Via Lens Rentals
Roger Cicala from LensRentals.com has posted his first resolution tests of the Canon EF 24-70 f/4L IS.
He has compared it with the EF 24-70 f/2.8L version 1 and 2, the EF 24-105 f/4L IS as well as the Tamron 24-70 f/2.8VC. All of which will probably get your consideration in a very crowded focal range.
At 24mm, the EF 24-70 f/4L IS is the second best performing lens behind the EF 24-70 f/2.8L II. Mind you, the results are all pretty close. It does look like Canon's MTF chart of the lens holds up against the others.
At 70mm, none of the lenses are as sharp as they are at 24mm. However, the EF 24-70 f/4L IS is again the 2nd best performing lens by a small amount.
Part of Roger's Conclusion
“Obviously this hasn’t told us a thing about autofocus accuracy, bokeh, or a dozen other things that have to be considered when choosing a lens. Just like you, I’ll be waiting for more complete reviews to tell us about that.
On the basis of this information, though, I’m . . . well, I don’t know what I am. This is a good lens, but I at the price point I’d probably prefer the f/2.8 of the Tamron VC to the new Canon’s f/4. The macro feature is nice and will certainly pull some people towards the Canon.”
Roger also notes that there was quite a bit of variation at 70mm between the 22 copies they tested.
Read the entire article | Canon EF 24-70 f/4L IS at B&H Photo $1499