What causes this?

Discussion in 'Mirrorless Digital Cameras' started by shannonholm, Feb 15, 2009.

  1. I was at a concert last night and shot a ton of pictures, and today, as I look through the shots I notice a line across about half of the images. It is in the same spot in all shots that it appears in, so I am worried that there is something wrong with my camera. The ISO was way higher than I usually shoot, but I wanted to see how they turned out anyway.....I was wondering if it is just simply an effect of pushing a digicam to 1600....or maybe possibly reflections from the crazy show lighting (we were up on a balcony). It's not in ALL images, but in quite a few random shots mixed throughout the evening, all in the same spot. Any ideas? Thanks in advance. I was shooting with a Canon sx10.
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  2. The line is caused by a "hot pixel". It will probably only show while shooting at very high iso's. If you shoot RAW, most raw converters will fix the issue while processing. Some cameras have a "pixel mapping" feature where 'hot pixels' are turned off so they won't cause this. Most cameras will have one or two hot pixels pop up as they age. It's more an irritant than a problem because it can be fixed with some careful photoshopping. Back in the film days occasionally a roll of film would be scratched while rewinding in the camera. A hot pixel is easier to deal with that that.
     
  3. my camera is only a few months old.....is it something the warranty generally covers?
     
  4. I think this is an electronic problem more important of a simple "hot pixel" problem. A single pixel problem or two or more are different: you see a luminous, dark or fixed colored pixel in any image shot at same ISO (I have 1 red pixel only at 1600 and 3200 ISO on my 40D).
    What is your camera model? You shot in JPEG or RAW? Your camera support "LIVE LCD MODE" and you use it?
    My first and not precise idea focus on a problem in sensor electronic or CPU because a full column of pixel are affected. Bye
     
  5. It is a Canon SX10, shooting Jpegs. ISO 1600. I have never noticed them before last night's shoot, but I really (maybe never) push the ISO up that high. And it's not in all pictures.
     
  6. Ok. Damaged Jpeg files are differents: horizontal lines.
    My experience with "hot pixel" on JPEG are differents: luminous or dark pixel blurred from jpeg algoritm.
    Your shot has one very marked line and another less marked line on the right and I suppose
    that the cause can be an electronic problem during read data from CCD. This kind of problem may be caused by several factors: 1) hardware failure 2) overheating of the CCD caused by the LCD monitor in Live view mode 3) High frequency radio disturbance (but in this case line change position on differents shots...)

    Point 2) and 3) can be excluded shotting 2 or 3 photo at 1600 at home without using LView. Use a medium gray background and try also at 800 and 3200 ISO (high iso mode).
    If you have another one try with different memory card to esclude this source of problem.
    I try to help you but now I have no other ideas...
     
  7. I'm with John. It's a hot pixel causing the rest of the row to be affected. You'll get hot pixels showing up more at high ISO.
     
  8. I have never happened that a single pixel ruin an entire column from the first to last scan raw (I assume that this photo is not a crop!). I still need to learn many things eheh ;-) !
    Bye
     
  9. I agree that a hot pixel can't (or at least shouldn't) cause a hot column. I don't know many specifics, and I'm sure someone can give a better explanation, but there are A/D converters and amplifiers that are common to entire rows and/or entire columns. It could be that one of those has gone on the fritz, thereby affecting an entire column. You often can see imbalances between these amplifiers and ADCs in the form of "banding" at high ISOs, evident in the shadow detail.
     
  10. It's not a crop, it goes straight across. It even seems to show up a little in the view finder and lcd. I have looked back through a bunch of pictures shot with that camera, and it never showed up until last night. looking back through the performance shots it is in most of them, to varying degrees.
    are these problems generally covered under warranty?
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  11. If your camera is under warranty, then yes, it should be covered. If your camera is photographing a "line" that's not there, it's malfunctioning. I'd send it in. If you're past warranty and paid for it on your credit card, your credit card company may offer a doubling of the warranty as one of their cardholder benefits.
    Since this problem doesn't happen reliably, you will want to send numerous sample images along with your camera. Canon will probably want to use the EXIF data to try to replicate the problem.
     
  12. Hot pixels at high ISO are ok but lines are usually from a sensor (or sensor readout) fault.
    It even seems to show up a little in the view finder and lcd.​
    Yes, it's the sensor. I've seen this three times on my friends' cameras. It won't fix itself. Your second blurry image has it too, it's just less visible. High ISO may accentuate the problem but it's not the cause.
     
  13. Okay. Thanks, that's what I figured.. I'll give them a call.
     

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