Today's digital cameras are capable of exceptional resolution and image quality, but still lack the umph to make really large prints that contain the detail available from medium and large format film cameras. The solution to this limitation is to learn how to make large images by stitching together multiple shots from a digital camera. In the case of this example, I've created an 80 megapixel master image that contains exceptional image detail and resolution exceeding that of any digital or film camera on the market today. By stitching 20 each, 18 megapixel images together, this image will stand up to a wall size print with resolution that will knock your socks off from just inches away.
The image used for this article was taken on a trip in early October 2011, south of Telluride, Colorado. My friend Andy Long and I were on a weeklong trip for Autumn photography and we got hit with the first snow storm of the year a couple of days into the trip. Neither of us are afraid of getting out in bad weather so we decided to brave the storm and hit a few spots near Lizard Head Pass. Trout Lake has long been a favorite spot of mine, so as the storm was blowing through, we made it down the slushy road to where this trestle bridge sits.
This image of the Abandoned Railroad Trestle Bridge at Trout Lake, Colorado was taken with a Canon EOS 7D using the Tamron 70-200mm zoom lens. The exposure time is 1/250th sec, ISO 200, aperture f/14, focal length is 70mm. The final image is cropped to a 2/3 aspect ratio and is roughly 80 megapixels in size.
To create this image I took 6 to 7 shots from left to right in three different layers from top to bottom. My bottom row had an extra shot, which wasn't an issue when stitching the images together.
Here is a sample row, indicative of the other two rows of shots. I'm not showing every photograph for each row as it isn't really necessary to understand the concept. The top most shot is the far left and the bottom shot is the far right.
With a group of shoes from left to right for each row, I then created three master row stitch images. The three stitched rows were then combined to make the final image.
I used a tripod to take these photographs, trying to overlap each scene by about 1/3 with the next scene. The real trick here is to make sure your tripod is level. By having a level tripod, when you spin the camera across the horizon, you'll end up with a group of shots that are in a level plane from left to right. The overlap allows for better stitching without seams in photoshop . The longer 70mm focal length minmumizes the lens distortions and gives a relativly flat view from each shot.
The stitching was done editing the original raw images in Adobe Lightroom and exporting as a panoramic to Adobe Photoshop. The white balance was set to be indentical for every image. Camera exposure was set manually. I scanned the camera around the scene and by using the internal exposure meter of the camera I was able to quickly find the brightest area, and that is what I used for the exposure for every frame.
I also dialed in lens correction for each shot. Same lens, same exact focal length on each shot, just a one click sync across every shot and lens distortions are fixed across the board.
I did very little sharpening on the original images. Exposure, brightness, contrast, saturation adjustments were set to identical across each image. Sharpening was limited to my normal very minimal capture sharpeninig in Lightroom.
Each row of images were processed as separate panoramic stitches.
I ended up with three panoramics, which were then stitched together to create the final image.
The final image was stitched together, cropped to a 2/3 aspect ration and final adjustments to color, stauration and sharpness were made.
In this case, I shot each individual image in a landscape view, but more often than not I take these master shots in a portrait angle from left to right. The portrait angle seems to work out very well for single row panoramic stitches when exporting to photoshop.
I can't recommend that one method is better than another other than when in a portrait angle, you get more pixels to work with from top to bottom and may not need as many up/down passes of the scene to make your master stitch.
I shoot the individual images using RAW because it gives me the most to work with. I've seen where some people use JPG files for these large stitched images, mainly because it allows them to process the stitching more quickly in Photoshop. Trying to compile a 20 image stitched image can take a while if your computer isn't quite decked out with memory and processor power. I'm using a MAC Pro with 8 gigs of memory, and this particular shot took about 10 minutes to process for each row.
Since the master images are roughly 18 megapixels and 14 bit Raw files, the newer cameras are going to take a lot longer to process the image files than the older cameras will. The problem with JPG masters though is you don't really have as much room for adjustment in post processing. A good middle ground would be to shoot raw, adjust everything and then create JPG files for stitching the final shots together. It's really up to you though.
One thing I try to do is crop each of the master stitch rows to eleminate the blank white space on the top/bottom or left/right. Photoshop has a tendency to barf with those massive white spaces in an image it is trying to use for stitching. By cleaning up the three row panoramics before I attempt to assemble them, photoshop is a happy camper and seldom gives me trouble with that final stitch.
Just make sure to not crop out too much of the edge of the row shot. Keep plenty of an overlap captured scene. Not only from image to image, but from stitch to stitch. That's where you're going to have your biggest problem. Not enough information to make a seamless stitch in photoshop.
This is the top level row master stitch
Here is the middle level stitch.
And here we have the lower level master stitch.
