I figured this had to exist somewhere. I looked around and found a nice
page of photo related calculators one of which is the amount of parallax
error from being off the no-parallax-point. The output is specified in
terms of degrees and also number of pixels in the image. Focal length
is not mentioned as an input parameter but is certainly there in another
form which is the image field of view. From another page I found some
discussion of having reasonable stitching results with errors of about 6
pixels. But there are probably a lot of caveats around that number.
Anyhow, after playing around with the calculator a bit (and assuming the
"nodal point offset" is about equal to the focal length of the lens
away from the tripod socket) it appears that one can make a rough
generalization for 35mm frames that no panorama head is needed if the
closest object is at least as far away in feet as the twice the focal
length of the lens in millimeters. eg; if you're shooting with a 50mm
lens and the closest object is 100 feet away you'll probably do OK with
no panorama head. You may even get away with less but, YMMV.
Chuck Norcutt
Chuck Norcutt wrote:
> I should also have added; before running out to buy a pano head try
> shooting some on a tripod but without a head. You may find that you
> really don't need a head. I've probably shot less than 15 or 20 panos
> but I don't have a head and haven't needed one. Probably half of them
> are shot hand held and are also successful. But shooting hand held I
> still try and make my body mimic the rotation on a tripod head. All of
> my panos are landscape type with the subject probably at least 2500
> times the focal length of the camera away from me. There's a value
> somewhere in the void and I don't know what it is that says if the
> subject is X times the focal length away you don't need to worry about
> parallax error.
>
> Chuck Norcutt
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