centon 500mm, why can't i focus with it?

[andytaff]

hi guys,
i've just got a centon 500mm mirror f/8 lens with an adapter to fit my sony alpha but, i cant get it to focus manually.what am i doing wrong??
cheers for any help
Andy

 

[dapprman]

Silly question, because I actually made this very mistake with my Tokina 500mm f8 mirror.

You've not got a screw on lens hood that you first of all have to remove ? (which is the same length as the barrel)

 

[towershot]

Adapter sounds at fault,is it screw adapter or baynet, if screw is it on tight ?

 

[andytaff]

Adapter sounds at fault,is it screw adapter or baynet, if screw is it on tight ?

hi towershot,
it's a sort of t mount screw and baynet fitting which is about 1/2" deep

 

[andytaff]

hi dapprman,
cant see any screw like that?

 

[Redpaul]

hi dapprman,
cant see any screw like that?

A screw-on lens hood not a screw on the lens hood

Paul