" MTFs curves also tend to get higher for longer focal lengths as well."
no they don't, longer focal lengths are measured around 10lp/mm which gives higher higher curves, for example Canons 300mm has higher resolution than 500 or 600 who are optimized for high contrast and do well at lower Lp/mm
300/2,8 and shorter lenses has higher resolution and are often measured around 30-50Lp/mm when they are compared to each other
So, there are nothing strange about that 300/2,8 are a sharper lens regarding resolution and contrast
Please explain. The Canon MTF charts have both thin and thick lines. I thought the thick lines corresponded to 10 lp/mm and that the thin lines corresponded to 30 lp/mm. We're not comparing thick from one lens to thin on the other. Unless you are saying that what the thick and thin lines represent (x lp/mm) varies depending on the Canon lens focal length. Does it?If it does not, then what Insanitybeard points out is correct.
The 300/2.8 has lower 30 lp/mm curves than the 500/4, yet it measures having higher resolution. That is the crux of the question. Neuro points out that MTF curves/sharpness do not have a 1:1 relationship, which is fine. However, we often get MTF curves in advance of lens testing results, so we often use them as proxies for sharpness, and most of time, it works well. Noting something that does not follow the pattern is interesting.
And my statement that longer focal lengths tend to produce higher MTF curves is a general trend
born out by Canon's MTFs. See the F/8 lines for the 24L II, 35L, 85L II and then the telephoto primes (200 and up).