[Tom Brown]

I apologize for the big pic. It's been coverted from RAW, cropped, and saved to JPEG. No other processing.

Is there a way I can get the sky smoother?

Also, this shot looks like the camera may have shaken a bit. I had the camera on a tripod and used the 2 second self timer but I was standing 2 feet away rubbing my hands together to try to keep them from freezing completely. It was -38C the other night when I took this shot.

Still, it doesn't look much worse than any of my shots from this location. They all look a little grainy. I've been assuming it's the lens.

Camera: PENTAX K100D
Timestamp: Mon Feb 12 17:08:39 2007
Shutter: 15 s
Aperture: F8
ISO speed: 200
Focal length: 21.0 mm
Focal length in 35mm equivalent: 31.0 mm

EXIF data read by Exiv2 0.10






Any advice?

---

Last edited by Tom Brown; 02-15-2007 at 01:02 AM.

[ccallana]

It may be a side effect of your 15 second exposure... leaving a sensor on that long could cause some undesired affects...

[Tom Brown]

Thank you. I appreciate the input. It seems obvious, now that you've pointed it out.

Perhaps I'll try ISO 400 and F5.6 when the weather breaks a little.

[Cideway]

Do you have the DFS noise reduction on, that would help cancel out most of the longer exposure noise.

[Tom Brown]

Good thought.

I just checked and it is turned on.

[GavinIvey]

That is a good question you are looking for an answer to. I like to take night shots and find it hard to get them with my DSLR. I will keep check on this thread for pointers myself.

I like the shot though. Were you using a star filter?

[Tom Brown]

No star filter. Just a bare 18-55mm kit lens.

[benjikan]

Did you cover the rear view finder?

Ben

[newtmaker]

As far as noise reduction being used, I have seen posts that some folks think the NR on actually increases the tonality problems. Might be worth some testing if you tend to do lots of longish exposure shots.
Also, the post about the rear ep cover is very good. I sometimes do some astrophotography through my scopes, as much as 4 minute exposures, and having that cover on is definately important.

Walt

[Mike Cash]

I do my night shots in manual mode, to prevent the problem of the viewfinder not being covered. Most of my shots are 30 seconds or less. I usually shoot at ISO 200 (lowest on the K100D) and about f5.6 or f8. Most of the noise problem can be handled satisfactorily with the freeware edition of Noiseware.

[trog100]

it could be that u are trying to do the impossible.. a noise free nice and sharp image taken in the dark..

i see pretty much what i would expect to see.. in fact i see better than it could be.. u need a yardstick.. how good should it be..

i think its quite good in the circumstances.. if u think of a sound type analogy.. your signal to noise ratio is very poor..

but if anyone knows any magic tricks i would be interested to hear or better still see them..

trog

[Ivan Glisin]

Shutter: 15 s
Aperture: F8
ISO speed: 200
Focal length: 21.0 mm

One question: why f/8 for low-light photography resulting in long shutter speeds? Also, signal to nose ratio seems to be very low (or simply speaking overcorrected underexposure -- hence the harsher noise appearance).

I presume you have used DA 18-55? If so, repeat the shot in M mode at f/4 and 8s which would be 1 stop brighter than your initial setting (+2 stops aperture with -1 stop shutter speed). If you have f/2.8 lens then try f/2.8 and 4s. Note: parameters may differ if the weather changes (clouds) or with different moon phase.

-= IVAN =-

[WMBP]

Did you cover the rear view finder?

I'm curious to know why Ben asks this question....

Will

[Tom Brown]

Did you cover the rear view finder?

Ben

No I didn't.

[Alvin]

I'm curious to know why Ben asks this question....

Will

During a long exposure, stray light can enter the camera through the viewfinder. This will throw off elements in the capture