PDA

View Full Version : Can anyone help?

bokeh'ed
1st of July 2007 (Sun), 08:37
I have a 20D + 580EX. Tried for fun to shoot at my apartment using direct-on flash (set to full power) to see how far it'll illuminate the picture.

but was shocked to see that even at ISO 100, the noise looks worse off than any P&S.

picture was taken raw, RAW-converted with CS2's parameters set to 20D's suggested settings.

http://i54.photobucket.com/albums/g94/musicexpression/photo/IMG_7561.jpg
1/160s 16mm f5.6

this noise problem appears when certain settings are made in ISO100, other settings give the usual noise-free picture.

is this a defect on the sensor, since I would expect noise to be very minimal in such low-light conditions.

any advises most appreciated. thanks.
SkipD
1st of July 2007 (Sun), 08:45
The image appears to be severely underexposed which would be the likely reason for the noise. Even the closest portion of the building was too far away to be illuminated properly by the Speedlite.
Michael
1st of July 2007 (Sun), 08:54
This it exactly what happens when you underexpose the picture a lot. I assume you raised the exposure in Camera Raw, and that is the cause of the noise.

Next time try putting the camera on a tripod and using a longer exposure, it may look nicer :).
jra
1st of July 2007 (Sun), 08:59
I agree with the others...underexpose a pic by this amount and you'll get noise no matter the ISO setting.
bokeh'ed
1st of July 2007 (Sun), 09:09
yes, put back my CF into the 20D again and previewed this picture, the histogram shows only one line on the leftmost and nothing else. but how come CS2 attempts to "guess" and in this case, "overcorrects" this exposure by "pulling" the histogram towards the centre by so much?
bokeh'ed
1st of July 2007 (Sun), 09:12
ok, so this is a case of a defective user rather than a defective camera. :p thanks all
Titus213
1st of July 2007 (Sun), 09:28
It sounds like you also have the auto correct functions turned on in CS2. I would suggest you turn those off and adjust it yourself.
bokeh'ed
1st of July 2007 (Sun), 09:43
bingo! u hit the jackpot!!! CS2's Auto Adjustment in RAW Converter is enabled...
Titus213
1st of July 2007 (Sun), 17:38
Turning that off was the first step after installation...:lol:
InspiredGraphix
3rd of July 2007 (Tue), 08:37
It sounds like you also have the auto correct functions turned on in CS2. I would suggest you turn those off and adjust it yourself.

Yeah, i second that. The auto correct function can give you a false sense of security sometimes...

Rob