It's no secret that we love rangefinder cameras around here. But we have to be honest. Like any tool, there are things it does well - and things it does not so well. You wouldn't use a screwdriver for driving nails, right? If you like to shoot macro or hunt big game with lenses that frighten small children, perhaps rangefinders aren't for you. That's not to say it's not possible, but let's be realistic here. So then, what exactly, is the rangefinder's "sweet spot" as far as focal lengths go?
The Bread-and-Butter Lenses
Rangefinders work best with focal lengths centering on - or perhaps up to the "standard" 50mm lens. Let's see why that is.
When shooting the 35mm format, be it film or full frame digital, the 50mm lens is considered to be the standard. The most common reason is that the lens sees more or less what the eye sees. On a more technical level, it's the focal length about equal to the diagonal size of the film or sensor format. With a medium of 24x36mm, the diagonal being 43.3 mm - makes the closest match either a 40mm or 50mm lens. On the M8 with its roughly 17×25 mm sensor and a diagonal of 30.1mm - this means either a 28mm or 35mm lens. This makes sense as once you apply a crop factor of 1.33x, these become roughly 37mm and 47mm lenses, respectively. This is why you'll see an absolutely bewildering array of lenses in these focal lengths, and less so towards the extremes.