I bought this lens as a replacement for a Canon 10-22mm f3.5/4.5 EF-S ultra wide zoom lens that I had faithfully used with an old Canon EOS 60D. The moment I upgraded to a Canon EOS 5D Mark IV dSLR body meant that I had no choice but to upgrade the lens as well as an EF-S lens is not compatible with the full-frame EOS 5D dSLR. What I've found is that this EF 16-35mm f/4L lens is worth every dollar for it. Pictures are crisp, and the ultra wide angle that it supports allows for me to capture landscape photography, which is the main reason why I use ultra-wide zoom lens. As a hobby photographer, this 16-35mm f/4L lens meets all my needs for an ultra-wide zoom lens for still landscape photography, and having its imager stabilizer feature, and an extra $1k in my wallet, is a worthy tradeoff than to go with its 16-35mm f/2.8L sibling. Highly recommended for any photographer, both amateur and professional, to add to his or her collection of lenses for landscape use.

I was considering the Canon 16-35/2.8L but then found that the f/4 IS L lens was much sharper per Canon's MTF curves, and it's $500 cheaper. I love the 16mm on full frame for fun, super-wide, distorted images. Wide angles are never as sharp as normal or telephoto lenses but this lens delivers the level of sharpness I was looking for. You can read the license plate on my car in the attached picture which is pretty solid. With a 10% off Best Buy coupon code, Best Buy credit card credit plus Best Buy Elite Plus membership points, and a $100 Canon rebate, you can't beat the price. I hope to buy more lenses this way in the future.

Exceptional image quality. Great landscape lense. Way better value than the f2.8, without losing that much low light function- can tripod and shoot slower speeds. Image below was a 20 second exposure with ND filter. Using on Canon 6D mii.

OK, it's not true macro but it has a very short focus distance. This allows for macro like photography with a wide angle lens. At f4 the lens have nice bokeh still. Colors are great, very sharp across the zoom range, and build quality is top notch.

I do a lot of club photography and this is my favorite lens for it. People are so amazing with how close I can be to them and get practically their whole body!