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Author Topic: Tilt Shift and Panoramas  (Read 29282 times)
Ronny Nilsen
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« Reply #40 on: August 05, 2010, 06:45:18 AM »
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Quote from: OldRoy
1) How would the horizontal fields of view compare between the 14mm end of my existing lens and a 3-shot stitch using the Nikon 24mm T/S in landscape orientation on the Agnos clamp?
2) Is the Agnos device intended, as I imagine, primarily to eliminate parallax errors? From what I've read on LL stitching shifted shots is quite a common technique (hitherto shifting lens, and thus entrance pupil, not body I assume) Hence the Agnos clamp?
3) Anyone got any other comments on this device?

Roy

That device will probably do for you in a bit easier way what I do with RRS focusing rail & slider:

Build a View Camera with your Canon 5D

Ronny
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Kirk Gittings
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« Reply #41 on: August 05, 2010, 09:52:40 AM »
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Quote from: Ronny Nilsen
That device will probably do for you in a bit easier way what I do with RRS focusing rail & slider:

Build a View Camera with your Canon 5D

Ronny

Maybe I am missing something in your tutorial, but I do a couple of dozen or so flat stitches, without a rail on Canon T/S lenses, every week for clients and simply stitch them in PS-CS4 perfectly. I own and used to use a rail to correct the small parallax shift, but since CS3 have found the rail and parallax correction unnecessary as the stitch programs can easily handle the issue.  The only problem I have seen in a couple of years is where there is not enough detail in the overlap areas (like a blank wall) to lock on to.
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BartvanderWolf
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« Reply #42 on: August 05, 2010, 11:58:46 AM »
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Quote from: Kirk Gittings
Maybe I am missing something in your tutorial, but I do a couple of dozen or so flat stitches, without a rail on Canon T/S lenses, every week for clients and simply stitch them in PS-CS4 perfectly. I own and used to use a rail to correct the small parallax shift, but since CS3 have found the rail and parallax correction unnecessary as the stitch programs can easily handle the issue.  The only problem I have seen in a couple of years is where there is not enough detail in the overlap areas (like a blank wall) to lock on to.

Hi Kirk,

That's possible if you don't have overlapping close foreground and background detail. Whenever you change the position of the entrance pupul, you will get a shift in perspective between foreground and background features. The blending operation of a good stitcher can often hide the flaws, especially with a liberal amount of overlap, but not always. The only way to really avoid surprises is to keep the entrance pupil stationary, thus keeping the perspective the same.

Cheers,
Bart
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Kirk Gittings
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« Reply #43 on: August 05, 2010, 01:54:08 PM »
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Quote from: BartvanderWolf
Hi Kirk,

That's possible if you don't have overlapping close foreground and background detail. Whenever you change the position of the entrance pupul, you will get a shift in perspective between foreground and background features. The blending operation of a good stitcher can often hide the flaws, especially with a liberal amount of overlap, but not always. The only way to really avoid surprises is to keep the entrance pupil stationary, thus keeping the perspective the same.

Cheers,
Bart

Sorry WADR but that is nonsense these days with flat stitches from T/S lenses. I shoot architecture and interiors professionally and very often have "overlapping close foreground and background detail". I haven't had to use my rail in a couple of years, not with CS3 or 4..
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Ronny Nilsen
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« Reply #44 on: August 05, 2010, 01:55:28 PM »
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Quote from: Kirk Gittings
Maybe I am missing something in your tutorial, but I do a couple of dozen or so flat stitches, without a rail on Canon T/S lenses, every week for clients and simply stitch them in PS-CS4 perfectly. I own and used to use a rail to correct the small parallax shift, but since CS3 have found the rail and parallax correction unnecessary as the stitch programs can easily handle the issue.  The only problem I have seen in a couple of years is where there is not enough detail in the overlap areas (like a blank wall) to lock on to.

Yes, for the most part things will go well doing what you do with modern SW, I to do that from time to time. But
the advantage of doing it with "a back shift" is:

1) I'm guaranteed a perfect stitch result back home.
2) Stitching becomes very easy, took me perhaps 3 min. to do it manually in CS2, and
    stitching is very fast in CS4 with "reposition only" as the SW don't need to do any correction.

Besides it takes me perhaps only 10 seconds extra time during capture compared to not using
the rails.

Ronny
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Kirk Gittings
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« Reply #45 on: August 05, 2010, 02:09:58 PM »
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Ronnie, you may be right somehow, but I just haven't seen it. Last week I was in Las Vegas for a 2 day shoot. I did 10 flat stitches (about 1 in 6 shots) with a 24 T/S II, some of them hand held from the top of a ladder, something I do regularly when I can't use a tripod. All of them worked perfectly as expected. I had a rail in my accessorie bag in the truck that never came out. Believe me, I have very demanding clients, on high profile out-of-town shoots, if there was any doubt whether these simple flat stitches would work, I would have used the rail, but as always they stitched perfectly. If they hadn't worked, I would have been flying back to redo them-not exactly a cost effective way of doing business.
« Last Edit: August 05, 2010, 02:13:13 PM by Kirk Gittings » Logged

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uaiomex
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« Reply #46 on: August 05, 2010, 08:13:49 PM »
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I second this 100%. Since using CS4 I quit using my rail. To say the truth, I don't undertand how PS does it. I tested Photomerge with a 5D2 and TS17 in interiors and exteriors using multiple planes with intersecting beams or furniture parts where you can see through. Probably a true nightmare before CS4 and rail support.
Everytime Photomerge came with a perfect stitch. I don't flatten so I can see where the software cuts each frame. Intrinsic! A true artwork of computing science. If the software distorts anything, I can't tell @100%. Of course, as I learned to trust more CS4 Photomerge the more stitching I've been doing. It's so easy!. This is one the main reasons I decided to strenghten my EOS system and forget about digital medium format. At least for the time being.  Maybe Adobe owns Canon stock    
Eduardo

 
Quote from: Kirk Gittings
Ronnie, you may be right somehow, but I just haven't seen it. Last week I was in Las Vegas for a 2 day shoot. I did 10 flat stitches (about 1 in 6 shots) with a 24 T/S II, some of them hand held from the top of a ladder, something I do regularly when I can't use a tripod. All of them worked perfectly as expected. I had a rail in my accessorie bag in the truck that never came out. Believe me, I have very demanding clients, on high profile out-of-town shoots, if there was any doubt whether these simple flat stitches would work, I would have used the rail, but as always they stitched perfectly. If they hadn't worked, I would have been flying back to redo them-not exactly a cost effective way of doing business.
« Last Edit: August 05, 2010, 08:15:49 PM by uaiomex » Logged
OldRoy
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« Reply #47 on: August 06, 2010, 07:33:36 AM »
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Well, I guess I shouldn't be too surprised that there are no direct answers to the questions I posed. Any discussion of stitching, whether involving TS lenses or not, usually evolves into a dispute about the necessity (or not) of using a "rail" - or a pano head. Personally I use PTGuiPro to stitch, which I think is generally accepted as being at the upper end of stitching software: I tried stitching with CS3 and it was useless - I've yet to upgrade to CS4. When stitching VR panos with a fish-eye lens it's absolutely  essential to set up the panhead (mine's currently a barely serviceable NN3) so that rotation takes place around the npp point. If it's too far out - and I mean by a few mm - the pano will not stitch accurately. I made dozens before I finally got this right. But that's applicable only to my own experience of the peculiarities of VR panos.

I've shot "regular" panos off a panhead or else hand-held with a subject without much in the way of coherent foreground. So I know that you can stitch acceptably with a degree of parallax error between the donor shots. But I'm a bit baffled by the contributor above who recounts shooting hand held panos with a TS lens. I assume that it was being used as a conventional lens, unshifted?

Can I try again to get some opinions about the problem as I see it? Let's put aside for the moment the issue of parallax error. If I shoot a series of shots using a wa lens in an interior and stitch them, I get - unavoidably - the characteristic curvature of horizontals above and below the "equator". So the combination of a 24 mm TS lens and the Agnos device looked to me like a perfect solution. No curvature, no parallax errors, just an effectively bigger sensor with a wide aspect ratio (assuming landscape orientation). I'm not so concerned about resolution so my main interest is in the effective FOV I could achieve overlapping 3 shots with this lens, by comparison with my existing 14-24 @ 14mm. The absence of the volume anamorphosis effect that 14mm exhibits would also be a big plus.

I would have thought that this requirement would be pretty common amongst those of us shooting in confined spaces using 35 mm gear. I confess to being at the low end of the food-chain in this respect; even a single TS lens is a big and possibly uneconomic outlay for me. Of course if it improves my results it may prove justified.

Roy
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haefnerphoto
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« Reply #48 on: August 06, 2010, 08:25:23 AM »
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I believe that this is a good example of what this thread is discussing.  Attached are the three images shot with a Canon 17mmT/S, then combined in CS5's Photomerge program.  The result is the fourth image, if you'd like try it yourself.  This shot was taken as part of a glorified walkthru of a house I'll be shooting in the near future, the architect had originally hired another photographer who wasn't able to produce an image like this (not the right equipment, etc) so now I'm involved.  I feel the process works quite well, while I'd love to be able to shift the back and never move the lens, I can find no fault with the final image.  Jim
[attachment=23531:6_30_10_...2_adjust.jpg]
[attachment=23532:6_30_10_...8_adjust.jpg]
[attachment=23533:6_30_10_...4_adjust.jpg]
[attachment=23534:Chang_Pa...ma_1_dc2.jpg]
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BartvanderWolf
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« Reply #49 on: August 06, 2010, 08:45:45 AM »
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Quote from: OldRoy
Can I try again to get some opinions about the problem as I see it? Let's put aside for the moment the issue of parallax error. If I shoot a series of shots using a wa lens in an interior and stitch them, I get - unavoidably - the characteristic curvature of horizontals above and below the "equator".

Hi Roy,

No you don't get a wavy horizon, provided(!) that you have your panning axis perfectly aligned. You can still get rid of the 'wave' if you point your horizon (pitch parameter) at a higher or lower position than you are doing when the 'wave' strikes. The resulting stitch will have a somewhat curved top and bottom edge, so you'll lose some FOV to cropping, unless you can fill in the missing parts with CS5s content aware fill (unlikely to be successful for most interiors). However much you try to get your rotation platform leveled, there will almost unavoidably be a small amount of error, but the panostitcher should be able to figure this out automatically if you can set some vertical line controlpoint pairs.

Quote
So the combination of a 24 mm TS lens and the Agnos device looked to me like a perfect solution. No curvature, no parallax errors, just an effectively bigger sensor with a wide aspect ratio (assuming landscape orientation). I'm not so concerned about resolution so my main interest is in the effective FOV I could achieve overlapping 3 shots with this lens, by comparison with my existing 14-24 @ 14mm. The absence of the volume anamorphosis effect that 14mm exhibits would also be a big plus.

The Argos device looks like a useful addition, I just don't know how it does in practice (e.g. can you work quickly between lens+camera shifts in opposing directions). In my experience, and within the image quality limitations of a large image circle near the edges, I use the horizontal flat-stitch most. For that it was very easy to equip my RRS setup with a few simple additions to make a very compact solution that also works fast (e.g. when trying to avoid cloud-cover to change light conditions between tiles).



I set my camera with the left shifted lens in the clamp and shift it to the right stop, I then shift the lens to the right and the camera to the left stop. With the camera in landscape mode that's all it takes, 2 exposures and 4 shits, quite fast. The stops are pre-set at the correct width (corresponding with 2x the amount of lens shift + clamp width). The result is very easy to composite in Photoshop with mostly a relative horizontal shift (and perhas a bit vertical to compensate for a rotated sensor). This is impossible to accomplish in Photoshop under all but the more favorable circumstances without the correction for entrance pupil shifts, especially in scenario's like interiors with furniture close to the camera. A good blender may get away with it under favorable circumstances, but I'm not going to second guess physics and hope Photoshop can manage (because when it can't, you're in big trouble). Prevention is still better than having to cure.

Quote
I would have thought that this requirement would be pretty common amongst those of us shooting in confined spaces using 35 mm gear. I confess to being at the low end of the food-chain in this respect; even a single TS lens is a big and possibly uneconomic outlay for me. Of course if it improves my results it may prove justified.

The requirement is there, and so is the solution.

Cheers,
Bart
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BartvanderWolf
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« Reply #50 on: August 06, 2010, 08:55:24 AM »
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Quote from: haefnerphoto
I feel the process works quite well, while I'd love to be able to shift the back and never move the lens, I can find no fault with the final image.g]

Hi Jim,

this is a good example of where fully automatic blending usually works (nice image by the way, given the shooting circumstances).  There is little foreground detail that overlaps with the background, so a good blend goes a long way with little difficulty. As long as you can avoid the foreground/background compositions, thing will probably work out fine. But if you want total freedom in composition and perspective/viewpoint, a small preparation can save your day (and night rest ;-)).

Cheers,
Bart
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JeffKohn
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« Reply #51 on: August 06, 2010, 09:51:31 AM »
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You guys may be right that parallax is rarely a problem with today's stitching software, but the problem is not completely eliminated so I'd rather take the safe approach and shift the camera in the QR clamp to avoid it in those rare cases where it could be a problem. It takes all of 5 seconds to guarantee I won't have to worry about parallax.

I don't carry a device to allow camera shifting for vertical's, but I don't shoot those as often and in my experience parallax is less of an issue. But for horizontals it _does_ come up on occasion, at least for me shooting landscapes. I do think a special sliding rail is overkill though. I have 10mm marked on my QR clamp and I just slide the camera over in the clamp. I may not get the shift exact down to .1mm, but I don't think that level of precision is necessary (unless maybe shooting macros).

I will say, that while I prefer PTGui over Photoshop for spherical and cylindrical panos, the "Reposition Images" option in Photoshop is preferred for shift-stitching, because you don't want to use a projection for flat stitching. You can get around this in PTGui by manually setting the focal lenth to something like 1000mm, but I just don't see the point when Photoshop has a tailor-made option.
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Kirk Gittings
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« Reply #52 on: August 06, 2010, 10:04:49 AM »
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Quote from: JeffKohn
........ the "Reposition Images" option in Photoshop is preferred for shift-stitching, because you don't want to use a projection for flat stitching. You can get around this in PTGui by manually setting the focal lenth to something like 1000mm, but I just don't see the point when Photoshop has a tailor-made option.

Just to further describe my very complex workflow , which always follows the KISS principle. I find the "automatic" setting in CS4 handles about 95% of flat stitches perfectly. FWIW I also own AutoPano Pro and PTGUI, but never need them for simple flat stitches.

My approach is incredibly simple. I make basic adjustments in Lightroom (images synced) to the DNG files highlight both and open from Lightroom>Photo>Edit In>Merge to Panorama in Photoshop (or just left click on one of the selected images and go to EDIT IN>. At the merge window in PS, I leave it on automatic and wallah! The whole process from conception to finished merged image hardly takes more time than a single image.
« Last Edit: August 06, 2010, 10:20:47 AM by Kirk Gittings » Logged

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uaiomex
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« Reply #53 on: August 06, 2010, 11:05:06 AM »
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Disclaimer.-
Last night I was stitching an image shot of a bedroom with the 17TS and no rail. The bedroom was a very tiny space of no more of 11X11 feet. There was this double bed with its closest angle at about 3.5 feet away from my lens. As you imagine, there was extreme distortion to the shape of the bed. With the 3 stitched images I managed to cover the entire bedroom from my position.
Photomerge couldn't do it. The parallax error was too much to handle. I had to do it manually and selectevely cutting my layers. I was lucky I could do it this way. I'm sure that with the rail this wouldn't have happenned.
So, for shots with objects very close to the lens or constrained spaces, I wil better use my rail.
Regards
Eduardo
« Last Edit: August 06, 2010, 11:06:37 AM by uaiomex » Logged
OldRoy
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« Reply #54 on: August 06, 2010, 12:39:44 PM »
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Thank you all for the valuable comments on my questions.
Never having used a TS lens or a view camera, this remains to some extent in the realms of the imagination. I may try hiring one to try although I doubt that anyone has the Agnos clamp available for hire. A pity there's nothing wider than 24 mm in the Nikon range too.

On the "curvature" issue, I'm a bit taken aback. Of course I know that moving the entire stitched image along the pitch axis will impact this - I have done it often enough to tweak landscape panos shot at longer focal lengths. From recollection though, to do this for even a two-shot stitch using focal lengths in the range <24mm is impossible to adjust without having to crop to an unusable extent.

It will be interesting to see if exposure in the Nikon Pro mag generates enough sales for Agnos for some informal reviews of their abominably named clamp. Any volunteers?

Roy
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OldRoy
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« Reply #55 on: August 09, 2010, 06:06:51 AM »
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http://www.nital.it/experience/jumbo-mbs.php#05
Link above (in Italian but online translation makes a reasonable job of it) has some detailed information and comments by users on the JumboMultiBigShoot. The name's even offensive to type...
Roy
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uaiomex
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« Reply #56 on: August 12, 2010, 01:11:11 AM »
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Now we need one for Canon EOS TS's
Eduardo
http://www.nital.it/experience/jumbo-mbs.php#05
Link above (in Italian but online translation makes a reasonable job of it) has some detailed information and comments by users on the JumboMultiBigShoot. The name's even offensive to type...
Roy
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Ronny Nilsen
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« Reply #57 on: August 12, 2010, 04:52:32 AM »
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Now we need one for Canon EOS TS's
Eduardo

I don't think I would like to let the tilt/shift part of the lens carry the weight of my 5DII and battery grip and L-bracket. I'll stick to my rails.  Wink

Ronny
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OldRoy
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« Reply #58 on: August 12, 2010, 07:32:22 AM »
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Re; Ronny Nilsen's comment. There's an interesting analysis by Joseph W. on the relevant thread at the DPreview site:
http://forums.dpreview.com/forums/readflat.asp?forum=1030&message=36022465
I wonder why Nikon are heavily advertising a device that may overstress an expensive lens? Definitely a legal problem for them if these comments prove to be well-founded.
Roy
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uaiomex
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« Reply #59 on: August 12, 2010, 01:18:07 PM »
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I've thought about that. That's the beauty of the 5 series, it's low weight. Why would you bother with a battery grip and bracket with such a setup?
If it's for wireless file transfer, I'd rather wire to save weight.
Regards
Eduardo


I don't think I would like to let the tilt/shift part of the lens carry the weight of my 5DII and battery grip and L-bracket. I'll stick to my rails.  Wink

Ronny
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