Taking Pictures of stars...

EDIT: I removed the pictures from the post because the site was not auto scaling.

I've been taking dozens of shots of the moon with my first DSLR, got it last week. No I'm ready for the eclipse tomorrow but I want to try taking pictures of the stars.

My issue is that I cannot get one clear and focused picture. I've tried dozens of settings to no avail. Also I'm relying on the auto focus on the moon then trying it on the stars because I cannot get a good focus manually.

Here are a couple I have tried. There is a ton of light pollution as you can tell from the bottom of every picture being lighter.

Using Canon T1i 55-250mm

This shot looks clear on the first take but at 100% the stars are ovals, then in the second take everything is lines, not dots.


http://img195.imagesha​ck.us/img195/9103/img1​701k.jpg

First Shot take 1
5 second exposure
F stop 1/4
ISO 200

http://img196.imagesha​ck.us/img196/8247/img1​702z.jpg


First Shot take 2
30 second exposure
F stop 1/4
ISO 200


Now in the second shot I have a really bright star center and Orion's belt in the top left. The first take shows the bright star clearly but nothing else, then in a longer exposure showing Orion's belt nothing is really sharp. Only the three star's in Orion's belt appear to be in focus and sharp. If you look at the 100% you can see streaks for stars or just ovals, or double circles like the bright star.


http://img151.imagesha​ck.us/img151/2792/img0​676b.jpg

Second Shot take 1
1 second exposure
F stop 1/11
ISO 100


http://img23.imageshac​k.us/img23/822/img0677​k.jpg

Second Shot take 2
6 second exposure
F stop 1/4
ISO 100

In this shot the stars are more like circles then in the other pictures but the bright star is not a circle at all in any of the pictures


http://img26.imageshac​k.us/img26/5416/img005​8xk.jpg

Third Shot take 1
2.5 second exposure
F stop 1/4
ISO 400
http://img594.imagesha​ck.us/img594/3532/img0​059xj.jpg


Third Shot take 2
5 second exposure
F stop 1/4
ISO 400

http://img641.imagesha​ck.us/img641/6876/img0​060ce.jpg
Third Shot take 3
10 second exposure
F stop 1/4
ISO 400

YIKES!

Might want to resize these to 1024X...

FlyingPhotog wrote in post #11482804
YIKES!

Might want to resize these to 1024X...

Im used to other forums that automatically resize. I just made them links instead.

InfiniteGrim wrote in post #11482888
Im used to other forums that automatically resize. I just made them links instead.

Yes, but I guess most people are like me and don't have the patience to wait for 15 megapixels to download.

a couple megabytes? takes about 2-3 seconds :-p

look great though!

i am just seeing black with a few speckles. not much interesting to look at.

I think that there are a combination of things wrong here. With the 7D you have a 1.6 crop factor, so the lens is behaving like a 88-400mm on a full frame camera. If you are not using a tracking device, at 400mm, even in focus, you will only be able to use very short exposures before the stars start to "trail". Short exposure (even at high ISO) will not give you much light. Similarly, at 88mm, you have a bit longer before trails start, but the light received will be limited. Also, to increase the depth of field and increase the chances of being in focus, it is advisable to stop the lens down at least two stops, further reducing the light received.

On top of this, auto-focus has very little to go on, so manual focus is the order of the day and this in itself is very difficult to see in the viewfinder.

So, without the benefit of tracking, if it was me (YMMV) I would use the 55mm end exclusively, stop down one stop, lock the lens in manual focus mode and use live view and 10x live view zoom to focus. Choose the highest ISO you can get away with, lock the mirror up to eliminate any possible shake from that and, ensuring you have a sturdy tripod well fixed, use a remote shutter release to trip the camera. Start with short exposures and lengthen them until the stars start to trail unacceptably.

Other thoughts
- buy a cheap but cheerful 24mm manual lens. This will give you a slightly wider angle and therefore longer exposure.
- include some foreground in all shots - makes them much more interesting
- go for star trail shots in the first place
- get a tracking device - expensive and painful to set up

Good luck and let us know how you get on!

Just my 2p

For shots of the stars I think there are a couple of pointers that may help you.

If you are struggling to focus on the stars themselves, is there a light in the far distance that you can use? Or perhaps if the moon is out, you could use that. After correctly focussing on infinity, put your lens on MF so that the focus doesn't subsequently change.

If you don't have the use of a tracking mount, you are better off using wide angle lenses. The reason for this is that a tele lens will emphasise the apparent movement of the stars, meaning that your exposures will need to be shorter to avoid star trailing.

Which brings us to exposure. Most of the stars out there are extremely faint, so we need to give the camera a helping hand to capture what light is out there. The first way to do this is to make a longer exposure. The length of exposure will be limited by the lens you are using. See the point made in the paragraph above. Secondly, boost your ISO. 800 should be OK on the 7D, as I believe it is quite good at higher ISO levels without suffering from excessive noise.

Have fun.