Canon 50D - Peripheral Illumination Correction

Okay - we now return you to our regularly scheduled 50D review series...

Today I'm taking a look at the Peripheral Illumination Correction feature. In short -most lenses will have a bit of falloff in the corners - a bit of vignetting. What Canon has done is to measure how much falloff there is in each of their lenses and have defined profiles for each. You can load up to 40 of them into the 50D (including combos w/ Canons 1.4x and 2x TCs) so that the camera can correct for this vignetting in the camera while it is creating the jpeg image, or can store that info in the RAW file for use by DPP.

The process of setting it up is pretty easy. Connect your camera to your computer with the USB cable, fire up the EOS Utility, choose "Camera settings/Remote shooting", then pic "Peripheral illumin. correct." from the "Shooting menu" and you'll get a screen like this: (click to enlarge)

From here you can check your Canon lenses from the list (note the category buttons in the top right, to help you sort through the long list). If you own either (or both) of the Canon TCs, you should click the appropriate extender buttons in the bottom left. The list will re-populate with all the canon lenses that can use the TCs listed again with the TCs in combination. (note the top right column in the photo above). The bottom left corner of the window will let you know how many lenses you've selected out of the forty allowed.

Once you have your camera loaded with the profiles for your lenses - you are ready to go.

As a quick example - I've done a quick test with my EF-S 10-22, I shot a light colored wall to show the falloff, and then did a quick export from Lightroom.  The top photo is the jpg (with the correction) the bottom photo is the RAW without.

The correction seemed to work pretty well in camera when shooting JPG. It didn't eliminate the falloff completely, but it did a pretty good job. If the shot was not of an evenly toned light wall, you might not even notice that all the falloff wasn't gone.

If you are a RAW shooter who uses DPP for their RAW processing, PIC will also work for you. When you review your image, DPP will let you know if PIC was on when a given image was shot. Below you can see a screen shot of some of the images I shot: (click to enlarge)

In the "frame" around each image, you can see an icon that looks like a white Canon lens. This indicates that the RAW image was shot with PIC enabled. From here you can turn off the correction, or can tweak it if you want.  Choose "View" then "Tool Palette" from the menu and you will get the tool popup. Choose the "NR/Lens/ALO" tab, then click the "Tune..." button. You will get this popup: (click to enlarge)

If you want to turn off the correction, you can un-check the box next to "Peripheral illumination". The slider can also be moved to adjust the amount of correction.

I also worked with the images in Lightroom 2.1 release candidate - which has "preliminary" support for the 50D. As I expected, the correction did not import, but a quick click to "develop" then adjustment of the "vignette" slider, and the same end result was achieved.

Another quick note - I pulled the jpeg files that are embedded in the RAW file (as a preview) out and took a look at them to see if the PIC was applied to those JPGs...   

Conclusion:

I think this is a feature aimed at .jpg or DPP users, and seems to work okay for those uses. Being a RAW shooter who post processes in Lightroom, I'm planning to leave it turned off all the time. Not only won't I use the data in LR, I don't want the camera to create previews that don't match the RAW files. The vignette tool in LR will do just fine for me.

Thanks for reading!

Comments

[Colin Bewes]

I note you say that the PIC feature does not import to Lightroom. Do you happen to know if the same applies to the Auto Lighting Optimiser? I am considering buying a 50D and like the idea of the ALO feature reducing some of my post-processing. I have wholly converted to Lightroom 2.2 and don't much fancy going back to DPP or even including DPP in my workflow before using Lightroom.

[WillShootPhotos]

Thanks for the question. No - neither the ALO nor the PIC features are visible in Lightroom if you are shooting RAW. Those are only utilized through DPP. If you shoot .jpg files - then both ALO and PIC will be visible in Lightroom. That said - I'd suggest you shoot RAW, use Lightroom and not worry about the PIC or ALO. Each adjustment is super easy in LR anyway. So just pull up the "Fill Light" to about 15 or so in Develop and you'll get the same effect as if you had used ALO. And as for the PIC - just tweak the vignette setting. I'd not let something like that sway your buying decision.

Hope this helped!

- Will

[Colin Bewes]

Very helpful - thanks. The only things that might sway or delay my decision now is the discussion about noise or the anticipation that a 60D might be out in August. Then again, there seem to be as many defenders as there are whiners on the noise issue and I have seen quite a few really nice 50D pics. As for waiting for a 60D, I suspect it will be more expensive initially and wonder what else they can cram into it apart from HD video, and I'm not sure I would use that at all. Cheers, Colin

[WillShootPhotos]

Colin,

I'd also consider what you might get out of buying now vs. later... Is there something that the 50D has now that you need or could really use? You can always keep thinking you'll wait for the *next* iteration - but at what point do you just pull the trigger and get something? Obviously - tis your call - but w/out an announcement as to features, delivery date, etc... who knows when the 60D would arrive.

- Will

[Ken Stoneman]

Is there sofware available for a Canon 15-85mm lens? Ken stoneman

[WillShootPhotos]

Ken, thanks for the question. I'm pretty sure the EF-S 15-85 IS is supported... I'd suggest you try connecting your camera, launching the EOS utility and following the directions above. The screen shot included in the post above wasn't of a full list of lenses to choose from, it shows the lenses I had chosen to configure in my camera. I'm pretty sure the 15-85 will be there. I'm not sure the 8-15mm FE Zoom is there yet, but perhaps a software upgrade from the Canon site will add missing lenses in. When I've some time later, I'll hook my camera up and see what is in the list. Let me know if you've any other questions.

- Will