Review – RealViz Stitcher Unlimited 5.5 Gets Fishy

Panoramic photography has been around as long as photography itself, but its existence in the digital realm has been a rocky one. When Apple first introduced Quicktime VR back in the late 1990’s, the best panoramas that could be produced amounted to nothing more than grainy thumbnail-sized images, and if that didn’t leave a bad enough impression then seeing the poorly produced, amateur IPIX panoramas that are often found on real estate web sites certainly did.

Luckily, in just the last few years there has been a huge leap forward in digital panoramic technologies, both on the content creation side and the viewer experience side. It is now possible to create full-screen, hi-resolution, 360ºx360º panoramas that bring a truly immersive experience to the viewer. Similarly, it is also now possible to create super-high-resolution “equirectangular” panoramas for large format printing.  It is not uncommon for photographers to produce panoramas well over 30,000 pixels wide.

To create a digital panorama, the photographer must shoot several shots to cover the entire visible area of the scene, and then “stitch” them together with a stitching software package. One of the leaders in this field is REALVIZ, the creators of “Stitcher”, and they have just released their latest version, Stitcher Unlimited 5.5, which adds a new feature that has been needed for a long time: support for fisheye lenses.

Fisheye lenses are the most efficient way to photograph a scene that is intended for interactive viewing such as with Quicktime VR because only a handful of shots need to be taken to capture the entire scene. When I shoot my panoramas with a 180º Sigma 8mm lens, I typically only shoot 4 shots around horizontally, and then one up (the “zenith”). This provides more than enough resolution to display the final panorama full-screen with stunning detail.


A series of 5 fisheye images

Prior to Stitcher Unlimited 5.5, photographers could only use regular wide-angle lenses with the application, and this meant that they had to shoot many, many more shots to cover the entire 360º scene. Depending on the lens, this could mean shooting 24, 48, or even more shots. For large format printing of panoramas, photographers still shoot with these narrower angle lenses in order to get more resolution, but a Sigma 8mm lens on a Canon Digital Rebel XT typically yields a final panorama that is over 8000x4000 in size –plenty for full-screen VR viewing on a computer screen.

Stitcher has a very intuitive and user-friendly interface, and it does most of the hard work for you automatically. All you have to do is drop your images into the Stitcher window, and then click the Automatic Stitch button to tell the application to magically figure out how to order, align, and stitch all of the images in your panorama. It also takes care of calibrating the lens for you – a process that is normally very tedious in other stitching software. Stitcher uses a powerful pattern matching algorithm to perform this feat, and it is really quite impressive how accurate it can be. However, the automatic stitching doesn’t always work well, especially with fisheye lenses where the image distortion is high.  Even with non-fisheye lenses the automatic stitcher often has trouble. For example, if the panorama was shot outside where the clouds were moving from shot to shot, then the automatic stitcher can get confused and try to align to the moving clouds. Or, sometimes the scene simply lacks enough detail for the pattern matching algorithm to accurately get a match, such as an indoor scene with lots of plain, brightly lit, white walls.

 After auto-stitching a very clean scene, there are still obvious stitching errors on the medicine cabinet.

Luckily, Stitcher also has a manual stitching mode that allows you to set control points in the images.  Stitcher will align the shots to those control points instead of trying to use automatic pattern matching.  As tedious as setting control points between each pair of images is, this is really the best way to get accurate results. Most modern stitching applications have some sort of auto-stitch feature, but I’ve yet to find one that works anywhere near as well as the old manual method of setting control points, and Stitcher is no exception. The auto-stitching feature in Stitcher does work well for some panoramas, but anyone doing serious panorama work is going to require the higher accuracy and reliability of manual stitching with control points.

 After manually setting several control points, the medicine cabinet is stitched perfectly.

Perhaps the best feature of Stitcher is its real-time preview of the panorama as shown in the above screenshots. OpenGL is used to display a medium-resolution mockup of the panorama in the main window, and you can interactively drag the individual shots around to align them. No other stitching application has anything that works as well as this, and this is Stitcher’s real selling point.

After stitching the shots together, Stitcher will render the final panorama, and you can choose from many different file formats: Quicktime VR, Shockwave 3D, VRML, Photoshop, TIFF, JPEG, etc. I created the following panorama by manually stitching all of the shots above with control points, and result was a perfectly stitched panorama. However, most of the stitching seams are still visible because of blending imperfections (see the ceiling above the window): 

Click the image to view the full-screen VR panorama

Stitcher has many settings dealing with blending, but despite rendering this scene probably a dozen times, each with different settings, I was unable to get it to stitch without noticeable blending problems at the seams. This happened with every panorama I tried to make with Stitcher. While the accuracy of the stitching in Stitcher is the best I’ve seen in any such application, the quality of the blending between shots is the poorest.

Luckily, however, when you render a panorama to a Photoshop file with Stitcher, each layer in the file contains one of the original shots; morphed and masked to build the full panorama:
The Photoshop layers with masks

By airbrushing the layer masks you can selectively alter the way the stitching seams blend together between shots. After about 15 minutes of work in Photoshop, the resulting panorama is seamless and perfect with no more blending problems:

Click the image to view the full-screen VR panorama

Along with Stitcher Unlimited 5.5 ($580), there are also two additional versions of Stitcher that are available:  Stitcher Express 2 ($120) and Stitcher Pro 5.5 ($350).  Unfortunately, neither of these other versions support fisheye lenses. There are other features only found in the Unlimited version such as the ability to convert between various panorama formats, and additional rendering and output options, but the fisheye capability is the main difference. Stitcher Express does not support Photoshop output, or any other kind of layered output, so there’s no way to effectively edit the stitching in the rendered panoramas. That seriously limits the usefulness of the program to any serious panorama photographer.  Panorama photographers who need a serious Stitching program, but do not intend on using a fisheye lens will probably be happiest with Stitcher Pro since it has most of the other features of Stitcher Unlimited. A product comparison chart is available on the REALVIS web site:

I think it is important at this point to mention Stitcher’s competition because some comparisons are in order. On Mac OS X, there are several panorama stitching applications, so let’s start with the easiest one:  Photoshop CS 2. Photoshop CS 2 has a feature called Photomerge that automatically stitches and blends together an arbitrary set of images that you give it. It is fast and accurate, but this is really for only the most basic panorama stitching because there are almost no configurable options, and it does not work with fisheye lenses.

Similar to Photomerge is a program from Kekus Digital ( called Calico ($40).  In Calico you simply drag and drop your set of images into the application and then it automatically orders, aligns, stitches, and blends them together to create a panorama.  Calico does a much better job than Photomerge, and it has many more configurable options, but it too does not work with fisheye lenses.  Calico can best be though of as something in between Photomerge and Stitcher Express, but for the price, Calico is definitely the choice for casual panorama creation.

Next is VR Worx ($300) from VR Toolbox ( This stitching program only creates cylindrical panoramas that are just one row of images and lack much vertical field of view, so you cannot see the floor or ceiling.  These are the old-style Quicktime VR panoramas that I mentioned at the beginning – the ones that gave Quicktime VR a bad name.  Pretty much all of the other stitching applications on OS X are more useful than this one. There’s very little use for a stitching application that only does cylinders, and for $50 more you can get Stitcher Pro which is far superior.

The only true competitor to Stitcher Unlimited is PTMac ($60), also from Kekus Digital, but unlike Kekus’ Calico application, PTMac is a full-featured, professional panorama editing solution. The user interface in PTMac is nowhere near as nice as the one in Stitcher, the application has a much steeper learning curve, and there is a fair amount of setup needed to initially configure the application for your lens type, but it does support the use of fisheye lenses, and it does output layered Photoshop files. PTMac also does have some auto-stitching capability, but Stitcher’s auto-stitching is better and easier to use. That being said, PTMac costs only $60 versus Stitcher Unlimited’s $580, and in the end PTMac stitches and renders just as well as Stitcher. Despite Stitcher’s far superior user interface, it takes about the same amount of time to create a panorama. In both Stitcher and PTMac the process is the same:  you set control points between each image pair (assuming you want accurate stitches), and in both applications you sit there for a while as the panorama is rendered. Then you go into Photoshop and clean things up.

So, the bottom line is that Stitcher Unlimited 5.5 is an excellent product with a great user interface and some unique features that make creating high-resolution panoramas both easy and enjoyable. I would recommend that anyone interested in making digital panoramas experiment with the demo versions of both PTMac and Stitcher to see which one works best for their purposes and workflow before making the investment.

Brian Greenstone, Posted 9/5/2006

For more information on Stitcher 5.5 Unlimited, visit:

Photographs by Brian Greenstone 2006. For more information, visit: