RF focusing question

[hockey44]

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Hello,

I have M240 and when I use my Lux 50 at infinity at some distance (more than 100m), a vertical pole appears to be slightly out of focus (thru the optical viewfinder).  However, when I zoom in to max. on LCD screen--- it looks tack sharp?  Is it possible that the RF focuses correctly at infinity however there is (what I believe) to be a soft focus (slightly out) at this distance when looking through the optical VF.  I have not tried looking through my EVF (which I seldom use), but wondering if this makes sense? Do I need to send camera back for focus check?  Thanks

PS I sent Lux 35 fle, Lux 50 and 90 elm.and camera to Wetzlar 2 years ago for focus issues.

[Jeff S]

Before jumping to conclusions, I suggest you first take advantage of the LV feature of the camera (LV shows what the sensor actually 'sees').  Put the camera on a tripod to eliminate user error, and compare the LV focus with the RF focus for each lens (at different apertures and distances).  They should match....if not, either your RF or your lens (or both) are not calibrated appropriately, given the range of tolerances, to suit.  (Stopping down from wide open might also cause focus shift with some lenses....that's another issue).  If there's a mismatch, you can play detective (comparing lenses) to determine if the RF and/or the lens(es) are the culprit.  Leica Service will nonetheless ask for camera and lenses to check (to avoid any guessing on your part), which is your next step (assuming you're not inclined to adjust the RF yourself).   

 

Jeff

[jaapv]

But only attempt to adjust if you know what you are about. If not, take your camera to your Leica dealer and ask them to help you check it out.

[hockey44]

Thanks for ideas-- will try LV on tripod.

[250swb]

Do you need a dioptre to correct your eyesight? The optical viewfinder cannot go in or out of focus, it is simply a window with the rangefinder patch projected in the centre. If you have made the rangefinder images converge this alone focuses the image, so if what you are seeing in the viewfinder looks soft and out of focus it can only be your eyesight.

[thighslapper]

Either the infinity adjustment on the RF mechanism in the camera is off ......

 

..... or the lens is not adjusted correctly for infinity. 

 

Unless you have multiple 50mm or longer lenses to run some more tests you cannot be sure which is the culprit. 

 

M240 RF adjustment is more accurate than previous RF models but still can be a smidgeon off which can show up with finicky lenses like the 50/1.4 and 75/2. It is very easy to make a slight adjustment with an allen key (search the forum on how to do it) and see what happens .... if only a tiny tweak is required it may not alter the other adjustments (any alteration of the far adjustment has effects on the near and vice versa) enough to cause near point focus problems .... 

 

Having said that I have had 2x 50/1.4's maladjusted for infinity that needed to go back to Leica ...... this is complex lens with several moving elements to achieve focus at all distances and is difficult to adjust.

 

nb. If the actual images are in focus at infinity I would be tempted to just leave it. If you check sub 50mm lenses at infinity you often find that the image patches don't line up at the infinity stop on the lens ...... but with such a large DOF it has no adverse consequences unless miles adrift ...... with very fast longer lenses wide open it's a different story