I'd like to try my micro 4/3, 25mm f1.4 Leica lens in the reverse direction for macro photographs. When it's off the body the aperture appears to be wide open. Ideally I'd like to stop it down to say f5.6 for optical performance and depth of field reasons, but of course the electrical contacts will not be connected when it is reversed. Is there any way to control the lens aperture to do this?
What a great idea, and it works for me, but not quite as described.
I'm using an Olympus OM-D E-M5 mark 2 which does have a DOF button. The lens is a Leica / Panasonic Summilux 25mm f1.4. Here's how it works for me.
- I put the camera on aperture priority so that I can dial up the aperture I want.
- I press and release the DOF button and the aperture of course changes to the one I set
- I then take the lens off the camera without switching the camera off, and the lens remains stopped down. The DOF preview doesn't have to be pressed whilst I do this.
If I switch the camera off even with the DOF pressed, the aperture reverts to fully open. I know taking the lens off with the camera on is said to increase the risk of dust getting on the sensor, but it's not something I'd do often so I don't think it would be a problem.
The aperture reverts to fully open when I put the lens back on.
I've tried it on all my Olympus lenses and the procedure works for them all.
Many thanks for putting me on the right track!
Not 100% sure of this (it's a trick that works for Canons, and I'm seeing a few reports around the interwebz this works with Olympus mft bodies that have a DoF preview button), but if you set the aperture on the lens and hold down the DoF preview button when you unmount the lens, the lens should hold the aperture setting when you reverse mount it. Obviously, you have to remount and go through this all over again any time you want to adjust the aperture setting.
You could also adapt an old manual lens (e.g., an Olympus OM lens) that has an aperture ring, or try to see if you can find a reverse mount rig that includes a cable for camera-to-lens contact communication.
For Canon you can use adapter ring that will arrange the communication between body and the lens.
On the other hand, if you are using primitive ring to attach the lens you have no way to control focal plane. You can buy cheap and good SLR from old times. Such lenses have manual apperture ring. Wikipedia image