Never ever try a PRIME lens.. Going back to a ZOOM, you get too obsessed w. IQ

gipper51 wrote:

I think "obliterate" and "smash" are a bit of poetic hyperbole here. I won't argue that primes offer better image quality than zooms, but for the better zooms out there (like the 70-200L class, or latest 16-35L or 24-70L versions) the differences aren't that dramatic any more. At least in terms of central sharpness wide open. Stop any of them down to f5.6-f8 and you'll have to 'peep hard to spot the differences across the whole frame from the primes listed.

The caveat is that zooms are far more complex and are much more prone to copy variation. Zooms will often have a weak point in the range, and where it occurs can vary between copies of the same lens. Doesn't mean it's bad, that's just reality. Primes are simpler beings and only have one focal length they need to be good at.

Your 24-105 is certainly going to be outclassed by any of the primes when both are shot at f4. But it shouldn't be terrible ("terrible" is subjective, and you appear to like exaggerated adjectives). If it really is that bad, then perhaps you have a faulty copy or your camera is missing focus and the lens needs MFA adjustment.

Center sharpness wide open should be at least close to any of the primes listed here (edges and corners are a different story). If that's not the case, check focus on a tripod with live view. If it's still mush, I'd say a bad copy.

Yes, probably a bad copy

Bought this zoom as 2nd hand

Similar experience with a 24-70 f/2.8 Mk ii where the pics were also very disappointing

Maybe best to buy primes as USED and zooms as NEW.. more fragile

Thx for your advice, rgds, Gaul