Unintuitive Use of Telephoto Lenses for Short-Range Closeups

Here's something weird I learned last week: I can do better closeup shots of small objects with my 200mm telephoto lens then I can with my 50mm prime lens. The 50mm/f1.4 can only focus to about a foot away; the 200mm/f4 can only focus up to about three feet away, but it enlarges the object at that distance enough to make it feel more intimate.

I have three lenses at present; a 50mm/f1.4, a 70-200mm/f4, and an 18-55mm/f3.5-f5.4. The 18-55 is the kit lens that comes with the Canon Digital Rebel. I don't tend to carry it, just because the 50mm is a faster lens, and I can only easily carry two lenses at a time. That being said, the 18-55 has got the best closeup performance, with the ability to focus at about 5" away when zoomed all the way in.

The 50mm, on the other hand, turns out to have kind of crummy closeup behavior. It'll focus at about a foot away. I just kind of figured that that was what I'd be stuck with, though, if I'm not carrying the other lens.

A funny thing happened when I was taking pictures of Feeps (one and two). I was carrying my 50mm and my 70-200mm, and I was pretty unsatisfied with shooting the itty bitty Feeps from a foot away. So I tried using the 200mm lens, and getting a little further back... and was extremely happy with the increased level of detail I got.

So I did some measuring today, and discovered the following numbers for how close I can get with my various lenses:

(Height is the height in inches of a theoretical piece of paper parallel with the plane of focus. So if I had a sheet of paper I was photographing head-on, and was using the 50mm lens, I'd get a slice of that piece of paper four inches high. The ratio of this image is 3x2, so multiply the height by 1.5 to get the width.)

The 55mm lens still clearly wins, but the 200mm does surprisingly well. The 55mm lens produces an image 75% bigger than the 50mm, but the 200mm gets an image 60% bigger, which is almost as good, assuming I want to minimize how much I lug.

Here's the same graph, with an image for context (the first attempt at the tomato shot, taken with the 50mm lens. The version I posted was taken with the 200mm lens).

(You'll note if you look at the actual 200mm shot, that it's bigger than this example image implies it will be; I guess I didn't actually get this 50mm shot as close as I possibly could. Also, I just now noticed that the spellchecker dots are visible in the screenshots I took to generate the images, which I'm prepared to live with if you are.)

The only real downside is one of space; to get the "closeup" effect, I have to be able to get three feet away -- and that's just the far end of the lens. I really need to have four or five feet of space to work in, which might require a chair to stand on if I'm trying to get a vertical shot. (Which, again, was what I did to get that tomato shot.)