Frank is correct. If the camera is not located in the same spot for all
shots each camera position sees a different view of the background
relative to the subject and this is called parallax error. Actually
moving the camera up the height of the vase and flower with the tripod
will have so much parallax error that no stitching software will be able
to put it together. You can try if you like but I think you'll be
wasting your time.
When taking landscape panoramas where everything (including the
foreground) is relatively far away one can often ignore parallax error
because it's very small. Just turning the camera on a tripod or even
carefully by hand will often work. But if there is a nearby object (and
macro is the extreme case) the camera must be rotated (both horizontally
and vertically) around the entrance pupil of the lens or "no parallax
point". Some say the "nodal point" but the nodal points of a lens are
actually different animals. See this link which describes parallax and
the no-parallax-point:
<http://www.panoguide.com/howto/panoramas/parallax.jsp>
Making a macro panorama will be tough since it will require some
precision in locating and using the no-parallax-point. That point is
also different for each lens and focal length. But I don't think it's
necessary.
Chuck Norcutt
Frank Wijsmuller wrote:
> I understand Chucks concern, and he might have a point.
>
> However adjusting the tripod height will make things worse. What you are
> about to make is actually a panorama, and imagine what happens if you make
> the left picture, walk several say 100 meters and make the middle picture,
> and then again 100 meters for the right picture. But what you want is
> 'emulate' a single camara shot, which will succeed best if you take the
> pictures from the same spot. Actually, for optimal stitching the camera
> needs to turn around the 'nodal' point (somewhere inside the lens), instead
> of the tripod screw (but with some luck you won't notice it too much).
>
> Regards, Frank.
>
> 2007/8/25, Rickard Nilsson <rickard.nilsson@xxxxxxxxx>:
>>
>> On Sat, 25 Aug 2007 04:22:06 +0200, Chuck Norcutt
>> <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
>>
>>> I've never tried stitching macro before either but I think it would be
>>> very difficult. It would place a real premium on having the camera/lens
>>> adjusted very, very precisely to avoid parallax error between frames.
>> The photo is really not very macro-ish. It's supposed to be of a flower
>> in a vase. I was hoping that stacking two or three horizontal shots
>> would not prove too difficult. It think it can be done by just adjusting
>> the tripod height.
>>
>>> I'm back. I was curious enough to perform my own 23 ppi experiment and
>>> the quality is actually better than I expected. I cropoed out a section
>>> of an image as described above and printed it on plain paper at low
>>> (text) quality to make an 8x10. At 6 feet away it looks pretty good but
>>> I can still see a bit of pixellation along the gunwale of a boat. By
>>> the time I'm 12 feet back all pixellation is gone.
>> That sounds great. I played around a bit with Rasterbator
>> (http://homokaasu.org/rasterbator/) some time ago, and it's amazing how
>> low resolution an image can be recognised in, from a distance.
>>
>>
>> / Rickard
>>
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