Something wrong with DSLR RAW exposures

Can’t attach fits / raw files here. But there seems to be some serious issues with Canon imaging at least with my 500D. Image taken with exactly the same settings with BackYardEOS show lot’s of stars and other details. With SGP I get only a few stars and mostly noise. RAW header seems to say that exposure time was 1s even though it was 120s on both programs. I seem to have same kind of problems with my QHY Minicam 5F every now and then.

What could be causing this?

Not sure off hand. We do have lots of Cannon users happily using the software though. Take a look here and we’ll see what we can find:

Hi. I’ve actually noticed this as well. I can take an image with BYEOS then disconnect and connect SGP and take an image with the same setting. If I open both raw images in PixInsight the BYEOS image looks relatively clean wrt noise whereas the SGP image is very noisy. Nothing has changed in the imaging train and both images are within seconds of each other.

I’ve had the same problem with mirror lock enabled so the exposure starts when the mirror should open and closes when the exposure should start, it means 3s mirror lock + 60s exposure comes out as a 3s image.
It seems SGP doesn’t support enabling/disabling the mirror lock feature on the camera?

There is also a problem with the mode dial with higher end Canon cameras.
The mode dial can be changed electronically so it doesn’t matter which mode the dial on the camera is set to.

Correct, you need to enable/disable the feature in camera when using the mirror lock timeout.

I’m not sure which cameras you’re referring to but this is not the case on my 6D or 60D. Maybe the 5D or 1D?


6D has this feature, you can test with BackyardEOS.

There is no need to manually enable/disable the mirror lock either as it can be done electronically if the software suports it.
I believe it’s for all newer xD and x0D models so both your cameras should support it.

Sorry, I’m a bit confused. In BYEOS there is a setting to lock or unlock the mirror. I don’t enable mirror lockup. I just checked my Canon 600d and confirmed that my in-camera setting is set to disable. Would there be anything else that might explain the difference in results?



I thought you were referring to the Mode (Bulb, Manual, etc).

Yes, it is possible to query for the Mirror Lock status and set it. But we chose not to with SGP. Unfortunately canon implements this feature different with every camera so it is not a simple setting.


The mode can be changed electronically too just like the mirror lock.

This is a couple great features because it allows the camera to be used remotely without thinking about which mode it’s in and if the mirror lock is enabled or disabled (if it’s implented in the the software of course)

Having these features implented for the most popular models (6D and 60D/a?) would be a good thing since some users trying to move over from other software might have problems since they are used to it being just automatic.
I certainly had a lot of problems when moving from BYE to SGP with the mode dial in a random position and mirror lock off :rage:

I don’t disagree, and the mirror lock has been on our “todo” list for a while (I did not know it was possible to change the Mode via software, so that’s pretty cool!) It’s obvious to see why BYEOS has them (as it’s a dedicated Canon capture application). Unfortunately features that are specific to a single hardware manufacturer generally end up lower in the pile as opposed to features that benefit all SGP users (more automation, better framing tools, better focus metrics, etc)

We may get to it eventually, but I can’t give you a guess as to when.