Peripheral Illumination Correction

The perfect lens. Oh how nice that would be. Sadly, it's just not possible. Well, not unless you're a multi millionaire and are willing to pay many millions for each lens. Even then optical physics gets in the way and there would have to be compromises. Oh, and if you had "the perfect lens" you wouldn't be able to carry many of them!

So, with that in mind, Canon introduced a feature to DPP a while ago to help correct the problem of corner shading. Essentially they used testing and optical data to work out how a lens responds on a particular camera and then it can be corrected automatically. Simply go to the DPP NR/Lens/ALO tab and choose tune next to Lens Aberration Correction.

Now, that's all well and good, but what about in camera? Well, since they've got the data, there is no reason why, in theory, it couldn't be put into the camera. And that's what they've done with the DIGIC 4 processor. So, on the EOS 50D and EOS 5D Mark II there is a Peripheral Illumination Correction option in the menu that allows you to enable or disable it.

Obviously it only works with Canon lenses, and currently it's only working for around 40 lenses. 26 are pre-loaded into the camera and the rest, up to a maximum of 40 at a time, can be added using EOS Utility.

What you should remember about this is that it's nothing to do with AF Microadjustment, which we'll look at in a future post.

What does it look like? Well, the images below should give you some idea.

Oh, and in the image that has darker corners, it's not vignetting! Vignetting is a hard corner and has different causes. This is a softer corner and is caused by light not striking the pixels in the corners of the frame squarely.

PIC OFF


PIC ON



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Lens aberration correction - compatible lenses

Canon added lens correction functions to Digital Photo Professional in version 3. In essence the software engineers got access to the lens designers manual for each lens. In the lens manual there's the full design specification and the known optical characteristics. The software guys thought that they could improve some lenses performance with some software processing, but having the original lens designers book they could implement one of the best corrections possible; so they did. The result is some kind of special since it actually works really well, and driven by their success the software guys were out drinking with the camera firmware team and challenged them to implement vignetting correction in the DIGIC 4 processor - and so since they had some spare time and some resource in DIGIC 4 to exploit they built peripheral illumination correction in the EOS 50D and subsequent models. However the correction in camera can be thought of as a helper rather than the full solution. In camera the correction for vignetting is 50% of what DPP can do. Also DPP with RAW images can do distortion - pin cushion & barrel, chromatic aberration and colour blur corrections. Suddenly those old lenses on ebay got a bit more useful.

Here's the current list of compatible cameras and lenses with the Digital Photo Professional software. This is going to be kept live so you may want to come back sometime in the future when new models of camera and lens come out.

You can perform lens correction with the following cameras

EOS-1Ds Mark III	EOS-1D Mark III	EOS-1D Mark II N
EOS-1Ds Mark II	EOS-1D Mark II	EOS-1Ds
EOS-1D	EOS 5D Mark II	EOS 5D *1
EOS 50D	EOS 40D	EOS 30D *2
EOS 450D EOS Digital Rebel XSi	EOS 400D EOS Digital Rebel XTi	EOS 1000D EOS Digital Rebel XS

^*1 - Requires firmware version 1.1.1 or higher for maximum lens compatibility

^*2 - Requires firmware version 1.0.6 or higher for maximum lens compatibility

Ultra wide and wide-angle lenses
EF14mm f/2.8L USM	EF 14mm f/2.8L II USM
EF 20mm f/2.8 USM	EF 24mm f/1.4L USM
EF 24mm f/1.4L II USM	EF 24mm f/2.8
EF 28mm f/1.8 USM	EF 28mm f/2.8
EF 35mm f/1.4L USM	EF 35mm f/2

Standard and medium telephoto lenses
EF 50mm f/1.2L USM	EF 50mm f/1.4 USM
EF 50mm f/1.8	EF 50mm f/1.8 II
EF 85mm f/1.2L USM	EF 85mm f/1.2L II USM
EF 85mm f/1.8 USM	EF 100mm f/2

Telephoto lenses
EF 135mm f/2L USM	EF 135mm f/2.8 (with soft focus mechanism)
EF 200mm f/2L IS USM	EF 200mm f/2.8L USM
EF 200mm f/2.8L II USM	EF 300mm f/2.8L IS USM
EF 300mm f/4L IS USM	EF 400mm f/2.8L IS USM
EF 400mm f/5.6L USM	EF 400mm f/4 DO IS USM
EF 500mm f/4L IS USM	EF 600mm f/4L IS USM
EF 800mm f/5.6L IS USM

Macro lenses
EF 100mm f/2.8 Macro USM	EF 180mm f/3.5L Macro USM

Zoom lenses
EF 16-35mm f/2.8L USM	EF 16-35mm f/2.L II USM
EF 17-35mm f/2.8L USM	EF 17-40mm f/4L USM
EF 20-35mm f/3.5-4.5 USM	EF 24-70mm f/2.8L USM
EF 24-85mm f/3.5-4.5 USM	EF 24-105mm f/4L IS USM
EF 28-70mm f/2.8L USM	EF 28-90mm f/4-5.6 USM
EF 28-90mm f/4-5.6 II USM	EF 28-90mm f/4-5.6
EF 28-90mm f/4-5.6 II	EF 28-90mm f.4-5.6 III
EF 28-105mm f/3.5-4.5 USM	EF 28-105mm f/3.5-4.5 II USM
EF 28-105mm f/4-5.6 USM	EF 28-105mm f/4-5.6
EF 28-135mm f/3.5-5.6 IS USM	EF 28-200mm f/3.5-5.6
EF 28-200mm f/3.5-5.6 USM	EF 28-300mm f/3.5-5.6L IS USM
EF 55-200 f/4-5.6 II USM	EF 55-200mm f/4-5.6 USM
EF 70-200mm f/2.8L USM	EF 70-200mm f/4L USM
EF 70-200mm f/2.8L IS USM	EF 70-200mm f/4L IS USM
EF 70-300mm f/4-5.6 IS USM	EF 70-300mm f/4.5-5.6 DO IS USM
EF 75-300mm f/4.5-5.6 II	EF 75-300mm f/4-5.6 III
EF 75-300mm f/4-5.6 USM	EF 75-300mm f/4-5.6 II USM
EF 75-300mm f/4-5.6 III USM	EF 90-300mm f/4.5-5.6
EF 90-300mm f/4.5-5.6 USM	EF 100-300mm f/4.5-5.6 USM
EF 100-400mm f/4.5-5.6L IS USM

EF-S lenses
EF-S 60mm f/2.8 Macro USM	EF-S 10-22mm f/3.5-5.6 USM
EF-S 17-55mm f/2.8 IS USM	EF-S 17-85mm f/4-5.6 IS USM
EF-S 18-55mm f/3.5-5.6	EF-S 18-55mm f/3.5-5.6 II
EF-S 18-55mm f/3.5-5.6 USM	EF-S 18-55mm f/3.5-5.6 II USM
EF-S 18-55mm f/3.5-5.6 IS	EF-S 18-200mm f/3.5-5.6 IS USM
EF-S 55-250mm f/4-5.6 IS

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