Is this a dead pixel ?

Magic_x_uk · 24 Feb 2013 at 18:43

Hi wonder if someone can give me some guidance.

I am slowly getting into photography and bought a Nikon D80 to learn with.

I noticed these very tiny white cross's on some of my photo's when I zoom in.

What are they and how do I sort them

(Yet to have any printed out, so not sure how they will print)

Very hard to see, unless you zoom in and do some PP

https://flic.kr/p/dXwLLJ

Thank you. (I have drawn a arrow where the cross is)

http://i465.photobucket.com/albums/rr20/Keith-UK/test1-1_zps9676ce0d.jpg

Not sure if Photo Bucket changes the photo or not.

Ksanti · 24 Feb 2013 at 18:47

Crosses? It's either dirt on the sensor (unlikely as it's white), a very strange cluster of dead pixels (they shouldn't be squares) or it's just noise that you're mistaking as dead pixels?

If you could give us a sample that would be great

Magic_x_uk · 24 Feb 2013 at 18:53

I have tried to give you a sample in that photo. But cannot see how you can zoom in on it.

Hold on. I shall see if I can do something and screen print it.

Ksanti · 24 Feb 2013 at 18:55

Upload the full resolution to something like imgur? I can't make anything out on that low resolution copy (photobucket limits the resolution upload on photos)

Magic_x_uk · 24 Feb 2013 at 19:00

http://imgur.com/wcKcHVI

Hope that has done it for you?

Ksanti · 24 Feb 2013 at 19:15

Looks like it's either a dead pixel and you're shooting at an odd resolution which is causing the cross, or there was just a piece of lint on his trousers

Nexus · 24 Feb 2013 at 19:24

Looks like all the EXIF has been stripped, so is it a High ISO photo?
Typically hot pixels give small crosses when zoomed in, they are pretty common on long exposures and high noise photos on just about any camera.

Depending on what software you are using, some will detect such problems.

L0rdMike · 24 Feb 2013 at 19:29

Just crop the image.

Raymond Lin · 24 Feb 2013 at 19:38

Your camera may be able to map these and remove in camera.

LR also auto clone dead pixels put when importing.

Magic_x_uk · 24 Feb 2013 at 19:39

Thanks. it doesn't really cause any problems. Just that I wondered what it was.

Andy90 · 25 Feb 2013 at 16:03

It isn't a dead pixel, since a dead pixel would not receive any data. It is a 'hot' pixel.

The sensor is made up of millions of receptor sites. Although the tolerances during manufacture are really high, sometimes you get the odd receptor site that is prone to signal leakage.

Each pixel receives photons. As it receives the photons it assigns an electrical charge to the amount of photons. This is then converted to an analogue voltage which is then processed into a digital value, which again is processed.

In the case of a 'hot' pixel the pixel is receiving a slightly increased electrical charge from one or other of the surrounding pixels, this causes the detected voltage to increase and as a result it becomes brighter.

All sensors are prone to this, it gets worse as the sensor warms.

In short as others have said, don't worry clone them out.