Here I was trying to get as close as I could to this butterfly wing with a Canon 1D MkIV and a Canon MP-E 65mm macro lens. This is a 1x to 5x macro zoom (on a full frame camera). On a Canon 1D MkIV with a 1.3 crop sensor it is more like a 1.3X to 6.5X macro zoom. The MP-E 65mm is definitely a special purpose lens and is a little funky to use. Sometimes it seems like your subject is right up against the front element. Here I backed the zoom down a little and moved the camera in on a rail until I achieved focus. I am guessing it was about 5X. Usually when I am done I photograph a small tape measure and compare it to the image of the sensor. I did not have an opportunity this time to do this. With this extreme close focus it is critical to get as parallel as possible to your subject to achieve focus as much as possible over the entire frame. The MP-E 65mm has a very limited depth of field so it is important. I had the lens set to f/16 and still had a very narrow depth of field. I used an off camera flash above and to the side and a small white reflector for fill flight. I also uploaded a closer crop of the same image.