With 15 elements in 10 groups, this appears to be an extremely well corrected lens. Focusing to 1:1, it could be a great portrait lens, and with autofocus and image stabilization, quite possibly one of the most versatile 100mm lenses around. Weight is reasonable at 705 grams with lens hood and caps, but it’s a large lens, and the lens hood is 8cm long so that when mounted the whole affair at 21cm long looks like a long telephoto!
The Canon MTF chart looks unbelievably good, with extreme central sharpness holding well across most of the frame, but with the very extreme corners going slightly softer. Ultra-high macro contrast suggests this lens will have some serious “bite” to its rendering.
Oddly enough for a 100mm macro lens, there is significant astigmatism, which indicates an unusual and probably new design. There are many aspects to a lens besides MTF, but it’s rare to see a Canon EF lens looks this promising, short of the super teles. Assuming I have a good sample, I suspect it will prove a spectacular performer, perhaps giving some relief to Canon users who have been lusting over the Zeiss ZF 100/2 Makro-Planar. Then again, compromises must be made with every lens, and the ZF 100/2 combines exceptional bokeh with exceptional contrast and sharpness.