Canon FD 50mm 1.4 with FD-NEX adapter on A7 problems

Started Jul 8, 2014 | Discussions thread
boardsy Senior Member • Posts: 2,215
Re: Canon FD 50mm 1.4 with FD-NEX adapter on A7 problems

dandoro wrote:

OK, now it works. The ON-OFF ring is turned to right, so I suppose it's set to ON. The aperture ring moves together with the blades with no problems

Are you sure the lens is now going from totally open/circular at 1.4 down to a tiny 6-sided hole at f22?

BUT...I took pictures at f1.4 and f22 and the same vignetting occurs in both pics exactly like before, and no aperture is shown on the LCD. A good adapter it should allow the camera to show the aperture, right? Or am I wrong? And the vignetting...is it due to a too short adaptor or...what's the difference between a FD-NEX built for APSC and those built for FF? What's the physical difference between them?

Camera will never know/show the aperture as it has no electronic communication with an all-manual lens like an FD. But it will react correctly to the amount of light the lens allows in, in A/P mode, and adjust shutter speeds correctly.

You should see a huge change in vignetting from f1.4 to f22, and in A mode with base fixed ISO you should see the shutter speed halve/double with each full successive aperture change.

Vignetting is caused by the lens not letting in a consistent amount of light across the frame at each aperture setting, is fairly normal, and always more pronounced at wider apertures like f1.4, and should be minimised at f8 viz a viz optimal sharpness.

There is no difference between the FD adapter for NEX and FF/A7 - NEX & A7 have same e-mount registration distance between the mount and the sensor, and just have different sized sensors.

Try setting your adapter's ON/Off ring to Off, mount the lens carefully, and turn to On, and look through the back to see if the protruding screw catches/turns the lens's aperture lever as you turn the On/Off ring, to then allow aperture to be changed on-lens. If that doesn't work, start with the ON/Off ring at On, then turn to Off with lens attached. FD's are a little tricky in this regard, but not really "notoriously difficult" - as soon as you get it on right once, you'll "get" it. Great lens, by the way, and rumoured to be almost better on the A7 than on the original Canon film cameras it was made for!

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Regards,
Alan
my Flickr

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