I have 3 different 300 mm lenses. An AF-S 300 F4, a 70-300 non VR G lens and a 28-300. Out of the 3, the 28-300 lens has much less magnification than the other 300 mm lenses. As a matter of fact, the 28-300 has slightly less magnification than my old 80-200 2.8 D lens. I really like my 28-300 lens and it is the lens that is usually on my D7000 but I kinda feel like I got cheated on reach. Oh, and FWIW, my 18-200 has noticeably less reach than my 80-200. There is a pattern here.
Good observation. However, have you tried this exercise at various subject ranges? I would hazard to say the effects that you observe are probably in the short-to-medium range (<10m). Try something farther out.
OK, I re-tested at longer ranges and got completely different results. The 300 f4 still has the most reach but the 70-300 is very close. I would guesstimate that I got maybe 5% less reach with the 28-300. That is OK with me. At longer ranges, the 80-200 has obviously less reach than any of the 300mm lenses. But it is still slightly more reach than the 18-200 lens.
Keep in mind that focal lengths are never exactly that stated on the lens. You are also seeing "lens breathing" - i.e., for some lens designs the focal length decreases as the focus distance gets shorter.
This is a phenomenon sometimes referred to as lens breathing. It's normal for your lenses. When close focusing, the element groups in the lens have to move so far that the effective focal length is altered.
I wonder how big and expensive a 70-200 2.8 with the same resolution and correction as the VR II would have to be to eliminate / mostly eliminate breathing.
Pretty big and expensive, I bet. Cine guys, at least, would probably still want it, though. Maybe not anybody else, but the cine market is very is willing to pay the low volume premium...
Lee Saxon wrote:
I wonder how big and expensive a 70-200 2.8 with the same resolution and correction as the VR II would have to be to eliminate / mostly eliminate breathing.
Considering that they have to take away a feature...
It also has the best IQ out of the bunch that you list.