Sony A77 lens adaptor

[keithp]

I have a Sony A77 111 and have noticed on Ebay, that a T2 lens adapter is available.
As I understand the T2 adapter is for Tamron lenses.
Also I understand that if I used this adapter I would lose the auto focus and aperture control, rendering the camera a manual only.
Am I correct in my assumptions ?

Regards
Keith

[fillum]

Hi Keith,

I assume the adapter you are referring to is for T-mount lenses. T-mount is a screw mount which probably hasn't been used for camera lenses since the 1960's or early 70's (as far as I'm aware). Lenses from this period were manual focus and aperture was set on the lens (so strictly speaking you are not 'losing' anything because autofocus and in-camera aperture control didn't exist at the time).

Tamron's design philosophy back then was to make a single version of each lens (with the T-mount) rather than multiple lens versions to fit each brand of camera mount. You would then buy the appropriate T-mount --> camera-mount adapter for your system. Tamron eventually replaced the T-mount (screw thread) with a bayonet mount that they called "Adaptall". If you are looking to use old Tamron lenses I'd suggest looking at Adaptall lenses as these were better performers than the earlier ones. Though still with manual focus and stop-down metering. Adaptall seemed to die out when autofocus became common - I suspect it was too difficult to make generic lenses for a wide variety of autofocus systems.

T-mount btw is still in use - for attaching cameras to telescopes for example.


Cheers.

[keithp]

Thank you Phil, that explanation clears it up for me.

Regards
Keith