what is it??

[B01NG]

hey everyone, i've just recently bought a canon 350d so im pretty new to the dslr world, i played around with the shutter speeds and noticed that in the slower speeds, specs of red and blue appear on the image, and its on the same place every single time. at first i thought it would be dust, but wouldnt dust appear to be black specs? i took a picture of a plain white wall and there appeared to be no specs what so ever. so im just wondering what the red and blue specs are? here is a link to one of the pictures. http://www.flickr.com/photo_zoom.gne?id ... 459&size=o

[losfp]

You're probably talking about hot pixels - they get more obvious at long shutter speeds because they are more sensitive to light than the surrounding pixels.

Some of the DSLRs have a noise reduction mode where it takes a "blank" image at the same shutter speed, then subtracts that from the taken image to remove the hot pixels. They are easily removed in photoshop etc, though of course they are annoying.

[B01NG]

oh ok then, so i cant get rid of it physically on the camera? blast. thanks for your help!

[Alpha_7]

The look like hot pixels to me, just like a LCD screen can get hot or dead pixels that are always on, or always off, or always red for instances.

You sensor can also suff the same fate, sadly yours seems to have a fair few if this shot is how it reacts all the time.

Some software, and even some cameras allow you to identify this problem photosites, and to turn them off (they just get the average of their neighbouring photosites, so you don't get the very obvious red or blue specks.

I'd be inclined if its new to take it back to the shop and get it swaped for a fully working one.

[Yi-P]

Hi, welcome to the forums


Does this red/blue pixel appear on shots taken on a bright day? With faster shutter speeds?

When you say slower shutter speeds, how slow are you going? 10sec? 30sec?

[B01NG]

Hi, welcome to the forums


Does this red/blue pixel appear on shots taken on a bright day? With faster shutter speeds?

When you say slower shutter speeds, how slow are you going? 10sec? 30sec?

thanks! , umm it only appears on shutter speeds over 10 seconds i think. normal day shots are perfect, night shots with flash/quicker shutter speeds are fine too, it just happends when the shutter speeds exceeds 10 secs or so.

[Yi-P]

Then that should be the 'hot pixel' mentioned earlier in this post. I think it is not a really big issue to worry about, unless you always shoot slower than 10 sec exposures.

[B01NG]

ok thanks so much for the info! i was getting worried for a second.