Problem with my nikon D300, viewfinder darken after taking pictures

Discussion in 'Nikon' started by xi_qiu, Jun 2, 2010.

  1. Hi everyone,
    I have a problem with my Nikon D300, the viewfinder will become dark after taking pictures, it can recover by pressing the Depth-of-field preview button. It seems that the mirror will not go back to it's original position. Anyone knows if this is a serious problem and if it's easy to fix it
    Thanks for the help.
  2. Set the lens to it's larger aperture. Does it go dark still? If not, change to a different lens and see if the problem stay or go with the lens. Seems like the lens aperture is sticking for some reason.
  3. "It seems that the mirror will not go back to it's original position. " - if this was the case, you would see a shifted or distorted image.
    What is the degree of darkness? Is is as dark as when you turn the camera Off ? - then you may have a power supply or battery problem. If it gets even darker... perhaps it is what Tommy suggests. Try another lens if it is dependent of the aperture in the lens.
  4. The problem is more often in smaller aperture, but still there in larger aperture, I do change to another lens and the problem is still there. The darkness is complete dark and even I changed to a fully charged battery, it will still become dark completely.
  5. Puzzle it is...
    Possibly, your camera mount aperture index follower ring may be dirty or deformed.
    Have you tried to install any "unusual" lens that could possibly bend the aperture index ?
  6. I just mount Nikon lens and Tamron 17-50 f2.8 lens. Is this a serious problem?
  7. Not a problem, but sometimes people try to mount weird lenses out there, that could possibly damage the mount, if forced.
    When the lens is mounted on a camera, the aperture should be kept in the wide open position, by the mechanical aperture lever that must have freee movement and spring back action.
    With lens mounted, see through the lens if possibly you can tell if aperture is closed. If it is closed, then dismount the lens and try to operate the camera lens mount mechanical lever, if springs back easily, or get stacked or slow and sticky.
    Do it against the light that should come through vewfinder eye, prism, mirror, and the lens. If it is completely dark, may be it is the mirror that did not come back to resting down position?
  8. Yes, it's the mirror did not come back to it's down position, seems like somewhere is stucked since it will come back by pressing the Depth of field preview button. I just do not know if the camera has a big problem and should I fix it or not
  9. Do you happen to have the camera in Mirror Lockup mode?
  10. "...seems like somewhere is stucked..." You need to have your D300 body serviced. If the mirror may be in a not-return-mode (as yours is doing,) a spring may need attention in the camera.
  11. There are perhaps 2 settings to either delay mirror in up position, or to keep it until a next event.
    One is the mirror up for shooting, and the other is the mirror up for sensor cleaning.
    Make sure both types of mirror up are turned Off.
    I think the mirror up position is kept up by the power of the battery.
    If you leave the camera in this state and you have the mirror up set, the bettery would get depleted quickly.
    If you power down the camera and remove the battery, the mirror should drop down, unless there is a spring problem, like Jerry described.
  12. No, the camera is not in Mirror lockup mode since it will not happen every time but quite often. I might take to repair shot to have them look it up. Thanks everyone.
  13. ShunCheung

    ShunCheung Administrator

  14. I did check the levers of both body and lens, they are both fine. Also I took my camera to two Nikon authorized repair station in Illinois, one said I need to replace some "sequencing unit" and the other said I need to fix the shutter. So it really confused me what to do, do you guys have any suggestions? Thanks
  15. ShunCheung

    ShunCheung Administrator

  16. You may e-mail Nikon USA
    and see if you can ship your D300 in for service. Hopefully the D300 you have is a Nikon USA model. If you do send the camera in, the estimate for repair is at no cost -- and they should be able to determine what is needed to get your D300 back to 100 percent.
  17. I did go to those two authorized service station today and they gave me different answers which puzzled me. My model is China model not USA model, will that still be no cost to repair?
  18. ShunCheung

    ShunCheung Administrator

    A Nikon D300 is a Nikon D300; there is no difference between one bought in China and one bought in the US, except for the warranties. Nikon USA will not provide any warranty repair. If you have a receipt from that store in China, Nikon USA can fix it for a fee. Therefore, you might as well check with APS as I mentioned in the link above. They are in Morton Grove, not far from Chicago.
  19. My camera is two more years old and out of warranty. I wonder is there any difference between local service station and I mail to nikonusa?
  20. I had the same problem recently (mirror stuck in up position, D300), and it's currently in for repair, though under warranty. Plenty of other posters out there with the same problem. Mine first had the problem once, then was fine for 30 frames or so, then it happened again and stayed that way. The camera flashes 'err' or something in the LCD, and when I took a shot only about 1/5 of the frame is exposed. It kind of looks like as if you were shooting with flash, but exceeding the max sync speed. Of course the viewfinder is black. Interesting thing though is that live view did not seem to work at all, just got a black screen. I saw that other people with a similar problem could still use their camera in live view, so I tried it myself, but it didn't work.
    I would be a little ticked off if it wasn't still in the warranty period.
  21. Funny, just got word than mine is ready, and here, in German, is what they replaced:
    IF Base Plate Unit, DG PCB Unit, Blendensteuerung und Verschluß erneuert. Belederung erneuern.
    Blendensteuerung must be something like 'aperture control' and verschluss is shutter. The cost was listed only as 0.0, so I don't know what it would have cost out of warranty.
  22. Sounds like they replaced a lot of circuitry. If this is common D300 fault, Nikon may need to provide speedy advice service, like the one for the D70 cameras, few years ago.
    I hope D300S does not have this problem, as Nikon had chance to do the justice with the "S" incremental version.
    Did that happen to D300S, the "S" camera ?
  23. The Nikon authorized repair station said it's the sequencing unit problem, since there is no error message and they need to replace the whole component, I do not know what that is. and the other service location said it's the shutter problem.
    I am not sure if I bent the lever not, seems not, I can still take pictures without Rob's problem and mirror can restore to default position by pressing preview button.
    I will ask the other shop and see what's going on, and if any one have suggestion , just let me know, thanks a lot.
  24. Sounds like we have somewhat different problems. Maybe the people you talked to simply didn't really know what they were talking about. I don't think the people that were working in the front office of the repair center I went to were actually technicians, they were just office staff. They just take the camera, a technician looks at it sometime in the next week, and then you find out what's wrong and how much it will cost to fix it.
    In any case you should be able to get an actual printed estimate for what it will cost to fix it. You could get two and take the less expensive one if you are worried about it.

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