We've drifted a bit off course, though, from Bill's original question. It was concerned specifically with the focusing system of rangefinders. And the modern autofocus camera has clearly obsoleted the manual rangefinder in its once advantage in focusing wide or fast lenses in low light. My 5D with the ST-E2 can focus my 20mm f1.8 lens perfectly in total darkness if I desire. You can't do that with a manual rangefinder.
Just because a relatively small number of people continue to cling to an outdated focusing method doesn't make it any less functionally obsolete.
Actually, I can focus my Contax G2 or Hexar (the AF one) in total darkness as well. Whether those cameras, or yours, have focused on what you want them to focus on is best left as an exercise for the reader.
And, in fact, you have not addressed the primary difference I, personally, find between focusing an SLR (AF or MF) and focusing a manual RF. Both SLR and RF systems give me positive confirmation I've focused on what I want to - the SLR by more-or-less direct confirmation (ie. I can see the image is in focus through the viewfinder) and the RF by coincidence of images at my desired point of focus (assuming my RF is in alignment).
The difference is that for practical purposes (at least in fast-moving hand-held work) the depth-of-field shown in the viewfinder of the SLR is that at the maximum aperture of the lens, and I have to imagine what will be included in the zone of acceptable focus and the transition to out-of-focus areas when the system stops down to my selected aperture as I release the shutter.
The RF system shows me essentially infinite DOF through the viewfinder and I have to imagine what will be
excluded from DOF, transition to OOF etc. when the image is recorded at my selected aperture.
With an SLR I imagine what I'm including while with the RF I imagine what I'm excluding. This changes the way I compose photographs when working with the different systems. (Perhaps it shouldn't, but it does.) For some things I prefer to do it one way, for others the other. Perhaps this doesn't matter to you - but it does to me and I know it does for at least some others.
Autofocus SLRs don't address this difference. Viewfinder AF systems (eg. the Contax Gs, the autofocus Hexar, other P&S cameras etc.) are more like the RF in terms of view through the finder - but they can't positively confirm focus is really where I want it to be. For example, when I use my Contax G2 focus tends to be spot-on or "missed by a mile" with nothing much in-between - my fault as I've had it focus on the wrong thing, but "its fault" in that I have no visual confirmation until I see the print. That doesn't help much with, say, zone focus as its no use having a 5m DOF if you've missed focus by 10m. (And, yes, I know I can scale-focus my G2 but that's a separate issue.)
So, if I want a viewfinder that shows everything in focus while composing yet gives me positive visual confirmation (
not an electronic signal from an AF system) that focus is where I want it to be then I'm pretty much stuck with a manual coincident image RF system, pretty much like a Leica M (note: I often use Hexar RFs). I don't see how this viewfinder system is obsolete if there's nothing more modern that can do what it does when that is what I want. (I like AF SLRs just fine when
that's what I want, too.)
Again, this may not be a concern of yours but it is one of mine.
...Mike
