Nikon F4 mirror sluggish / not rising properly

Hi all,

Well the thread title kind of says it all, but I noticed, starting a few weeks ago, unexposed regions at the bottom of some negatives produced from my F4s. (By the bottom of the negative, I mean the bottom of the normally-oriented image, so the top of the projected image in the camera). Over a few rolls the problem became more frequent and more serious -- so I'd say on about 1/4 of the frames from my last roll, I'm missing about 1/4 of the image. I initially thought I may have a shutter problem, but looking at the negatives and thinking about how the F4 shutter works, it seemed more likely that the mirror was not flipping up all the way when it is supposed to.

So today I took the lens off and had a look at the mirror while test-firing the shutter a few times and indeed, the mirror is moving up sluggishly and sometimes not making it all the way up to the top of the mirror box when it's supposed to.

Possibly relevant fact: I recently moved from a much warmer part of the world, so this autumn is the coldest the camera has ever had to operate (it's not particularly cold yet but the camera is used to much, much warmer weather ). I wondered if some lubricant somewhere might have got gungy?

SO -- I appreciate that the F4 is not something to be tinkered with lightly, but does anyone have any ideas of anything I might look at before spending money on this?

Secondly, if it does need to be cleaned / lubricated professionally, what kind of range might I expect to pay for that kind of service?
I ask because I have little income at the moment, and if it's likely to be more than €100-150 or so, it might be cheaper to buy another lighter, MF camera (that I've been thinking of getting anyway) and wait until I'm a bit more flush to do the F4 repair.

Thanks!
Hal

The F4 is a professional camera Hal and needs professional servicing, I suggest you have a camera technician look at the problem and quote you a price to correct the fault, any"ball park" price anyone may give you means nothing.

benjiboy said:

The F4 is a professional camera Hal and needs professional servicing, I suggest you have a camera technician look at the problem and quote you a price to correct the fault, any"ball park" price anyone may give you means nothing.

Click to expand...

Thanks -- as I said, it is not a camera I intend to tinker with. But many people here have more experience than I with the pricing of camera repair. I'm not asking for a quote, just to hear other people's experience. When I can pick up a perfectly serviceable F-mount camera for < €100, the decision to spend money shipping it to a repair shop is not necessarily an obvious one right now.

Have you tried a fresh set of batteries? What frame advance mode do you use? Put a scrap roll of film in, install fresh batteries, put in Ch then press and hold the shutter button until ens of the roll is reached, rewind the film and repeat.
Use manual exposure and a fast shutter speed. Observe the mirror during the procedure.

While I've not worked on an F4, I suspect something else may be amiss.

On many cameras, the release button starts the release process, but the actual release happens as a result of the mirror rising to the top of its travel. The raised mirror causes the release. I could be wrong assuming the F4 works this way as well.

My vote is for a CLA rather than just getting some other body. Who knows what issues another body might have? After a CLA on your F4, you'll have a great working camera. I've got two of them.

Service manual available at http://arcticwolfs.net/
A F4s with fresh batteries, a lens at f4 or faster, shutter speed of 1/250 or faster should expose a 36 exposure roll of film in 5 to 6 seconds.

Thanks for the constructive input guys. After developing a test roll it looks like it really does need some pro attention. I'll send it in as soon as I can be reasonably sure I can pay for the service