p.1 #1 · 5DSR on LV completely black but image looks fine?
Currently, I am on top of a small mountain in Norway and just witnessed the aurora for the first time. And it was AMAZING! I was snapping away.
However, I noticed no matter how much light I let into the camera via ISO, SS and aperture, Live View and the viewfinder is pitch black. However, after I snap the picture, the result looks good. The odd part is that I'm adjusting the settings where the final image is more like ISO 800, SS 13 seconds and f/2.4. This make something like composing a shot difficult because I'm just moving the ball head based on an approximation of where I think it should go based on the previous shot.
I am using a 5DSR with the Samyang 14mm f/2.4 lens. I set the camera at ISO 64000, f/2.4 and 30 seconds to see if I can get a clear picture in LV or the viewfinder, but it's pitch black.
p.1 #3 · 5DSR on LV completely black but image looks fine?
I do not have my camera in front of me to check right now, but I think there is a setting called “exposure simulation i” or similar that normally gives you a usefully bright view in dark settings by showing what the exposure will look like rather than the objectively very low light level at night.
It might be worth looking for that setting and making sure that it is turned on.
(The result of it being off would be pretty much the symptoms you describe.)
p.1 #4 · 5DSR on LV completely black but image looks fine?
The answer is fairly simple. A 13 second exposure combines 13 seconds of exposure into a single photo. The screen can't magically bend time to take 13 seconds of light and display it all at once. So the duration is the limitation of the system and it's not physically possible for it to show something which is so dim.
So like gdanmitchell said, you can attempt to fake it by overexposing the image by like 10 stops to see something in the screen, but it's going to be very noisy.
The settings are:
Menu: First menu which is the "camera" icon and is a red colored menu. It's dot / tab number 5. The first option on that tab is "live view shoot." which should be enabled. The very bottom setting is "expo. simulation" which you want set to enable.
EDIT: To add a bit more conversation to this topic:
An EOS 5DS or EOS 5DS R will exhibit exposure simulation failure at any EV less than 2. This is normal behavior. As you note, the EOS R has a significantly lower limit as it can continue exposure simulation all the way down to -4 EV, six stops lower. That is also normal. Sorry, but I am unaware of a technical workaround for your EOS 5DS R, as I am assuming you want to use a live histogram at an EV lower than 2.
It very much sounds like you're well below what the camera could expose properly. To help put it into perspective, think about the LV screen. Let's assume it refreshes at 30fps. that's 1/30 second per frame. So just to get to 1 second exposure, you need to increase the EV by 5 stops. to get to 13 seconds is approx 4 more stops. You would need the camera to somehow increase the brightness by about 9 stops for you to see what the 13 second exposure is if the camera is displaying exposures which are 1/30th of a second. (I would add one way to overcome that would be if the camera were to slow down the screen refresh, so some camera might be able to do like 1/2 second exposures and only refresh the image on the screen twice a second. I don't know if the 5DSr can use exposures that are longer than the screen refresh rate however.)
The highest iso on that camera is only 12800 in expanded mode, which is 4 stops above iso 800. The camera would need to simulate 5 additional stops somehow but can't use ISO, shutter, or aperture to do it. So it's 100% a software simulation if it could do it, but it kind of sounds like at that level the camera simply may not be capable.
