[Leica] (LUG) srews

["Rod Fleming" <rodfleming@sol.co.uk>]

Hi

Arthur Lenberger wrote

"I bought a 25mm SKOPAR this week (and LTM to bayonet
adapter) to use on my M3. I plan to test it this
weekend, but my question is that I need to use
hyperfocal distance since the lens does not engage the
focusing images (sorry for the non-technical names for
these things). Should this be?
1) Are there different adapters for different focal
lengths in the M mount?
2) If I buy the 15MM Heliar will I have the same
problem? I realize that at 15mm, almost the whole
world will be in focus.
3) If I were to buy and use Leica SM lenses, would
they to have to be focused hyperfocally (sp?)?"

The Voigtlander 25mm  lens has no RF cam, so it won't work the rangefinder.
If this troubles you and the vendor did not explain it at the point of sale,
I'd go back and kick up.

The 15mm is the same. Both lenses use "zone focussing"- or, "Hey, that's
about 10 feet away so I'll turn this here  focus dial to to 10 feet (or 3
metres)" In fact UK versions of the 25mm  lens are click-stopped at 4 focus
points- a throwback to Instamatic technology if you ask me- but which should
work well enough.

You don't HAVE to use the hyperfocal, but it makes sense to leave the lens
set on that as you have no confirmation of focus in the viewfinder. This
willl make grab shots much easier, and the click-stops should at least mean
that the focus will stay where you left it.

You won't have this problem with most LTM (Leica Thread Mount) lenses,
including the Russians, because they have the rangefinder cams built in, and
they will work the RF on your M just as well as they do on the bodies they
were built for.

There are three different LTM- M adapters available, and the framelines they
bring up depend on the M camera you're using. However, none of them are
accurate for the 25mm field of view, so it doesn't really matter which one
you have, as you'll need the matched Voigtlander optical finder in any case.
(Again, if the vendor did not explain this, you might like to ask him why
not). Since you have no rangefinder coupling, using a separate viewfinder is
not as bad as you might at first think, as you  won't be jumping from
rangefinder to viewfinder to focus and frame.

FWIW I personally think that the absence of a rangefinder cam on the 25mm
would take some getting used to. Part of the point of using rangefinder
cameras, at least for me, is the vastly greater ease and accuracy of
focussing with short lenses when compared to SLRs, so not to have the
rangefinder seems perverse to put it mildly.. .......    Having said that,
the 25mm is not very fast, so your results should be okay.

Have fun


Rod