Archived posting to the Leica Users Group, 1999/02/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>> It seems to me to be more direct, useful and simple to quote >>film speed and shutter speed only. I, for one, agree with you Malcolm. >But thru-the-lens light meters in cameras must also take into account the >speed of the lens on the camera to guage the minimum and maximum >EV values they can measure. If you are in EV 1 light and you have >a camera with built in meter that is just barely reading the light with >an F1.4 lens on the camera, will the camera be able to meter the >light if you put an F4 lens on the camera? The answer is no. The above is also true. A TTL meter with an F4 lens will not be able to meter in as low light as with an F1.4 lens, but neither will the F4 lens be able to expose a properly exposed photo in as low a light at the same shutter speed (at a given film speed). So with a given TTL meter the speed of the lens makes no difference to the lowest shutter speed you can meter at (at a given film speed). > >Thus, when quoting the sensitivity of a TTL light meter in a camera >specs are usually given as: >EV 1 @ 100ASA and F1.4 > Yes, this seems to be the industry standard in magazine tests, etc, but I find the first method simpler & more useful.