My N90S can meter at ASA 6 and it has plus or minus 5 stops of compensation.... I'm not even sure what that would be on the low end. Or even if it would be accurate. I recently shot some Adox CMS 20 film and the recommendations I read for metering and processing were ALL over the map!
Nikon S2, S3, F, F2, F3, FM2, FA, N90S, D80, D7000, D750, Sony a6000, Canon IIf, Leica CL, Tower type 3, Zorki 4, Vito B, Perkeo II, Rollei 35....