Upload & Sell: On
Jon Tainton wrote:
I think you've dodged a nasty bullet there Despite some continuing reservations, from a landscape perspective I've really warmed to this lens for its size, weight, IQ stopped down, versatility and build quality.
I agree. There are so many things to like about this lens, but some people give it a miss because it isn't perfect.
Of the many things I could wax poetic about, I feel compelled to mention distortion. The 21-35 at 21mm has about 3.5% barrel distortion. Horrible, right? What I've learned is that, simply stated, no, it isn't horrible at all. Distortion is like bokeh. There is pleasant and unpleasant bokeh, and there are pleasant and unpleasant uses of bokeh; the same applies to distortion. There are two kinds of distortion: linear and areal. Having straight lines (low linear distortion) requires having stretched surfaces (high areal distortion). Balancing between the two, and how they trade off out to the extreme corners, is a lot like how bokeh can take on different shapes and intensity profiles. I've found that linear distortion is immediately apparent, but disappears when an image is closely inspected; and that areal distortion isn't immediately noticeable, but becomes pernicious when the image is viewed critically. Balancing between the two is a personal choice, but I've found that having moderate linear distortion, with the ability to straighten in post, is far preferable to starting with no linear distortion at all. (And either is preferable to mustache distortion. I think mustaches bug me the way blurry corners bother other people, and that's coming from someone who wears a full beard.) The 21-35 has a steady progression out to the corners and it achieves a good balance between linear and areal distortions.
That felt good to write. I've been wanting to put together a primer on distortion for a while, because my impression is that most people think "less distortion is always better," and there aren't many discussions about the nuances of distortion like there are for the nuances of bokeh. I could just be nuts. If others think the idea is worth exploring, though, I might be persuaded to put something together with samples.
tl;dr -- the 21-35 is underrated.