Get To Know Your Lenses

Here's another thing to look for so you can anticipate how a photograph will turn out using a particular lens. You can check for differences in sharpness and color in different parts of an image.

Using the same checkerboard image I used to check the focal point and DOF I cropped a super close view of the squares at the center.

Then I cropped a same size view of the squares at the edge of the image. In the case of my Canon EF 24-105 f/4L IS USM lens there wasn't a great difference but there is just a tiny bit of loss of sharpness in this extreme close-up cropping.

It won't be noticeable in 99% of the images even if I crop out half of the image.

If you do a test like this you may be surprised by just how much your image changes in both sharpness and color from the center to the edge.

There will always be some aberations even in the finest lenses. One way to reduce their effects is with software that lets you adjust for those aberations. I use Adobe's Lightroom 3 which has a develop module that is the same as Adobe's Camera RAW Editor which I'll also use on some images. It includes adjustments for just about all the popular cameras and lenses out there.