This shows the depth of field is not influenced by the sensor size when aperture, focal length, and distance to the subject are kept the same. This becomes visible when we enlarge part of the full frame photo to match that of the crop photo. Of course, the 120mm acts like a 192mm lens when used with the crop camera, but the depth of field is exactly the same with both sensor sizes. There are a few things that we see when these pictures are held next to one another. The distance to the subject was kept exactly the same. To test the depth of field, I placed my camera on a tripod and shot a scene with full frame and crop, with the same focal length of 120mm and both with the same aperture of f/2.8. I don't want to make it more difficult than necessary. But let us ignore this for the sake of simplicity. Although the minimum focal length of the EF-S lens is shorter, it acts like a 27mm lens.ĭepth of field is affected also by the way you view a picture, how much it is enlarged, what the viewing distance is, and the pixel density on the sensor. Two lenses at the left the EF 24-70mm and at right the EF-S 17-85mm for crop. This is visible in the example below, which shows what you capture with a full frame and a crop when using exactly the same focal length (120mm in this case). In other words, it looks like the picture is shot with the focal length of the lens multiplied by the crop factor. Thus, the picture with a crop sensor looks like it is magnified compared to what a full frame would show. Therefore, it captures only a part of what a full sensor would capture when using the same focal length. But before I do so, I find it important to realize a few things.įirst of all, a crop sensor is smaller than a full frame sensor (which is obvious).
So I took a Canon 1.6x crop camera and a Canon full frame camera to make some shots and to figure out how much difference there is. (Canon 1D X 85mm f/1.2L II | ISO100 | f/1.2 | 1/250)Because I give workshops and masterclasses, I found it important to see the difference myself and to be able to explain it to my students when the question arises. Using a small depth of field can isolate your subject from the surroundings, like this shot where the bride is in focus and the hair dresser not.
