Pros & Cons
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- Makes lens focus calibration easier.
- Relatively inexpensive.
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- Durability could prove to be an issue.
- Free alternatives available.
The Focus Pyramid ($24.95) isn't the most complex accessory you can buy for your digital camera, but it's plenty functional. It's designed to help you calibrate the focus of a camera and lens pair, as there is sometimes a disconnect there, especially when shooting at wider apertures. Many SLRs support focus calibration of lenses, but you'll need a focus test chart for proper adjustment. You can print one out for free at home, but you'll need to mount it at a 45 degree angle for the best results. If you prefer a solution that's a bit more refined, but not too expensive, consider the Focus Pyramid.
The Pyramid ($24.95 at Amazon) is, at its heart, a sheet of cardboard. It's got marks for folding and tabs to make it take shape. It only takes a minute or two to construct, and unfolds easily for flat storage. You'll want to take care when storing it, as a bend or crease could turn the calibration tool into just another piece of cardboard.
When constructed, the Pyramid is angled properly for focus calibration, and the center line and top point help position the camera so that it's perfectly parallel. To test the chart I placed it flat on a table, but found that it was a bit low to comfortably look through the viewfinder of a tripod-mounted Nikon D810 ($1,996.95 at Amazon) . I used the D810's Live View display with a grid overlay to square up my test shot, making sure that the center line of the Pyramid (marked with the company logo and the numbers 00) was perfectly centered in the frame. If you use a similar method, you'll want to disable Live View before taking a test shot—most Live View uses a contrast-based focus method that is completely independent of the phase detection focus sensor used by D-SLRs. Look through your viewfinder and make sure that the center focus point is the only one active, and that it's perfectly centered on the blue area that sits at the center of the Focus Pyramid logo.
I took a few test shots with a Nikkor 35mm f/1.4G lens. Those confirmed that the focus was fine out of the box, but I went into the D810's focus adjustment menu anyway and dialed in some adjustment. When setting negative adjustment it brought the point of focus closer to the bottom of the chart, and adding a positive adjustment figure moved it up. If you've got a lens that's showing that focus is off, it's easy enough to make the appropriate adjustment in-camera and continue to fine-tune the settings until you've got one that is spot-on in terms of focus performance.
The Focus Pyramid is a fine product. It's inexpensive, and makes it a simple matter to calibrate autofocus. There are free alternatives available that you can print yourself at home, but they're not quite as easy to use, so the money you're paying for the Pyramid is really for convenience. In that regard, it's one of the better values you'll find; similar products like the Datacolor SpyderLensCal ($64) and LensAlign MkII ($85) are more expensive. My only real concern about the Focus Pyramid is how well it will survive the test of time; it is, after all, cardboard. But you aren't likely to be using it every week—once a lens is properly adjusted, it's not likely to drift, so really it's something you'll only break out when you get a new lens or a new camera body. If you have a lens that's not spot-on with focus, and your camera supports autofocus adjustment, the Focus Pyramid is definitely worth consideration.