#photography nerdity:
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Basically, the more the perspective changes among the components, the more geometric transformation the software has to do in order to line up the edges to tile them together. And any transformation comes at the expense of resolution and distortion of other parts of the final image.
So the first thing you want is a tripod placed in a single position to make the component captures. That's essential - but still not completely sufficient - for maintaining a fixed perspective
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Once you've selected where the tripod goes, the simplest thing to do is pan and tilt the camera on the tripod head between captures, pointing it at different areas of the subject such that there's some overlap between captures.
For best results, this must be done with the camera mounted on the tripod head in a way that the tilting and panning pivots around the central "nodal point" of the lens. Otherwise, the camera is effectively moving its position, even if the tripod itself isn't.
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Once you've selected where the tripod goes, the simplest thing to do is pan and tilt the camera on the tripod head between captures, pointing it at different areas of the subject such that there's some overlap between captures.
For best results, this must be done with the camera mounted on the tripod head in a way that the tilting and panning pivots around the central "nodal point" of the lens. Otherwise, the camera is effectively moving its position, even if the tripod itself isn't.
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Finding the nodal point can be tricky. There are special rigs for this that move the camera on the tripod head to make this easier and more systematic and repeatable.
But even with the panning and tilting done at the exact nodal point, the software still has to do considerable, resolution eating, transformation. To create a rectangular final image, each component has to be stretched at one edge or squeezed at the other, murdering pixels in the process. But results can still be pretty good.
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Finding the nodal point can be tricky. There are special rigs for this that move the camera on the tripod head to make this easier and more systematic and repeatable.
But even with the panning and tilting done at the exact nodal point, the software still has to do considerable, resolution eating, transformation. To create a rectangular final image, each component has to be stretched at one edge or squeezed at the other, murdering pixels in the process. But results can still be pretty good.
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To avoid having to do any transforms at all, you need to capture the component images without moving the camera AT ALL. No panning, no tilting.
But with most cameras, that would mean every component would be of exactly the same image. There'd be nothing to stitch together!
Enter the "technical camera", which is what I generally use for making stitched images.
6/
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To avoid having to do any transforms at all, you need to capture the component images without moving the camera AT ALL. No panning, no tilting.
But with most cameras, that would mean every component would be of exactly the same image. There'd be nothing to stitch together!
Enter the "technical camera", which is what I generally use for making stitched images.
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A technical camera provides internal "shift" movements that move the sensor (or film) with respect to the lens. That is, the lens (which is what determines perspective) stays in one place, but the sensor (or film) can be moved left, right, up, or down.
This effectively moves where the center of the captured image is. So if you make one photo, then shift the sensor to the left and make a second, the two photos together capture a "wide" view of the subject but with no change in perspective.
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A technical camera provides internal "shift" movements that move the sensor (or film) with respect to the lens. That is, the lens (which is what determines perspective) stays in one place, but the sensor (or film) can be moved left, right, up, or down.
This effectively moves where the center of the captured image is. So if you make one photo, then shift the sensor to the left and make a second, the two photos together capture a "wide" view of the subject but with no change in perspective.
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Technical cameras are specialized devices, and they need special lenses that can "cover" - project an image onto - an area larger than the sensor (to allow the shifting). All this is makes everything bigger, heavier, and more expensive. But they allow for making stitched composites without reducing the resolution or distorting geometry the way you'd have to when you capture the components by panning or tilting the whole camera.
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Technical cameras are specialized devices, and they need special lenses that can "cover" - project an image onto - an area larger than the sensor (to allow the shifting). All this is makes everything bigger, heavier, and more expensive. But they allow for making stitched composites without reducing the resolution or distorting geometry the way you'd have to when you capture the components by panning or tilting the whole camera.
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I generally use a Phase One (medium format) digital back on a Cambo "WRS" camera for making my stitched images. This system provides a fair amount of room for movements.
But there are less expensive and cumbersome alternatives. For 35mm-format, both Canon and Nikon make a few "perspective control" (sometimes called "Tilt/Shift") lenses that can be used for this technique on an existing DSLR or mirrorless camera.
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I generally use a Phase One (medium format) digital back on a Cambo "WRS" camera for making my stitched images. This system provides a fair amount of room for movements.
But there are less expensive and cumbersome alternatives. For 35mm-format, both Canon and Nikon make a few "perspective control" (sometimes called "Tilt/Shift") lenses that can be used for this technique on an existing DSLR or mirrorless camera.
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The 35mm shifting lenses aren't absolutely theoretically ideal for this. They generally shift the lens rather than the sensor when the camera is mounted on a tripod, changing perspective with each shift. But the change of perspective between captures is very small, and barely an issue in the final result. And they provide a much less expensive alternative to a full technical camera system.
If this sounds fun, I suggest renting a shifting lens and playing around with the technique.
10/10
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The 35mm shifting lenses aren't absolutely theoretically ideal for this. They generally shift the lens rather than the sensor when the camera is mounted on a tripod, changing perspective with each shift. But the change of perspective between captures is very small, and barely an issue in the final result. And they provide a much less expensive alternative to a full technical camera system.
If this sounds fun, I suggest renting a shifting lens and playing around with the technique.
10/10
Thanks for the great thread!
During my conscription (in 1980) I learned by myself how to use the Linhof 8×10" of the military school, without any clue, just making experiments.
But since film was expensive, I often had to resort to thin tracing paper
on the film plate to make correct drawings of devices for manuals (to make them was my "official" duty). -
The 35mm shifting lenses aren't absolutely theoretically ideal for this. They generally shift the lens rather than the sensor when the camera is mounted on a tripod, changing perspective with each shift. But the change of perspective between captures is very small, and barely an issue in the final result. And they provide a much less expensive alternative to a full technical camera system.
If this sounds fun, I suggest renting a shifting lens and playing around with the technique.
10/10
Related: Shift is also (more often) used to maintain geometric accuracy in certain subjects even in non-stitched images. It's the secret weapon of architectural photography. Here's a little thread I did on it a while back.
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Related: Shift is also (more often) used to maintain geometric accuracy in certain subjects even in non-stitched images. It's the secret weapon of architectural photography. Here's a little thread I did on it a while back.
Also, whenI use the term “quality” here, I’m using it a strictly technical sense to refer to the fidelity of the image, not the aesthetic qualities of the image. I very much dislike this usage, but it’s fairly standard in discussing this stuff.
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Nelle ultime 24 ore, le forze russe hanno effettuato 668 attacchi contro 32 insediamenti nella regione di Zaporizhzhia. Sei persone sono rimaste ferite a seguito di attacchi nemici nello stesso distretto. Lo ha riferito su Telegram Ivan Fedorov, capo dell'amministrazione militare regionale di Zaporizhzhia, scrive Ukrinform.
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ok...uhm...la domanda di oggi è: chi è che dà i nomi alle interfacce di rete?
premessa: la mia rete viene gestita con dhcpcd e wpa_supplicant.
Vabbeh...non è importante, solo che non capisco:
# ip link set [interface] down
# ip link set [interface] name unnomeacaso
$ ip link
mostra il nome cambiato ma:
$ route
vuoto
non che la route di default punta all'interfaccia sbagliata, no, proprio vuoto.
Prima c'era default route poi nulla.
# reboot
Torna tutto come prima.
Ora...non è importante perchè "tutto come prima" funziona, però mi chiedo chi è il gremlin che fa succedere queste cose?
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@MikeTheGray ma partecipasse a titolo personale non da premier...chessò...da cortigiana!
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@matz i treni in Grecia mi sembrano peggiori che in Italia come comodità, e sono Gruppo Ferrovie dello Stato italiane
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Quindi nel CSM vigerebbe un sistema para mafioso secondo Nordio? Essendo il CSM presieduto dal Presidente della Repubblica, questi sarebbe a capo di un sistema para mafioso?
Apperò, non si vince a spararle più grosse, si fa solo brutta figura
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@tante boosting for reach. Consider editing the post to add Gibraltar as a tag, might help reach more.
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Chi é ora che si comporta con atteggiamento "eversivo"?.
