Saltar al contenido principal

⚠️ Please note that this topic or post has been archived. The information contained here may no longer be accurate or up-to-date. ⚠️

Dead Pixels on shorter exposures

jim frenak
I understand that long exposures can cause dead pixels, however, I was shooting today and realized I was getting dead pixels on all of my exposures that were 10 seconds or less. All that were over 10 seconds did not have any.

I was using C1 9, with a Canon 5d Mark iii, tethered to a Macbook pro.

Any thoughts on why?
0

Comentarios

9 comentarios

Fecha Votos
  • harald_walker
    Dead, stuck or hot pixels? Do you have an example image?

    It is quiet common unfortunately in modern DSLR cameras. Depending on the model, there are different ways to deal with it (or not). C1 can remove them quiet well using the Single Pixel slider in noise reduction.
    0
  • jim frenak
    I'm not sure how to post an image to the forum, but i do have a sample. Can someone please advise?
    0
  • RichardT
    [quote="NN202332UL2" wrote:
    I'm not sure how to post an image to the forum, but i do have a sample. Can someone please advise?


    You need to upload your image to a hosting site that allows linking (such as Photobucket).

    Then add the URL of the image to your post here and surround it with "img" and "/img" tags:

    [img]http://image_url[/img]

    (Edit) Alternatively, if it is file type that can't be displayed in a browser (such as a RAW), upload it to somewhere like dropbox for people to download.

    Richard
    0
  • jim frenak
    Thanks. I've uploaded them to site where they can be downloaded.

    Link: http://fpistudios.photoshelter.com/gall ... 1uqRjswseg

    Password: pixel

    Image 0007 is an 8 second exposure. Image 0006 is 13 seconds. Today I tested it by processing the image through photoshop and the bad pixels were not there. Through Capture one, they show up.
    0
  • harald_walker
    [quote="NN202332UL2" wrote:

    Image 0007 is an 8 second exposure. Image 0006 is 13 seconds. Today I tested it by processing the image through photoshop and the bad pixels were not there. Through Capture one, they show up.


    They are there but as far as I know Adobe's raw converter automatically detects and removes them. In C1 you have to do it yourself.

    Do you see them in the camera when you zoom it?
    0
  • jim frenak
    Not sure what you meant by zoom it, do you mean on the back? If so, I tried that, but nothing.
    0
  • SFA
    Hot and dead pixels will usually disappear at some point in processing.

    As far as I know I have only one camera that is exhibiting such a problem (pocket camera) and I only see any evidence occasionally when editing RAW files. The cameras I have seem to deal with things in the jpg files. I think Canon maps out what the camera is aware of.

    Was this shot as jpg? And into the camera rather than tethered?

    It does seem odd - unless the camera is doing something special because the sensor is getting hotter for the longer exposure.

    None of that seems logical if you shot it RAW unless there was some unnoticed difference in the processing to output jpg.


    Grant
    0
  • jim frenak
    For the record, I was shooting in Raw mode, tethered to my Macbook Pro. It was a major project with a lot of bracketing. The pixels were showing up in every exposure 10 seconds or less. All longer exposures were fine. The pixels could be seen in the RAW image and the processed tiff's.

    Now for an update - No idea what caused the issue, but it's gone. I found this on another site, tried it and it worked.

    [color=#FF0000:23enw3xn]*Put the camera into manual sensor clean mode, turn it off and back on. fixed my dead pixel problem.*[/color:23enw3xn]

    I want to thank everyone for your help. If anyone has an idea why it happened, I'd still like to hear from you.
    0
  • SFA
    [quote="NN202332UL2" wrote:
    For the record, I was shooting in Raw mode, tethered to my Macbook Pro. It was a major project with a lot of bracketing. The pixels were showing up in every exposure 10 seconds or less. All longer exposures were fine. The pixels could be seen in the RAW image and the processed tiff's.

    Now for an update - No idea what caused the issue, but it's gone. I found this on another site, tried it and it worked.

    [color=#FF0000:1a7hyock]*Put the camera into manual sensor clean mode, turn it off and back on. fixed my dead pixel problem.*[/color:1a7hyock]

    I want to thank everyone for your help. If anyone has an idea why it happened, I'd still like to hear from you.


    I found a load of search results like that but was not sure how valid they were. And I had nothing to test the theory on! I presumed you might have found it already. If not I would have mentioned it.

    It doesn't seem to answer you problem though.

    CO spot removal works fine but obviously requires a little work, though once done it could be applied to multiple images if required.

    I could make the red spots go white without seeming to mess with the rest of the image but the whites stayed white. As I was not getting far with the jpg I asked about the original format. Probably not much more on could discover withouth starting over with your processing to see what happens.

    Grant
    0

La publicación no admite más comentarios.