess if you've dialed down exposure compensation as well... and it's easy to do accidentally.
In Tv mode, the front dial (by the shutter button) controls your shutter speed, but the rear dial controls "exposure compensation". The rear dial will only be active to do this when the camera meters the exposure... e.g. half-press the shutter button and then turn the rear dial to adjust exposure compensation. The rear dial also controls exposure compensation in P and Av modes as well.
You can see if you've done this by looking at the meter either on the top LCD or through the viewfinder. In Tv or Av mode, the arrow normally points to the center mark if exposure compensation has not been adjusted. (this is the scale that shows -3..2..1..|..1..2..+3 )
You can also adjust exposure compensation via the rear LCD by pressing the [Q] button and navigating to the -3..2..1..0..1..2..+3 scale and then pressing the 'Set' button and it'll let you change the compensation.
The center position on the scale means you want to use the exposure recommended by the meter. But you would want to use exposure compensation in situations where you realize the meter is unlikely to be accurate. Camera's use a light meter that measures reflected light coming off the subject. A hand-held (aka "incident" light meter) measures light falling on the subject (you actually walk up to the subject, hold the meter in front of them/it and take the reading while standing in the subject light). An incident meter is extremely accurate becuase it's measuring the light itself... not a reflecttion of the light. A reflected meter is subject to the fact that some subjects will reflect more light back to the camera than others. E.g. a "white" subject reflects significantly more light than a "black" subject.) Hence cameras tend to attempt to overexpose when shooting scenes dominated by dark or black objects and they tend to underexpose when shooting scenes dominated by mostly white or light objects. The compensation control allows you to tell the computer that want it to shoot for an exposure darker or brighter than what the meter believes is needed.
08-15-2013 07:57 PM
08-16-2013 12:37 AM
But the linked article says the 6D is fine... apparently a damaged D600 was over-exposing and in comparison they thought it was the 6D under-exposing.
I always have a _very_ hard time believing a modern camera would under-expose or over-expose with correct settings. Canon has been at this a while and that'd be a fairly rookie mistake they aren't likely to make. It's also _very_ easy to properly test the camera.
08-16-2013 10:43 AM
I read that article before purchasing mine and had some concerns, but I find mine to be within reason. I consider perfect exposure to be a bit subjective though, give or take 1/3 stop. Especially if you like to shoot dark and contrasty compositions.
The major difference for me, coming from a Rebel, was that I used to keep my rebel -1/3 exposure if shooting Av/Tv, because I found it to overexpose. I did it out of habit with my 6D at first until I learned it didn't need it. I think the difference was actually the viewfinder and LCD display. The 6D displays are much brighter, so you see more of the shadows. With the Rebel it always looked dark so I thought I needed to expose more, but it was actually fine.
08-16-2013 02:39 PM
I put an expo-disc (for white balance) on the lens and take a picture. According to Expoimaging, the disc is supposed to a neutral grey exposure. If I use automatic setting on Canon, I would not get the histogram spike in the middle. It is toward the left. But I shoot manual all the time so it has not been a problem to me yet. Just find it's interesting.
08-18-2013 07:36 PM
Thanks very much for response. Typically I have no exposure compensation; sometimes I add 1/3. I rarely change more than once during a game.
Based on your suggestion, I checked metering mode and discovered I had it in Spot Metering rather than in Evaluative Metering. Have reset it to Evaluative to see if that helps this Friday evening during football opener. The early light will be similar to when I had this problem in Spring.
Someone else had asked about what meter is doing in view finder. When this problem is occurring in TV mode, the meter is screaming back and forth between -3 and +3 like a ping pong ball in a lotto cage! Just took it outside now on an overcast evening and it is steady as a rock in TV mode. Problem only occurs in really bright late afternoon (probably early AM too) light.
08-18-2013 07:40 PM
Thanks, Tim. Am familiar with the compensation control and am definitely not moving it. Typically I have no exposure compensation; sometimes I add 1/3. I rarely change more than once during a game.
Am going to set camera on Evaluative Metering. At some point I put it on Spot Metering; perhaps that is contributing to problem.
When this problem is occurring in TV mode, the meter is screaming back and forth between -3 and +3 like a ping pong ball in a lotto cage!