Olympus OM-1n

[Loovic]

I recently bought a OM-1n from Japan which is in MINT condition, it really looks as if it has never been used. I also have several Zuiko lenses and decided to test the camera with a 135mm f 2.8. I always use the same test target (Lens Align) whether for digital or film. I proceeded to shoot the target at all apertures on a tripod. I shot each aperture 3 times, twice without mirror lock up and once with. Normally with any camera (my experience anyway) the MLU exposure is always sharper. In this case it's the reverse. The camera performs perfect for each exposure at each aperture, however each frame at each aperture with MLU is much less sharp as if there is camera shake. I've never experienced this, does anyone have any idea what is going on here?

 

[dynachrome]

I have many cameras with mirror lock-up but no OM-1n examples. Are you sure the mirror lock-up switch is fully in place in the lock-up position?

 

[MattKing]

Any chance that you are inadvertently changing the focus when you engage the MLU?

 

[Les Sarile]

Are you also using a sufficiently high shutter speed, heavy tripod and remote cable? For these types of testing, I always make sure vibration is not a factor.

 

[4season]

Interesting. Maybe a bit of mechanical resonance going on, due to your specific combination of components? Very possible that there's more total vibration being generated when the mirror is engaged, but at different frequencies. You might test this by sandbagging the camera or otherwise altering the mass.

 

[Loovic]

Thanks for your replies. All shutter speeds where either 1/125 or 1/250. My tripod is a heavy Gitzo with a RRS BH-55 ballhead so its adequate for such a small camera. The focus was not changed during the test. I really cannot explain it. I have shot another roll since the test, handheld, of general photography and they are all spot on focused. I guess I will live with it and just avoid MLU.