Ever thought how much easier it would be if you could just have a sensor shaped like a 8x10 or similar format? Well not really, but if you are shooting images which you plan to crop for a 8x10 print, take the time to use the provided grid in your 7D's viewfinder. It will help get your images, so you won't lose information on the cropping end. If you are using Lightroom, and you want to crop a bunch of images to 8x10, and you use this grid to line up you composed shot, then you can synchronize the Crop throughout your images.
In the image shown, we have Charlie centered just in between the top Black line and bottom black line of the grid you would see in your viewfinder. If you can keep your composition within those lines you will have a little extra for the top and bottom for crop adjustment. This would hold true to be left and right in a landscape shot. The red lines represent the 8x10 format. This set up will also help you get formats such as 4x5, and 16x20. If you are like me and like to frame with Mats on the cheap, you need to crop your images to standard sizes. You can have your mat cut to any shape you want. However, to save yourself time and money, just take advantage of the grid in the 7D. Before, I really thought about how the grid in my viewfinder related to an 8x10 shot, I ended up cropping out stuff I wanted, or had to remove things I didn't want in post production. Keep life simple. Get it right in the shot the first time.
Any other Cameras with the Grid? My 40D which was the camera I had before my current Canon 7D does not have the grid. Not sure which other Canons have this feature, and not sure about other Brands that do. If people have a Nikon, Sony or whatever with this feature, how does your grid relate to an 8x10 image? We would love you to post, if your camera has this feature and how it works for you.