Lens Aberration Correction
Lens aberration correction. So this is another one of the image manipulation modes and let's look at what the options are in this sub-menu. So first off is Peripheral Illumination and this is going to fix the problem that you sometimes get with either very fast lenses, or very wide lenses as we can see in this example here. This was shot with the 11 to 24 millimeter lens I think at 11, and you can see how the corners are much darker than the middle of the frame, and this is very common with very wide angle lenses. And so if you turn this particular feature on, it will correct for that feature - and now let me jump back and forth between these two - it will correct for that feature on JPEG images. It will not fix it on raw images but it will fix it on JPEG images, and it will fix it at least in camera as far as what you look at on the back of the camera. And so this is a feature that you can turn on but is of limited use when you are using raw images, and you can see how much impact it ...
has there on an image. Thing is is that sometimes people like adding that vignette effect to their images and so it's something that I often add to my images when I'm shooting people photographs, and I wanna draw the attention away from the corners, and so I wanna darken those corners up a little bit. And so there are many photographers and many styles where you don't care about Peripheral Illumination Correction at all; you're perfectly fine with the natural vignette of the lenses. And so, some people may wanna leave this turned on, some people may want it turned off. Now as we go through this part of the class, I will be making general recommendations and I will also have advanced recommendations where maybe more advanced users might prefer to have their settings, and these are, these are good starting points for people, this is your camera, I want you to customize it the way you like it, any way you need it, and so I'm just trying to give people a starting point if they're not sure on where to set it at. And so I know many of the more advanced photographers just like to get the natural look from the lenses, and they'll fix it later if they need to in Lightroom, Photoshop, or whatever program. Chromatic Aberration is a problem that nobody really likes to deal with, and this happens when you have a very bright background and light kinda comes around solid objects. It creates a halo that has a distinctive color, either blue or red color to it, and this has been a problem with digital, pretty much all digital cameras, and the lenses try to correct for this, and the cameras wanna try to correct for it with a feature like this is in Chromatic Aberration. And so once again, this will only fix it on the JPEGs but nobody really likes this on their images and so this is something that most people are gonna wanna leave turned on. Distortion Correction is gonna deal with lenses that have a little bit of distortion to it. And so as good as the lenses are sometimes they have a little bit of distortion. This image here has distortion. Let me go back and forth between the corrected image and the before image, and you can see that there's a little bit of distortion in this wide angle shot. And so you can fix that once again on JPEG images only; it does not fix it on raw images. If you wanna fix it on a raw image, you'll either need Canon software or some of the other post-production software. Diffraction Correction, this is a new one that we haven't seen on many Canon cameras, I think this may be the only one, maybe the 5D Mark IV will have it as well, and it'll probably be on future cameras. So when you stop down to f/22 to get maximum depth of field, there is a diffraction problem that causes a loss of sharpness, and the camera will go in and add a little bit extra sharpness, will sharpen that image up if you are shooting at those really small apertures, and it's not a huge difference but I can see that the image on the right has more sharpness than the one in the middle. And so this is something that does work once again, only on JPEGs, doesn't work on raw images. And so, that extra sharpness looks pretty good to me, it's not over sharpened, and so I'm recommending at keeping that turned on. So that's our little sub-menu of fixing little lens problems.