Understanding canon mount

[alaios]

Hi,
I got a tokina lens that is for canon mount. I am trying to understand what I can do to see if the aperture blades are closing. Someone told me that the lens first has to be mounted to be able to see the apertures closing or opening. I do not have yet a canon to nex adapter to see what is going on. Is it possible somehow if the apertures are closing and opening when I move the dial`?

Regards
Alex

[Lloydy]

I have a rear cap that I've cut off that cocks the aperture mechanism and allows you to turn the aperture ring and see the blades move. The lock is a bit hidden in the mount, and a proper cap unlocks it.

[philslizzy]

I've had a few lenses knocked down in price as faulty by using the salesman's ignorance of these matters. Much to my shame.

[alaios]

Thanks guys.. without making this adaptor I was able to press this small lever and make the aperture moving!! I wonder though that I can still hear some of sound when moving the lens... IS this normal? It is like small metals clinging...

Regards
Alex

[Lightshow]

Ball bearings in the aperture assembly most likely, so it's normal.

[Pancolart]

Topic title says it all perhaps check also this entry :
http://forum.mflenses.com/canon-fd-the-most-stupid-mount-ever-t24942.html