Reversing digital lenses

[Guido]

I just discovered a trick to control the diaframa on a reversed digital lens.

If you use a mount adapter with a lever to control the F-stop you can use this on the bayonet of a reversed lens.


Link for an pentax K example

[Macro_Cosmos]

You can also pull apart an extension tube with contacts that allow electronic pass through.
On the male mount side, glue an appropriate adaptor with threads for common filter sizes, 52mm is a good choice.
Now use wires and solder/bridge each contact to the female mount end, make sure the wires aren't too short.
You can now mount the adaptor onto the rear end of the lens. This will allow you to electronically control the iris, have full metering, and sometimes even auto-focus.

Some companies actually make them: https://www.movophoto.com/products/movo ... -canon-eos
It's very cheap however to make your own, so why not?

[Guido]

I know canon has an adapter like that.

I sometimes reverse a 24mm reversed on a 100mm. The these electronic pass trough wil not help.

[Ichthyophthirius]

If you use a mount adapter with a lever to control the F-stop you can use this on the bayonet of a reversed lens.

Hi,

That's interesting. I can't see a power supply for the aperture change - so does it depend on the manufacturer whether this will work? Which lens do you use? I don't think it would work for Canon EF - EF can hold an aperture open without power but it needs power to change the aperture.

Regards, Ichty

[Guido]

I tried it with a pentax dfa 24-70/2.8 andit works. It is an adapter to use pentax lenses on four thirds.