Monday, 14 November 2011

Dead Pixels

As some of you may know, we were in Oxfordshire this weekend attend Rob and Rhona's wedding. There will be a number of posts about the wedding but while sorting through the photographs we took (all 321 of them) I noticed that there appeared to be a problem with the camera.

In nearly all the photos a little red dot was present and it was always in the same place. Fortunately it's only a tiny dot and so a small use of the clone tool will get rid of them. Having cleaned the lens and taken some test shots the problem was still there though and so I assume this is actually a dead pixel on the camera's sensor and the first sign that the camera is slowly dying.

After a quick hunt around the web I did find that some more modern cameras actually include a function for "pixel remapping". Essentially the camera runs a diagnostic routine to determine if any pixels are failing to respond and then ignores them (by doing some interpolation) when generating an image from the sensor.

Now as I said our camera, a Sony DSC-F828, doesn't list this function in the menus and so I thought I was stuck with a dying camera. In computer software/hardware diagnostic routines (such as checking hard disks for bad sectors) are often performed only when the system is fully restarted. So as I had nothing to lose I decided to do a full reset of the camera. Once I'd located a paper-clip (I don't work in a paperless environment but neither am I awash with stationary supplies) I pressed the reset button and turned on the camera. Once I'd reset the clock and some other basic settings I went to try and take a photo and... the red dot was gone! Now I'm hoping it will stay gone and that some pixel remapping did take place but even if it was just a coincidence it will allow me to hold off for a little longer before having to buy a new camera.
14 November 2011 at 16:17 , ADRIAN said...

You have it sorted. It will hopefully go for ages now. Or until the shutter packs up which is usually the first thing to go. In my case bouncing them on concrete usually does the job first.

14 November 2011 at 16:54 , Mark said...

Well I've got my fingers crossed it will continue to work!

So far I've managed to avoid dropping it on concrete, although I did manage to drop it in a snow drift and leave it outside on the garden bench until about 11pm. On both occasions it was very cold and damp and I left it to try for quite a while before risking turning it on. It's been on the way out for a while now anyway as it has stopped recognizing Sony MemoryStick cards. Fortunately it also has a separate slot for Compact Flash cards so it is still usable, although the burst feature doesn't work as well as it can't write the photos to the card as quickly.

I'm going to start looking around for an alternative but at least I can keep using it in the meantime.

15 November 2011 at 08:24 , GB said...

One of life's necessities. I hope it keeps going whilst you look for an alternative. Touch wood I've never had a camera expire before I replaced it unless, as with the Olympus, it was dropped and mortally wounded.

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