Weird Nikon F2 flash sync problem -- only flashes above X speed

[RLangham]

Some of you may remember my last post, in which I detailed how my new Nikon F2 (SB) won't fire a flash via the PC socket. I finally got it to, but there's still a problem: it will literally only fire the flash if the speed is set to 1/125th or higher (and as many of you will know, the X speed on this particular camera is 1/90th.) Naturally I didn't discover this at first, as I had only tried firing the shutter at X speed.

Moreover, I looked through the shutter while firing the flash and I didn't even see partial illumination--at half a stop above X speed, I should have seen some light from the flash, but I saw nothing. This leads me to believe there is something more wrong with the internal sync terminals than is immediately apparent, since the timing must be quite far off.

Do any of you recognize these bizarre symptoms? Great camera besides all this flash business, and having flash on it would make it far and away my most useful canera.

 

[reddesert]

An obscure fact: the F2 switches between X and FP sync based on shutter speed. Speeds of 1/125 and up are FP-sync, not X-sync. This is implied, but not literally stated, on the flash sync page of the F2 manual. It's also mentioned here: http://www.mir.com.my/rb/photography/hardwares/classics/nikonf2/flash/index.htm This is in contrast to the F, where you have to move a little dial inside the speed dial to switch between X, M, and FP.

What this means, and I verified it with my F2, is that you shouldn't see the electronic flash through the shutter at speeds of 1/125 and up, because the camera is triggering the flash just before the shutter opens as if it were an FP-bulb.

That doesn't explain why your camera doesn't fire the flash at the X-sync speed and slower. But at least now you know the PC terminal works; perhaps the problem is internal to the X-sync contacts.

 

[millardmt]

([A]nd as many of you will know, the X speed on this particular camera is 1/90th.)

Flash X-sync speed is 1/80 sec.

Marc

 

[RLangham]

An obscure fact: the F2 switches between X and FP sync based on shutter speed. Speeds of 1/125 and up are FP-sync, not X-sync. This is implied, but not literally stated, on the flash sync page of the F2 manual. It's also mentioned here: http://www.mir.com.my/rb/photography/hardwares/classics/nikonf2/flash/index.htm This is in contrast to the F, where you have to move a little dial inside the speed dial to switch between X, M, and FP.

What this means, and I verified it with my F2, is that you shouldn't see the electronic flash through the shutter at speeds of 1/125 and up, because the camera is triggering the flash just before the shutter opens as if it were an FP-bulb.

That doesn't explain why your camera doesn't fire the flash at the X-sync speed and slower. But at least now you know the PC terminal works; perhaps the problem is internal to the X-sync contacts.

Yes, this makes sense. I had no idea anyone was still bothering with flat peak bulbs in the seventies, though. I have seen and used many flashbulbs, but never an FP...

 

[RLangham]

Flash X-sync speed is 1/80 sec.

Marc

That's very strange and a little annoying. A true half stop would be circa 1/95th, I think. I suppose they designed the shutter and took the X speed it gave them, though...

 

[millardmt]

That's very strange and a little annoying. A true half stop would be circa 1/95th, I think. I suppose they designed the shutter and took the X speed it gave them, though...

During 40 years of using Nikkormats, I've never thought to question why the "Seiko"(?) shutter design of that vintage implies that particular X-sync speed ceiling. If you figure it out let me know.

Marc

 

[RLangham]

During 40 years of using Nikkormats, I've never thought to question why the "Seiko"(?) shutter design of that vintage implies that particular X-sync speed ceiling. If you figure it out let me know.

Marc

Which Nikkormats? The FT's are the only ones I know anything about, and their Copal Square copies have high X-sync ceilings because they're vertical travel shutters--shorter distance to travel. Same for the Nikkorex F, the Mamiya-made predecessor to the Nikkormat. I don't know about later models.

As for the F2, I suspect its (horizontal rubber and foil) curtains travel faster than most horizontal focal plane shutters so that 1/2000th is easier to achieve. The faster the curtains, obviously the wider the slit at any given speed, and wider slits mean fewer capping and tapering problems at high speeds. As a side effect, X speed would be higher as well.

 

[ronnies]

During 40 years of using Nikkormats, I've never thought to question why the "Seiko"(?) shutter design of that vintage implies that particular X-sync speed ceiling. If you figure it out let me know.

Marc

The X sync speed is the fastest speed at which the whole frame is exposed at the same time. Faster speeds will be a slit travelling across the frame so the whole frame is not all exposed at once.

Oh, and F2 shutter does run horizontally but is made of titanium foil.

Ronnie