I bought this to work in conjunction with a 24-105 f4 L ... but found the cheaper lens had more contrast and effectively the same sharpness !
This lens is light ... a great size and weight when used with an R5 in my case.
The cost is high and not too far off the 28-70 f2 (though many may be buying this for it's handling which is superb).
The focus speed is awesome and it is near silent.
Image quality is superb and sharpness, well, you simply can't complain. Why then, do I not rate it as much as the 24-105 f4 or indeed my 28-70 f2 ?
Well, the 24-105 f4 is smaller, lighter, cheaper and has better contrast. I think this lens is sharper but with less contrast seems less pleasing than the 24-105.
The 28-70 f2 whilst losing 4mm at the wide end is noticeably a better lens for IQ. Yes, heavier, bigger, slower focusing and more costly ... but the way the larger 28-70 renders images is in a different league. I can't put my finger on it in any other way but this lens is just 'flatter' in terms of what it delivers than a 28-70. It just doesn't (didn't) grab me in the same way, yet I couldn't fault it in any one area.
I have just sold my copy. It did nothing wrong but didn't grab me + I have the 24-105 and the 28-70 so was a bit spoilt to say the least (though something had to go!)
The best things I can say are, it did no wrong, it focuses soooo silently and speedily .... giving s really sharp image. BUT ... not ones as pleasing as the 24-105 or (especially) the 28-70.
If you want a sharp f2.8 that weighs not too much ... is not big at all, then look no further. This lens suits an R/R5/R6 as it has IS and is a great size. If you want better then you need to use a 28-70 f2 on an R5/R6.
I sold my copy buy only as I had the 28-70 f2.
