February 02, 2013

Working with Canon Tilt/Shift Lenses

         Using the Free-Transform Tool in Photoshop can do wonders for correcting perspective in a digital photo, but at what price do we pay in pixels for all that distortion correction. The perfectionist in every digital photographer is always searching for a better way to achieve the best quality.  There are many perspective control - tilt/shift lenses available for the digital SLR cameras. These manual exposure, manual focus specialty lenses allow the photographer to straighten the perspective or extend the depth of field by changing the rise/fall and tilt/shift of the focus plane. This is the closet thing to view camera control I have found since the transition to digital capture from film.

click to enlarge images

            In these examples, I am using the Canon TS-E 17mm f/4L lens on the 1Ds Mark III camera on this outdoor scene of a new pool  installation. In the first shot, you can see that when the camera is pointed downward toward the pool, the posts of the screened in pool area are angled and distorted. When doing wide-angle photography, the wider the lens you use, the more extreme the distortion is in the image. To correct the problem in the initial image, the camera is leveled out to look straight ahead instead of at a downward angle. The lens is then adjusted to shift the view downward using precision adjustment knobs on the lens to bring the pool area into view while keeping the image sensor level. This corrects the general perspective of the scene to have areas that are straight to look straight while still looking downward to the pool surface. This saves computer time and increases quality in the final image as you don’t transform and interpolate any of the pixels in free transform.

            In this next example, this interior staircase shot is a tough angle to get without really distorting the railings as you look down to the first floor. The Canon TS-E 17mm lens is wide enough to cover the area, but the distortion level is very high.  By leveling out the camera view first, the image viewing area can be shifted downward to view the first floor. The distorted staircase is corrected at the point of image exposure and this means the Raw file is correct from the very beginning.

            The perspective control lens is very important in the studio as well. The Canon TS-E 90mm f2.8 lens is great as a choice for product photography. The longer focal length allows the photographer to work a little further away from the set making it easier to work in the lighting. The ability to tilt or swing the lens can extend the depth of field to follow the direction of the product placement and allows more control of what is sharp. In this example the Canon 1Ds Mark III and the TS-E 90mm f2.8 lens was set up to photograph this circuit board. The lens was tilted away from the subject so the depth of field is very shallow. In the next image, the lens was tilted toward the subject to extend the focus to make the product sharper. The more control we have on the front end of the image, the better the quality is going to be after our Photoshop enhancements.  Till next time… Work smarter…  Not harder..