Star trails.. sorta.

[Nocturnus]

So while I was out camping this weekend, I gave it a try. Set the lens to Manual and set focus to infinity. Tried some test shots at different apertures. It seemed that all my pictures were out of focus. No nice little pin points of light. Longest exposure was a 30 second one. I'll get an example up later.

Was I correct in setting focus to infiinity?

[The Philos]

Tripod and MLU I assume?

[Nocturnus]

Tripod. I forgot MLU. I was also going past the mark for infinity on the lens. Seems I should of stopped at the mark before the sign. I'll be trying this again in a few weeks and will need to remember MLU along with a few other things.

[The Loft Studios]

You don't want to really set you focus for infinity, but rather a hair turn slightly before the infinity mark.....
A 30 second exposure is fine but you'll need to set your ISO to about 3200 or 6400 and shoot wide open at f/2.8
I usually like an ISO 1600 at f/2.8 and an exposure of about 2 minutes.
Also, mirror lock-up is really not necessary because the slight vibration of the lens during a 30 second to 2 minute exposure is nominal.....
But make sure to weigh down your tripod with weights, bricks, what you can find that's heavy, because during your exposure the slightest breeze from the wind blowing throughout your long exposure can affect your image. And sometimes your tripod, no matter how stable or expensive, can experience vibrations.

[Nocturnus]

40d goes up to whatever H is (i'd assume thats 3200). I did a shot at that and i could see enough noise on the viewfinder. I shot at different stops and ISO for some testing. Should be going out camping again next weekend and will try yet again.

I hope this time there is no moon.

Well, looks to be last quarter... Which is better then full moon like this past weekend.

[The Loft Studios]

I would stick with the ISO 1600 range but nothing less than ISO 1000.
The 40D should produce a great image at that ISO. I had a 30D several years ago when I did it at ISO 1600 and the final print was AMAZING..... So I know the 40D should do even better. Now the reason you don't want to go any less than an ISO of 1000 is that you'll start getting "exposure" noise. This means the longer that camera's shutter stays open to allow for more light, you'll still get noise, even at very low ISO's that would normally not give you any noise at all. So, you'll have to find that perfect equilibrium between ISO and exposure.....

Good Luck!

[dryicerx]

I've never found focusing just looking at the lens dial very accurate. Instead put the camera on live-view, zoom in, and then focusing manually until the stars/dots are sharp. (Live view because you can't really see through the viewfinder...)

And 30 seconds isn't really a good time either, it'll give you very very short trails (not pleasant imho)... either something in the order or 5s to get star points, or something longer than 5minutes (more the longer trails of course) to get a decent amount of trails. Make sure to have a low-medium ISO, and the heat build up on the sensor might give you a few hot pixels you'll need to remove in post. Best to do it in cool/cold weather.

Lot of trail and error to get exposure right.

[Nocturnus]

I tried a live view, and couldn't see a single star on it, didn't zoom in via LV either. What I was going to do if it worked out was do a bunch of shorter exposures then stack them.

[Patti Edens]

Ed, Check out this thread. It is loaded with great tips and info on star trails. Howard takes some great star trail shots.

[kamekaze]

Make sure to shut off IS if you're using an IS lens

[snakesat]

I gave that a shot a few years ago.

[Nocturnus]

That was the best one out of the whole lot. But now that I know a little more, i'll try my few test shots to make sure focus is right, then go for some longer exposures.

[Dobick]

this one is f/8 iso 100 at 31.5 minutes shot with a 40d
the lights on the ground in the trees are from a street light



this one is pointed due north (put the north star as center to the viewfinder as I could get)
f/5.6 iso 100 and 41.7 minutes

[Dobick]

for your problem -- it looks as if you shot your image in auto exposure mode and at f/1.4

change that to something like 5.6 to get a bit more depth of field, and change to bulb mode and use a release.

Play around with the iso to get where you have nice bright points of light in the sky, and then open the shutter, go inside and get a drink, or brew some coffee, when the coffee is done, come back out, then remember that you are hungry, go inside make a pb&j sandwich (taking time to cut off the crust of the sandwich very carefully) sit down and eat the sandwich, finish your coffee, and then you go back outside and check on the camera. carefully release the shutter, and then bring the gear in and check your results on your computer.

[Nocturnus]

Like I say, these were test shots to see if I was even going to be close. I did shots at 5.6 and some other aperture settings, which were by far worse then the above image. I didn't see a point in doing long exposures when trying to see if my focus was on or off.

At the point I started taking the pics, I kinda wanted to go for something that was less trails and more like just a decent shot of Orion. I'll be camping next weekend so I will get this all this a try again.

Though, I prob will not take 2 hours worth of exposures.