Open letter to Camera mfrs re:Av/Tv/ISO etc.

<p>Dear Camera Manufacturers,</p>

<p>Decades ago cameras had a mechanical shutter and films had a fixed speed. So it made a little sense to set the ISO value and for automatic metering modes offer a choice of fixed aperture or fixed shutter time, the other varying according to the metering.</p>

<p>Now I've got a digital camera, you and I both know that the Av, Tv, variable-ISO and exposure compensation settings are simply different ways of choosing a value for each of {aperture, shutter time, sensitivity} given the results of the light metering.</p>

<p>What I'd like to do is to upload to the camera my own choice for each of these settings for any given light reading. Tabular if you like, like this:</p>

<p>For this metered EV use these settings:<br>

EV -1: f/2.8, 1/60, ISO400<br /> EV 0: f/2.8 1/60, ISO200<br /> EV 1: f/2.8 1/60 ISO100<br /> EV 2: f/2.8 1/125 ISO100<br /> EV 3: f/4 1/125 ISO100 <br /> EV 4 ....</p>

<p>and so on.<br /><br /> So I can program my own custom modes. The example above would be, for example, keeping the shutter speed between 1/60 and 1/125, using the ISO to compensate for low light and reducing the aperture for brighter scenes.</p>

<p>Personally I'd like to be able to specify a table that had the following features:<br /> * keep f/2.8 throughout<br /> * keep the shutter speed faster than 1/100 less than 1/300<br /> * vary the ISO, but no higher than 1600<br /> * don't worry about underexposure because I'm using a flash</p>

<p>Obviously the trad. Av and Tv settings are just special cases of a more general program. No need for special programming if you're happy with these, so no downside to speak of. No extra hardware needed, so no component cost. I also forsee a computer program to help work out the programs, and to upload them to the camera. Or build it into the camera utility programs you already supply, please.</p>

<p> </p>

<p>I would have zero interest in such a solution. I set everything by hand - I make the decisions, not the camera.</p>

<p>Doesn't auto ISO safety shift go some way towards this? I always switch it off but I presume it kicks in when the selected shutter or aperture value cannot get a correct exposure without changing the ISO?</p>

 

<p>I think Juergen has missed the point. By setting a complete programme, you are making the decisions.</p>

<p>Paul: about 2% of the way. I'd like to get the other 98%.</p>

<p>I personally like the idea. I would like to take it one step more. Allow up to say 5 sets to be saved in the camera, with alpha tags, and be able to select which program to use. I have been in situations where that feature would have been ideal.</p>

<p>Why did they name aperture priority AV and shutter priority TV ? That is so confusing. Why not name them Ap and Sp. </p>

<p>Probably something like Aperature Variable (AV) and Timing Variable (TV). Variable as in that is the variable input by the user and the camera determines the rest.</p>

<p>Just a guess.</p>

<p>Hmm... on my Nikons its A for aperture, S for shutter, M for manual, P for program-shift.</p>

<p>Which camera manufacturer are you referring to?</p>

<p>Zero interest here too.</p>

<p>I'm all for scientific experiments, but that's more work than just learning to use the camera.</p>

<p>I am really lovin' the snidey comments from some people in this thread.</p>

<p>Wally: multiple sets? absolutely. And I'd like to be able to tie them to different lenses: one program for the 24mm prime, a totally different one for the 70-200 zoom.</p>

<p> </p>

<p>Sounds good to me. When I got the D2H in 2005 I expected to use mostly manual everything. Nope. I use various auto exposure settings more often. And I'd like to have the ability to custom program certain features within user specified parameters very much like Alec suggested.</p>

<p>For example, an upper and lower limit for shutter speeds would be very useful. The D2H already features this in connection with flash, but not for available light scenarios. A more convenient EV lock option would be useful as well, a feature that dates back to some Rolleiflex TLRs, but is implemented with only fuzzy logic in Program mode in the D2H.</p>