I love digital! My last “gear review” Blog covered high dynamic range imaging software (HDRI) . I reviewed and illustrated the concept of HDR using Photomatix. The ability to illustrate in print and on screen, something the eye has always been capable of seeing, but traditional photographic techniques and equipment simply unable to duplicate, is fascinating. I am not talking about the unrealistic and often surreal effects (though they may well have their place in an artistic media) you see, but simply the ability to present a wider dynamic range of an image–closer to what that magnificent optical instrument of nature–our eye–can see. Digital imagery has brought that to us, as well, the capability, I am certain, not too far in the future of HDR capture in camera sensors.
Just when I thought I’d seen the most significant recent development in this area, I stumbled on the similar and equally amazing (in my view) digital technology, known as “focus stacking.” This technology takes advantage of digital images by combining a series of images with different focal points, using the in-focus portions of each image, to give greater depth of field (DOF) from front to back than is possible with a single image on any lens.
One of the “selling” points of wide angle lenses is their ability to resolve great depth of field from front to back. Those “wow” landscape photos you often see with the sharply focused foreground elements (often flowers or rocks) and sharply focused distance background elements are often taken with a wide angle lens (28mm or wider) focused a very close distance to the foreground element. However, I often find that my preferred focal length is usually something significantly longer. The focus stacking technology will now allow me to get that wide angle look with a lens that has less inherent DOF.
The illustrative photographs were taken with an 18-200 zoom lens, with the focal length set at 80 mm, at f16. I took a series of 4 exposures, all at the same shutter speed and all in essentially the same light. Using the multi-area AF sensors on my Nikon D200, I had 4 focus points in the viewfinder in portrait orientation. I shot the first using the sensor closest to the foreground, and each succeeding photograph, focused further into the photograph, with the final exposure focusing on the shed. In the illustrations, here, the first photo (top) is the result of combining all 4 exposures with focus stacking.
The second photograph is focused on a point about 1/3 into the photo (the traditional “wisdom” of focusing for the greatest DOF in a landscape photo), and the third is focused on the shed in the background.
You can see that there is much greater DOF from foreground to background on the first image. In the second, the shed is, perhaps, “acceptably” sharp. On closer inspection, it is clearly not as sharp as it is in the final image. In the final image, the foreground wheat is not in sharp focus. This may not be the best image to illustrate the technique, as the foreground wheat is a rather “busy” subject, which, in my view, makes it more difficult to assess sharpness. I have just begun to experiment with this, and can see some real promise. I have had photos, in the past, which would have been, in my view, stunning, but were missing that critically sharp focus throughout, particularly in foreground elements. I am excited to try this with some of the rocks and streams images I like to make when I next get a chance to photograph the subject.
So, how did I do that? There is (of course–why else would it be posted under the “gear review” category?) software that does all the math and technology. I couldn’t begin to tell you what is happening “under the hood.” Thank God though, that there are folks out there who can and have made this possible. There are two programs I am aware of. Perhaps the most well known is a program called Helicon Focus. It is very slick and professional, with a very user-friendly interface. However, it comes at a cost — approximately $200. You can download a watermarked trial version at (SITE). Given its potential, it is a relatively inexpensive software.
Recently I found a “shareware” software called CombineZP, which is free. It is not particularly intuitive nor “user-friendly” to use, but with some experimentation, work very well. The author has a website and is very receptive to questions, comments and suggestions. The illustration here was made using CombineZP. I did find that using the “all methods” combination, took an extremely long time to process. However, I converted 3 RAW images to TIFF and they were fairly large. I might be inclined to size to my final use size before using it next time. However, I did find that it caused some artifacting around the outside of the frame, so you will need to plan for cropping.
I think this is a really cool technology and will be adding it to my “arsenal” along with HDRI for my next serious photo trip to Acadia NP in October.