Mundane Carl Zeizz Planar 80mm F2.8 CF question

[Helinophoto]

Hi

Just purchased a Hasselblad 503 CW and thanks to the help from this forum, I've now been able to load the camera with film correctly and I have a better understanding on how it works.

But, the camera also came with a Carl Seiss 80mm F2.8 CF Planar T* (I believe)

Looks like this:

Question:

Next to the flash sync port on the lens, there is a sliding knob.

I cannot find any information on this knob's function (I don't have the manual and googling it is a nightmare).

What is the function of this knob?

Also, there is a input port on the left side of my camera, what's this for?
Sorry for still newbie questions, will post some photos later to make good

 

[fdisilvestro]

You may find info and manuals here http://www.hasselbladhistorical.eu/

The manuals you need: 503CW ; CF lenses

The sliding knob on the lens should be the Depth of Field preview, The input port in the camera is the dedicated flash connector for SCA module

 

[brucemuir]

I have older "C" lenses but if I recall correctly:
The larger tab is a depth of field preview.
Slide it one way and it stops the lens down to the preset aperture.
Slide it back and it give full aperture for focussing.

 

[Helinophoto]

Ok, thanks, was wondering if it had something to do with curtain sync settings or something like that, thanks for the link as well =)

Regards