Let\'s not start a war of words because there is no material gain or loss for winning or loosing.
All of us here are trying to figure out what caused the symptoms which was initially classified as light leak. But as time goes by with more available information, things seems to show it might be something else.
Let\'s use what variables we were given by those who owns the camera and apply the best method in the industry for identifying the problem. The method is known as Process of Elimination used in the aircraft industry for air crash investigation. Remembered that there could be more than a single cause for most of the air crashes , so our problem here is no exception.
1) initially the problem was thought to be light leak, but after someone tested it with a lens cap on and found that there were none.
We can now dismiss this as a possible cause.
2) next we have flares, there are many kinds of flares: lens flares, flares caused by internal reflection which could be of any shape and size. Here we have users who have tested it with and without lenses, wide and telephoto. The issue was found with wide angle lens but not with telephoto, and it was also found without a lens.
So the lens can be a source. I will go into this further later.
3) then we have the edge of the focusing screen that might have caused the problem. As one of the user have noticed that it only happens using LV and not with the VF, the next thing is it was also on still photos. Both of these happened with the reflex mirror in the up position, which means that there is no possibility that the focusing screen can cause it, because it will be completely blocked by the mirror and the rubber damper at the edge of the mirror box.
So the focusing screen can be ruled out.
4) let\'s concentrate on just the mirror box with the mirror in the up position as in LV or picture taking mode. Here we have eliminate the lens, the focusing screen, and what we are left with is just the blackened mirror box and the shutter behind. Remembered that one of the user said that he encountered the problem without the lens.
Now! What do we have here? A blackened mirror box, a secondary reflex mirror sitting behind the primary mirror in the up position, and the shutter.
We can rule out the blackened mirror box. But the edge of the secondary mirror can cause reflection if it is not sitting well or painted, and not only that, because it is sitting on top, whatever reflection it can produce can only be directed towards the lower section of the sensor, which means the top of the picture.
So some owners here must do a check to confirm or eliminate it. The best way to do it is in sensor cleaning mode with a flash light shinning from the very edge of the lens mount with a steep angle, and watch the reflection on the sensor surface. Also watch for inter-reflection caused by the AA filter.
5) finally the shutter. This might be a little tricky because no one other than Nikon knew exactly how it should work. Initially I thought that the timing sequence could play a part in this because of the dark band found on top of the pictures which looks like one of the shutter plate caused by information recording of the sensor was either too early or too late with respect to the 1st or 2nd shutter. But then I recalled that the D750 has an electronic 1st shutter for video. Could this be another cause? Now the timing of the sequence is something new and critical and Nikon does not have as much of expertise as Panasonic, Sony or Canon on video.
Like I said let\'s not start a war of words but just add to the discussion and hopefully we are able to come to a conclusion and help to resolve this issue, so that all those owners of this camera can enjoy their photography.
Let\'s not start a war of words because there is no material gain or loss for winning or loosing.
All of us here are trying to figure out what caused the symptoms which was initially classified as light leak. But as time goes by with more available information, things seems to show it might be something else.
Let\'s use what variables we were given by those who owns the camera and apply the best method in the industry for identifying the problem. The method is known as Process of Elimination used in the aircraft industry for air crash investigation. Remembered that there could be more than a single cause for most of the air crashes , so our problem here is no exception.
1) initially the problem was thought to be light leak, but after someone tested it with a lens cap on and found that there were none.
We can now dismiss this as a possible cause.
2) next we have flares, there are many kinds of flares: lens flares, flares caused by internal reflection which could be of any shape and size. Here we have users who have tested it with and without lenses, wide and telephoto. The issue was found with wide angle lens but not with telephoto, and it was also found without a lens.
So the lens can be a source. I will go into this further later.
3) then we have the edge of the focusing screen that might have caused the problem. As one of the user have noticed that it only happens using LV and not with the VF, the next thing is it was also on still photos. Both of these happened with the reflex mirror in the up position, which means that there is no possibility that the focusing screen can cause it, because it will be completely blocked by the mirror and the rubber damper at the edge of the mirror box.
So the focusing screen can be ruled out.
4) now let\'s concentrate on just the mirror box with the mirror in the up position as in LV or picture taking mode. Now we have eliminate the lens, the focusing screen, and what we are left with is just the blackened mirror box and the shutter behind. Remembered that one of the user said that he encountered the problem without the lens.
Now! What do we have here? A blackened mirror box, a secondary reflex mirror sitting behind the primary mirror in the up position, and the shutter.
We can rule out the blackened mirror box. But the edge of the secondary mirror can cause reflection if it is not sitting well or painted, and not only that, because it is sitting on top, whatever reflection it can produce can only be directed towards the lower section of the sensor, which means the top of the picture.
So some owners here must do a check to confirm or eliminate it. The best way to do it is in sensor cleaning mode with a flash light shinning from the very edge of the lens mount with a steep angle, and watch the reflection on the sensor surface. Also watch for inter-reflection caused by the AA filter.
5) finally the shutter. This might be a little tricky because no one other than Nikon knew exactly how it should work. Initially I thought that the timing sequence could play a part in this because of the dark band found on top of the pictures which looks like one of the shutter plate caused by the information recording of the sensor is either too early or too late with respect to the 1st or 2nd shutter. But then I recalled that the D750 has an electronic 1st shutter for video. Could this be another cause? Now the timing of the sequence is something new and critical and Nikon does not have the expertise as Panasonic, Sony or Canon does.
Like I said let\'s not start a war of words but just add to the discussion and hopefully we are able to come to a conclusion and help to resolve this issue, so that all those owners of this camera can enjoy their photography.
Let\'s not start a war of words because there is no material gain or loss for winning or loosing.
All of us here are trying to figure out what caused the symptoms which was initially classified as light leak. But as time goes by with more available information, things seems to show it might be something else.
Let\'s use what variables we were given by those who owns the camera and apply the best method in the industry for identifying the problem. The method is known as Process of Elimination used in the aircraft industry for air crash investigation. Remembered that there could be more than a single cause for most of the air crashes , so our problem here is no exception.
1) initially the problem was thought to be light leak, but after someone tested it with a lens cap on and found that there were none.
We can now dismiss this as a possible cause.
2) next we have flares, there are many kinds of flares: lens flares, flares caused by internal reflection which could be of any shape and size. Here we have users who have tested it with and without lenses, wide and telephoto. The issue was found with wide angle lens but not with telephoto, and it was also found without a lens.
So the lens can be a source. I will go into this further later.
3)then we have the edge of the focusing screen that might have caused the problem. As one of the user have noticed that it only happens using LV and not with the VF, the next thing is it was also on still photos. Both of these happened with the reflex mirror in the up position, which means that there is no possibility that the focusing screen can cause it, because it will be completely blocked by the mirror and the rubber damper at the edge of the mirror box.
So the focusing screen can be ruled out.
4) now let\'s concentrate on just the mirror box with the mirror in the up position as in LV or picture taking mode. Now we have eliminate the lens, the focusing screen, and what we are left with is just the blackened mirror box and the shutter behind. Remembered that one of the user said that he encountered the problem without the lens.
Now! What do we have here? A blackened mirror box, a secondary reflex mirror sitting behind the primary mirror in the up position, and the shutter.
We can rule out the blackened mirror box. But the edge of the secondary mirror can cause reflection if it is not sitting well or painted, and not only that, because it is sitting on top, whatever reflection it can produce can only be directed towards the lower section of the sensor, which means the top of the picture.
So some owners here must do a check to confirm or eliminate it. The best way to do it is in sensor cleaning mode with a flash light shinning from the very edge of the lens mount with a steep angle, and watch the reflection on the sensor surface. Also watch for inter-reflection caused by the AA filter.
5)finally the shutter. This might be a little tricky because no one other than Nikon knew exactly how it should work. Initially I thought that the timing sequence could play a part in this because of the dark band found on top of the pictures which looks like one of the shutter plate caused by the information recording of the sensor is either too early or too late with respect to the 1st or 2nd shutter. But then I recalled that the D750 has an electronic 1st shutter for video. Could this be another cause? Now the timing of the sequence is something new and critical and Nikon does not have the expertise as Panasonic, Sony or Canon does.
Like I said let\'s not start a war of words but just add to the discussion and hopefully we are able to come to a conclusion and help to resolve this issue, so that all those owners of this camera can enjoy their photography.
Let\'s not start a war of words because there is no material gain or loss for winning or loosing.
All of us here are trying to figure out what caused the symptoms which was initially classified as light leak. But as time goes by with more available information, things seems to show it might be something else.
Let\'s use what variables we were given by those who owns the camera and apply the best method in the industry for identifying the problem. The method is known as Process of Elimination used in the aircraft industry for air crash investigation. Remembered that there could be more than a single cause for most of the air crashes , so our problem here is no exception.
1) initially the problem was thought to be light leak, but after someone tested it with a lens cap on and found that there were none.
We can now dismiss this as a possible cause.
2) next we have flares, there are many kinds of flares: lens flares, flares caused by internal reflection which could be of any shape and size. Here we have users who have tested it with and without lenses, wide and telephoto. The issue was found with wide angle lens but not with telephoto, and it was also found without a lens.
So the lens can be a source. I will go into this further later.
3)then we have the edge of the focusing screen that might have caused the problem. As one of the user have noticed that it only happens using LV and not with the VF, the next thing is it was also on still photos. Both of these happened with the reflex mirror in the up position, which means that there is no possibility that the focusing screen can cause it, because it will be completely blocked by the mirror and the rubber damper at the edge of the mirror box.
So the focusing screen can be ruled out.
4) now let\'s concentrate on just the mirror box with the mirror in the up position as in LV or picture taking mode. Now we have eliminate the lens, the focusing screen, and what we are left with is just the blackened mirror box and the shutter behind. Remembered that one of the user said that he encountered the problem without the lens.
Now! What do we have here? A blackened mirror box, a secondary reflex mirror sitting behind the primary mirror in the up position, and the shutter.
We can rule out the blackened mirror box. But the edge of the secondary mirror can cause reflection if it is not sitting well or painted, and not only that, because it is sitting on top, whatever reflection it can produce can only be directed towards the lower section of the sensor, which means the top of the picture.
So some owners here must do a check to confirm or eliminate it. The best way to do it is in sensor cleaning mode with a flash light shinning from the very edge of the lens mount with a steep angle, and watch the reflection on the sensor surface. Also watch for inter-reflection caused by the AA filter.
5)finally the shutter. This might be a little tricky because no one other than Nikon knew exactly how it should work. Initially I thought that the timing sequence could play a part in this because of the dark band found on top of the pictures which looks like one of the shutter plate caused by the recording of information by the sensor is either too early or too late with respect to the 1st or 2nd shutter. But then I recalled that the D750 has an electronic 1st shutter for video. Could this be another cause? Now the timing of the sequence is something new and critical and Nikon does not have the expertise as Panasonic, Sony or Canon does.
Like I said let\'s not start a war of words but just add to the discussion and hopefully we are able to come to a conclusion and help to resolve this issue, so that all those owners of this camera can enjoy their photography.
