Since these terms come up (see 90/2.8 T.E questions) every now and then, I'd like to ask: what is better, and why? Or is it personal preference that counts?

Thanks and best whishes for the season

-- Hans Berkhout (berkhout@cadvision.com), December 10, 2001

Answers

I guess it is more a matter of personal preference; though many consider the Leica M a wide angle camera, it works very well with a 90 or a 135, but I most admit diferent than in a SLR, and since a wide angle lens makes it a very fast rection camera, and finder for 35 and 50 are the most verstile and comfortable to see, my preferences goes to the 35 and the 50.

Best whishes too.

-- r watson (al1231234@hotmail.com), December 10, 2001.

I can't speak as to the 90/2.8 Tele-Elmarit, but I prefer a longer focus throw because it's more precise, albeit slower (& that's 1 thing I prefer about the Zeiss Ikon Contax RFs over the Leica M system--the other is the direction of the bayonet mount, which I think is much more intuitive on the Contax).

-- Chris Chen (furcafe@cris.com), December 10, 2001.

"Focus throw" refers to how many degrees of rotation of the focusing ring it takes to get from infinity to minimum focus. It varies from one lens barrel design to another, depending on the steepness of the helical that converts the rotation into forward movement of the glass. E.G., the current 90 f/2.8 covers INF - 1m in about 120 degrees, while some older 90s have throws of up to 190 degrees.

Like Chris said. In THEORY, if you have to rotate the focus ring 190 degrees to get from infinity to 3 feet, you can give the focus a much finer touch than if you cover the same focus range in only 120 degrees of rotation. It gives your 'hand/eye coordination' a better chance of getting the RF images lined up correctly.

Whether that counts as 'better' in practice is probably personal taste.

As with viewfinder magnification, it doesn't make a lot of difference with short lenses, but can be a big help with anything longer than a 50mm.

And it's just one factor that has to be mixed in with RF magnification, focusing stiffness, and the 'fit' of a given tele to your camera.

-- Andy Piper (apidens@denver.infi.net), December 11, 2001.

Short focus throw for wide angles (where dof forgives precipitation) and longer focus throw for teles (where nitpicking on millimeters can be crucial at shorter distances).

Focus throw is the main problem when using AF lenses in manual focus fashion on most systems. More than the "looseness" of the ring, it is the lack of precision due to ultra short focus throws that makes those lenses such a pain in the a.. in manual mode (especially the middle range teles, zooms and macro lenses). In auto mode however, the AF motors and linkage mechanisms allow management of extremely minute and precise focusing movements, despite the very short throw offered through the outer manual focus ring.

That is why most AF lenses beg to be used in AF mode. And that is why manual focus control freaks turn to Leica, Contax or AI systems...;-)

-- Jacques (jacquesbalthazar@hotmail.com), December 11, 2001.

I agree with the posts above. I simply want to add that MF lenses with wide maximum openings generally have a longer focusing throw than lenses of the same focal length with narrower max. openings. On a Noctilux or Summilux you need much more focusing precision than on an Elmar for example. Some people complain about the long focusing throw of the 75 'lux when in fact this is needed when you work at 1.4

-- Xavier (xcolmant@powerir.com), December 11, 2001.

One distinct advantage I see to a short throw on an M lens is being able to focus the entire range without getting your fingers in front of the viewing/rangefinder windows. another advantage is that since the rangefinder is in the center of view, 99% of the time I need to focus and then recompose, so the quicker I can do the first and get on to the next, the more chances my shot will not evaporate first.

-- Jay (infinitydt@aol.com), December 11, 2001.