panoramas with view camera movements

[michael_dellitalia]

Greetings,

 

I am interested in panoramic photography. I want to create

panoramas of architechture without the distortion caused by tilting

the camera up towards a building. I also want to avoid the

curvature tha occurs in panoramas made by rotating the camera. I

have been using a 28mm pc lense on a D70S (with which I stitch

composites from) which produces decent results, however the angle of

view that I can potentially capture is limited. I recently began

researching the Really Right Stuff Nodal Slide Rail, which centers

the lense's Nodal Point (optical center) over the center of the

pivoting axis. This alignment elliminates parallax, but so far as

I know it won't correct distortion or bowing (in the perspective

lines of buildings) which results from panning the camera from left

to right to form an angle of view as wide as 180 degrees.

 

The only method that I know of to eliminate distortion in

panoramas of architechture is to use a view camera or pc lense and

keep the film plane fixed (parallel to the subject) and shift the

lens board laterally or vertically(depending on which direction the

composition is).

 

Is it possible (when using a 4x5 camera) to capture a 180 degree

angle of view by only shifting the lense to form a composite of

stitched images? A 65 mm lense has a 105 degree angle of view. If

I shift the lense from left to right creating several images that

will be stitched together, shouldn't I be able to cover an angle of

view as wide as 180 degrees without the bow or curvature (in the

perspective lines of the architechture) that results from panoramas

made by rotating the camera?

 

Any help will be greatly appreciated.

 

Thanks,

 

Michael<div></div>

[greglyon]

Once you go beyond about 100 degrees you're going to have some sort of distortion or another unless you plan to print or project onto a curved surface!

 

Here's a 5 image stitched panorama (I used panotools/ptstitcher) created by pivoting my camera around the nodal/entry point of the lens. FL was 18mm on 1.5 crop digital camera. Note that I chose the 'spherical' option when stitching because panotools/ptstitcher can't handle more than about 120 degrees in a rectilinear fashion without going somewhat crazy. I also happen to like the look of the spherical stitch.

 

The end result is that long horizontal lines near the edge of the frame curve. If I were to print this out and then hold the print in an arc in front of me with me standing in the center the lines would look straight again...

 

There's no way around it, as you get wider and wider angle of view you introduce some sort of distortion when you try to represent it in a flat plane.

 

As for getting 180 degrees without moving the film plane, I'll leave that to someone else but I don't think it'll work.<div></div>

[andy_shand1]

you can shift the back around all you want but you will be limited to the fall off circle of that particular lens.

 

I have a 6x17 chinese back on a 4x5 sinar f2 body and using a 72 schneider sa xl giving an undistorted 115 degrees. This setup has limited movement. A 90 sa xl on 6x17 will give you 83 degrees but masses of movement..so you could shift and stich and be back up to about 110 deg. Problem is that the 4x5 body hits the back of the lens. If you where to use and 8x10 body and say a 72 sa xl lens..well you could get some pretty wide images with shift because the lateral shifty wont be restricted by the camera body at all..so you are up to 115 degrees. The 38 and 43 xl lenses are 120 deg ..so if you were to use these on an 8x10 ...well thats about as big as you can get.

 

Problem is that you dont want distortion but the further away from the centre you get the more stretched the image becomes ...which acctually isnt distortion at all but everyone will think it is.

 

For architecture stretching is unusable.

 

The only way you could get an really wide true undistorted images of a wide building landscape is to take shots without using a wide lens say every 30m along a line parallel to the building and then stitch the bits in the middle that have minimum stretching. I think this is a photogrametric survey????..usually done from cherry pickers i think.

[greglyon]

I should also mention that I didn't manage to get the tripod quite level for that shot...it was ever so sligtly aimed up so the verticals do converge a bit...

[donald_hutton]

Seitz roundshot....

[ralph_jensen]

" If I shift the lense from left to right creating several images that will be stitched together,

shouldn't I be able to cover an angle of view as wide as 180 degrees without the bow or

curvature (in the perspective lines of the architechture) that results from panoramas made

by rotating the camera?"

 

To see the shortcoming of this suggestion, imagine stitching together some shots taken

with a 12mm lens on your Nikon, which is roughly equivalent to a wide view lens. The

edge distortion (perspective, not optical) would make stitching fairly difficult.

[stephen hazelton]

If you took a lens intended for 4x5 and shoot it on 8x10, you should get the full image circle of the lens- once you do, no amount of shifting is going to reveal any more image than what you get.

 

I'm not sure exactly what you're after- seems you're going to have SOME kind of distortion when you do what you're trying.

 

Imagine you want to stand beside a street, and shoot a 180-degree panorama, looking straight at the street, with no distortion. What will it look like? The height of buildings down the street, and width of the street has to remain constant, even though the field of view extends to infinity. Meanwhile, the actual buildings cover less and less area horizontally as you get closer to the edge. So you're going to have things progressively squished at the edges, so things look skinnier there. But that contradicts the assumption of no distortion...

[john_hennessy4]

I use a Technikardan for panoramas and quite a bit can be done by shifting alone --though not 180 degrees. The way the Technikardan folds up, it has about 50mm (if I remember rightly) shift right and left front and back. So I have a pattern worked out to shift the back one way, the front the other and then work my way till they're the other way around over four or five exposures. The total angle of view depends on the lens of course. For maximum effect, a huge image circle is needed. That tends to mean longer lenses such as a Nikkor 300m but a Schneider 90xl can be used for about three exposures. I have it all on a table taped to my tripod. If anyone is interested, I'll e-mail it.

[razzledog]

I guess we all would like to minimise convergence when tilting the camera anything from level, especially when using a wide angle lens. I run a 90mm SA on my 6x17`s but unless the camera is exactly aligned with the subject`s centre it will occur. One method is to pull the verticals parallel, then cropping in Photoshop, very simple but it`s cheating! The next step is to figure a rising front into the equation, but that will probably require a large image circle from the likes of a Schneider XL. Unfortunately highly prized, consequently highly priced as well. A tall ladder is also helpful.

The shot I have included was at 24mm (equivalent 35mm) wide with shocking convergence due to lack of height on my part. Easily corrected in PS.

Cheers.<div></div>

[michael_briggs2]

With LF lenses it is best to distinguish between "angle of coverage" and "angle of view". The angle of coverage is the full angle of the cone of quality image that the lens projects. Probably this is the meaning of the 105 degree value for the 65 mm lens -- it is a characteristic of the optical design of the lens. The angle of view is how much of the scene appears on the film. If you put a small piece of film behind the lens, you will get a small angle of view. If you put a larger piece of film behind the same lens, you will get a larger angle of view. As Stephen says, if you put an 8x10 inch piece of film behind this 65 mm lens, you would capture the entire coverage of the lens and get a 105 degree circular angle of view.

 

LF lenses are designed to render perspective in a rectilinear manner. If an object has angle theta off-axis, it will be distance h = f tan theta from the center of the image, where f is the focal length of the lens. This is the same as a pin hole.

 

If you want more than the 105 degrees of this example 65 mm lens, then you are going to have to rotate the entire camera (or have something more complicated like a moving film camera). When you make multiple photos by rotating the camera and then combine them with some program, you will have to use some perspective other than rectilinear. A analog camera that does this automatically (spinning camera with rotating film) also changes the perspective. Somewhere past roughly 120 degrees it gets too difficult to make a lens do rectilinear perspective. For example, the illumination becomes very uneven.

 

If you really want more than about 120 degrees, there is no way to get rectilinear perspective. A lens that does this in a single shot will be a fisheye, which has a different perspective.

 

If you decide to use a LF camera for stitching several shifted images together, the best way would be to shift the back. That way you are not shifting the entrance pupil of the lens and have no parallax effects to contend with when you merge the photos.

 

Shifting works if the several film pieces will fit within the circle of coverage of the lens. If you want more coverage, then you have use rotation techniques.

 

Panaromic photography doesn't have to mean as wide angle of view as possible. The other way to think about it is compositional: how to organize a long frame.

 

It might be better to step a bit farther back from the buildings so that you are not trying to cover 180 degrees. This will make a more "natural" looking photo; trying to push the angular coverage will make a photo that emphasizes the technology. With a view camera, plumb the back, then use front rise to frame the buildings without converging verticals. Then if you want more of the subject sideways, you could take several photos with the back shifted, left, center, right.

[michael_briggs2]

<p>If your goal is pleasing architectural photography, the easiest way (but perhaps not the cheapest) may be to use a view camera with some of the recent wide-coverage LF lenses and front rise. The coverage of the Super-Angulon-XL and Apo-Grandgon lenses are amazing, and one can be quite surprising close to a building and still photograph it in a single exposure without converging verticals. (You can't all of a sky scraper from one block away, but really tall buildings don't make good photographs in their entirety when viewed too close.)</p>

 

<p>Your example photos don't seem very wide at all, and from could be easily setup in a single exposure with a view camera. They are very far from 180 degrees.</p>

 

<p>You might want to rent a view camera and a wide angle lens to try out. Maybe a 90 mm lens (which about the same as 28 mm on 135, and wider than 28 mm on a non-FF DSLR), or wider, perhaps 65 to 75 mm. Even wider lenses are available that cover 4x5.</p>

 

<p>Here's some example photos: <a href="http://home.earthlink.net/~michaelbriggs/huntsville/2000BW45-39.jpg">http://home.earthlink.net/~michaelbriggs/huntsville/2000BW45-39.jpg</a> was taken with a 110 mm lens with a 4x5 camera, which is only moderately wide. Front rise was 42 mm, the lens has enough coverage to support 34 mm additional front rise. Here's a wider view, cropped from a 4x5 to be a panaroma: <a href="http://home.earthlink.net/~michaelbriggs/russia/2000C45-42_pan.jpg">http://home.earthlink.net/~michaelbriggs/russia/2000C45-42_pan.jpg</a>

That one was taken with a 72 mm lens.</p>

[andy_shand1]

i think the bang for your buck could be a schneider 47 sa on a viewcamera like a sinar f2 with a 6x12 roll film back. Something about that combination..widest angle..lightest weight ..largest shift and all on a good old roll film.. ideal.

[andy_shand1]

6x12 + schneider 47 + f2. No distortion and the distance to that reading room aint much.

 

http://afwphoto.com/britmus01.jpg

[michael_dellitalia]

Thanks for the feedback gentlemen,

 

To clarify my intent, the two images at the top of the page where both shot from the same position-the center of the house. the image on the left (which appears to have severe barrel distortion) was made by panning the camera (with a 28mm lense) from left to right making approx 8 exposures. The image on the right was made using the pc lense's shift function to form a composite of five exposures. I want to apply the same principle of "lense shift panoramas" for larger structures, however the angle of coverage made with a 28mm on a D70S (1.5 focal factor)isn't sufficient.

 

I assume that using a large format monorail camera would be better suited for such an extreme application. The two examples below illustrate the same techniques as the above images. In the image on the left I stood across the street (at the center of the building) and panned the camera from left to right.From where I was standing I couldn't move back any further. The resulting image has extreme curvature, which I find unacceptable. The image on the right was photographed from one end of the building, and I used the pc lense's lateral shift movement to form a composite panorama. This image indeed has distotion (extreme one point perspective or "ship's prow"), however it is far more acceptable than the curvative of perspective lines that results from panning the camera.

 

Perhaps the solution for capturing architechture is more of a matter of vantage point than optics. Ideally I would like to stand in the center of a building the size of the bottom left image and make a composite panorama by shifting the lense and film plane laterally (with a view camera).The key point for me is keeping the camera square to the building in order to avoid verticle convergence.

 

Any thoughts?

 

Thanks,

 

Michael<div></div>

[michael_briggs2]

Michael, as I tried to explain in my answer of 3:28 AM, my thinking is that with a LF camera you might not even need stitching to accomplish your goals. The photos of the house and of the building at night

look like they would be technically easy to make with a single exposure with a moderate wide angle lens on a LF camera. I'd guess that a 90 mm to 120 mm lens would work, which isn't even very wide. It's a little harder to judge the photo of the apartment building because of the perspective distortion.

 

I think the small sensor size of the the D70 is causing you to think that wide-angle architectural photography is an extreme application that requires stitching multiple photos. On the D70, a single photo from the 28 mm lens is showing an angle of view of 30 x 46 degrees. This is barely wider than normal, so to make a wide view you have to stitch. For 4x5 cameras, genuine wide-angle lenses are available, so you can make architecture photos without converging verticals in a single exposure.

 

Did you look at the examples on my post of 3:28 AM? The single building was take with a 110 mm Super-Symmar XL lens. The angle of view on 4x5 is 46 x 57 degrees. This lens is only a moderate wide -- normal for 4x5 is about 150 mm. The coverage of this lens is 105 degrees, which can be used for front rise to eliminate converging verticals (as I have done). With this photo, some (not a great amount) additional coverage was still available, which would have allowed shifting the back to capture more the scene for merging with stitching.

 

The row of buildings was taken with a 72 mm Super-Angulon-XL. The horizontal angle of view is 80 degrees (already almost twice that of the 28 mm lens on the DX sensor). The coverage of the lens is an amazing 115 degrees, so if one wanted to show more buildings, the back of the camera could have been shifted 42 mm left, then right. The 42 mm figure is for keeping a 4x5 film (95 x 120 mm) within the circle of coverage. If you cropped to a narrow rectangle vertically (as I have done), you could get some more horizontal coverage (i.e., a bit more shift than 42 mm), extending the possible angle of view to almost 115 degrees.

 

But easier then merging several images to get a wider view than that offered by the 72 mm lens in a single exposure would be to use an even shorter lens. Both the 55 mm Apo-Grandagon and 58 mm Super-Angulon-XL cover 4x5 with the possiblity of slight movements. For example, the angle of view with the 55 mm lens is 80 x 95 degrees.

 

What you call the "ships prow" perspective can also be controlled with a view camera by swinging the back to create a false rendition of the perspective.

[stephen hazelton]

On the left photo, the main problem is pointing the camera up. Use a shift lens and do the same thing, or a wider angle lens held horizontally, and much of that effect would be gone.

 

On the right photo, you've essentially made a wide-angle rectilinear shot out of several photos. If you took the shift lens and mounted it on larger film where you could see the whole image circle, you could do the shot in ONE shot. But you'll never get real close to 180 degrees that way.

[andy_shand1]

i just get the feeling that either you ignored or didnt understand my first post..

[andy_shand1]

not just the previous post..everything after.

[andy_shand1]

i find people answering posts read the last two and the first and then just spout whatever it is that comes to mind.

[dr_smith]

The short answer is no, you can't get a 180 degree panorama by shifting the lens. The angle of coverage limits you to about 115 degrees using shift alone - to go beyond that, you must rotate the camera and deal with the distortion problems that come with it.

 

Either way, I think doing this with 4x5 would be prohibitively expensive. Where I am, it's $4/shot for chromes, and trying to cover one subject with multiple shots just makes it that much more expensive. It's not worthwhile if you take multiple images and are unable to get the result you want. Given the options, I'd go wide on 4x5 if you can cover the subject in a single shot or switch to a digital camera with stitching multiple images in software.

 

If you want to compare techniques for creating panoramic images, you will have to post two images of the *same* subject. It's difficult to give an accurate comparison when the subject changes between images(I'm referring to the right/left posting above).

[michael_dellitalia]

Andy,

 

I certainly did read your response. I had to do more research to understand what you were explaining. From what I understand on the Sinar website(in addition to what you explained earlier), when one is describing a Large Format lense, the covering power or image circle (not solely the focal length) is what determines a lenses potential for allowing shift movements etc. If one wants to crop close to the edge of a large image circle such as 105 degrees(in one shot without shifting), a larger filmback (ie 8x10) must be used. An image circle of 105 degrees on a 65 mm lense (when used on a 4x5 back) is actually larger than what the film back is cropping. This is why a certain amount of shift movement without vignetting is possible.

 

Thanks,

 

Michael

[michael_dellitalia]

An 8x10 back with the same lense as the 4x5 would have far less range of movement.

 

Michael

[andy_shand1]

there is a new emerging technology which i am playing around with at the moment ..its all about having a 180 fisheye lens on the end of a capture chip. The clever stuff is the computer being able to decode the fisheye image into an undistorted image in any direction. This includes of course 360 not just 180. Its nowhere near being useable for anything apart from web type res but you can see that this is the future.... the idea of pointing a camera in a particular direction with a set format will be a little odd to our grandchildren.

[andy_shand1]

michael..thanks for that ...its worth also considering that if you cant see the lens from the side ..well there is no way that it can see you....but the idea of moving the camera along a line say ten times at twenty metres with a normal lens and then stitching each shot together sounds like a very interesting experiment...i might even try it myself.