Archived posting to the Leica Users Group, 1999/02/16
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>>Because it is a TTL meter, I think that it is more informative to quote ASA >>and shutter speed. So you would quote the M6's sensitivity as 1/2 sec with >>100 ASA film. The f-stop doesn't matter, so the EV is meaningless. Does >>anyone agree with me? Does anyone see what I am trying to get at? >> >>Regards, >>Malcolm >> > > >Actually, you need to express EV with film speed (typically 100 ASA is used) >AND the lens' largest F-stop (typicall 50mm F1.4). The EV range is dependant >on both. > >Mark Hammons > Mark, That is what I was trying to say - I musn't have explained it very well. As you say, if you quote EV you need to quote three things: film speed, EV and aperture. It seems to me to be more direct, useful and simple to quote film speed and shutter speed only. The sensitivity of the M6 would then be quoted as equivalent to 2 sec with 100 ASA film (I made an error in my original post). That simple statement gives directly useful information - you can quickly calculate the longest shutter speed that the meter will work at for any film speed. So, for example, you know that the meter will work to 1/2 sec with 400 ASA film, regardless of the aperture. It has nothing to do with aperture. The CLE's sensitivity was quoted by shutter speed and film speed. I guess that the only reason for using an EV/film speed/aperture combination is to allow comparison with hand-held meters. Any comments? Regards, Malcolm