Photo Pixel Issue - Problem?

[r1flyguy]

Hi All

I have read a couple of threads on here about, hot pixels, dust etc and not fully understanding which is which or how to differentiate so please help.

I took the below photo last night on the following setting

Camera Canon 650D (purchased October 2012)

Canon lens (10-22)

22mm, 8s shutter, f/20, 100 ISO

you can clearly see at least one coloured pixel in the night sky upper left side, on editing there are several, red & green!

Advice & thoughts sought please as its really annoying.

Thanks in anticipation


Untitled by r1flyguy, on Flickr

 

[sep9001]

Looks like a hot pixel, to check if it is dust on your sensor take a photo of the sky or a white paper with an aperture above F18. Have a look at the pic on a PC enlarged to see if you have any black marks.

 

[Phil V]

They're hot pixels, you can program them out in Canon DPP, there's a tutorial on Canon's site.

Sensor dust looks completely different and is most visible in bright areas (large shadow)

 

[modchild]

They are definitely hot pixels, they are too small and too precise to be dust on the sensor. I don't know if it has anything to do with the exposure time of the photograph or whether they are there on every shot. Having had a look at full size I can see at least a dozen pixels in the sky and water that are giving you problems, there may be more in the centre of the photo where the buildings are, that does seem a bit high for a camera that's only around 8 months old.

Might be worth contacting Canon to see what they advise or try mapping them out in camera. I think there are other ways to try and recover them and I'm sure if you do a search on here or the rest of the web you'll find out the best way. Hopefully, someone will come on here and tell you the best way. I think it's a long exposure with the lens cap on but I might be completely wrong with that so try to verify before you try.

 

[philwillmedia]

Definitely hot pixels.
Apparently an easy way of solving the problem is to remove the lens and put the body cap on or leave the lens attached with the lens cap on then take something like a 20 second exposure.
It apparently fixes the problem.
I've not had to do it myself but have seen multiple threads on various fora that extoll the virtues of doing that.
Do a Google search and you should come up with something.

 

[ChrisJ_SLH]

As everyone has said they are definitely hot pixels. Nothing to panic about though.

Literally every sensor has them and they are usually mapped out in the camera in firmware/software so they are not a problem in practive

Occasionally new ones develop though and need dealing with.

As Phil alludes, with Canons there is reputedly a trick of removing the lens and putting the body cap on and performing a Manual Sensor Clean procedure for 30 to 60 seconds.

If not, Canon will be able to sort it as a matter of routine.