Odd bit of business with the focusing on my M4

[J J Kapsberger]

I put the 50mm lens on the body with the focus set at infinity. I turn the focus all the way to the lens' minimum focus and the image in the RF patch travels all the way. I then turn the focus toward infinity; the RF patch image travels again. No problem.

Then I turn the focus toward minimum and the RF patch image stops traveling at around 0.8m. Subsequently, it stops at around 0.9m.

Something loose in the RF assembly?

I can replicate this with both the 50 Elmar and Summicron, so it appears it's not lens-dependent.

 

[Rob-F]

Sounds like the lubricant on the cam follower mechanism may have become old and congealed, leading to inconsistent action. An M4 is certainly old enough for that to be the case. CLA time.

 

[payasam]

You might try giving the cam follower some "exercise" with a finger tip.