No matter what camera you have, Adobe’s brilliant move in securing all the lens data from Sigma needed to provide off the shelf correction profiles for CS5 Adobe Camera Raw 6.2 and Lightroom 3.2 will have improved your output and saved you loads of adjustment time. Richard Kilpatrick looks at the benefits.

Some camera makes are so short of profiles for their lenses that Sigma’s list is the only one to cover a decent range. It is a very comprehensive list, all the current lenses up to May 2010 as far as we can tell. We’ve done some testing and found, for example, that profiles made for current lenses like the 15mm f/2.8 EX DG full frame fisheye can be applied with pretty good results to shots taken with much older 16mm Sigma fisheyes. Not that you would always want to correct a fisheye shot the way Adobe make it happen.
Here’s what an Adobe profile applied at normal distortion-correcting strength (100 on their slider) will do to a fisheye shot, in this case the 8mm f/3.5 EX DG which is designed as a full circle fisheye for full frame but will nearly cover the entire sensor of the SD14 used here:

This is a fisheye perspective which can be cropped to remove the clipped corners. But is the .X3F raw file is processed using the latest Adobe Camera Raw with Sigma lens correction profiles, it is transformed into this:

This has been given 85% per cent distortion correction, leaving a gentle amount of barrel distortion in place for a more natural look and widest coverage. You will see that the 8mm fisheye now appears to have an angle similar to a very extreme wideangle with straight-line drawing – it’s actually not far off the result achieved by the 8-16mm zoom at 8mm, but that lens it far sharper than the ‘stretched’ pixels of the fisheye view can ever hope to be.
What if you don’t have CS5? The lowest cost way to access all the Sigma lens profiles is through Lightroom 3.2. With auto lens correction turned on, the program recognises both the lens and the camera body (it may need manual entry with some makes) and identifies the focal length used for zooms. We have been using it with the 18-250mm OS lens and it neatly deals with the range of distortions inevitable at different focal lengths in a zoom of this type. Chromatic fringes are eliminated, something which is easy enough with manual controls but also easy to forget when they are barely visible to start with.
Vignetting is something you do not always want to remove. The darkening towards the edges of the image can ‘hold in’ the shot and deepen sky blue. So often it’s a good idea to reduce the slider value from 100, perhaps even to 0 for vignetting.
Making an Adobe lens profile using their Profile Maker software takes about an hour for the simplest two-aperture profile of a mid range zoom with four or five focal length steps. The Sigma profiles would take months to produce if you had to work on the entire lens range and all the camera formats and bodies covered.
Lightroom can be used with Photoshop Elements 8 as a post-process editor. If you apply the profiles in Lightroom, and then later open the raw file again in Elements (direct with the camera raw plugin) all the corrections you made will be remembered and applied – though you can not get at them through Elements, as you can with full Photoshop.