Star trails and longer exposures

The Lazy Destroyer

I toyed around with longer Bulb exposures when I first got my dSLR a few years ago. But wanted to try it again more seriously last night. Clear sky so I headed up to the N GA mountains for a couple hours.

If anyone cares to C&C I'd appreciate it!

I got some okay images, just a few I thought were keepers, but only one or two that were "good". I guess not bad for a first real outing. Mostly worked with a new body/lens so I had a little learning curve.

I made the mistake of not checking the lens's infinity focus in daylight and just relied on the vertical part of the "L" on the focus ring marks. I tried just a hair left and right of it too and results were about the same. Despite the pics, it was complete darkness where I was at. I wasn't terribly happy with the stars' focus, they seemed a bit blurry. Maybe it is over-exposure and not a focus thing. But my Tamron 17-50 @ 17mm/f2.8 on my 30D at similar ISO doesn't seem this blurry.

This was on a 40D @ iso500 and Canon 10-22 at 10mm/f3.5
The best image I was able to get:

#1:


Lens had a magenta filter and I illuminated with the amber parking lights of my car. Exposure was 11 minutes and I illuminated the foreground for 4 minutes. I was kinda shooting blind with the exposure/illumination times so the result wasn't too bad I think.

I don't really like how the stars are a bit blurry, I couldn't get them any better than this. Image has been processed in LR: Noise Reduction Luminance to +60 and Sharpening +38. Which helped a little.



I also took this image:

#2:


Not bad but I'm sure the problem is the image is "flat" as in not much going on w/ the color.
This was was illuminated with a small camping lantern, on the ground just below the camera.
Exposure was 8 minutes with 4 minutes with the lantern on. I did change ISO to 800.


This one I just "painted" the light on the tree and frozen cliff with a flashlight:
#3:


iso 800, exposure for 6 minutes.
The darker subjects have a little more contrast on the sky but not sure it's really a good image.


I think I really just need to work on different techniques to get the foreground illuminated. I went out there with no moon which probably helped the star exposure but everything on the ground was so dark most of the images I took weren't really good at all. The car's headlights were pretty convenient and maybe using a sheet over the headlights would help soften it up and change color too. Or some 12v lamps with different colors for different parts of the foreground. :dunno Or just come back when the moon is out.

jnickoson

I've had issues as well with the infinite focus in the past. The first time I tried for some long exposures I was able to just auto focus on the brightest star and then set it to manual for the duration of my shoot.



The second time I went for long exposures I wasn't able to trick the focus into a good zone because the auto focus wasn't grabbing anything, so I had to fudge around with the manual focus, nudging it slowly, taking a picture, comparing the results, nudge it some more... took at least 20-30 min to get it 'close' to where it needed to be but not quite there. Ended up somewhere in the middle of the L line before you get to the infinite mark.



So on the second one I'm kinda with you, don't quite like the focus on the focus for the stars and wish there was a better way to nail it every time. I might just have to cheat and next time I see a really bright star out I'll just grab it with auto focus and then maybe put a mark on the lens so I know where to put the focus.

Both pictures were ISO 100, f2.8, 30 min exposure. Different parts of the country through, first was in southern Ohio, 2nd was at the Grand Canyon.

JC

Your stars look pretty well focused to me, you've got some tack sharp lines in there. Also, remember that not all 'stars' are stars, some are compound objects that will look a little bit more blurry, plus you have the milky way in there providing some 'background' blur that don't resolve as stars. On longer exposures those features would tend to blend in more. Personally, I find it more important to have the foreground elements in sharp focus, so depending on the focal length and the distance to the foreground, my startrails aren't always shot at infinity. You can also try setting up at dusk when you can still see some very distant terrestrial objects at essentially infinity to pre-focus on then switching the lens/camera to manual focus and leaving that focus dialed in, or marking on the lens.

Light painting with standard flashlights or lanterns is very tricky to do. You might try to experiment with stacking shots with a shutter speed of anywhere from 20 seconds to 2 minutes depending on the amount of sky noise you have in the direction you are shooting (instead of one long exposure). that way you can grab the best foreground shot to use in the final image, illuminated either by light painting, or timing the shot series, as you said, to include about a half hour of moon at the beginning or the end, or catching some twilight or early dawn exposures for the foreground.