It's just that when I zoom in, the images just seem to have a lot of noise and don't seem that sharp.
I suppose I just need to learn how to use it after using a 100L constantly for months.
i own both lenses and love using both! but it's important to understand, your baseline of comparison for sharpness is a world-class, L macro lens
if memory serves me right, even 3rd party so-so macro lenses are still amazing when it comes to sharpness, and is generally a simpler lens design.
UWA from what i understand is very difficult to design and engineer and is prone to distortion, CA, and can be subject to compromises in IQ for a number of reasons.
when it comes to sharpness, many (if not most) zoom lenses will look unfavorable 100%, side by side with a macro. prepare to be dissappointed if the 100L is your baseline