Hopefully easy Nikon F3 question

Discussion in 'Nikon' started by jamesippoliti, Apr 11, 2019.

  1. Hi. I have a Nikon F3 and a SB-16 Speedlight. I have a SC-14 sync cord to use the flash off camera but is only 1 meter long. Can I connect two SC-14 sync chords to double the length?

  2. Shouting over the massive hubbub of replies... I don't have one to try it, but I don't see a reason why it shouldn't work. Well, mostly, because my "I'll just check..." moment led me down a rabbit hole of how F3 TTL flash works. Given that film ISO with F3 flashes is apparently picked up mechanically from the ASA dial on the F3... oh, I was going to say I don't know how that works, but the SC-14 has an ASA dial on the flash end, so I assume you're supposed to replicate the camera's film ISO setting there (and probably only the one at the flash end matters).

    So, probably it's fine. But I (now) believe the F3's flash system just relays the output of the TTL OTF sensor to the flash, so if you chain too much cabling in the way you might find yourself introducing enough resistance that it overexposes (guessing). "Normal" TTL flash is, I think, more digital, and probably less sensitive. If you want to go a long distance and can live without TTL, might you be better off using the PC sync, if only because the cables are cheap?

    Please bear in mind that my oldest Nikon is an F5 and all this is based on reading stuff on the internet, which is famously never wrong, so if someone corrects me, they're probably right. :)

    Good luck. Please report back if you try it, especially if it's on my say so and you just want to shout at me because it didn't work - it'll mean I've learned something!
  3. The film TTL control line is in no way analogue Andrew. It's a simple on/off quench signal that effectively says to the flash 'Shut that darned light off. I've had enough!'
    I once tried to do something clever by adding manual control to a film TTL ringflash, using the quench pin to control the flash duration. It just needed a TTL level (Oops, confusing! - Transistor-Transistor Logic in this context) signal to curtail the flash. I ran into problems trying to make the thing self-powered, and it ended up being yet another shelved project awaiting an inspired brainwave that hasn't yet materialised.

    So, short answer: There should be no issue daisy-chaining sync cables together.... within reason.
  4. RJ: Are you sure? What I read about the F3 flash system suggested that the flash connector is directly wired to the TTL OTF meter, and the flash itself makes a decision about when it's seen enough light. This, among a few other resources, seems to claim this oddness with the F3 (and confirms the "you have to set the ISO setting on the SC14 to match the camera" theory) - I've no personal experience.

    This is obviously not how more recent flash systems work - they do, as you say, have a fire/quench thing, and the metering decision is made in the camera. (I actually don't know much about flash connections - a little rummage suggests that Nikon have a separate "quench pin", so presumably it's not just a connection open/connection closed or double pulse thing.)

    I've struggled a little to find a correct pinout for the F3 flash connector, but it seems to be ground, signal, flash ready (for the viewfinder LED) rather than any way to indicate a quench. I assume the resistance must be inversely related to the light hitting the sensor (the reverse of a typical photoresistor), if infinite resistance also means "shutter is closed, don't fire the flash", but at this point I'm guessing. This suggests that there actually is another pin, but it wasn't used for these flashes (the description isn't 100% clear).

    I'm still prepared to be wrong, though. And I think the basic answer "it should just work" still applies, even if everything is analogue, unless there's a lot of resistance in the cabling.

    This would all be educational if I ever decide to own an F3 and use a flash with it. :) Not that I've ever used my F5 with my SB600s, but I did buy SB600s rather than anything newer just in case...
    Last edited: Apr 12, 2019
  6. If the parts add up to too much resistance ("resistance is futile"), it won't work. That would have to be determined empirically for any given set of cords. Try it and see.
  7. Nothing wrong with wanting to own an F3 - but a lot of wanting to use it with flash. 1/60s sync speed is a relic from using the shutter mechanism from the F2 - not exactly fast by today's standards and a big hindrance when it comes to using fill-flash.
  8. I actually wouldn't mind owning an F3, but, as with most interesting film bodies, the prices are a bit steep for me given that I'm insufficiently fond of the recording medium. (I've just acquired a new fridge, and spent last night transferring all the film that's been sitting in my old one for the last few years into the new one. At some point I'll bite the financial bullet and try to get anything that was exposed developed, if it's still okay, and probably ditch the rest unless I'm very confident about its performance. I don't want to claim they've been there a while, but there are some APS cartridges, and I think several of the other films are discontinued.)

    Thanks for confirming, BeBu - I was quite prepared for you to tell me that I'd misunderstood. :)
  9. I have much better result using TTL flash with the F3 than the F5. The F5 gave me so bad exposure with TTL so much so I never use it again. The slow speed sync never bother me as I don't use flash in broad daylight.
  10. From the flash compatibility chart, it appears that the AS-17 converts the raw OTF signal to a standard 'digital' quench signal. Otherwise the combination would only be compatible with those speedlights specifically designed for the F3.

    That only leaves the question of whether AS-14s can be daisy-chained.

    The resistance in an AS-14 cable should be minimal (maybe in the region of 1 ohm). This should make almost no difference to any voltage or current passing from camera to flash.

    Sorry for my previous assumption that the F3's TTL protocol worked in the same way as every other film TTL Nikon that followed it.
    Last edited: Apr 15, 2019
    Andrew Garrard likes this.

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