The R4s have lines down to 21 but be sure you understand the implications of the extremely short effective baselength and the relative difficulty of using it with longer lenses. Other than the R4M/A, the Leica M4-P, M6, M6TTL, M7 and Zeiss Ikon has 28mm lines. The ZIs finder is truly breathtaking and beats the Leicas hand down, IMO.