Olympus lens help

xkaes · Nov 20, 2023

I'm not an Olympus user, and I need some assistance. I have what looks like a nice 135mm f2.8 lens, but I can't figure out how to get the lens to stop down. I can set it on f22, and a pin on the rear of the lens moves, but the aperture stays open. Do I need to do something else to get it to stop down -- or is it likely defective?

Flighter · Nov 20, 2023

xkaes said:
I'm not an Olympus user, and I need some assistance. I have what looks like a nice 135mm f2.8 lens, but I can't figure out how to get the lens to stop down. I can set it on f22, and a pin on the rear of the lens moves, but the aperture stays open. Do I need to do something else to get it to stop down -- or is it likely defective?

If you press and hold the depth of field preview button you should the aperture close down. It's the smooth topped button on the opposite side of the lens mount from the ribbed lens release button.

Rayt · Nov 20, 2023

There should be a lever in the side you can push to stop down the lens. If you mount it on an Olympus body it will stop down when you fire the shutter. I have an Olympus Pen F kit and should work the same for OM series.

Flighter · Nov 20, 2023

Looking at the rear of the lens mount:

A is the ribbed top lens release
B is the smooth topped depth of field preview
C is the lever that closes down the aperture when the shutter is released
D is the lever that moves when the aperture ring is turned to communicate the chosen aperture to the camera

MattKing · Nov 20, 2023

Just for clarity, is this is an OM system lens?
Not a lens for the FTl, the Pen series, or the digital series (which may or may not have included a 135mm f/2.8 offering).

Flighter · Nov 20, 2023

OM I'm guessing, as far as I can tell the 135mm for the FTL was f3.5 only and the Pen series didn't have a 135mm lens, they went from 100 mm f3.5 to 150mm f4.0.

The OM system had both f2.8 and f3.5 versions of the 135mm. I've no idea about the digital lenses.

p.s. the lens in my pictures above is an OM system 135mm f2.8

xkaes · Nov 20, 2023

It's an OM lens, but neither the DOF button nor the lever marked "C:" stops down the lens.

So I guess it's a repair bin lens.

Flighter · Nov 20, 2023

Yes, sounds like there is something amiss inside. That's a pity. I can't recall the details of the internal mechanism and whether there is a possibility of something being out of alignment or whether it's more likely that something is broken.

Marcelo Paniagua · Nov 20, 2023

Yep mostly something disengaged inside the lens. On my few lens repair forays, I remember Olympus lenses not being overly complex but then again, wasted a good 50mm on that foray so probably that lens previous owner was someone like me.

albada · Nov 20, 2023

Oil might have crept onto the blades and frozen them open. This is a common problem with lenses for SLRs.

xkaes · Nov 20, 2023

Yeah. I notice that when the stop-down button is pressed, the lever on the rear rotates -- as it should -- but the aperture blades don't budge. Still it's usable as is, and being a 135mm stuck at f2.8, it should make a great portrait lens.

Andreas Thaler · Nov 21, 2023

xkaes said:
Yeah. I notice that when the stop-down button is pressed, the lever on the rear rotates -- as it should -- but the aperture blades don't budge. Still it's usable as is, and being a 135mm stuck at f2.8, it should make a great portrait lens.

The mount for OM is not that complicated. You could open the lens from the back and check whether the transmission of the stop button works or whether the aperture blades are oily and therefore do not close.

This is the mount of a Zuiko 65-200:

Olympus lens help

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