Tokina 70-210mm zoom lens

[Stivi]

Hi All

Wonder if someone could help. I have just purchased a Tokina EMZ 70-210mm/F4.5 zoom lens off ebay that came with my Minolta X-300 but can't understand why it has two aperture setting rings, also there is a small catch at the base of the lens which switches to green can anyone tell me what they are for.

Kind Regards
Alan

 

[AgX]

I only see one ring (though with two scales).

Please link to a photo of your sample, if yours is different.

Two scales at a aperture setting ring are used enabling to set that ring to a mark at the barrel and still bring the figures in sight of an optic that transfers an image of the set aperture figure into the finder. A feature several SLR's have.

 

[Ricardo Miranda]

there is a small catch at the base of the lens which switches to green can anyone tell me what they are for.

Not for use with the X-300 as far as I know, but the green switch should only be active when lens is set to minimum aperture as in the image you have shown.
It is for the cameras with Shutter priority and Program modes.
You'll see that the X-700 for example the P mode is coloured green. So, it is a colour coded system when the lens is set to green and the mode dial to a green position.

 

[Stivi]

Thank you for the info. Does this mean I just disregard the switch when using my X-300?

 

[John Koehrer]

The smaller scale should be to see the f number through the viewfinder like Nikon.