Strange pixels?

[Vincent]

Goodevening everyone!

Not aviation related, but I was testing my 50D a few days ago by making some nightshots.
When I took a good look at the photos on the PC, I found out that there were some strange pixels on the photos.
Below an example:

1. Strange spots marked ( made at 18 mm/ 977 sec. exposure/ F7.1)


2.



I made a total of 3 of these shots and the strange spots are all on the same place.

Think it has something to do with hot pixels but I hope someone can tell me exactly what this is and what to do with it?

Thanks in advance!

[evhest]

As far as I know, these are not 'hot' but dead pixels and there's nothing you can do about it except photoshop them out. Somebody correct me if I'm wrong.

[Delta12]

Yes these are dead/defecte/stuck pixels mostly they show up during long exposure time shots. You can have a camera that is 5 years old and doesnt have any. And you can have a camera 5 days old with dead pixels. I had some too in the beginning with my 300D but I decided to leave it as it is. (Too much effort for such a small thing) At the moment the warranty had ended. A new sensor would cost 150 euro.

They are easy to remove with editing software. Best you can do is stop worrying and enjoy your hobby!

[Herbertvh]

Vincent, it's not uncommon at all to find these "hot pixels" during long exposure. Just about every digital camera has some. As long as they don't show up during short exposures, there's nothing to be worried about.

But just in case they bug you too much, read this thread that includes a non-scientific way to remove them (at your very own risk, I don't believe this as working at all): http://photography-on-the.net/forum/sho ... apping+hot.

A better way of preventing these hot pixels from showing up is to make multiple shorter exposures and stack these images to make up one new image. That method will cut out much of the noise too, by the way. You'll have to search the web for the stacking software, as I don't have the experience with stacking to recommend you a particular solution.

Cheers,
Herbert

[Vincent]

I never saw them on short exposures, so I will indeed stop worrying!!
Many thanks again for the support and tips!

Greetings,

Vincent

[Iwan Bogels]

Hi Vincent,

I think you can easily check for dead pixels by making a shot with the lenscap still on. Do use a regular shutterspeed like 1/250 or so, at ISO 100 or ISO 200. The whole photo should be black, and all dead pixels should be easily spotted as they show up bright coloured.

Can you let me know what you find out, after checking ?

Cheers,
Iwan

[Vincent]

Iwan,

Sorry for the late response, but I've tested the camera by making a photo with the settings you recommended, and the photo seems to have no
strange/dead/ pixels!

Grtz

Vincent