Image Help Wanted

Info, discussion, repair manuals, downloads, home fixes, horror stories!
lightlord
Acolyte
Posts: 4
Joined: Sat Mar 21, 2009 1:33 am

Image Help Wanted

Unread post by lightlord »

Hi All,

I wanted to shoot some star-trails from my backyard with my sony a350 and got some wierd results.
I shot this picture with no lights around in pitch black surroundings.
Settings where 18mm Manual f8 iso-100 30minute exposure
I expected an black picture with star trails instead i got ALOT of purple.
And look at the left an right hand corners???
Is this the norm for sony dslr camera's ?

original shot.

Image

auto-level in ps to get rid of the purple to no avial ;(

Image

Any ideas or help please :)

greetings Lightlord
User avatar
KevinBarrett
Emperor of a Minor Galaxy
Posts: 2449
Joined: Wed Aug 13, 2008 5:32 pm
Location: Seattle, Washington, USA
Contact:

Re: Image Help Wanted

Unread post by KevinBarrett »

Did you have the optical viewfinder covered? I may not know much else about the problem, but with long exposures, any ambient light can creep in through an unguarded viewfinder.
Kevin Barrett
-- Photos --
David Kilpatrick
Site Admin
Posts: 5985
Joined: Sat May 19, 2007 1:14 pm
Location: Kelso, Scotland
Contact:

Re: Image Help Wanted

Unread post by David Kilpatrick »

This effect is quite common - it happens in just one corner on the A100. It seems to be caused be proximity of electronic components to the sensor. Experienced astro shooters just crop the frame - the 14 megapixels allows you to do this and still have a good resolution.

David
lightlord
Acolyte
Posts: 4
Joined: Sat Mar 21, 2009 1:33 am

Re: Image Help Wanted

Unread post by lightlord »

Tiny update from my side ;)

Itook my camera lens cap on and put it into my vault inside my closet and took another picture..i totatly forgot about it so after an hour and 40 minuten i rememberd i had my camera on :P

With this result.

Image
marktuma
Initiate
Posts: 47
Joined: Fri Jan 04, 2008 12:05 pm

Re: Image Help Wanted

Unread post by marktuma »

Isn't this what the long-exposure noise reduction is for? I thought the purple is noise caused by the sensor heating over time, but it's repeatable, so you can take a frame with the shutter closed and subtract it.
lightlord
Acolyte
Posts: 4
Joined: Sat Mar 21, 2009 1:33 am

Re: Image Help Wanted

Unread post by lightlord »

Thats my next step :) thanks..
Post Reply

Who is online

Users browsing this forum: No registered users and 8 guests