One of the great things about this time of the year, especially when it is a blizzard, is that I have time to catch up on projects. Yesterday after a shoot I did some research on doing a focus test on my lens and came across a great video about a different way of checking the focus on your lenses. Now before I go any further let me say a couple things; one is that not all cameras can do what I am going to describe in that you can adjust the focus yourself and two I am not recommending the guy that is doing the video (I only watched this one that he did and it looks like he has done dozens) other than this is the best video that describes how to do a lens focus check that I have seen and it is explained perfectly.
So what is a lens focus check? It is a way to check to see if when your camera says that the image is in focus, and thereby should be sharp, that it is actually in focus and sharp. Plus, some newer cameras have a menu that allows the photographer to make changes to this focus setting without sending the camera away. In the past we would have to bundle up the camera body and lens(es) and send them away to be adjusted.
Should you test your lenses? I have always checked my lenses as much to know what they were doing as anything. Now with the 70D not only can I check the focus but I can adjust it. I would say that if you are curious go ahead and check your lenses, but understand that having an adjustment made is only needed if the lens is way out.
Before seeing this video I would do the in field test of focusing on something, taking an image then looking at the image on the computer and seeing if what I focused on was sharp and if not what was in focus – simple but it worked. Now with this video and the free focus chart that he provides you can see exactly how good a lens is and what way you need to adjust it. Yesterday I did both tests (my old way and the new way) and have to say that I had the lenses close my way but when I switched to using the focus chart I was able to nail it, and it was so much faster that I was very impressed. As an extra benefit with using the chart I know a number of people that like their lenses to rear focus a little and this will allow you to set that easily and precisely.
So if you have some time and are curious here is the link to the video http://youtu.be/m2tKs1zQ58E
Here is a link to download a free focus test page https://www.firstchoicephoto.ca/FocusTestChart.pdf