There are enough things to improve in Canon EOS 5D Mark III (5D3 for short), things which we hope (one can dream...) that will be improved in the next firmware update coming in April. (one can dream - again...)
Well, it is known that nowadays the market's opinion is that Canon lags in sensor tech and not only (no flame wars please, thank you) - effect which was "achieved" by disputable strategy in R & D and pricing.
In this situation, one of the most effective ways to improve the things is through firmware. Hence, I will try - I hope that I'll succed - to post (in different posts) some problems which I've found in the 5D3's firmware.
First, which is one of the simplest ones - is that when one enters in at least one of the custom modes (C1,C2,C3) by rotating the dial, the LiveView screen starts to lit even if it doesn't display anything. And since this, this dim light appears at least every time when one engages the AF subsystem (IIRC it appears also in other situations but I don't have now at hand use cases to give the steps). And this phenomenon happens if one goes away from custom modes to M, Av, Tv, P etc. In order to stop it, you should close and reopen the camera.
Steps to reproduce:
1. Open the camera and keep it in a place with very low light (for example under the desk)
2. (If you haven't done it already) save some settings in C1 custom more (the same applies for C2 and C3)
3. (optional) Close and reopen the camera
4. Change the custom mode C1 to (let's say) Av (the same applies for M, Tv, B, P and Auto).
5. In your low-light-place of choice (wedding, riot, war zone, under the desk...) half-press the shutter in order to engage the AF.
Expected: The LiveView should remain as is. (inactive, closed)
Actual: The LiveView start to lit with a light which is clearly distinguishable in the dark environment.
1. Am I the only one who's seen this?
2. If not - can I avoid this except by rebooting the camera?
3. If not - can be fixed somehow?
After testing this on our own EOS 5D Mark III camera bodies, we did not experience the same issue you are describing, but we think we may have an idea what you are seeing. When the camera powers up, the LCD powers on for the sensor cleaning and to display a message if no card is in the camera. Aside from this, Live View Shooting will only start if it is started by the user, not on its own.
If this is a time sensitive-matter, additional support options are available at Contact Us.
First of all, thanks a lot for your response!
I'm aware about the "sensor cleaning" message. However I'm speaking about another thing.
I've uploaded a video at http://we.tl/LkKepKqtW1 showing the phenomenon.
The video is in AVI format, shoot (with a Nikon - sorry! <big sheepish green>) in a dark place (my office in the morning with the light turned off) in order to make the LCD behavior more clearer.
The file is compressed with 7-zip. Please use the freeware 7-ZIp Manager from www.7-zip.org or any other similar program to unpack it.
You can see the movie with the default media player(s) of your OSes but I'd recommend VLC (www.videolan.org/vlc/index.html) which renders way better the video showing much more clearer what happens on LCD, compared with Windows Media Player from Win7 (where I tested it) - sorry I don't have a Mac handy now. Also, is better to have some working speakers in order to hear "the narrator" (ok, myself).
I think that it is clear that the LiveView opens at different light intensities, if the camera enters at least once in at least one from C1, C2 or C3 modes.
If you need any further clarifications I'm at your disposition.