Is it possible

... to take astro shots with a 1Dmkii? I seem to struggle really badly with noise in low light, and have had a couple of unsuccessful attempts at shooting stars.

Any tips on settings, and/or processing would be more than welcome.


Thanks

Here's an attempt from last night. Forecast was all lies, and the clouds started coming in as soon as we arrived.

IMAGE LINK: http://www.flickr.com …/scott-talbot/9643795231/

beano wrote in post #16258501
Here's an attempt from last night. Forecast was all lies, and the clouds started coming in as soon as we arrived.


Stars Above Surrey Hill by stalb, on Flickr

Still, not a bad shot

Cheers jimmy... Didn't really get time to find a better composition, so had to make do. I'm still trying to get my head round the basics!?! I set the lens to infinity here, but the stars aren't particularly sharp. Not sure if 25 seconds was too long at 17mm? Does anyone know the formula for working that out?
Also. How do you get the stars, and the foreground in focus!?! Do you have to focus stack?

beano wrote in post #16259491
Cheers jimmy... Didn't really get time to find a better composition, so had to make do. I'm still trying to get my head round the basics!?! I set the lens to infinity here, but the stars aren't particularly sharp. Not sure if 25 seconds was too long at 17mm? Does anyone know the formula for working that out?
Also. How do you get the stars, and the foreground in focus!?! Do you have to focus stack?

When you have both stars and a foreground in the frame this typically means you're using a wide angle lens, which has a large DOF, so "typically" being in focus isn't an issue concerning the foreground.
Also most lens will focus past infinity, so you really need to focus carefully. Using live view and 5x or 10x magnification on a bright star or planet will allow you to achieve correct focus, then you can compose your shot and start shooting.

There is a way to find out how long you can expose with a given focal length before you'll see star trails form, this formula will cover full frame and 1.6 crop bodies.

divide 600 by the focal length of the lens = maximum number of seconds before star trails form, for a full frame camera body.

For a crop body first convert the lens to the full frame equivalent; ex. 14mm lens x 1.6 = 22.4mm

600 / 22.4 = 26 seconds

the jimmy wrote in post #16259625
When you have both stars and a foreground in the frame this typically means you're using a wide angle lens, which has a large DOF, so "typically" being in focus isn't an issue concerning the foreground.
Also most lens will focus past infinity, so you really need to focus carefully. Using live view and 5x or 10x magnification on a bright star or planet will allow you to achieve correct focus, then you can compose your shot and start shooting.

There is a way to find out how long you can expose with a given focal length before you'll see star trails form, this formula will cover full frame and 1.6 crop bodies.

divide 600 by the focal length of the lens = maximum number of seconds before star trails form, for a full frame camera body.

For a crop body first convert the lens to the full frame equivalent; ex. 14mm lens x 1.6 = 22.4mm

600 / 22.4 = 26 seconds

Ah! Thanks for the info jimmy!

Not sure how to resolve the focus issue, as I'm shooting with a 17-40, and can't even see the stars, let alone focus on them!?! Live view isn't an option either with the mk2, unless there's a way to do this via laptop, or iPad...?

How about using a Bahtinov Mask. I believe they work pretty well.

Levina de Ruijter wrote in post #16261846
How about using a Bahtinov Mask. I believe they work pretty well.

They work very well but not on short, wide lenses.

For a wide lens, work out the hyperfocal distance for your lens wide open, beforehand. Then make something easy to focus on and put it further than that distance away.
For example, I use a 40D with an 11-16 f/2.8 and a 17-50mm f/2.8.
I just have to remember 3 paces, 5 paces and one street light. If I'm using the 11-16 wide open and at 11mm, I can put a light down, take 3 paces back and focus on that. If I'm using the 17-50 at 50mm, I can focus on a street lamp.

The other technique I use with a 350D is to take a shot, move the focus a little and take another. Zoom right in on the LCD and when you move between shots, the zoom stays the same so you can see if the focus gets better or worse. It usually only takes a few iterations to nail it.

Steve

SteveInNZ wrote in post #16261946
They work very well but not on short, wide lenses.

Ah right. Glad you read it and corrected me!

I should quantify that. In my experience, they are no use at all below about 50mm focal length and between 50-200mm you can do just as well with live-view, zoomed in on a bright star or planet.

SteveInNZ wrote in post #16262902
I should quantify that. In my experience, they are no use at all below about 50mm focal length and between 50-200mm you can do just as well with live-view, zoomed in on a bright star or planet.

There's no live view on a 1D Mk II.

Beano, here is a link to a great website full with info and tutorials. The man behind the website is POTN member A.S.I.G.N. Observatory.
His Profile page: https://photography-on-the.net/forum/member.p​hp?u=159979
His website: http://www.asignobserv​atoryii.com/

Thanks for the tips everyone, much appreciated!

Levina, thank you... I'll check out his site right now.