Re: [OM] ......TTL and OTF.......

[ZuikoholicRI]

TTL - through the lens - almost all SLRs meter TTL, usually off of the 
focusing screens. Later OMs (OM-2S, OM-3(Ti), OM-4(T(i)), OM-PC/40) mirror 
off of the sub-mirror, so they are immune to changes from focussing screens 
with different brightnesses.
OTF - Off the film - the only SLR besides the automatic OMs that meters 
non-flash exposure off the film (and off the curtain) is the Pentax LX. Most 
SLRs today do OTF for flash only.

Hope this helps.

Paul Schings