Can someone explain what happens if you turn shutter speed w/o cocking shutter?

[Martytoof]

Apologies in advance if this is a really fundamental question, but I have two FSU cameras coming in the mail (Zorki 6, FED-2) and I'd love to understand more about them:

I'm very curious as to what happens behind the scenes in this scenario, where you turn the shutter speed knob before you've cocked the shutter. I've read that this can lead to a catastrophic failure, but then I also read that it's not a guaranteed failure; just that there is a CHANCE of internal failure.

It's likely because I don't understand how everything interconnects, but I have a hard time figuring out exactly what could be going wrong.

Thanks

[reagan]

I've never committed this unpardonable sin ... [yet] but from what I understand, wOrLDs CoLLiDe!!

For a more technical explanation, you might take a look at this 2008 thread. wolves3012 gives some pretty good detail.

[Martytoof]

Excellent link, thank you very much

[rxmd]

Your cameras don't have slow shutter speeds, so there's nothing that can break; and they have a more "clever" shutter speed indicator, so you can't end up setting the camera to a different speed than indicated. Ergo, don't worry

[Martytoof]

Very interesting. That takes a load off my mind, though I suspect it's still best practice to not change shutter speed until the shutter is cocked

Thanks, everyone!

[wolves3012]

What RXMD says is correct, for both those cameras you can set the speed safely and correctly at any time, cocked or not. This will be true for (almost) any FSU with the two-piece speed dial, i.e. an inner shaft with a dot or line and an outer rim that carries the speed markings. As ever, there's one exception, some early FED 3s had two-piece dials and I don't think it's safe on those.

On Kievs, you can set before or after but the mechanism may not set properly if you set before. Depending on what speeds you change between, you may get the wrong speed but you won't do any damage.

On any of the FED/Zorki models with slow speeds, changing speed uncocked can result in the slow speed mechanism being over-wound and damaged when you cock the shutter. On models with one-piece dials but no slow speeds, you can change uncocked but it's a bit pointless since it's hard to judge what speed will be set. Also, if you're careless you can change between B and 1/500th (or vice-versa) and break the pin that prevents this. You do need to be clumsy and use some force though.

In short, because there are various "rules", it's just simpler to play safe and cock first. This is especially true if you own several models, it avoids having to remember whether the model you're using can or can't do it.