I am aware of the differences in framing various lens focal lengths using the .58, .72, and .85 magnification viewfinders. Is there a meaningful difference in focusing ease and accuracy between the viewfinders? Would I find that the .85 allows focusing of the 90mm lens much easier and more accurately? Thanks, Jack

-- Jack Belen (jbelen@aol.com), March 25, 2002

Answers

Jack,

The "numbers" say that the higher the VF magnification, both the ease of focusing and its accuracy will increase.

Never have checked the numbers but know that with the 90 you mentioned, or a 50 for that matter, my eyes would back-up what those numbers say.

Best,

Jerry

-- Jerome R. Pfile, Jr. (JerryPfile@msn.com), March 25, 2002.

When the rangefinder patch flares out on the M6 all three magnifications are equally easy to focus with any focal length. ;-)

-- John (ouroboros_2001@yahoo.com), March 25, 2002.

I have M2, M3 & M6 classic. For me, focussing the 50 and 90, the M3 is the winner by a lot. Cheers.

-- Don (wgpinc@yahoo.com), March 26, 2002.

How to put this? All of the finder magnifications are equally 'easy' to use from the point of view of your eye - you just line up the images. i.e. the .58 won't cause eyestrain just because it's low-mag. (Did that make sense?)

Similarly, the .85 is not 'easier' to use - but it gives you MORE accuracy while being AS easy to use as - say - a .58. The increase in accuracy is roughly in direct relationship to the magnification. So the .85 is rough 50% more accurate (1.46x) than the .58, and seems to be about 50% less likely to produce an OOF picture in practice - with 50/ 75/90 lenses.

-- Andy Piper (apidens@denver.infi.net), March 26, 2002.

I find my 0.85 excels with the Nocti and 90; while my 0.58 works great with the 35, 24, 15. The 50 micron can be used with both, but the Nocti is the pits with the 0.58

Regards, Don

-- Don M (maldos@cox.net), March 26, 2002.

The ease of focussing with a .85 is due to the increased size of the rangefinder rectangle, plus something to do with the increased (or decreased?) length of the rangefinder base?? Theres a web site that explains this though its pretty technical.

-- Karl Yik (karl.yik@dk.com), March 26, 2002.

In theory the 0.85 would focus the longer lenses more accurately. In practice the ease of focusing is the same. I own 2 0.72 bodies, one of which has the 1.25x mounted semi-permanently, making it an 0.85, and I use it with the 90 or 135. If my "naked" 0.72 were to need service I could remove the 1.25x from the other body. That made more sense to me. My gripe with the 0.58 is the lack of a 135 frameline, plus I much prefer the accessory 28mm finder to using the in-camera frame. The accessory just "looks" more like an SLR view through a 28mm. Therefore to me, the 0.72 is the only finder I'd ever choose.

-- Jay (infinitydt@aol.com), March 26, 2002.

rf accuracy is a very complex issued, a fact belied by the simplicity of the formulas typically used to express rf accuracy. in theory, accuracy of an rf is simply base length of the finder system (i.e. the length of the "leg" of the triangle at the camera end -- or, more simply put, distance between the RF windows on the camera) multiplied by the mag of the finder. however, many other factors actually affect acuracy. for example, some rfs are simply coincident type (you get one image to line up (or superimpose) with another. others are split image type. some systems, like leica, have both (the edge of the box gives the split). many people achieve the greatest accuracy in practice with the dual type. additionally, contrast of the images plays a huge role in determining accuracy. no matter how wide the baselength or how great the mag, it will be more difficult to focus with low contrast images. this is why some systems add contrast enhancing filters to the finder. finally, there is another bit of complexity. where there is error in the system (due to poor mfring or misalignment for example), magnification compounds this error. however, in the main, increasing the mag increases accuracy by making it easier to see the two images (or the split) coincide. i do not understand the dichotomy expressed above suggesting that accuracy and ease of focus are two different things WHEN MAG IS THE ISSUE. this point is valid when discussing baselength (at a given mag, it will be just as easy to make the images coincide perfectly whether baselength is an inch or a mile [although the larger baselength will produce the more accurate range estimate]), but not when discussing mag. it is precisely because the higher mag makes it easier to focus that greater accuracy is achieved (for a given baselength). simple test: focus through a iiig and a .58 (or .72). it will be far easier to see the images converge in the iiig due to the higher mag. the same will be true of a .72 with a 1.25x magnifier as compared to an unadorned .72.

-- roger michel (michel@tcn.org), March 26, 2002.