Advice needed : Perseid photography

[+bryand]

I now have a super-wide lens for my mirrorless Canon, along with an intervalometer.  I am keen to try for some Perseid photos and would welcome suggestions or recomendations for getting good contrasty pics, e.g. the best ISO to use (or how to find out what the optimum is); exposure length for static or skytracker mounted camera etc.

If we had some decent skies, I could experiment for myself, but weather doesn't look promising this week.

 

[+Graham]

A good starting point would be 30 second exposures at ISO 1600 

[Clive]

It depends on how much light polution you have and f stop of your lens. From my bortle 5/6 sky the maximum exposure at ISO1600 with my wide-angle lens is about 60sec at f4.5 before the light pollution becomes a serious problem.

[+Bino-viewer]

I find to do a 30 sec exposure from home (without filters) i need to be shooting at f/8 or narrower

 

If i tried to do a 30 sec exposure with the lens wide open at f2.8 at iso 1600

here the result would be pure white. Bortle 7 here. 

[+bryand]

Thanks for the help guys.  I finally managed to get out for a play tonight.  Looks like 10 seconds is the longest I can get away with on a statically-mounted camera:

Nice to be able to pick out the Double Double with a 12 mm lens.

 

[Clive]

11 hours ago, bryand said:

... Looks like 10 seconds is the longest I can get away with on a statically-mounted camera ...

 

 

I don't know how long your canera needs between images so that can it save to the memory card but if it's any thing like mine I have to set the intervalometer for a gap of 5 sec which would be half your imaging time (and you can guess when a meteor will cross your field of view!)

[8472]

What specific Canon do you own, as many models tend to be ISO-variant?

 

I tend to use Photonstophotos website to determine the best ISO settings for any given camera. Lots of invaluable info there.

 

Kev

 

 

Edited August 5, 2021 by 8472

[+bryand]

Hi Kev,

I have both an M10 with its filters removed and an unmodified M6, which is a close relative of the EOS 77D.

l’ve looked at the site you suggest, but l’m not clear which data I need.

[8472]

I tend to look at the Input-referred Read Noise versus ISO Setting link first, Bryan.

 

Sadly, it appears Bill hasn't got round to testing the EOS M10 yet, but the 77D and M6 are shown below.

 

https://www.photonstophotos.net/Charts/RN_e.htm#Canon EOS 77D_14,Canon EOS M6_14

 

If you click on the graph's key, It will display all tested values throughout each camera's ISO range. 

 

For stacked DSO AP, I tend to look for read noise values at around 3 electrons or below, whilst balacing it against the the highest dynamic range value available (here called Engineering DR (EV)).

 

So by that measure, ISO 400 might be worth trying (~3.5e- of read noise, 11 stops of dynamic range). Shooting at ISO 1600 only drops just over half an electron in read noise, but you will lose nearly 2 stops of dynamic range (thus crushing star colour and blowing out cores faster) and also quartering your well depth.

 

This is only my take, so YMMV.

 

Astro-landscape imaging takes a different approach altogether.

 

Regards,

 

Kev

 

 

 

[+bryand]

That’s fascinating because my tests last night led me to the conclusion that ISO 400 would be a good compromise on my M6.

Nice when a plan come together…

[+RonC]

I set my Canon 1100 up tonight for a practise run,  ISO 800  45s at f4 seems to work for me.

I'll be fitting a dew band tomorrow as it seems a very dewy night tonight!!

 

Ron

Edited August 8, 2021 by RonC

[Guest]

Sorry I didn't see this thread until now! Using an intervalometer, there are always sporadic meteors about, so I average close to one per hour.

 

I would advise against 30 second exposures, as satellite trails look similar to meteor trails. I also find that many meteors appear faint, or are missed completely. Through trial and error, I have arrived at 18mm focal length (any shorter and the meteor trails appear too short), ISO 6400 and 6 seconds exposure. It takes 6 seconds to save the photo to memory card, so I miss about half the meteors.

 

The only snag is that I can only record 399 exposures, so need to reset the intervalometer after about 80 minutes. My battery usually runs out after 3-4 hours.