NEX and Vectis lenses

[David Kilpatrick]

With Zenith 39mm (Leica type SLR) thread T-mount the Vectis 80-240mm nearly focused OK attached to the Leica adaptor of the NEX, but the bayonet is only just able to fit a doctored T-mount. Using a Leica thread lens reversing ring and duct tape, I was able to fit one of my two 80-240mm APO guinea-pigs to the mount within 1mm or so of correct register (38mm).

vectis80240-onnex5.jpg (84.24 KiB) Viewed 2911 times

Effectively it's got a Leica taped as close to the mount as anything will allow. A custom mount for NEX would seem possible, but the NEX lens has electronic operation of both focus and aperture, like the NEX, and may use entirely different pinouts, power levels and protocols. The most likely match would be the aperture mechanism, and if this could be made to function, the lens would be half usable. If power could be supplied to the correct pins to enable the focus-by-wire action, that would complete the job.

As it stands, the 80-240mm Vectis APO f/4.5-5.6 is a really neat size of lens for the NEX and Sony could do far worse than remake this in an OS version for NEX. At full aperture, performance up to 200mm is very good but a familiar softness (like ther 100-300mm APO D etc) creeps in at 240mm. For 1996, the lens is pretty amazing.


80mm wide open, http://www.pbase.com/davidkilpatrick/im ... iginal.jpg for original


240mm wide open - http://www.pbase.com/davidkilpatrick/im ... iginal.jpg

Close focus at around 135mm wide open (because the lens can not be stopped down):

http://www.pbase.com/davidkilpatrick/im ... iginal.jpg

Around 100mm, same conditions apply:

http://www.pbase.com/davidkilpatrick/im ... iginal.jpg

And at 240mm close focus again:

http://www.pbase.com/davidkilpatrick/im ... iginal.jpg

This lens has some really good qualities, considering it is not even mounted correctly and is definitely not correctly set up for register, which alters the way the zoom/focus correction functions.

David

[youpii]

This lens has some really good qualities, considering it is not even mounted correctly and is definitely not correctly set up for register, which alters the way the zoom/focus correction functions.
David

I recall that the 50 Macro had good reputation.
Now someone should reverse engineer the pin layouts.

Could you please share some pic of the mount on the camera and the lens?

[Kenneth Sky]

The mirror 400mm & the 17mm are outstanding. Please let me know if an adapter ever gets made.

[David Kilpatrick]

The mirror might be a possible choice for a 'dumb' adaptor. I can not remember whether it has manual focus, like the 80-240mm, which can be 'forced' without the lens having power. The aperture is fixed, so no real problem there.

I have tried applying low DC voltages (from a multimeter resistance test setting) across various pins of one of my Vectis 80-240mms, but to no effect either actuating the aperture or making the focus motor shift. I've bid for an old S100 body at £15 which should be on its way. That will at least give me an idea of what voltages are supplied by the Vectis body, and I can test my NEX to compare.

The real issue is what digital control signals are sent, what the protocol is, and whether the NEX pinouts can ever be compatible with Vectis lenses - at all.

David

[Dusty]

David, I doubt if it's direct voltage. More likely a series of current pulses that actuate the motors.

Dusty

[Kenneth Sky]

The 400mm has manual control and I'm almost certain the other primes as well. Wouldn't that be sweet if an adapter could be made? Vectis lenses go for "bubkas" on eBay. All of the Contax G2 lenses are going for at least $100 more than they did 6 months ago.