Camera and Tripod on the night Sky

[Stu Ward]

Last night was clear !!!
First time for what seems like ages

So I took out the dob, but also my new 550D on a tripod, thinking i might be able to get some nice widefield shots with semi-longish exposures

What i fail to understand is how i set the focus when you cannot see through liveview or the viewfinder clearly

Are there any hints, tips or tricks to this ?

Thanks

Stu

[Chancellor (Jeff)]

You should generally be able to get rough focus by pointing to a bright star and looking through the viewfinder. After that, try with liveview on the same star. I have been able to get reasonable focus by doing this.

When you think that you have focus set pretty well, take a few shorter exposures and play with the focus a little, checking if focus is getting better or worse between shots.

Other than that, if you have a laptop there is a test photo option in the EOS utility software which works very well. Use the laptop to control the camera and view the images directly on the screen. It's MUCH easier to get good focus while you are viewing images directly on the laptop.

[Octane (Humayun)]

As an adjunct to Jeff's advice, tether the camera to the laptop, load up EOS Utility, and go into Remote Shooting Live View mode.

Place a bright star (like Sirius) in the centre of the frame, set the lens to AF (auto focus) and within the Live View controls, you can use the focus utility to nudge the focus in and out, with varying degrees of coarseness.

It depends on the lenses you're using; if it's the cheapy plastic kit lens, you will see loads of chromatic aberration. What you want to do is continue nudging the focus until you get rid of either the blue or the red fringing around the star. One of the two is going to be worse than the other, so, keep playing until you minimise the fringing.

Once you've reached an acceptable level of focus, make sure you set the lens back to MF (manual focus).

That should get you in good enough focus for widefields.

H

[Rob_K]

There's a very low-tech solution if you're willing to score your lenses. Only tiny marks - all my lenses are scored for focus at the various widefield zooms I use. If you can auto-focus on a bright object like the Moon, this will also be good focus at widefield (say, 18mm up to 50mm)for the starry background. At a tighter zoom of say 200mm you can auto-focus on the brightest stars (the very brightest) or planets, using the centre focus box. I used a Stanley knife to do the score marks - a bright LED light shone sideways across the scores will enable precise alignment using manual focus.

Simple but effective, but I would bet that a lot of people would regard this as sacrilege!

Cheers -

[Stu Ward]

This was my Lowest Tech Effort.
I had just bought my 550D for a holiday in Nelligen.

Well the skies were just amazing, so i thought what the hell lets have a go.
All i had to lean on was my mates Ford Territory roof. Pressed the shutter and button held my breath and hoped i didn't wobble

Please don't zoom in, cause the stars aint points lol .

[dannat (Daniel)]

You could focus at twilight, download then check
Phil H had a small marker arro on his tak focuser - same idea as rob's just not as damging
Stu that shots not so bad - why is the foreground so lit up?

Where is nelligen?

[Stu Ward]

Nelligen is near Batemans Bay NSW.
We were at a campsite so very little light pollution.
The glow in the background is Batemans the foreground I assumed was just light gathering at 30 secs exp ?