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View Full Version : Red / Multicolored dots for dark photos???



Joeyd
15th August 2011, 11:58 PM
So I took some pics at a local arcade shop. I may have to reupload hte pic since it may come out crappy in the upload.

But basically I would leave the shutter open for about 20 seconds since it was super dark in there and I didn't want to use a flash. I think I used the lowest iso setting as well with the lumix 14-140mm lens..but in every pic I had colored dots all over the place..

Is this some big mistake I made on my part??

Rene
16th August 2011, 10:25 AM
I believe that what you see is noise.
I use an old E520 and at low light and long exposioure I'll get noise at allmost every setting. Try overexposing the photo when you take it = longer exposioure time at same ISO and aperture, then bring exposure down in PP, that might do the trick.
It can be difficult to get noiseless photots when shooting in very low ambient light.

Edit:
I've seen photos with loads of more noise in, than this one :)

John Perriment
16th August 2011, 10:26 AM
Even at low ISO sensor noise increases with long exposures, but the noise is in a more predictable pattern than noise caused by high ISO. There is a Noise Reduction (NR) facility on your camera (not to be confused with Noise Filter) to deal with this. It works by a method called dark frame subtraction and in this mode basically the camera makes two exposures; one with the shutter open to record the picture in the normal way and one with the shutter closed but for an identical length of time. The camera then measures noise from the dark frame and then subtracts it from the normal frame.

That, I believe is basically how it works and hopefully Ian or another will correct me if I haven't got that quite right, but in practice it works really well. I suspect that you did not have this enabled.

Also, despite the long exposure, this image still looks underexposed which will also increase noise. Next time try bracketing exposures by several stops, particularly on the plus side.

Hope this helps and good luck. :)

Joeyd
17th August 2011, 06:14 PM
I bet it was the NR..I turned it off the night before too! Uggg..well next time I'll leave it on,see if that fixes it.