Roger, You could use a prime lens. Then you don't have to worry about adjusting the focal length...
The focal length is reported by the lens from the readings off of some tracks that run inside the zoom ring. I don't know what the resolution of this arrangement, nor do I know the accuracy, but I would think it's on the same order of magnitude as just reading the setting on the lens barrel -- although, you do have a finer resolution on the digital readout. Anyway... To answer your question: I don't know of a way to get the focal length electronically on the camera in the field. The other thing is that it'll be rather challenging to get the exact same composition anyway. The only way to get exactly the same composition would be to use the same approach as surveyers use when they measure stuff. I suggest the following: Note the position of the camera, focal length of the lens (read it off the barrel), bring a print of the desired composition and adjust the camera/tripod until you get what you want. Take the shot... Tom On 6/13/06, Roger Eichhorn <[EMAIL PROTECTED]> wrote:
Is there a way, on a Canon 10D, to learn the exact focal length before taking a photo? I want to return to the same spot and set the camera up the same way each time. The lens (70-300 DO IS) has a scale, but the divisions aren't very fine and there are no indicating marks on it. I can learn the focal length, in photoshop, after I've taken a picture and downloaded the image, but I'd like a simpler way that isn't trial and error. Roger Roger Eichhorn [EMAIL PROTECTED]
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