Nikon F3 weird mirror problem..please help!!

[geetist]

Ok, so recently I sold all my leica stuff and switched to Nikon SLRs. The F3 is my favorite among the bunch, and actually among all 35mm cameras.

However, this particular sample that I bought is giving me headaches.. Here is the issue: when shooting in portrait position with the F3, the mirror would not flip back down after firing the shutter. I can keep rewinding the lever and firing the shutter ( I can see that the shutter moves) but the mirror would stay up like that. If you put the camera in landscape position, the mirror would slowly fall down due to gravity. Oh and one thing worth mentioning is that the mirror is more likely to stuck when in portrait position in one particular direction than the other (rotating clockwise vs counterclockwise).

What seems to be the problem? Is this a sign of a weak battery or it's something more serious?

Thanks in advance for any answers.

Jack

 

[Phil_F_NM]

The mirror return is not motor driven, so is not battery dependent. There are no motors in the F3, so to speak, just the light meter and the shutter, which is mechanical but controlled by an electronic circuit which sets the slit width and timing. Mirror is simply pushed down by a spring after exposure.

The problem you have is a weak or very dirty (probably the latter) return spring and mechanism for the mirror. A CLA will remedy this just fine.

Phil Forrest

 

[vitaly66]

Likely the mirror bumper foam is just a bit sticky.

Remove lens, get mirror in down position, lightly touch mirror bumper foam with back of fingernail of pinky finger. Is it a little bit sticky?

Also, inspect mirror for evidence of adhesive residue at leading edge.

If this is the problem, it is a fairly simple fix, may be done DIY, and is well-documented on the internet.

 

[Gumby]

The above replies are more likely the problem, but are you sure you didn't inadvertently lock the mirror up? It is unlikely because mirror lock-up on F3 isn't very easy and if you did so you'd likely know so. But then a gain, if it were locked up it wouldn't fall slowly when shooting in a landscape orientation, would it. Forget I said anything.

 

[Calzone]

Likely the mirror bumper foam is just a bit sticky.

Remove lens, get mirror in down position, lightly touch mirror bumper foam with back of fingernail of pinky finger. Is it a little bit sticky?

Also, inspect mirror for evidence of adhesive residue at leading edge.

If this is the problem, it is a fairly simple fix, may be done DIY, and is well-documented on the internet.

I think this is the most probable. The foam seals around the mirror are acting like double sided tape.

Check out John Goodman's site on foam seal replacements. I bought a sheet of foam from a hobby store. Not a difficult job unless you have sausage fingers.

Cal

 

[geetist]

Thanks Phil, I think this is more likely the case since the mirror cushion foam is clean.

 

[geetist]

Thanks for the comments on the possibility of a sticky mirror cushion foam. This is not the cause of the problem though, since the foam is clean and the mirror is not attached to it while locking up. see picture.

Maybe a weak spring but I'm still curious to hear other opinions.

Thanks again.

 

[leica M2 fan]

This really sounds like what Phil says- a weak return spring.
Can be sorted out quickly. Good luck!

 

[nobbylon]

Sorry to disagree but this sounds like text book secondary mirror foam!
I had exactly this problem on my last F3 and although a pain to sort out it's possible.
Using a cotton bud dipped in acetone, wipe off the excess and then whilst holding the mirror halfway up clean the foam strip from the rear of the main mirror that the secondary mirror closes on. It takes patience and small q tips. Replace the strip of foam and enjoy the mirror return in any position!

 

[Calzone]

Sorry to disagree but this sounds like text book secondary mirror foam!
I had exactly this problem on my last F3 and although a pain to sort out it's possible.
Using a cotton bud dipped in acetone, wipe off the excess and then whilst holding the mirror halfway up clean the foam strip from the rear of the main mirror that the secondary mirror closes on. It takes patience and small q tips. Replace the strip of foam and enjoy the mirror return in any position!

I agree with John's post above. It is a carefull job.

BTW when I do a foam seal job on a F3 I actually remove the mirror. There are two spring clips, one on each side. I use a dental pick to lift the springs.

Cal

 

[Dwig]

Sorry to disagree but this sounds like text book secondary mirror foam!
...

I question the decomposing mirror foam theory based on the OP's statement that "If you put the camera in landscape position, the mirror would slowly fall down due to gravity.". With bad foam, the mirror will return with its normal fast 'snap' once it is released from the foam bumper. A sluggish or slow return points to a failed return spring or some failure in the mirror hinges and/or linkage.

 

[geetist]

Thanks guys for your replies. I will first double check the foam and then maybe find a repair person to have the spring checked. RFF has always been helpful for these random camera problems!

 

[nobbylon]

I question the decomposing mirror foam theory based on the OP's statement that "If you put the camera in landscape position, the mirror would slowly fall down due to gravity.". With bad foam, the mirror will return with its normal fast 'snap' once it is released from the foam bumper. A sluggish or slow return points to a failed return spring or some failure in the mirror hinges and/or linkage.

I agree with your assumption IF we are talking about a single mirror.
The F3 has a secondary mirror and because they are a PITA to replace, most have not had this secondary foam replaced. I have never heard of failed or weakened springs in any F3 and having had this exact problem of a sluggish return mirror on an F3 would wager this is the case here. It's very easy to check by turning the camera upside down and slowly lifting the main mirror to the top of it's travel. Now slowly allow the main mirror to return whilst maintaining finger resistance and carefully watch the secondary mirror. It's quite obvious if it's sticking slightly.

 

[nikon_sam]

Pull the lens and carefully lift the mirror to make contact with the foam bumper...hold it there for a few seconds then let it go...it should snap back in any format...even upside down...
Next lift it without touching the foam and see if it snaps back...if it doesn't snap back it could be the spring...

 

[Calzone]

Pull the lens and carefully lift the mirror to make contact with the foam bumper...hold it there for a few seconds then let it go...it should snap back in any format...even upside down...
Next lift it without touching the foam and see if it snaps back...if it doesn't snap back it could be the spring...

Sam,

Good advice. Very smart and clever.

Cal

 

[nobbylon]

Sam,

Good advice. Very smart and clever.

Cal

Cal and Sam,
a waste of time in this case because of the secondary mirror!! lift the mirror up and before the main mirror contacts the foam strip the secondary has probably already stuck to the rear of the main. j

 

[Calzone]

Cal and Sam,
a waste of time in this case because of the secondary mirror!! lift the mirror up and before the main mirror contacts the foam strip the secondary has probably already stuck to the rear of the main. j

John,

Thanks. I forgot about the secondary mirror.

Cal

 

[Dwig]

I agree with your assumption IF we are talking about a single mirror.
The F3 has a secondary mirror and because they are a PITA to replace, most have not had this secondary foam replaced. I have never heard of failed or weakened springs in any F3 and having had this exact problem of a sluggish return mirror on an F3 would wager this is the case here. It's very easy to check by turning the camera upside down and slowly lifting the main mirror to the top of it's travel. Now slowly allow the main mirror to return whilst maintaining finger resistance and carefully watch the secondary mirror. It's quite obvious if it's sticking slightly.

While true, sticky foam doesn't affect the mirror travel after the adhesion releases. This occurs after a very short amount of travel when it's the main mirror's foam. It possibly could impact the travel over a slightly greater portion of travel range when it is the secondary mirror that has the issue, but still, once the foam releases the mirror travel should be brisk.

If the mirror return is "limp" (read: falling only due to gravity) or slow/sluggish over the whole range then the mirror foam is not the primary cause.

 

[rbsinto]

Unless the repair person you are considering sending the body to for repairs lives across the street, by the time you box it, ship it and pay for the repairs and shipping back to you, you will have spent as much as it will cost to pick up a working body from KEH, ebay or perhaps locally from craigslist.
KEH currently has a bargain grade F3 for $119.00 plus shipping, and perhaps you can do a swap with them for yours and defray some of the cost. Even better deal.

 

[nobbylon]

While true, sticky foam doesn't affect the mirror travel after the adhesion releases. This occurs after a very short amount of travel when it's the main mirror's foam. It possibly could impact the travel over a slightly greater portion of travel range when it is the secondary mirror that has the issue, but still, once the foam releases the mirror travel should be brisk.

If the mirror return is "limp" (read: falling only due to gravity) or slow/sluggish over the whole range then the mirror foam is not the primary cause.

You've obviously had this on an F3 and know it's not the foam, i'll get my coat 🙂

To the OP, get some acetone/ nail polish remover and some small q tips. Turn camera upside down and carefully lift the main mirror. watch the secondary mirror as it closes and before it does gently wipe a clean q tip on the foam on the back of the main mirror. Is there any tell tale signs on the secondary mirror face ie black smudges on the closing edge? If the foam crumbles or smears off then that is the problem. Clean the rest off using the acetone and try the camera again.
I will say again, I have never heard of anything related to weak springs in an F3 mirror box.