>
> Mark wrote:
> > I believe it produces focal lengths that are 7X longer than if used with
> > 35mm gear (I.E. A 100mm lens would become a 700mm lens !!!, Or a 400mm
lens
> > would become a 2800mm lens !!!!!!!!!! :-) )
>
> I'll contribute the obligatory correction here:
>
> No. It is still a 100 (or 400) mm lens. The focal length doesn't
> change. The XL1 (or APS, or digicam...) just crop out an area in
> the center of the image you get at 100mm (or 400mm). This may
> sound picky, but if you use a 20mm lens on an XL1 and expect to get
> the same thing as a 144mm on your EOS, you will be really surprised.
> The angle of view is truly divided by 7.2 as you expect, but the
> perspective is still that of a 20mm, wide angle distortion and all.
> So don't try to get a good portrait shot with a 20mm on your XL1.
> At least don't ever show that video to the subject :-)
>
Mark,
sorry, but I have to disagree here. Lenses don't control or affect
perspective. The film to subject distance determines perspective, then you
select a lens to give you the coverage you want.
Yes, wide angle lenses do have linear distortion towards the edges, but that
is not the same thing as perspective (the relative distance between near and
far objects in the scene).
Because of the small size of the image sensors on a video camera the
"normal" lens for a video camera is in the 10mm range. A 20mm lens on a
video camera is going to look like a telephoto. The outside edges of the
lenses projected image (where the distortion would show) fall outside the
imaging area of the camera's imaging sensor.
JohnC
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