Closing/opening aperture blades on lens without adapter

[niels123]

Old lenses have an aperture ring so one can always move the aperture blades manually. All modern Canon(mount) lenses only have lens contacts.

Would it somehow be possible to use those contacts to set the aperture blades of a lens to a chosen f-stop without using a camera body?

 

[neuroanatomist]

A song as you have full knowledge of Canon’s lens control protocols, something to connect to the contacts that provides power to the lens and electronic communication, and the ability to code the connected device so the appropriate signals are sent to the lens, probably.

But...why?

If you want the aperture closed down to a certain f/stop, attach the lens to a camera, set that f/stop, press and hold the DoF Preview button, and detach the lens from the camera. That will leave the aperture closed down to the selected setting.

 

[niels123]

A song as you have full knowledge of Canon’s lens control protocols, something to connect to the contacts that provides power to the lens and electronic communication, and the ability to code the connected device so the appropriate signals are sent to the lens, probably.

But...why?

If you want the aperture closed down to a certain f/stop, attach the lens to a camera, set that f/stop, press and hold the DoF Preview button, and detach the lens from the camera. That will leave the aperture closed down to the selected setting.

I use a Kipon adapter for my Sony camera because it has space to glue a uv filter ring adapter inside. I attached a uv filter so the sensor is sealed from dust and the adapter permanently attached to my camera. Dust is an annoying issue with high magnification photography and this keeps the sensor clean. The only thing is: it is a metal-only adapter with no contacts or electronics whatsoever.

I know you can take a body to do this, but if I want to go in the field I need to bring an entire body just to close the aperture....a bit silly

I have not been able to find an adapter (sony to canon) that has the space to mount a filter ring + uv filter inside and that also has electronics to the lens.

 

[bhf3737]

Old lenses have an aperture ring so one can always move the aperture blades manually. All modern Canon(mount) lenses only have lens contacts.

Would it somehow be possible to use those contacts to set the aperture blades of a lens to a chosen f-stop without using a camera body?

I guess the rough solution is using an adapter with built-in iris. For example:
https://www.amazon.ca/Fotodiox-Mount-Adapter-Built-Clicked/dp/B005ODK5LC/ref=sr_1_4?ie=UTF8&qid=1529359649&sr=8-4&keywords=adapter+with+aperture+canon+sony
But note that the iris will be quite approximate.

 

[jolyonralph]

You're using the wrong kind of lenses. Pick up some old Manual Focus lenses (nikon pre-G, canon FD, etc, etc) and you'll be much happier.

 

[jolyonralph]

There's another way you can make this work, sort of, but it's totally insane.

Get a reversing ring with electronic passthrough for EF lenses (they have a cable connecting the two parts, connect to a real Canon camera, connect the other side to your Sony Camera (you may need to make a new mount for this.

Then use the canon camera to control aperture.

Not idea, by any means

alternatively, hack up a cable to do the same connecting the pins on the EF mount of your canon to the lens while it's in the Sony mount.