Tokina lens AF to MF swtich

[nickzou]

Can anyone make sense of this thing for me? It's a pull down switch right? When the ring is pushed up, it is in AF mode. When you pull it down, it goes into MF mode. Great, how come sometimes it seems to get stuck and can't pull it down, or it can only be pulled down at a certain spot? And that that spot never seems consistent. I'm so confused.

 

[Overread19]

Hmm its the other way around for me - push it up and its in manual mode and pull it down and its in AF mode - but it might differ lens to lens or depending which way is "up" for a lens.

As for the reason, I assume its because pulling it down locks the cogs into place to enable AF to work, whilst pulling it up pulls them apart. So a bit like your clutch on the car, sometimes you get thing out of alignment and it won't come down. That said on my 35mm I've never noticed a problem; though I do find that it won't work if you don't pull with equal pressure around the whole of the ring (ie you can't just pull one side down easily and have it slip into place).

 

[analog.universe]

My 11-16 does that, and I suspect it's from the reason Overread mentioned. Usually I just rotate it slightly as I move it from auto to manual, so that it can find the space it needs. I'm really not super keen on the design honestly, but since it's so crazy wide it's practically never in auto anyway. It does sort of make it impossible to autofocus and then switch to manual for fine tuning, because the switching process inevitably changes the focus.