Problem with Exposure in Aperture Mode

[Josh66]

I called canon technical support. She tried a 6D and 7D and got similar results. I may start a post in the canon forum and ask for people to try a specific setting on their cameras and see what the results are on various models. It seems to be a failure of the camera to be able to expose properly in extreme conditions...

If a Canon rep was able to reproduce the problem on two separate cameras, I'd say it's pretty clear that it's an issue with the camera, and not something that you're doing wrong...

I wonder how long they've known about it, lol - you can't be the first one to notice it... Are you using the latest firmware?

If you have updated the firmware, did you ever notice this issue before that?

 

[RxForB3]

I do have the latest firmware. I hadn't noticed the problem before, but that doesn't mean it wasn't there. The rep had the same issue with a 7D, but at least one person I spoke with had no problems with a Mark III and I don't recall and issue like this on my t3i. It certainly makes time lapses more difficult...

 

[Josh66]

It might be worth installing the old firmware, just to see if that fixes the problem - it could just be a bug in the latest firmware. Just an idea ... I kinda doubt it will work, but it's worth trying.

 

[TCampbell]

I'm doing landscapes with individual stars, not star trails. I do use a tripod, but in order to avoid trails, you use shorter shutter speeds.

I can get 40 seconds at ISO 1600, f/2.8 at 14mm. At 60 seconds I can see the trails are just starting to grow... so I back it off a bit. How long you can hold the shutter open before you start to see trails depends on the focal length of your lens. Very wide lenses can go long... narrower angles of view will very quickly get trails.

 

[RxForB3]

Correct. I'm using a 24mm, generally, so by the "rule of 500," 25 is a bit over. If you use 600 as is sometimes recommended, 25 seconds is perfect...all depends, also, on how picky you want to be about your stars. But that's not what my problem is...