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Author Topic: Shooting wide architectural facades - stitch or shift?  (Read 2299 times)

Dinarius

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Shooting wide architectural facades - stitch or shift?
« on: October 17, 2018, 09:18:51 am »

I use my Canon 45mm Tilt-Shift a lot.

Occasionally, I'm in a situation where the lens isn't wide enough for an architectural view. Usually, in these situations, I use a wide (non tilt-shift) lens and fix the verticals afterwards in Capture One.

What I'd like to know is this: if I want to shoot a flat building facade that is too wide for my 45mm, should I pan and stitch, or should I shift left and right and then stitch?

I've tried panning in portrait format, allowing about 2/3 overlap, but I'm not happy with what I'm getting from CS6 afterwards. I'm careful about keeping everything parallel and vertical while panning, but I still don't like it.

What is the best way to get a wide building flat and upright, without hiring a 24mm T/S! :)

Thanks.

D.

Ps. If this is the wrong forum, please move.
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Slobodan Blagojevic

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #1 on: October 17, 2018, 01:43:01 pm »

There will be people more experienced than me chiming in, but I would venture to say that a shifted-then-stitched image would be the way to go, with more natural look and less distortion. I think (just think) that in order to achieve the same result with a panoramic photo (I assume that is what you meant by "pan") you would need to know exactly where the entrance pupil (a.k.a. nodal point) is and use a special panoramic contraption.

I captured this using Canon's 24mm T/S, Mark II, using shifting and stitching:

Dinarius

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #2 on: October 17, 2018, 01:56:54 pm »

There will be people more experienced than me chiming in, but I would venture to say that a shifted-then-stitched image would be the way to go, with more natural look and less distortion. I think (just think) that in order to achieve the same result with a panoramic photo (I assume that is what you meant by "pan") you would need to know exactly where the entrance pupil (a.k.a. nodal point) is and use a special panoramic contraption.

I captured this using Canon's 24mm T/S, Mark II, using shifting and stitching:

Slobodan,

Thanks for the reply.

My problem with shift and stitch is that I usually use vertical shift to take in the upper stories of a building and remove unwanted ground.

If I use vertical shift, then I canít use lateral shift to create a multi image shot.

Or am I missing something?

Thanks.

D.
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Slobodan Blagojevic

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #3 on: October 17, 2018, 02:14:10 pm »

Actually, you can, but you will be losing comers. I have an example, will post later, when I find it.

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TimoK

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #5 on: October 17, 2018, 03:03:49 pm »

I use my Canon 45mm Tilt-Shift a lot.

Occasionally, I'm in a situation where the lens isn't wide enough for an architectural view. Usually, in these situations, I use a wide (non tilt-shift) lens and fix the verticals afterwards in Capture One.

What I'd like to know is this: if I want to shoot a flat building facade that is too wide for my 45mm, should I pan and stitch, or should I shift left and right and then stitch?

I've tried panning in portrait format, allowing about 2/3 overlap, but I'm not happy with what I'm getting from CS6 afterwards. I'm careful about keeping everything parallel and vertical while panning, but I still don't like it.

What is the best way to get a wide building flat and upright, without hiring a 24mm T/S! :)

Thanks.

D.

Ps. If this is the wrong forum, please move.
Maybe it was good an idea to use both techniques at the same time. I sometimes do.
If the building is too high and broad to fit into my picture, I try horizontal shifting the camera in vertical position and same time tilting the camera upwards.
Then I stitch shifted shots in Photoshop (CS6) and straighten vertical lines, which is often easy in architectural shots.
When correcting verticals in post you loose some sharpness, but with shift-stitch technique you get more pixels into picture and can possibly downsample it to get
better final photo.
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #6 on: October 17, 2018, 03:12:11 pm »

I use my Canon 45mm Tilt-Shift a lot.

Occasionally, I'm in a situation where the lens isn't wide enough for an architectural view. Usually, in these situations, I use a wide (non tilt-shift) lens and fix the verticals afterwards in Capture One.

What I'd like to know is this: if I want to shoot a flat building facade that is too wide for my 45mm, should I pan and stitch, or should I shift left and right and then stitch?

I've tried panning in portrait format, allowing about 2/3 overlap, but I'm not happy with what I'm getting from CS6 afterwards. I'm careful about keeping everything parallel and vertical while panning, but I still don't like it.

What is the best way to get a wide building flat and upright, without hiring a 24mm T/S! :)

Hi D.,

The highest quality would be delivered by a 'Pan and Stitch', because you're shooting with the center of the image circle. The problem with CS6 is that it offers too little control, so one can quickly run into limitations of the Stitching module. If you were to use a better Pano Stitcher, e.g. PTGUI, you would have all the required controls (even for shifted image tiles), and it allows to compensate for keystone distortions, and rotations, and it removes any residual lens distortions (no need for separate distortion correction per image tile).

Left and Right shifting, if used with an entrance pupil correction while shooting, is the simplest, because the files only need to be shifted in alignment in Photoshop, not warped.  But shifting the lens means that the edges of the image circle are used on the L/R edges of the composite.

Cheers,
Bart
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #7 on: October 17, 2018, 03:49:37 pm »

Slobodan,

Thanks for the reply.

My problem with shift and stitch is that I usually use vertical shift to take in the upper stories of a building and remove unwanted ground.

Photoshop doesn't like that. PTGUI can handle that just fine.

Quote
If I use vertical shift, then I canít use lateral shift to create a multi image shot.


In that case, you could try and shift 45 and 135 degrees up if that allows a wide enough FoV (also vertically). But Panning is easier and only requires a minimum of hardware for the alignment of the entrance pupil of the lens. You can pan with a shifted lens, but you can also correct for keystoning in the Panostitcher (PTGUI understands shifted tiles and can stitch them, but it can also correct keystoning afterwards on unshifted tiles).

Cheers,
Bart
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MattBurt

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #8 on: October 17, 2018, 04:07:34 pm »

My gut says you should do one method or the other, but using both may muddy your results. But I'm no expert on T/S since I have never used one.
When needed I always pan, stitch, and correct for architecture. I leave some extra room if I can to give me some "slack" I can sacrifice for corrections.
I have found Lightroom's Upright feature to work very well most of the time (but not all) for straightening this kind of distortion.
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Dinarius

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #9 on: October 18, 2018, 05:33:48 am »

Thanks for all the replies.

On a shoot at the weekend I had shot a few horizontal and vertical panoramas using the 45mm T/S, as well a shooting the same building with a wide lens tilted up, just to cover myself.

In the end, having tried CS6, I used a single shot from the wide lens and just corrected the verticals. I had tons of file for what I needed.

However, I just downloaded the PTGUI trial (thanks Bart!) and processed a three shot, landscape-format, panorama (where I had shifted the 45mm up a bit to take in the top of the building and some sky, and lose some of the lower foreground and then panned three exposures) and the result is flawless. One big gorgeous file.

In order to have as little as possible to do in CS6 after creating the panorama, I processed the files in C1 and then saved them as TIFFs.

1. Is this what others would do? There is no option to create a RAW format panorama; correct?

2. I watched the PTGUI demos and I cannot get my head around the positioning of the lens and the use of that tripod rail gadget to keep it in the same position. Any better video you can point me to? (I had also shot a portrait-format six-shot panorama of the same building and I suspect that this would have benefited from keeping the lens in the right position.)

3. Any other PTGUI workflow suggestions?

For what I do, using PTGUI would be a lot cheaper than hiring (or buying) a 24mm T/S, which I do occasionally.

Thanks.

D.

Ps. This is the head I'm currently using: https://www.manfrotto.ie/405-geared-tripod-head-strong-and-lightweight-aluminium

« Last Edit: October 18, 2018, 06:06:02 am by Dinarius »
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #10 on: October 18, 2018, 12:32:26 pm »

Quote
However, I just downloaded the PTGUI trial (thanks Bart!) and processed a three shot, landscape-format, panorama (where I had shifted the 45mm up a bit to take in the top of the building and some sky, and lose some of the lower foreground and then panned three exposures) and the result is flawless. One big gorgeous file.

In order to have as little as possible to do in CS6 after creating the panorama, I processed the files in C1 and then saved them as TIFFs.

Yes, that would produce excellent input tiles for PTGUI. Stellar Raw conversion quality, Chromatic Aberration correction, Diffraction Correction, and if preferred Structure and Clarity in addition to Color and Tonal corrections.

Quote
1. Is this what others would do? There is no option to create a RAW format panorama; correct?

I would, and no, neither CaptureOne nor PTGUI offers to save to a Raw (because it's not Raw anymore).

Quote
2. I watched the PTGUI demos and I cannot get my head around the positioning of the lens and the use of that tripod rail gadget to keep it in the same position. Any better video you can point me to? (I had also shot a portrait-format six-shot panorama of the same building and I suspect that this would have benefited from keeping the lens in the right position.)

The most benefit of keeping the entrance pupil in a stationary position comes from total freedom when adding tiles to expand the FoV. For facades with little detail in the foreground (street furniture, trees/(lamp)posts/etc.), alignment to keep the entrance pupil stationary is less critical. The more depth there is in the image, the more critical alignment becomes.

One can use gear to optimize the setup for either single row, or multi-row stitches.
  • Single Row: If the optical axis of the lens does not align with the horizontal center of rotation, one will first need a horizontal bar for shifting the optical axis into alignment such that it intersects with that rotation center.
  • Single Row: Requires a minimum of gear, usually only a bar that allows shifting the camera/lens forward or aft, to align the vertical axis through which one rotates with the entrance pupil of the lens. That works if the lens is already aligned with the horizontal tripod/rotating head offset. This then also allows using a vertically shifted lens and only horizontal panning.
  • Multi-Row: If one also wants to tilt the lens axis up/down, then that rotation also needs centering on the axis through the entrance pupil, by vertical shifting on a bar. That will add some complexity to the setup.

So to summarize; single row stitching requires alignment of the entrance pupil with 2 axes (horizontal shift and fore/aft shift aligns the vertical axis of rotation), and multirow stitching requires alignment of 3 axes, to keep the intersection of 3 axes aligned with the center of the entrance pupil.

Quote
3. Any other PTGUI workflow suggestions?

Meticulous leveling on tripod is not necessary anymore (approx. horizontal leveling does help because it results in less cropping / content aware filling), so there's a lot of time saving and no requirement for high quality (electronic) levels (which also need calibration). Leveling can be a part of the stitching process and can be helped by manually adding vertical control points (that are often available with architecture). Horizontal control points only make sense when shooting exactly perpendicular to the front of the facade. Once keystoning is minimized, it can help to deliberately add back a little keystoning by dialing a small amount of pitch, especially on shots from a relatively short distance (that get stretched vertically a lot).

Saving the project file (and the tiles, or the Raw converter parameters) will allow recreating a new stitch at a different size (even from a somewhat different angle). PTGUI uses excellent resampling algorithms that preserve lots of detail despite the warping that takes place.

Quote
For what I do, using PTGUI would be a lot cheaper than hiring (or buying) a 24mm T/S, which I do occasionally.

Absolutely. It can even replace an expensive Tilt and Shift lens with a very high quality regular fixed focus length lens. On a 36x24mm full frame sensor, an approx. 50 mm lens offers a very good compromise between lots of magnification of detail (compared to a wide-angle) and still enough depth of field.

Cheers,
Bart

P.S. I also have the Manfrotto 405, but use it more for product shots and macro work. For Panos / Architecture, I use a lighter weight (but a just as sturdy combination of an EZ-leveler II and an indexing rotator on top of that, with an RRS clamp and bars on top of that). Relatively lightweight and easy to transport compactly.
« Last Edit: October 19, 2018, 06:09:17 pm by BartvanderWolf »
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Dinarius

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #11 on: October 18, 2018, 01:56:53 pm »

Bart,

Thanks again. Much to take in - Iíll be back to you.

Meanwhile, Helicon Focus (excellent software) will take any number of RAWs and give you back a .dng.

Would be nice if PTGUI could do likewise.

Thanks.

D.
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #12 on: October 18, 2018, 02:20:34 pm »

Bart,

Thanks again. Much to take in - Iíll be back to you.

You're welcome.

Quote
Meanwhile, Helicon Focus (excellent software) will take any number of RAWs and give you back a .dng.

Would be nice if PTGUI could do likewise.

I think that one of the issues is that DNGs are a variation of a TIFF. Focus-stacking will produce a file that has approx. the same pixel dimensions of the source images. Panos, on the other hand, can easily exceed the 4GB TIFF file limit. PTGUI, therefore, does support PSB file output (e.g. for Gigapixel panos).

Cheers,
Bart
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MattBurt

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #13 on: October 18, 2018, 04:23:06 pm »

Lightroom 6 and newer produces dng files for either hdr or panoramas.
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #14 on: October 18, 2018, 07:06:41 pm »

Lightroom 6 and newer produces dng files for either hdr or panoramas.

Hi Matt,

I'm not sure if Adobe has fixed it by now, but the LR Version 6 Pano's didn't allow to remove Chromatic Aberrations in the individual tiles of such composite "Raws", effectively making it impossible to remove it afterward in Panos. Besides, I believe there is a dimension limit in Lightroom of 65000 pixels maximum, which can be a real limitation for wide Panos (and I don't know if it has the same 4GB total filesize limit as TIFFs).

Cheers,
Bart
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Dinarius

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #16 on: October 19, 2018, 05:18:35 am »


The most benefit of keeping the entrance pupil in a stationary position comes from total freedom when adding tiles to expand the FoV. For facades with little detail in the foreground (street furniture, trees/(lamp)posts/etc.), alignment to keep the entrance pupil stationary is less critical. The more depth there is in the image, the more critical alignment becomes.

Bart,

What is the difference between entrance pupil and nodal point?

Must both be used when shooting panos?

A lot of what I'm doing in an upcoming project will simply involve capturing buildings that would fit fine into a 24mm T/S, but which I'll want to capture with the 45mm T/S to keep the budget down.

As I wrote above, a three-shot pan of a building I did the other day worked fine in PTGUI. That was done without having a head to correct for the nodal point - there was nothing in the near ground that would have been affected anyway.

Am looking at one of these in combination with one of these

But, do I need either or both for the exteriors I'll be doing?

Thanks.

D.
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vjbelle

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #17 on: October 19, 2018, 07:58:20 am »

I'm sure Bart will chime in but the entrance pupil and nodal point are different and not at the same point of the lens.  You only should concern yourself with the entrance pupil.

The Manfrotto examples you linked to are very cumbersome - I owned both.  Take a look at what is available at RRS. 

When I pan (usually single row) I don't concern myself with any special equipment except a short rail to move the camera forward or backward to the entrance pupil.  Lots of times I just eyeball in the finder for the next panned shot.  Its always best to be a little wider and crop the final image. 

Victor

Edit:  You can find a lot of useful information at https://www.panoramic-photo-guide.com/finding-the-nodal-point.html
« Last Edit: October 19, 2018, 08:02:27 am by vjbelle »
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Bart_van_der_Wolf

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #18 on: October 19, 2018, 09:24:36 am »

Bart,

What is the difference between entrance pupil and nodal point?

The technical difference only matters for optics designers (https://en.wikipedia.org/wiki/Entrance_pupil and https://en.wikipedia.org/wiki/Cardinal_point_(optics)#Nodal_points), for Panoshooters we use the Entrance Pupil or No-Parallax point (the single apparent position of the aperture when looking in the lens from the subject side). The entrance pupil can shift a bit foreward or backward with focus distance, depending on optical design. For architecture, the distance is usuall large enough to allow a single No-Parallax point setting, for interiors if can help to calibrate for a closer focus distance, typical for the size of interior.

PTGUI is very capable in solving small inaccuracies, but mathematically can only achieve zero parallax in a single plane unless the No-Parallax point was used.

Quote
Must both be used when shooting panos?

Only Entrance Pupil / No-Parallax point matters.

Quote
A lot of what I'm doing in an upcoming project will simply involve capturing buildings that would fit fine into a 24mm T/S, but which I'll want to capture with the 45mm T/S to keep the budget down.

Totally doable, with minimal additional postprocessing, and with great resolution. You can choose whether to use multiple Shifted lens shots or Unshifted tilted shots, all perspective issues can be solved by the Stitching application and, at a distance, any parallax caused by unaligned entrance pupil positions will be small. You will want to nail the alignment of the rotation axis through the entrance pupil with subjects that have a lot of depth, or occlusions like looking through gates/arches or with street furniture, or brick roads.

Quote
As I wrote above, a three-shot pan of a building I did the other day worked fine in PTGUI. That was done without having a head to correct for the nodal point - there was nothing in the near ground that would have been affected anyway.

That's key, nothing nearby, and PTGUI by default automatically corrects for the decentered/shifted optical axis. For such a single row setup there is some leeway.

Quote
Am looking at one of these in combination with one of these

But, do I need either or both for the exteriors I'll be doing?

I also use the 300N Panoramic Rotation Unit, because the indexed stops allow me to get consistent overlaps, and I now rarely skip a shot in large stitching projects by getting distracted with many shots per row. It also allows faster shooting without having to look through the viewfinder. That can help when clouds are racing by due to high wind speeds (I shoot in the opposite direction of cloud travel, to avoid repeating ghosts anyway, so sometimes left-to-right, sometimes right-to-left). The indexing click-stops make life a lot easier, and also allow to shoot with the camera close to a back wall (often the case with interiors), because there is no need to look through the viewfinder while rotating.

I do not like the 303 Panoramic Head, too heavy and the vertical support plate cannot be shifted vertically (which might be required for some cameras if you want to expand to a multirow setup). So it only allows a single row approach and weighs a lot.

Personally I invested in a more modular system based on Really Right Stuff components (http://www.reallyrightstuff.com/RRS-pano-gear) that can be expanded over time as the requirements grow.

For a single Row setup (assuming the optical axis is aligned sideways with the vertical panning (Yaw) axis), the "Package For Shooting Single-Row Panos: Pano Elements, LR" suffices. A camera model specific L-bracket is required.

My multirow setup was assembled over time and the individual components can be reassembled into all sorts of setups (see attached). For my Fisheye lens for 360-degrees VR shots I use a shorter MPR rail with an integrated clamp instead of the longer MPR II, to keep the rail out of the lens' 180 FoV.

EDIT: I've also added the Single Row configuration, which assumes that the optical axis aligns with the center of rotation along the Yaw axis. As you can see, simple, lightweight and quite compact. And when used with a vertically shifted TS lens, the EZ leveler II allows enough adjustment to also shoot some higher buildings without the need for a Ballhead or 3-axis tripod head with a rotator on top.

Cheers,
Bart
« Last Edit: October 19, 2018, 10:08:00 am by BartvanderWolf »
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kers

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Re: Shooting wide architectural facades - stitch or shift?
« Reply #19 on: October 19, 2018, 09:37:44 am »

The discussion shift or stitch is intersting.

I think i depends a lot on the quality of the lenses.
TS lenses are usually not that good when fully shifted, so at some point a stitch will give better results.

In this case the canon 45TS is an old design - my guess is that a stitch with a good 50mm lens ( Sigma ART par example) will give better results.
on the other hand the new 50mm TS from Canon might be better again.

If i make an 19mm photo by stitching with a 24mm lens and compare it with the very good 19mm PCE from Nikon-  the PCE wins.
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