Stitching with Tilt Shift Lenses to Create High Resolution Images

March 7, 2011

With digital SLRs it has become very easy to combine or stitch multiple pictures together to create high resolution images. For example, the picture below shows a composite image of the Conservatory of Flowers in San Francisco stitched together from three source images.

Figure 1. Conservatory of Flowers in Golden Gate Park. San Francisco, California.

Source images for the stitched image.

Figure 2. Three source images for the stitched composite of the Conservatory of Flowers.

The three individual source files were taken with my Canon 5D mk II and are roughly 21 megapixels in size (5616 x 3744). However, they can be combined in software to create a 40 megapixel stitched image (7229 x 5623). Right now, the only way to get 40MP images without stitching is to buy a medium format digital camera like the Hasselblad H4D where a starter kit will run nearly $20K. Jack Dykinga, a well known large format photographer claims the quality achieved by this process is similar to that achieved with 4×5 film (Outdoor Photographer, Jan 09).

There are two main ways of stitching or combining multiple images to get a high resolution composite:

  1. Using a special panoramic head to rotate the camera and lens while taking multiple overlapping images
  2. Using a tilt shift lens and take several shots at different shift settings.

In this article, I’m going to discuss the second method, using a tilt shift lens, for making high resolution images.

What is a tilt shift lens?

A tilt-shift lens allows one to use camera movements typically only found in 4×5 (or larger) view cameras on a 35mm based (or medium format) based camera. There are two movements that can be made:

  • Tilt the front of the lens. This allows the photograph to manipulate focus and is typically used in landscape images to make everything from a few feet to infinity in focus. The same technique can also be used to create selective focus and just have a narrow range of the image sharp.
  • Shift the lens up/down (or left/right) relative to the film/sensor. This function is typically used in architecture to take pictures of buildings without having to point the camera upward. Basically you would point the camera at the horizon and then to get the building in the frame, shift the lens upward.

For stitching we are going to be relying on the shift function. The key to understanding the shift is to recognize that lenses often project an image circle that is larger than the sensor. By shifting you can move the sensor from the center of the image circle and capture a wider scene. The three images in Figure 2 were created by shifting the lens to the left, center, and right.

Both Nikon and Canon have an excellent set of tilt-shift lenses. With Nikon you can get the 24mm, 45mm, and 85mm lenses as well as an older 35mm PC (shift only). With Canon you have the option of 17mm, 24mm, 45mm, and 90mm. In my personal kit, I use the Canon 24mm TS/E II, Canon 45mm, and Nikon 85mm TS (with an adaptor).

Capturing Images for Stitching

Stitching with a tilt shift lens and DSLR is a very simple process:

  1. Zero all movements (shift/tilt on the lens). I list this as a first step because it’s very easy to forget settings used from previous pictures.
  2. Setup the camera on the tripod. For horizontal picture I set the camera vertically and shift left and right. For a vertical picture set the camera horizontally and shift up and down.
  3. Set the focus, exposure, and white balance manually.
  4. Take the center picture.
  5. Shift the lens all the way to the left (top) and expose.
  6. Shift the lens all the way to the right (bottom) and expose.

While at first this method seems a little complicated, with very little practice the entire process becomes very quite quick and taking the 3 exposures can be done in a matter of seconds.

Note that technically to avoid all parallax errors you should keep the lens fixed and move the back of the camera. You can do this by moving the camera in the ballhead clamp in the opposite direction of the lens shift. However, I’ve found this to be unneccessary as the software for compositing CS5 photomerge has never had any problems with the very small amount of parallax error introduced (even when there are close objects)

Post processing the Images

Post processing the images for stitching is very easy. I use the following steps:

  1. Import the images into Lightroom (or your prefered program).
  2. Adjust one image of the series for exposure, color, white balance, saturation, etc.
  3. Copy adjustments to other images.
  4. Send images to CS5 photomerge for stitching with the reposition only option.

Using CS5 photomerge should provide a file with three layers and masks to produce a final image. The stitching has always worked extremely well for me and I’ve never had to make adjustments to the masks. The entire stitching process takes about about a minute on my Mac Pro.

Dimensions

When I create composite images with a T/S lens I generally use one of the following two setups:

  • Position the camera vertically with shift left/right which yields a horizontal image with roughly a 4:3 aspect ratio.
  • Position the camera horizontally with shift up/down which yields a vertical iamge with roughly a 4:3 aspect ratio.

However, there are several alternative ways of shifting the lens to get different final dimensions. For example, you could set the camera horizontally and shift left and right to create a horizontal panorama with aspect ratio of 1:2.4 (similarly you could create a vertical panorama). Generally, I do not use tilt-shift lenses for making panoramas and prefer to use a dedicated pan head. The main reason is that the number of vertical pixels is small and edge performance often degrades on T/S lenses when shifted in the long dimension.

Advantages over stitching with Pan heads

Stitching with tilt-shift lenses provides a number of advantages over using a panorma head.

  • Quick and easy capture. I make stitched images using both tilt-shift lenses and panorama heads. However the Tilt-shift approach is much faster in capture than pan heads as you don’t need to spend any time leveling the base or adjusting the nodal rail.
  • No post processing glitches. Photomerge stitches images very quickly and I’ve never experienced any problems. In contrast, using a panorma head I sometimes struggle with issues such as distortion or registering common points between images.
  • No extra equipment required. The tilt-shift lens is all you need. Admittedly tilt shift lenses are expensive and often cost more than a panoramic head.
  • Rectilinear projection. Using tilt-shift preserves the rectilinear projection of the lens. Practically, this means that straight lines remain straight in the composite.
  • Precise framing. You can achieve very precise framing with tilt-shift lenses as you can preview the final image by simply shifting the lens while looking through the viewfinder. This lets you compose with objects near the edge of the image and accurately set the amount of border space.
  • Consistent image size. Because you are always making three images with a set amount of shift, the final composite comes out with a very consistent image size. This is very important for a photographer that sells stock or fine art prints and who wants to have identical sizes for their images.
  • Can use tilts. With tilt shift lenses you can apply tilt for a near-far composition and then use shift for stitching. The image of the Conservatory of Flowers used tilt to ensure that both the flowers and building were in focus.

Disadvantages

  • Limited lens selection. With a pan head you can use any lens in your kit including zooms. With tilt/shift you are limited to three or four (nikon has 24,45,85 ts, canon has 17,24,45,90)
  • Price. Tilt/Shift lenses are expensive and run from $1000 to $2000 USD each. Some inexpensive pan heads can be just a few hundred dollars and it’s even possible to make your own head with a little ingenuity.
  • Less flexibility in image dimensions. With a tilt-shift lens you are limited to only a handful of image dimensions (without cropping). with a regular pan-head you are essentially limited only by how many pictures you want to take.
  • Image Quality. There are two factors that can lead to increased image quality with a pan head. First, with a pan head you can make composite images from any number of pictures. So far example, instead of using a 45mm TS lens with three pictures you could use a pan head, 90mm lens and take 12 images to cover the same scene. Second, with a T/S lens you may be using more pixels at the extreme edge of the image circle projected by the lens. Naturally, this will result in an image that is less sharp and with more chromatic abberation compared to using the center of the image. To some extent this is mitigated by the fact that the T/S lenses are all very high quality and stopping down improves performance.

Summary

Stitching with tilt-shift lenses has become a core part of my image making process for two reasons. First stitching delivers image quality that rivals pictures from digital medium format cameras costing tens of thousands of dollars and may even match 4×5 film quality. Second, stitching with tilt-shift lenses is extremely convenient and fast both in terms of the image capture and the post-processing required. In the field, I simply set the exposure and focus manually, and then shoot off three images in quick succession. In post-processing, I combine the files with CS5′s photomerge and it works beautifully to produce a perfect stitch with no intervention or manual inputs required.

{ 13 comments… read them below or add one }

Ira Wagner May 11, 2011 at 3:34 pm

Stephen, I just tried this method and like you said, you can get large images easily. I was wondering if you happen to have an idea of what the equivalent lens would be for a single shot versus the stitching method. For example if you use a 45mm tilt shift vertically on the camera and take the 3 images – center, maximum shift right and maximum shift left, what regular lens would capture a similar angle of view?

Stephen May 11, 2011 at 7:24 pm

Good question. I’m guessing we can think about this like a reverse crop factor (i.e., we effectively get a bigger sensor). Since the stitched image is about 1.3 times the size in the long dimension, the equivalent focal length to give the same field of view would be about 45/1.3 = 35mm.

Jay A Frogel January 12, 2012 at 11:24 am

This is a technique that I have been considering for awhile. I have a couple of questions. I use Nikon bodies – currently a D300. My understanding is that the Nikon T/S lenses shift in only one direction – along the short axis of the sensor. So this would mean that you most usually need to mount the camera vertically on the tripod to get a horizontal shift, correct? I also recall reading that you can send lens back to Nikon to change the orientation but you cannot have it shift in both directions no matter what, yes? Although I am considering getting a full frame camera like the D700 or whatever intermediate price camera Nikon comes out with next, it seems to me that given the samller size of the D300 sensor I’d get more “bang for the buck” with the smaller sensor since the same maximum shift translates into a bigger field of view. Finally, for landscape work and for “portraits” of very old buildings do you think the Nikon 24mm would be best rather than the longer lenses? Your advice would be much appreciated.

Jay

Jay A Frogel January 12, 2012 at 11:38 am

A PS to my last comment: What about using teleconverters with the T/S lens? For example if I use a 1.4X TC with a 24mm T/S lens, I get equivalent 33 mm but instead of say a +/- 11 mm shift I would get an equivalent of a 11 x 1.4 = 15.4 +/- shift if I understand things correctly.

Stephen January 12, 2012 at 7:56 pm

I have the older 85mm nikon T/S lens and you can definitely shift in all directions (I think there are stops at every 45 degrees). What you cannot do is shift in the same direction as the tilt — they are at right angles to each other. My canon T/S lenses have the same issue except for the newer 24mm T/S II which lets you change the offset between the shift and tilt angles.

For a lot of my stitched pictures, I’m shifting left-right and tilting forward to get the near and far parts of the scene in focus (camera vertical). This works out great most of the time. You can also shift left-right with the camera horizontal. This will result in a panoramic image but I don’t like doing this because at extreme shift the pixel quality degrades.

The 24mm T/S is one of my favorite lenses but I don’t use it for stitching very often as I find it’s often too wide (when stitched). However, it’s a great lens for buildings especially if you hate converging verticals. (If you use the shift to eliminate the converging verticals, you won’t be able to shift to get a bigger composite image.)

Many people on forums talk about using the T/S lenses with a teleconverter. I haven’t tried this yet, but it would be helpful when you need a lens halfway between the 24 and 45.

Jay A Frogel January 14, 2012 at 8:19 pm

Thanks, Stephen.
Thanks for clarifying the shift vs. tilt directions. Your first sentence, though is a bit confusing – how can there be measurements in degrees when shift if measured in mm ??

Good point about shifting with camera horizontal. Ditto on 24mm for stitchiong landscapes. In doing a spot check of my favorite landscapes with film cameras most were with 30-35 mm or equivalent 24 mm with DX format so shifting WOULD make it too wide. The 45 mm on the other hand on DX would give close to that achieved with film but with the increased pixels. So if I stick with DX, the 45 mm would make more sense for landscapes with the 24 mm for buildings. Need to think about this some more.

Jay

Stephen January 15, 2012 at 9:33 am

Sorry for the confusion. The entire lens is mounted on a plate that acts like a “lazy susan” that rotates. So if the initial configuration is that you can shift the lens vertically (up and down), you can rotate the plate so that the shift is now on a horizontal plane (left to right). The tilt is always at right angles to the shift (unless you have the lens modified).

Steve Walkington June 2, 2012 at 1:36 am

Hi Stephen, firstly thanks for the informative post. You are the first person I’ve come across that has finally helped me understand more what I need to achieve! I am looking for a lens that can give me a panoramic view, not greater than an aspect ratio of 4:1 where I can create a narrow depth of field for the model I am shooting. Basically I want the model to remain clearly in focus and the background to be blurred but not distorted. The shoot location will give a blurred panoramic view i.e. seascape, woodland etc. This is required for banner photographs for a website. Can you advise me please? I am shooting with a Canon EOS 500D.

Stephen June 2, 2012 at 7:02 am

Steve — see my comments on your other post at http://bayimages.net/blog/articles/shooting-handheld-panoramas/

Buddy October 6, 2012 at 3:29 am

Stephen,

thank You for explaining this “Pano made simple” technique !
Used to visit GG Park in sep2011, but the area was under maintenance then, no flowers…
Would this stitching method work with just the two outer pictures (fully shifted up/down)?
Come to think of it when looking at the already existing overlap between the two.

Kind regards,

Buddy

Stephen October 6, 2012 at 7:20 am

The stitching can work with just the two outer picture as there is a little overlap between them. But I prefer to use three images out of habit and redundancy.

Alex July 6, 2013 at 4:42 am

Interesting post. I wonder if the stitching technique could be improved by shifting only the camera body and not moving the lens. As would be possible with a monorail camera. Difficult with a tilt/shift lens I wonder if anyone has tried this?

Christopher March 5, 2014 at 11:18 am

Alex; for panos involving taking 3 shots using the left-to-center-to-right horizontal shifting of the lens (I’m on a Canon 17mm TSE) I do move the camera body correspondingly, after moving the lens itself. I placed 3 markings on tape, centered on my ball head’s mounting bracket clip (ie, the flange that grips the “plate” of my L-bracket, which is screwed into my camera.) The L-bracket already has an etched center marking corresponding to the center of the sensor within the camera.

So I start by aligning my L-bracket’s etched center mark with the *leftmost* tape mark (added to my ball head flange). I then shift the lens elements 12mm to the right, from the lens’ original zero-point setting. In this configuration, the lens’ center axis now lines up with my tape’s center marking on the ball head flange. Fire the first shot.

Slide the camera body right 12mm in the ball head bracket, so the L-bracket etched center mark now aligns with my tape’s center mark. (But now the lens axis is no longer where it was… so, shift the lens back 12mm to the left; the lens axis is once again aligned with the ballhead tape center marking.) Fire the second shot.
Move the camera once more, another 12mm more to the right — the L-bracket etched center point now aligns with my tape’s *rightmost* mark. Again, the lens is no longer in the desired position, so shift the lens 12mm left, so the lens axis once again returns to the tape’s center mark.
The end result is that the lens has stayed in 1 place in space, for all 3 shots, but the camera body has moved +/- 12mm.

I saw a really slick, expensive custom mounting bracket, that actually grips the TSE17mm body itself, and that bracket then mounts directly to your tripod—so the camera body is “hanging” from lens mount. Then when you use the lens’ “shift” knob to dial in some shift, you truly are shifting the camera body, in relation to the stationary lens.

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