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Author Topic: Stitching-Redux  (Read 1214 times)

vandevanterSH

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Stitching-Redux
« on: October 01, 2010, 12:40:58 PM »

I am setting up my 'blad 203 FE with a Mutar 1.4 in order to do horizontal stitching.  It is my rather fuzzy understanding that if the lens is the moving component used to create the "stitch" then parallax can occur.  (If the lens is stationary and the back moves, ie. 'blad Flexbody,  then parallax isn't an issue?)  If my camera is mounted on a rail and I move the rail in an equal and opposite direction to the lens movement then "no parallax"?  Or am I totally confuses. :>)

Steve
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BartvanderWolf

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Re: Stitching-Redux
« Reply #1 on: October 01, 2010, 01:16:33 PM »

I am setting up my 'blad 203 FE with a Mutar 1.4 in order to do horizontal stitching.  It is my rather fuzzy understanding that if the lens is the moving component used to create the "stitch" then parallax can occur.  (If the lens is stationary and the back moves, ie. 'blad Flexbody,  then parallax isn't an issue?)  If my camera is mounted on a rail and I move the rail in an equal and opposite direction to the lens movement then "no parallax"?  Or am I totally confuses. :>)

Hi Steve,

There are 2 possibilities.
1. You use a horizontal rail from left to right, and offset the lateral shift of the lens' entrance pupil caused by rotating at an axis that's too far back. Drawback is that the lateral offset is different for each different amount of rotation.
2. You use a fore/aft rail and slide the camera back until the rotation axis coincides with the entrance pupil. This is the preferred approach because the amount of rotation becomes unimportant. The only thing to watch out for is with close-up photography where the focusing itself may cause a fore/aft shift of the entrance pupil.

For scenarios without any near foreground detail, and a liberal amount of overlap, one can sometimes skip the no-parallax preventative cure. However, doing it the correct way has it's benefits (reducing the srew-up potential usually does...).

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

vandevanterSH

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Re: Stitching-Redux
« Reply #2 on: October 01, 2010, 02:26:27 PM »

Thanks for the reply....I'm still confused....I am not sure where "rotation" come into play when the lens motion and the camera body/rail move in the same plane laterally when doing a horizontal stitch.  Basically the "Mutar" is an adapter that widens the image circle, increases the focal length of the lens somewhat and allows 16mm of lens shift in each direction from center.

Steve
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Dick Roadnight

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Re: Stitching-Redux
« Reply #3 on: October 01, 2010, 02:42:38 PM »

Thanks for the reply....I'm still confused....I am not sure where "rotation" come into play when the lens motion and the camera body/rail move in the same plane laterally when doing a horizontal stitch.  Basically the "Mutar" is an adapter that widens the image circle, increases the focal length of the lens somewhat and allows 16mm of lens shift in each direction from center.

Steve
Streve...

There are two basic ways of stitching, pan-and-stitch and shift-and-stitch.

You are concerned about parallax cause by shifting the lens sideways, when you pan-and-stitch.

Bart is on about positioning the entrance pupil on the vertical axis of rotation of your tripod... (assuming that you want to pan-and-stitch) so that you would not get parallax when you pan (rotate the camera/lens assembly about a vertical axis).

If you cannot attach your lens to a tripod, then moving the camera sideways to compensate for the lens shift should work in theory, but I think that in practice you would get inaccuracies - which software might be able to fix for you.
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vandevanterSH

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Re: Stitching-Redux
« Reply #4 on: October 01, 2010, 05:28:38 PM »

There are two basic ways of stitching, pan-and-stitch and shift-and-stitch.
*********
I may be "mis"-understanding the terminology.  I have done rotational image capture for pano ie. pan-and-stitch(?) using a rail to set the "nodal" point....what I am trying to set up is horizontal shift-and-stitch (?) with my old Hasselblad gear.  If I am in fact doing a "shift-and-stitch" with a shift lens, does moving the camera body counter to the lens shift eliminate parallax?

Steve
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Dick Roadnight

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Re: Stitching-Redux
« Reply #5 on: October 01, 2010, 05:45:09 PM »

There are two basic ways of stitching, pan-and-stitch and shift-and-stitch.
*********
I may be "mis"-understanding the terminology.  I have done rotational image capture for pano ie. pan-and-stitch(?) using a rail to set the "nodal" point....what I am trying to set up is horizontal shift-and-stitch (?) with my old Hasselblad gear.  If I am in fact doing a "shift-and-stitch" with a shift lens, does moving the camera body counter to the lens shift eliminate parallax?

Steve
Yes
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vandevanterSH

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Re: Stitching-Redux
« Reply #6 on: October 01, 2010, 07:34:44 PM »

Thanks..

Steve
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