Dslr AV vs M

[Simon Dunsmore]

Hi Folks, 

Hoping for a little help. I'm just trying to get my head around shooting flats with a dslr through my telescope. I have a light pad with a dimable led. I've read it's best to use AV mode and let the camera select the correct exposure but I've also read its best to use Manual. Bit confused here, which do I use and is it best to dim/ brighten the light on the pad or reduce/lengthen the shutter speed? 

If I understand this correctly, I'm looking for the histogram to be somewhere in the middle right? 

Thanks for your help 

A baffled would be Astrophotographer

Simon 

[michael8554]

I've always used AV on a Canon DSLR, with the light panel dimmed to produce exposures of around 1 second.

If very fast exposures are used because the panel is too bright, the shutter can leave a shadow.

The LCD on DSLRs shows a pseudo JPG display of a Raw, with the histogram at 50% on AV setting.

If the Raw was displayed it would be very dark due to lack of the gamma correction that occurs in processing.

With dedicated Astro cameras I believe the exposure is set to 50% of max ADU for Flats.

So depending on the software used for viewing that image, it may have a histogram way to the left, or at 50%.

Michael

Edited March 26, 2021 by michael8554

[alacant]

17 hours ago, Simon Dunsmore said:

best to use AV mode

Hi

Imaging apps like M:)

Find the exposure using Av, then switch to M and dial the same settings into your imaging app or intervalometer or WHY. 

HTH