I've recently been experimenting with the Brenizer Method of photography, a technique invented by wedding photographer Ryan Brenizer for accenting the depth-of-field in photos. Initially called "panoramic stitching" the Brenizer Method allows you to create very large full-frame photos using a standard DSLR and wide-aperture lens, the results of which have an incredibly shallow area of focus. While an off-the-shelf wide-aperture lens like a 50mm f/1.4 lens will already produce a great photo with a smooth bokeh depth-of-field effect, your shot won't be that wide because of the focal length--50mm is considered mid-range telephoto, especially with an APS-C sensor crop. That's where the trade-offs come in when buying lenses: the shorter the focal length (and hence wider the frame), the most costly it is to buy a lens with a wide-aperture. For example, while a 50mm f/1.4 lens will cost under $500, a 28mm f/1.4 lens can cost over four times as much. That's because the aperture value (f number) is directly proportional to the focal length.
So what many photographers are learning is that they can use post-processing methods after the fact to fake the look of a more expensive lens using a more practical one. And in the case of the Brenizer Method, it's not faking bokeh by adding blur to an image, it's faking the wide frame of an ultra-wide angle lens using stitching. It's the same kind of panoramic stitching that gigapixel photographers use to create giant photos can be used to create an image with an equivalent f-number of 0.44. The exaggerated depth of field on such a large image creates a sense of focus and sharpness on the subject that's akin to what your eyes see--the focal length of the human eye is the approximate equivalent of a 22mm camera lens. Ryan Brenizer's blog gives superb examples of what you can do with photographic stitching.
But most photographers using the Brenizer Method already have good DSLRs and wide aperture lenses. I wanted to find out what the Brenizer Method could do for a more affordable camera, like my Sony NEX-C3 and even the iPhone 4S. Here's what I found.
- You'll ideally have your camera on a tripod, with fixed manual settings. That means aperture, shutter speed, white balance, exposure compensation and ISO are locked so the photos can be stitched together without looking weird.
- You start with the camera pointed at your subject--whether that's a person or static object--and lock your settings so the subject looks good. The lens should be opened up to its widest aperture setting too.
- Then, you systematically take a series of photos around the subject, overlapping the photos by about 25% so that the stitching program can figure out how the photos fit with each other. The camera should be swiveling and tilting on the tripod, not physically moving on the horizontal or vertical axes--that leads to distorted stitching.
- After taking enough photos to cover a wide frame--usually 12-15 will suffice--you import them into Photoshop using the File=>Automate=>Photomerge feature.
Sounds simple enough, right? But what if you don't have all of the required components, like a tripod, wide-aperture lens, or Photoshop? You can still shoot with the Brenizer Method, just with a few adjustments.
Brenizer on the Cheap
With my setup, I used the 18-55mm f/3.5-5.6 lens that came with my Sony mirrorless camera. The best depth-of-field images are the ones I get with the lens zoomed in (at 55mm f/5.6), but the frame is obviously extremely tight at that zoom level. I had to find the right balance between wanting an image that would be easy for software to stitch and one that would have overly-dramatic depth of field. For my subjects, I used a set of Mighty Muggs toys. Here's what they look like in a single photo taken without any post-processing (18mm, f/3.5):
I zoomed in with my lens a little bit to about 50mm and started taking photos in a circular pattern, keeping about 25% overlap between photos. Since I didn't have a tripod, I had to keep my hands fairly still between shots, using the LCD viewfinder to judge how to overlap the images without moving the camera in unnecessary axes. I ended up with 16 photos:
Since I wanted to keep this as cheap as possible, I used a free stitching program instead of using Photoshop. Microsoft Research offers a free panoramic stitching program called Image Composite Editor for Windows (Hugin is another free panoramic stitcher that also works on OS X). I found it much faster than Photoshop CS4's Photomerge tool, and it was able to handle two dozen 16 megapixel photos without crashing. Both Photoshop and ICE are very memory-dependent, so I recommend shutting down other programs to free up RAM before running them. If Photoshop's Photomerge works for you, you can also stitch images in batches, merging a few photos at a time, saving them, and then remerging the resulting photos to save on memory.
The finished product looked really great. Without a tripod, I was wary about branching out too far away from the subject, but even with the image cropped, you can tell that it has much more depth than the original single-shot photo above. And not only is it simulating a more expensive lens, the extra sensor data makes the photo much larger and sharper as well. The dimensions of this final image are actually 14874x8139 pixels, totaling to more than 100 megapixels. That's kind of ridiculous. I've resized it for this page but have also uploaded the full image here if you want to see its detail.
Here's another example of the Brenizer Method with my f/3.5 lens. This time, I only shot eight overlapping frames and stitched them together. Below is what the subject looks like when taken without any stitching--just one photo at 18mm and f/3.5:
And now here's eight frames stitched together for a 9149x6077 image (click to enlarge). You can see that the stitching isn't perfect--there's a little bit of tearing on the figure's head and some doubling of the traffic lights in the background. This is a fault of not having a tripod--compensating by taking fewer photos can only help so much. But I was successful in getting a wider frame while keeping focus relatively shallow. There are also inherent limitations in the stitching software, since Image Composite Editor doesn't let you manually position or blend the images you throw into it. I think it still works better than Photoshop, though.
Brenizer on the Really Cheap
With the case of the iPhone 4S, the aperture goes as wide as f/2.4, which gives the potential for an even more effective stitched panorama than my Sony's f/3.5. Of course, you have no direct control over the aperture setting--you can only lock shallow focus when you're up close to a subject. That makes getting a wide frame fairly difficult. Given the iPhone's small size and lack of tripod mount (unless you have a Glif or other similar accessory), it's difficult to keep the shots consistent for stitching.
I used the free Camera Awesome app to lock my exposure, white balance, and focus up close to a static figure, and then imported to my desktop to process in Microsoft ICE. As you can see, I didn't have much success here--the photo below was the best I could do after several attempts with a 9-image stitch. Again, a tripod would've really helped here.
The upshot is that the Brenizer Method definitely doesn't require expensive equipment or software--you can try it the camera you already have, steady hands, and some patience. I hope you guys get a chance to try it out, and please post the results of your own efforts in the comments below.