A Google search later, it seems that the last non telephoto primes lenses released, were the 17mm TSE, 24mm TSE and the 100mm L Macro in 2009.
I believe it's fair to say these lenses are extraordinary in performance, with few faults.
But I'm beginning to wonder, just how far Canon can turn up the performance dial for any new prime they intend to release?
When I began photography three years back, a common bit of wisdom I found was that primes are just better than zooms and this was due to the simplified engineering required.
Then along comes 4 zooms, 16-35 f/4.0L IS, 24-70 f/2.8L ii, 70-200 f/2.8L ii & the 200-400 that had reviewers saying something along the lines of "this zoom performs good enough to make me sell any prime lens covered by that range."
I'm paraphrasing there, don't sue me
So back to the subject of what a brand new prime could bring to the table.
1. Sharpness from corner to corner at largest aperture
4. Colour rendering
5. Bokeh/Aperture blades
6. Image Stabilization
Canon's latest zooms are a strong indication that the engineering process has become highly refined and that the next primes should truly shine.
I feel that Canon's next L prime should be able to deliver astounding image quality and simultaneously consign issues such as jittery or slow AF, sterile contrast and any fringing to the past.