Post-modification issues with Canon 6d - has anyone had this?

[Dezerker]

Hi All,

I recently had my Canon 6d astro-modified.  There is now a considerable issue with the images (amp glow / light leak?) - but only when live view is turned on when the image started.

I use live view because it locks up the mirror - something my ASIair (the original model) cannot currently do.  Not using live view means that shutter vibrations spoil more subs.

Has anyone else experienced this?  Wondering if anyone found a fix other than 'don't use live view'?  Dark frames don't seem to fully combat the glow...

Any advice would be great!

Image of typical sub and dark frame when using live view:

 

 

[Alien 13]

Cant help with the amp glow but you can enable the mirror lock in menu and use it in combination with the self timer function, this locks the mirror up and starts the required sub length after a few seconds with a single trigger pulse (assuming you are using the remote shutter port).

Alan

[TakMan]

Could this be light leak from the viewfinder..? With my old Nikon D3, there is a manual shutter on the viewfinder to stop that when working remotely (so your face isn’t a natural light shield).

Worth a dark frame test with and without a home made cover on the back to see if that helps…

Damian

[Dezerker]

50 minutes ago, Alien 13 said:

Cant help with the amp glow but you can enable the mirror lock in menu and use it in combination with the self timer function, this locks the mirror up and starts the required sub length after a few seconds with a single trigger pulse (assuming you are using the remote shutter port).

Alan

Thanks Alan - I just hadn't thought to use the lock-up function along with the self-timer!  Just tested and it seems to work.  Brilliant!  So regardless of the countdown I set on the ASIair, the pulse it then sends triggers the mirror lock-up and starts in-camera countdown on the camera.  Thankfully the ASIair doesn't register that the actual exposure doesn't start straight away, so despite the (completely inconsequential) side-effect of having 298s exposures rather than 300, this might do the trick!

Fabulous!  Clear skies are forecast tonight (though currently the sky is white, rather than blue) so I'll give this a proper test.  Many thanks again, Alan.

[Dezerker]

58 minutes ago, TakMan said:

Could this be light leak from the viewfinder..? With my old Nikon D3, there is a manual shutter on the viewfinder to stop that when working remotely (so your face isn’t a natural light shield).

Worth a dark frame test with and without a home made cover on the back to see if that helps…

Damian

Thanks for this, Damian. 

I've had a look at this as I'd read it could be a thing, and the pattern on the dark frame seems way more 'structured' than some of the amp-glow effects I've found on my search of the internet. 

Spent a fun half hour in the cupboard trying different variations of covering the viewfinder, and preventing the light from the LED on the back of the camera getting in.  The glow doesn't seem to be getting in through the viewfinder, so I think it must be something in-camera, but many thanks for the sense-check though.

[Alien 13]

13 minutes ago, Dezerker said:

Thanks Alan - I just hadn't thought to use the lock-up function along with the self-timer!  Just tested and it seems to work.  Brilliant!  So regardless of the countdown I set on the ASIair, the pulse it then sends triggers the mirror lock-up and starts in-camera countdown on the camera.  Thankfully the ASIair doesn't register that the actual exposure doesn't start straight away, so despite the (completely inconsequential) side-effect of having 298s exposures rather than 300, this might do the trick!

Fabulous!  Clear skies are forecast tonight (though currently the sky is white, rather than blue) so I'll give this a proper test.  Many thanks again, Alan.

I use this function all the time with a std intervalometer, the few seconds delay due to the self timer allows for the mirror slap to dissipate anyway so no bad thing plus you can always add this delay onto your chosen exposure timings.

Alan

Edited June 21, 2022 by Alien 13

[david_taurus83]

Live view adds significant thermal noise to the sensor. It really needs to be kept to a minimum if possible as you haven't got the luxury of a cooled sensor. I even avoid it for focusing and use single snapshots instead. If mirror lockup works with the ASI Air then great! I can tell you my old 600D mirror action was a lot louder and stronger than the 6D action. I don't use any lock up feature with it and I don't get any spoiled subs.

[StuartJPP]

A bit late to this but this is what I found regarding live-view usage in the 6D.

Pretty similar image as to what you got.

 

 

Edited June 30, 2022 by StuartJPP

[Dezerker]

On 22/06/2022 at 11:25, david_taurus83 said:

Live view adds significant thermal noise to the sensor. It really needs to be kept to a minimum if possible as you haven't got the luxury of a cooled sensor. I even avoid it for focusing and use single snapshots instead. If mirror lockup works with the ASI Air then great! I can tell you my old 600D mirror action was a lot louder and stronger than the 6D action. I don't use any lock up feature with it and I don't get any spoiled subs.

Thanks David (and sorry for the slow reply), it's confusing and fascinating, I've never had a problem with live view on the 6d before the modification.  I've done 20 minute exposures with live view on the 6d and the noise is still low enough to present single frames as respectable images on their own.  It led me to wonder if this was a light leak (either previously contained by the now-removed filter or where something had gone wrong with the mod), but then I wasn't sure how you tell the difference between thermal noise and a light leak!

And yes I have an old 600d too and it feels like it gives a heck of a kick compared to the 6d!  It's significant enough to see a spike in the guiding for me, though thankfully with the mirror lockup and timer delay used together, the ASI Air seems to have time to recover the guiding before the exposure starts, which is a relief!

[Dezerker]

On 30/06/2022 at 01:40, StuartJPP said:

A bit late to this but this is what I found regarding live-view usage in the 6D.

Pretty similar image as to what you got.

 

 

Thanks Stuart (and sorry for the slow reply) - really interesting to see, and helpful to see SharkMelley's response and links too.  Was your 6d modded?  I had no issues with live view prior to the modding, even 20 minute subs looked respectable (in cool weather at least), so was pretty alarmed when I saw that glow appear even on 30 second subs with live view on after modding.

Like you I was pondering whether it was heat or light-leak.  I'd assumed light, as I couldn't imagine how having a filter removed through astro-modifying it would suddenly affect the thermal noise, but unlike Mark I'm not sure I have the guts to bust the 6d open again and investigate possible light sources!  I'll stick with turning off live view from here on!

Thanks for sharing - it's super-helpful to hear others experiences and what they've learned!

[StuartJPP]

I'm almost certain that the 6D would have been modified when I took these images.

Light leak could be a cause but not sure, there's definitely more heat generated with live-view so was assuming that was the cause.

Besides I always image with live-view off, so it is almost immaterial what the root cause is.

[Alien 13]

If your sensor is more sensitive to heat it might be worth while moving the battery from inside the camera to a battery grip too..

Alan

Edited July 12, 2022 by Alien 13