Blackmagic Forum

Hi Blackmagic folks!

I am planning to use a 5D Mark IV to record a ~2 hour lecture. I know there is a 30-minute internal recording limit, which is why I am interested in the BM Video Assist product.

The issue that I am running into is that after about 35 minutes outputting to HDMI in movie mode, the LCD screen goes black and displays "Press START STOP button to activate movie shooting." I've tried this twice, both times using a Canon 17-40 f/4 L lens.

This seems like it would preclude me from using the BM Video Assist product to record the HDMI stream for 2 hours...

Any advice or suggestions? Is there a way around this?

I learned that the way to get around this is to simply press a button on the camera every so often to keep it awake. Pressing "Rate" every 20 minutes seemed to do the trick.

Can anyone think of a way to do this that won't jostle the camera? some sort of external remote perhaps?

The reason the Canon shuts down after 20-min, is it will overheat the sensor at or after 30 to 40 min., so a Canon DSLR (or most DSLRs) is not the camera to use to record a long event, like your 2-hr lecture. I tried this with a Nikon D7100, same issue, even forcing the camera bsckmin right after it shut down, resulted in it overheating a turning off 10-min. later. I would suggest getting a video camera to shoot your 2-hr lecture, youmwill get better results,

Thanks, Denny!

For what it's worth, I was able to keep it going for a couple of hours without it shutting down. But point taken: this might not work consistently or in a warm room, for instance.

Indeed.. DSLR's are not for long recordings.. The sensor heats up very quickly and does not have the decent cooling to run it like that for hours..

You are reducing the lifetime of your DSLR quick in this way and you will notish that after a few times recording longer than recommended that pixels will fail.. (Dead pixels / hotpixels) Sending it in for repair under waranty will not go as planned.. The repair centers can read out the internal memory and they can see that you kept it in movie mode longer then recomended.. Also they can see temperature peaks.. So they will decide quickly that it is user error and you will be billed for the whole price of a sensor replacement..

So buy a cheap HD handycam and you will be better off..

Xtreemtec wrote:So buy a cheap HD handycam and you will be better off..

You beat me to it. That's exactly what I'd recommend, too. People expect too much from D-SLRs.