Vivitar 28~70 Auto Focus Zoom

[grain]

I just picked up the oddest gadget. It's an auto focus lens for FD. It works well, too bad the lens is a

Wibitar. But anyhow, can anyone tell what the extra pc socket is there for?

[SCL]

Canon & Tamron also made these type of zoom lenses before the introduction of autofocus mechanisms in the camera bodies.

[grain]

Right, but does the PC socket do anything? It doesn't fire a flash, so is it supposed to go

into the cameras PC to read the synch time info or some such? I find almost NO images of

it anywhere, and the one I did find all the text was in japanese.

[joe_nash1]

Alexander,

I have one too, I had one almost brand new, if not new, but I didn't like the pictures enough, so sold it. I did scan the owners manual though, so if you send me your email, I will send it to you.

[HenryUK]

It really is a photographic curiosity. I never knew Vivitar made these. I have the Canon AF 35-70 equivalent, which works remarkably well.

 

Maybe the lens needs to know when to stop focusing, so it uses the flash contacts to detect the start of the exposure?

 

I'd be interested to see the instructions too.

 

Henry

[grain]

Henry, if Joe doesn't send you a copy I can.

[grain]

"It" being my email address that is. Still need the I.B.

Thanks again.

[grain]

Okay so that is it, a pc to pc cord goes there to stop focus after frame is shot so as to

conserve battery between shots. Stranger and stranger this thing gets. The canon version is

bidding low on you know where, might go for it. Thanks again.

[HenryUK]

My guess was not quite right. Looking at the manual that Joe so kindly sent, it appears that there was an accessory cord that connected the lens AF system to the shutter button. This enabled the shutter half-press to initiate AF automatically. Otherwise you have to press a button on the lens to do AF.

 

How does the accessory cord detect a half press on a Canon FD body? Maybe it fitted to the cable release socket on the shutter button? If the lens is rare, then the cord must be even more scarce. Perhaps we'll never know.

 

Anyway, enjoy your lens.

 

Henry