Noise at ISO 100 using sony alpha

[godzilla60]

hi guys...

I tried taking night shots and when viewed at actual pixels, the night sky is full of noise even though i am using iso 100.

is it normal? or is my settings wrong?

[Rashkae]

That's very very very wrong...

How long was your exposure time? 30 minutes? :P

[godzilla60]

Originally Posted by Rashkae That's very very very wrong... How long was your exposure time? 30 minutes? :P

30 seconds.....

[Rashkae]

Originally Posted by godzilla60 30 seconds.....

30 secs at iso 100 is nothing... You shouldn't have noise.

[godzilla60]

Originally Posted by Rashkae 30 secs at iso 100 is nothing... You shouldn't have noise.

that's why. i am using f18 aperture at 30 secs

[UY79]

Originally Posted by Rashkae 30 secs at iso 100 is nothing... You shouldn't have noise.

That is wrong. Noise is always present, it's just how much of it. The longer you work the sensor, the more noise it has.

There's NR function in KM/Sony DSLRs which uses the method of dark frame subtraction which are used to reduce noise in exposures more than 1 second. It should improve long exposures in this case. The drawback is that the NR process takes as long as the exposure.

[Rashkae]

Originally Posted by UY79 That is wrong. Noise is always present, it's just how much of it. The longer you work the sensor, the more noise it has. There's NR function in KM/Sony DSLRs which uses the method of dark frame subtraction which are used to reduce noise in exposures more than 1 second. It should improve long exposures in this case. The drawback is that the NR process takes as long as the exposure.

I am fully aware of that. Nevertheless, I've taken long exposures at ISO100 with NR off and not found any noticeable noise.

[tirza]

30 sec exposure quite long, i think its normal to have noise.. especially if you shots a few in a time with long exposure coz the ccd will be quite hot... how bad is the noise?

[godzilla60]

Originally Posted by Rashkae I am fully aware of that. Nevertheless, I've taken long exposures at ISO100 with NR off and not found any noticeable noise.

maybe i need to emphasize that when viewing it on maybe a4 size, can't really see noise. what i meant is when seeing in actual pixel size which means 100%, not zoomed out. that's when i see noise....so i wondering if it is normal....

[godzilla60]

Originally Posted by tirza 30 sec exposure quite long, i think its normal to have noise.. especially if you shots a few in a time with long exposure coz the ccd will be quite hot... how bad is the noise?

u mean there should be a long interval between shots?

[tankm]

Why not post some sample, both full picture and crop 100%.

Originally Posted by godzilla60 maybe i need to emphasize that when viewing it on maybe a4 size, can't really see noise. what i meant is when seeing in actual pixel size which means 100%, not zoomed out. that's when i see noise....so i wondering if it is normal....

[Rashkae]

Originally Posted by godzilla60 u mean there should be a long interval between shots?

If you took multiple shots, do you see a difference in noise between shot 1 and X?

[godzilla60]

Originally Posted by tankm Why not post some sample, both full picture and crop 100%.

seriously, i would love to......

however, i am unable to post pics on the forum....(think i am technically challenged ...)

how do i post it?

[Rashkae]

Originally Posted by godzilla60 seriously, i would love to...... however, i am unable to post pics on the forum....(think i am technically challenged ...) how do i post it?

Check the stickies in the "Newbies Corner" threads...

This gets asked about once a week at least.

[godzilla60]

Originally Posted by Rashkae Check the stickies in the "Newbies Corner" threads... This gets asked about once a week at least.

now i know why i am unable to post the files up... the file limit of 100kb... posted the re-sized one, not sure if u can see the noise, though....

but i am unable to log in to the gallery after uploading....

[Galdor]

Originally Posted by godzilla60 now i know why i am unable to post the files up... the file limit of 100kb... posted the re-sized one, not sure if u can see the noise, though.... but i am unable to log in to the gallery after uploading....

Try uploading to Flickr or Photobucket and give us the link.

[godzilla60]

ok, here goes....

multiply website....

image-intensive, original hi-res (that's what they say)....

http://godzilla60.multiply.com/photo...t_shots_170907

[Galdor]

OK, I can't access Multiply from office. Guys, please help our bro here.

[Rashkae]

Originally Posted by Galdor OK, I can't access Multiply from office. Guys, please help our bro here.

I'm blocked too. I'll check it later.

[Drudkh]

Originally Posted by godzilla60 ok, here goes.... multiply website.... image-intensive, original hi-res (that's what they say).... http://godzilla60.multiply.com/photo...t_shots_170907

Looks fine to me.