Re: [Leica] 100mm f2 focussing

["Peter A. Klein" <pklein@2alpha.net>]

Mark:  Most people (including me) rack the lens in to infinity and focus
in from there.  

I tried the opposite, and (when I remember) it works better for me. 
Start the lens focused closer than your subject and focus out.  Then
when it looks right, *don't fiddle.*  Take the picture.

This is a modification of Ted Grant's advice on focusing wide angles
with an SLR.  I think it works because 1, the rangefinder is often more
positive than an SLR--it's only right in one place, rather than variou
degrees of blurred.  Also, if you guess wrong, you will be focused a
little too close, which gives you greater margin for error.  As Dante
noted, depth of field is distributed 1/3 in front of the point of focus
and 2/3 behind.  So if you're focused a teeny bit too close, you have
twice as much chance of being in the ballpark.

I don't have a Canon 100/2, but I do have the 85/1.9.  

- --Peter

Dante says:  

>         A 100 f/2 still has some DOF, so what I would suggest is aiming
> for the nose.  Since there is more DOF behind the focused point than in
> fron (by a factor of 2, I believe), you should be able to get the eyes.
> It is very easy to focus behind the subject with an RF.  The other thing
> is, as you said, you may need more magnification, or perfect RF alignment.
> You might also have the lens checked on a collimator.

> On Thu, 9 Aug 2001, Mark Langer wrote:
> 
> > I've recently purchased a long-coveted 100mm f2 Canon lens in Leica thread
(snip)
> > ...But my technique with
> > the M6 (.72) seems to need work.  Does anyone have suggestions or tips to
> > accurate focssing in relatively low light levels when working with very
> > limited depth of field -- other than getting a M3 or M6 w. .85 viewfinder?
> > I'm now kicking myself for selling my M3.....