Originally posted by stevebrot Unless you have one that works with a zoom. My Canon G2 has a zooming optical finder, but it is directly coupled to the zoom mechanism. It would not be impossible to make an optical finder that zoomed with a compatible interchangeable zoom, but probably would not be cost effective.
What would be nice is if Pentax provided accessory optical viewfinders to support available primes.
Steve
Later model film P&S cameras had long zooms with OVFs, but they were always approximate and contained wide/tele framelines, as well as a macro frameline.
Small sensor zoom can have a coupled OVF but not with a larger sensor.
The Ricoh GR has 2 options for external OVF's (I have one. Works well but at $200 for only 2 FL's (21/28mm) is very expensive.
Anything small optical element with high acuity is going to be pricey. Anything with a zoom capability is going to be very limited in FL or acuity or get very, very large very fast. If you take an APS-C lens and then try and match it to a non-mirror OVF, you'd have to magnify (cost, distort, people with glasses) on the ocular. You can only shrink the OVF a fraction of hat the size of the mirror is or else you would be peering through a tiny, tiny opening. Really long tele, like over 150mm would be impossible. That is why RF cameras were only able to go to 135mm on 135 realistically, and practically it was 90mm.
That is why no one does it.