Grainy Night Photos (iso at 100)

[squeemu]

Since getting my new tripod a few weeks ago, I have been trying out night photography. A few times I have been happy with the results, but often I find that photos are grainier or blurrier than I'd like. I have made sure to turn off image stabilizer and turned the ISO to 100. I'm fairly confident that my tripod is not moving, and I have the camera set to a timer. Are there other issues that might be causing graininess or bluriness? For example, in the following photo:


LAX by squeemu, on Flickr

It's a little harder to tell at smaller sizes, but at full size it's clearly very grainy and slightly blurry. Is it simply the conditions, or is there more to it than that? Thanks for any help or tips!

[RichardTaylor]

I think the reason for the grain is that a lot of the dark areas are under exposed, including the tower.
The exif data shows ISO to be 800
Try shooting at minimum ISO.

Re the softness

(1) Do you have a filter on the lens?
If so remove it.
(2) Are you using a lens hood? (helps reduce image degradation caused by flare).
(3) How are you focussing (do you get a focus confirmation light?
(4) Are you using mirror lock up?
(5) What was the atmosphere like (perfectly clear or hazy/polluted).
(6) Are you shooting RAW?.
(7) Are you using noise reduction when PPing.
(8) Are you sharpening when Pping?

[squeemu]

Thank you for your reply, Richard!
First off, you'll have to forgive. I had forgotten that toward the end of my experiment, I did shoot a few photos at 800 iso without a tripod, to see how they would come out. Here is the best I could come up with at 100 iso. As you can see, still fairly noisy and blurry:


LAX by squeemu, on Flickr

To answer your questions:
1. No filter on
2. I did have a lens hood on
3. I was using auto focus a few times and manual a few times. I'm fairly new to photography and don't quite trust my manual focusing abilities yet, but auto was having a very hard time that night.
4. No mirror lockup. Should I have this on?
5. There was a very small amount of fog in the air. I thought this perhaps contributed to the problems?
6. High quality JPEG. Should I switch to RAW?
7. I didn't do any noise reduction. I will read up on how to do this.
8. I did a bit of sharpening.

It looks like a might have a few issues going on that I need to look into. Thanks again for your input!

[RichardTaylor]

At least the noise looks better.

With focussing in the dark.
Try;
Centre focus point only active.
One shot focusing.
Manual focus.
Pick an are of contrast to focus on (like the number on a tail)
Partly depress the shutter button and rack the lens back and forth as sharpness changes a little in the viewfinder . You will see the focus light toggling on & off as it acquires focus.
If you change the focal length the focus may shift a little.
Also try shooting around f8-f11 as this will give you a little more DOF and your lens will probably be sharper.

[Doug Sundseth]

Grain:

Long exposure tends to amplify any noise from your sensor. I'd try using long-exposure noise reduction if you didn't here. (1.6 seconds is kind of short for that to be an issue, but it's worth a try.)

And make sure that you're not increasing the exposure of the photo in post, as that will amplify random effects at the bottom of the sensitivity scale and result in noise.

Fuzziness:

Assuming a crop-sensor Canon (since you had autofocus troubles ) and assuming that you didn't crop the frame before posting, it looks like you were around 3500' (a bit more than 1000m) away from the subjects. At that distance, depth of field should be a non-factor, since you're about triple the hyperfocal distance.

The building isn't moving but it's still out of focus, so subject movement is out, too.

That leaves missed focus, camera movement, and air turbulence.

For the first, do what Richard said. (You might also consider manually focusing with live view zoomed in tight).

For camera movement, 1.6sec is in the range where mirror slap could be a problem, so mirror lockup is a good idea (use a remote trigger of some sort). Consider how sturdy your tripod is; at that focal length, even a little bit of movement is likely to show up in frame. And even a very sturdy tripod can show movement if you have wind.

For air turbulence (usually seen when the ground is a very different temperature than the air), come back another day. (Sorry.)


HTH