Why you shouldn't use LiveView during exposure on a DSLR.

[StuartJPP]

I know it is common knowledge not to have LiveView enabled during image acquisition but I was testing a battery coupler for my Canon 6D and wanted to max out the current that the camera could possibly draw. (For clarity the same issue below happens with batteries as well).

The image on the left is with LiveView disabled and the one one the right with LiveView enabled, stretched the same amount. Both are 300 second exposures with the lens cap on and the eyepiece covered.

 

Conclusion: Don't do it!

 

[johnfosteruk]

Wowsers, what a difference. Live view kills the battery as well so I can't imagine why anybody would want to do it but you've just sealed the deal I'm sure.

[The Admiral]

Well, I use a mirrorless camera which only works because of live view. I always make a point though, of switching off both the viewfinder and rear LCD displays during an imaging run. I'm not particularly familiar with the detail of DSLR operation, though I realise that DSLRs allow a choice between modes, but is it not a question of the display rather than mode? In other words, is it a question of light leakage from the display or sensor heating that you are seeing?

Ian

[Alien 13]

Interesting, I use mine over wifi for initial focusing with live view but do switch over to a separate remote intervalometer for the run. I wonder how much of the effect is like Ian mentioned  attributed to the sensor vs the display screen and in my case would any further noise be generated by the wifi circuits (these are quite power hungry).

Alan

[StuartJPP]

In response to the above two posts I am not really sure but I suspect it is a combination of heat (largest contribution) and possible light leak from the LCD backlight.

On the 6D, if the rear LCD is left on during bulb exposures the display is totally blank whereas on the 650D there is a countdown timer. The 6D has a small LCD on top of the camera that indicates the count down time.

I will try the same experiment with the 650D which has a flip out display which would tell me if it is light leak or heat...I suspect heat.

Regarding WiFi, I would expect that any extra power usage/dissipation will have some effect but I suppose it depends on where the WiFi chip is located and if it even gets warm.

[pete_l]

There is definitely a huge amount of heat given off by live view.

Even after I had finished using that mode for focusing, the RAWs I took afterwards were terrible. APT reported the temperature at 58°C. I had to leave the camera (1100D) to cool off for a good 20 minutes to get it back down to ambient.

[The Admiral]

22 minutes ago, pete_l said:

There is definitely a huge amount of heat given off by live view.

Even after I had finished using that mode for focusing, the RAWs I took afterwards were terrible. APT reported the temperature at 58°C. I had to leave the camera (1100D) to cool off for a good 20 minutes to get it back down to ambient.

There is a lot of heat, and my back LCD is at least flip-out so I generally keep that away from the camera body. That's useful anyway because the 'scope is pointed upwards so viewing the screen becomes more ergonomic. And of course, the fact that a screen is black doesn't mean that the back-light is off, though when I switch mine off, I think they are, because I get a decent run-time from a battery charge. With mirrorless cameras the viewfinder lcd also needs to be off.

Ian

[Alien 13]

It sounds like I might need to experiment with various scenarios, on the flip out screen models the LCD can be flipped so its facing the camera and permanently off but can still be tethered (cable or wifi if available) to show remote live view screen.

Alan

[sharkmelley]

It's a known issue on the Canon 6D though the exact cause seems to be a matter of debate.  In any case, the solution appears to be to switch off liveview and/or silent shooting:

https://www.cloudynights.com/topic/466027-filter-mod-eos-6d-extraneous-signal-in-live-view/

https://www.cloudynights.com/topic/545012-weird-bloom-problem-canon-6d-and-astronomik-uvir-clip-filter/

Mark

[Stub Mandrel]

My 450D will show a seconds-count if you let it, I always switch it off to max battery life, I now realise I'm also reducing noise.

[Chris]

Wow, it's particularly profound on the 6D isn't it! 

[StuartJPP]

On the 650D it is definitely amp glow/heating caused by LiveView being on, not by light leak.

The left hand image is with LiveView and LCD turned off and the one on the right is with the LCD on (with countdown timer) with the LCD up against the body. I did the same with the LCD flipped out away from the body and covered and the result was the same.

Both images are 5 minute exposures and stretched the same amount.

 

[StuartJPP]

And for completion, the same test sequence with an unmodified Canon 5D Mark III. Left hand image with LiveView off, right hand image with LiveView on. Again, stretched the same amount with 5 minute exposures.

[Tommohawk]

Hmmm. got me thinking. Been while since I did DSOs with the DSLR but cant remember what I do with Live view. I use EOS utilities on laptop to control and I think I must turn it off once imaging, but whether that turns off the liveview on the camera I'm not sure. Need to have a play with this and see!

Thanks for the heads up

[stash_old]

Stuart ,

You say liveview but what about the standard item you see when connect remotely (via the USB a nice PC  logo ) surely its any use of the LCD (power being used so causes heat ) or have I missed something here. APT switches liveview off (or so I thought) when you connect remotely unless you ask APT  for a Liveview which I think (as I have never tried) it will not take exposures while Liveview is enabled. I know there is a setting on the camera to switch off after x secs which I use to safe battery when I used my canon 100d for normal daylight images.