In early September I did a comparison between the 4 lenses I had at the time. I've added a lens since then, a Tamron 70-200 mm zoom. In a pro world I'd set up the tripod exactly in the same place and try to repeat the shots, and display the new photos with the existing photos. Only problem is I'm not sure exactly where the tripod was, and for another, those plants aren't there anymore. Something about winter. Maybe I'll do it again next spring.
One would think that a 200 mm lens would be able to zoom in closer and show more detail than a 100 mm lens. Not so fast! The difference is that the 100mm is a macro lens so you can get right up into the flower's little face. The minimum focus distance is listed as a foot in the spec's page, but there's times I think I've been closer.
The 200 is not a macro lens. The minimum focus distance is just over 51 inches, so the bigger zoom has to be more than 4 times further away. Here's two comparison shots. The first is the 100 mm lens, and the second is the 200. The processing is identical. Unfortunately the light changed slightly so the second shot doesn't look quite as bright. You can easily see how much closer the 100 mm is.
That doesn't make the 100 mm a better lens. Like so many things, "better" depends on what you want. That nice landscape shot yesterday? That was shot with the 200 mm lens because it gave me more options about composition. (And thanks for the kind words about it!)
Another fun shot with the 100 mm, showing a plain old metal ruler. (Anyone care to take a guess about the background?) First there is a surprising amount of detail in the metal. And second, there's a lot of space between the mm marks. I suppose I should have included this in my blog about the resolution of our eyes and hairy flowers. At the closest focal distance the 100 mm lens has a field of view only 37.5 mm wide, which when displayed on my screen comes out to an image 18 inches wide. You figure out the magnification factor. It means you are seeing lots of fine detail in whatever is in proper focus. A work in progress.