Nikon F4S in trouble

Discussion in '35mm Cameras and Accessories' started by rhmimac, Nov 22, 2011.

  1. rhmimac

    rhmimac Member

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    My Nikon F4s is in trouble. See attachment.
    Upper frame A mode, middle frame P mode, lower frame M mode.
    Shot 3 frames each of a scene in "A","P" and "M". "P" underexposes in each frame of the 36exp E6 roll.
    Comparing F100 and F4s in S mode yields a F4S exposure time which is much shorter than F100 exposure times ( 1,2 and 4 secs tested because you can "hear" it starting and stopping).

    So my conclusions:
    1) matrix meter's fine in viewfinder prism as "A"mode is 100% ok
    2) shutter's OK as A and M work fine.
    3) "computerised" program and shutter priority are sh.tt.

    What would you do next? Anyone who's got this problem on his F4/F4s/F4e and got it solved?

    I'm considering a KEH body without prism to swap the defect body and have a spare one for parts.

    Any answers and tips welcome!

    Thanks.
     
  2. Chan Tran

    Chan Tran Member

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    Redo the test! Make sure that the shutter speed are right. My suspicion is that the camera when it controls the aperture it doesn't do it correctly. The level moved a bit more than it was supposed to. When in A and M mode the aperture is set via the aperture ring and the aperture stop down level in the camera would move all the way. The setting on the aperture ring limit the aperture to stop down to only the set aperture. In P and S mode the aperture ring is set to minimum aperture, the stop down level would move just enough to stop down to the aperture that the camera determines as correct. This level may have moved a bit further than is was supposed to.
     
  3. rhmimac

    rhmimac Member

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    Thanks for replying. I checked the S and P modes when pointing the lens to a bright lamp checking this way if the lever is stopping down and it's all working as it should: bright light in S mode yields in a small aperture at 1/8sec, aperture is almost max when pointed to a dark area.
    So I still believe after experiencing the big differences between F100 & F4 at long shutter times of 1,2 and 4 secs-up to 50% less for the F4s on 2secs - that my shutter unit isn't working properly in P and S modes. Why this happens is the question now.
    Strangely the A and M modes are firing away just perfect.
    I've got another F4s body for 90$(without prism) or 250$ for a complete unit. So maybe I have to head towards one of these. I just love the grip and the weight of this camera too much. Old School "VR", 1,5kg lens and body in your hand.
     
  4. RidingWaves

    RidingWaves Member

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    I'd check that the aperture stop down lever is moving fully, you can check the full movement by doing a stop down/ mirror lock-up sequence. One of the 3 or 4 motors in an F4 moves this lever, and shares duty with shutter charging. Its my theory that as either the motor wears or as other parts wear or stick then this lever motion isn't complete, which then can cause the lens to not fully stop down.

    I am not 100% sure, but I believe in the case of P and S modes, the lens is precisely stopped down by this lever movement, (which is what the Ai-S series lenses do different than Ai or the F and K do, a linear stop-down lever movement).

    (Which *may not* apply in your case).


    I have 2 F4s that are doing this.
     
  5. Chan Tran

    Chan Tran Member

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    I think in S and P mode the camera stops the lens down further than is supposed to. That is the lever moved more than it should. What I would do is to compare the aperture opening in manual vs P or S.
     
  6. RidingWaves

    RidingWaves Member

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    Yes Chan, and we should also find out which lens he was using. Of course he can't do P or S with a non P or AF lens with CPU.
    I would not rule out the meter as well. No indication from OP whether or not either matrix CW or spot was used.
     
  7. rhmimac

    rhmimac Member

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    So another thank you for your contributions.

    My test roll E6 was shot on all 36 exp's in matrix metering, subsequently 12 series of A, P and M modes. Each P frame(total of 12) came out underexposed. All 24 A and M frames were OK.

    I used all true nikon lenses(I own only 1 sigma 105mmf2.8): the first 23 frames a 28-80 f3.5-5.6 AFD zoom and all the rest a 75-300 f4.5-5.6 AF to rule out if this D thing is of any influence in P/S mode.

    I checked P and S mode again in spot and matrix: dark subjects yield in opening aperture almost completely(f4,F3,5), very light subjects and same shutter speed dailed in yields in smaller aperture(F11,F16,f22), my conclusion is here: the camera is stopping down correctly.

    Leaves the big differences in shutter speeds when compared to the F100 - all were almost half, thus underexposing a lot .The F100 is a trusty machine, never had any troubles with it.
    So the shutter operation in S and P is not correct and needs checking or replacing I assume.

    Any further thoughts from your side?

    Thanks.
     
  8. Chan Tran

    Chan Tran Member

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    When you said the shutter speed isn't correct, do you mean that the display isn't correct or the display is correct but the actual shutter speed is different?
     
  9. RidingWaves

    RidingWaves Member

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    If it was a shutter issue it would mean that in M the exposure would be off. In S and P mode the lens must be put in to the max, f22. That way the aperture has full range of motion. The F4 then stops its lever at what it thinks is the appropriate spot along the liner travel of the aperture lever.
    If the lever as I described above doesn't or can't got the full range then the lens would continue to stop down, and that I think is what is causing the under exposure. You need to check that lever inside the f4 as its shooting, try it in S and P and get back to us.
     
  10. rhmimac

    rhmimac Member

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    The shutter times where checked/compared with long shutter speeds 1sec,2sec and 4sec which is easy to check against the same speeds on the F100. I pushed the shutter on both camera's simuntaneously and counted with a stopwatch for the secs. The F4s always closed the shutter first up to halve the speeds compared to the F100, underexposing in this way. So I'm sure the shutter's not ok in S(and in P?)
    There's only the internal LCD in the viewfinder to check if speeds dailed in are corresponding, which I did: all speeds on the internal lcd correspond with the dailed in speeds on the top shutter speed wheel.
     
  11. rhmimac

    rhmimac Member

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    RidingWaves,
    couldn't it be a pure electronic problem? All M exposures on my roll were 100% ok. I agree this is without use of the stop down lever which acts only in S and P.
    I made all A and P exposures identical to my M exposures . So the meter performed ok in M which was the same exposure on the meter in P and A.
    I made some shots of the aperture's action in S. See attachements. I could clearly see the aperture closing at max f22 when pointed to the light blue sky in spot metering mode, shutter speed on 2s and 4s . When pointed to a dark subject the aperture widens up to almost maximum f3.5 in this case.

    I really appreciate your input!

    Thanks.
     
  12. rolleiman

    rolleiman Member

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    Were your pics taken at the 80mm end of your lens?..If so then 5.6 is the max aperture. Some lenses with a "macro" mode on will lose up to a stop further than that in reality, when used in close up mode. Perhaps when you used it in auto mode you thought you were getting 3.5, when in effect it was 5.6?
     
  13. rhmimac

    rhmimac Member

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    Hi Rolleiman,
    I didn't note the zoom setting but you're right @ 80mm it's limited to f5.6. I'll check that again. I posted the images to show the stopping down lever actually works as it's opening up in S mode from f22 to f3.5 or f5.6 or in between depending on the (spot)metering.
    Thanks for your input.