answers: 120

  1. Denis
    14.01.2015

    A little story from my practice may be useful ... I wanted to take an interesting long exposure photo on my Nikon D80, but not stars, but a very ordinary subject. With the help of a cable, I set the shooting time to hour. However, when I returned to the place of shooting earlier, I found that the picture had already been taken, i.e. having not fully worked out the time I needed, I cannot say for sure what influenced this, but with a probability of 97% we can say that the remaining battery charge is low, I also thought that this could be a function of protecting the matrix from overheating. Naturally, the picture was underexposed, instead of 1 hour - 25 minutes (1505,4 seconds) and this is what came of it https://yadi.sk/i/ot2dHO1qdxmkT Most likely, the shooting was carried out without JVI (it seems to have regretted it), since there was a flare in the upper corners of the frame. Later, I still decided to see what can be obtained from this image, and, increasing the exposure in the Republic of Lithuania by 10 stops and adjusting the BB, I got the following https://yadi.sk/i/Ikg9BGp5dxn6z . So this question can be useful not only when shooting astrophotography. Thanks to Arkady for the article and readers for comments.

    Reply

    • Denis
      14.01.2015

      The room had a temperature of about 10 degrees C + - 5 degrees.

      Reply

      • Dima
        24.02.2024

        Monsieur knows a lot about perversions; on such an ancient camera it takes an hour and a half to set the shutter speed)

        Reply

  2. anonym
    30.01.2015

    So this amplifier heats up - from this and the characteristic flare, Canon's amplifier turns off, unlike Nikon, this explains that astrophotographers are either canon or special cameras.

    Reply

  3. Dmitriy
    19.05.2015

    1. "How much" -> how much
    2. "What vertical stripes appear on the Canon EOS 5D shots?" - banding
    3. "Do some Canon, Sony, Pentax cameras force noise reduction at high ISO values ​​when the noise reduction function itself has been turned off?" - produce. even in RAW. from a certain threshold. complete information is not yet available for all manufacturers. here, for example, by Sony

    Reply

    • Arkady Shapoval
      19.05.2015

      1.Fixed.

      Reply

  4. Alexey
    07.01.2017

    I own several years Nikon D600.
    Recently noticed a red hot pixel near the center.
    How can I remove it forever?
    Is this due to the fact that lately I shot a lot of videos, because the matrix works constantly and heats up?

    Reply

    • Jury
      07.01.2017

      carry the camera to a service or search the network for service software and clean it yourself

      Reply

    • Valery A.
      21.02.2019

      I'm sorry, I was a little late. I also had a burning red pixel near the center at d600, and at short shutter speeds and at ISO 100, it can be clearly seen. I began to look for solutions on the Internet (I thought, in the form of a thread of the program), I came across a simple advice to the Nikon Club - to forcefully clear the matrix (my cleaning function was disabled). I cleaned it, lo and behold - it was lost, it was so retouched that it could not be found. I looked through the manual - there is nothing like that in the section about cleaning, why?

      Reply

      • Nicholas
        20.07.2020

        and it is possible to clarify whether the internal function of cleaning the matrix is ​​meant? or straight clean with a mop? also found a hot pixel in the camera yesterday. filmed a comet at night.

        Reply

  5. Sergei
    07.01.2017

    Hello Arkady!
    I have a Nikon D700! I decided to check it for broken, hot pixels. Found 2 hot, but it's not scary! Found another! When approaching and enlarging this black photograph, it is black, but not uniformly black, it is all in squares and rectangles of different shades, some kind of light black, gray, light gray, dark gray, randomly arranged, and it gives the impression as if the entire matrix is ​​chopped and pokotsan, in general it is not clear! And with every black photograph, these squares and rectangles change their locations! Although compared with other black photographs of other cameras, for some reason everything else is uniformly black on others, no matter how you bring it closer! Arkady, what could it be? Something with the matrix, or should it be? Explain please! Thank you in advance!!! I tried to insert this photo, but not inserted!

    Reply

  6. Alexander
    22.03.2017

    I looked. Everyday, it makes no sense to shoot for more than 30 seconds. At ISO100 / 30sec - if you do not look pixel by pixel, it is not noticeable. At ISO6400 / 30sec - the starry sky within a large metropolis.
    How I solved the problem - I just don't bother, which is what I wish everyone)

    Reply

  7. Sergei
    11.08.2017

    About “crazy alpha particles”.
    The range of alpha particles in air is a few centimeters.
    To influence alpha radiation on the matrix, an alpha radiation source should be placed in front of the matrix and all glass in front of the matrix should be removed.

    Reply

  8. Edward
    26.12.2017

    He conducted several of his own experiments on this topic. I got unexpected (for myself) conclusions. Ready to share.
    First, the first unexpected conclusion: the viewer program is of fundamental importance for viewing a picture with hot pixels. I will show in the pictures from the computer screen.
    The experiment carried out as follows. Pictures were taken with the lens cap closed.
    The first shot at high light sensitivity (800) with a shutter speed of 15 s. This is how it looks in XnView 2.39 2015. Like a continuous noise. https://ibb.co/kTJp0R Same picture
    in the program ViewNX 2 2.8.1 2013 looks quite decent. 400% increase. https://ibb.co/ieQPZm Defective pixels are visible.
    So, in order not to be intimidated by the "starry sky", you need to choose a viewing program.

    About the second experiment and the second conclusion - a little later.

    Reply

    • Valentine
      28.12.2017

      VieNX looks at the NEF file well because it is a native Nikon program that understands the algorithm of its raw file. The XnView program is a third-party software viewer, which is not sharpened for raw in principle, but can view them. Nikon's proprietary raw viewing algorithms have not been passed on to XnView and other viewers, so they basically reproduce raw raw poorly. The exception is the jpeg embedded in the raw file for previewing - they play it normally, like all other jpegs.

      Reply

      • Edward
        09.01.2018

        It is obvious. Another thing is more interesting: it is possible that Nikon's program masks the "starry sky", and XnView shows it as it is.

        Reply

      • Valentine
        09.01.2018

        Nikon's program, when interpreting a raw RAW file, uses its algorithms and many parameters that form the final image on the screen. XnView interprets the file as it can (in practice, very primitive), so it often displays with multi-colored pixels even those files in which there is no 'starry sky' effect. Nikon's program (camera firmware or converter core) must remove all kinds of extraneous defects that reduce image quality. If you like to apply the word masking to this interpretation of the file, let it be masking. Note that such a negative effect as noise is not always removed by default, because eliminating it can both improve image quality (in terms of image clarity) and worsen it (in terms of reducing detail). The manufacturer already partially transfers control of the parameters of such effects to the user.

        Reply

  9. Edward
    27.12.2017

    Second experiment. Dependence of defective pixels on whether the viewfinder is open or closed.

    Shooting with the lens cap closed indoors under home lighting. Pictures were taken on two devices: D40X and D610. In all cases, ISO 800, aperture fully open, shutter speed 15 sec. From the point of view of the effect on the pictures of an open or closed viewfinder, I note that the experiment took place indoors under home lighting. Defective pixels in the images were counted using the 1.0 program DeadPixelTest 2001.

    The full comparison table is here.

    The results of the experiment. On one device (new), when the JVI was open, three “hot” pixels were found, with the closed one, four. On the second device (old), 99 “hot” pixels were found with open JVI and 111 with closed pixels. On repeated images on the same device, the coordinates of the hot pixels remain the same, which indicates the repeatability of the experiment and the randomness of the results. I can’t explain yet why there are more “hot” pixels when the JVI is closed, than when it is open.

    Output. Preliminary conclusion: the number and brightness of hot pixels are not strongly affected, the JVI is closed or open. For clarity, it is worthwhile to conduct an experiment in bright sunlight. Wait for spring.

    Reply

    • Valentine
      28.12.2017

      Flashlight in the JVI. There was already such an experiment. Only a direct hit of sufficiently bright light affects a little. In other cases, you can neglect. In general, you are right, there is no significant influence. But when shooting in bright light in LiveView mode (when the eye is not pressed to the JVI), you can play it safe and cover the viewfinder with available tools.

      Reply

  10. Edward
    27.12.2017

    Here is the link https://ibb.co/dAr2NG

    Reply

  11. Edward
    28.12.2017

    With what, in fact, the experiments began.
    I noticed in my pictures a lot of gray round spots. Hundreds Thought: dust on the matrix. I took the device for cleaning. Cleaned. But they said that it was not dust, but broken or hot pixels. Began to experiment. Found out that defective pixels are not like these round spots. The spots are much larger in size, they do not have sharp edges with a halo and a round shape.
    In the attached picture, these differences are clearly visible.

    What are these specks? Who can guess?

    Big picture https://ibb.co/fbF3Wb

    Reply

    • Valentine
      28.12.2017

      As an option for the influence of the lens. Lens dust, inhomogeneous glass structure, etc. On the diaphragm 22, this can occur. On real shots, this can interfere very, very rarely, only if you do not have any purely specific tasks when shooting.

      Reply

      • Edward
        09.01.2018

        I tried to shoot with this camera with a different lens. The defects are the same. Apparently it's not the lens. Only the matrix remains. But it was being cleaned ... Riddle.

        Reply

      • Edward
        09.01.2018

        ... "I tried it on this device" ...

        Reply

      • anonym
        25.01.2018

        "Cleaned" and "Cleaned up" are very different concepts.

        Reply

      • Michael
        25.01.2018

        Classic frame with dust. Only her more than a lot. I've never seen so much. I have not seen other options for the appearance of such a picture

        Reply

      • Michael
        25.01.2018

        Although met, the oil on the matrix gives a similar picture

        Reply

  12. Andrei
    04.06.2018

    Damn, I decided to check the camera down for broken pixels (I’ve been using it for two years) set ISO100 and 8 shutter speed. Found a bunch of hot pixels. Got upset. I decided to check for less shutter speed. I put 500 and almost did not find them, what does this mean? can I wasted in vain?

    Reply

    • KalekseyG
      04.06.2018

      "Hot pixels are usually lonely, but with very long exposures, their number increases, as shown in the examples in this article."
      If you don’t shoot stars and a night city, then don’t worry.

      Reply

  13. Paul
    01.02.2019

    How to make a remap at home on Nikon D3xxx?
    Bold, hot pixels at ISO 1600 and shutter speeds of 1/100.

    Reply

  14. Dmitriy
    24.10.2019

    What to do with a lot of dead pixels on the matrix? More than 15.

    Reply

    • Michael
      24.10.2019

      Remap. SC is waiting for you

      Reply

  15. Dmitriy
    24.10.2019

    What is the price in ye?

    Reply

    • Dmitriy
      24.10.2019

      50 dollars remap. I think it’s worth it to make an old device for $ 250.

      Reply

  16. Dmitriy
    25.10.2019

    If white and colored dots appear in the photo on iso 640 and higher, and with iso 100 at 1/200 on black I can’t find them, then maybe it’s not broken pixels? Clear, confused.

    Reply

    • Michael
      25.10.2019

      These are the so-called “hot pixels”. The article is just about them

      Reply

  17. Dmitriy
    25.10.2019

    Thanks. And I thought that whites are beaten.

    Reply

  18. Maria
    06.12.2019

    I first noticed it on Canon. And with low mileage. 5d Mark 2. Before that, I had no idea what this could be with the Nikons ...

    Reply

    • Roman
      06.12.2019

      Well, if 5D2 was taken away by filming, because they were shot by everyone who is not lazy, but Nikon is not, then how can one be compared?

      Reply

      • Maria
        06.12.2019

        Her, well, Nikon also experienced, which D800). In Canon, by the way, the mileage is not so very. I just chose this principle. The service confirmed 20 k.
        I can’t say that the 800-ka in any more advantageous position. unless on a computer 800 displays 7k points, and five to 5k. Maybe this also somehow affects.

        Reply

      • Jury
        06.12.2019

        a lot of video was filmed on 5d Mark 2, therefore, the mileage is small (the shutter is not worn out), but the matrix is ​​all in hot pixels. On D800, the pixel is smaller - hot ones are less noticeable, plus they can be easily removed.

        Reply

      • Maria
        06.12.2019

        Clear. HERE, too, such an idea overtook. But everything is logical. It remains to google how to programmatically remove. In general, without zooming it is not particularly visible.

        Reply

      • Maria
        08.12.2019

        By the way, I apologize to everyone for the misinformation.
        I looked closely. The pixels are “knocked out” there. Where, out of ignorance of the converter, I “twisted” this software contour sharpness. Without her, problems are generally not visible. And each pixel is filled with some information according to the corresponding, not starry tone.
        Although the seller from the overbought confirmed that the camera was often used for video.
        So your truth turned out to be)

        In general, it is clear that the miser pays twice, of course. If you want a BU - expect surprises.
        After all, as I understand it, for Cannon and programin like ShowExif there is no way to check the shutter mileage.

        Here with this photo everything should be in order https://vk.com/albums636784?z=photo636784_457248590%2Fphotos636784
        And here - whitish spots https://vk.com/albums636784?z=photo636784_457248591%2Fphotos636784
        I don’t know what hosting to throw, so that it can be seen and you can give advice on photos.

        Thanks for helping everyone)

        Reply

      • Maria
        08.12.2019

        And in fact, the hot pixels were confused with the single killed post-processing. After carefully reading the article. Full Fail) Sorry.

        Reply

      • Iskander
        10.04.2020

        To check the mileage of Canon there is a program Canon EOS Digital INFO.

        Reply

      • Yurko
        01.12.2020

        Tilkyot on exclusive OS is not a canaє .. (

        The one that is very principled - that try? .. To cope with your tasks, then th ok. If you can't cope - it’s tricky))

        Reply

  19. Larion
    05.03.2020

    I got rid of hot pixels on the Nikon d7500 by cleaning the matrix twice in a row. The method has been described here. https://www.dpreview.com/forums/post/61670711

    Reply

  20. Yurko
    01.12.2020

    oh єs! When video is shown, especially if you catch fire .. - mind - you need to minify the camerat (drive to steer! Not to beat "zirok", not to play)).

    and for a photo, it is effective - rav ryatuє. Tai, jpeґ in a large number of correctly projected scenes є in solidarity, to tsyo zorepadu.

    ps I, to the tsії statty, do not know the same, tsі "zirki" in the photographs. Zrobiv 30sec test camera. І .. oh-yo-y - my eyes didn't see it)))

    Reply

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