What is the best landscape lens recommendation for Canon EOS R5?

Question

So Ive been shooting with Canon for like twelve years now and I finally bit the bullet and upgraded from my 5D Mark IV to the EOS R5 last month. I thought it would be a seamless transition using my old EF 16-35mm f/2.8 II with the adapter but man I am just getting so frustrated with the results. The 45MP sensor is absolutely brutal on my old glass and the edge softness is driving me crazy when Im looking at my landscape shots on a big monitor. I tried the RF 24-105mm f/4 that came with the kit but it feels like it lacks that punchy contrast I need for professional prints. Im planning this huge bucket list trip to the Dolomites in three weeks and I really dont want to spend the whole time worrying if my files are gonna be sharp enough when I get home. I have about 2500 bucks to drop on a dedicated landscape lens and I cant decide if I should go for the RF 15-35mm or if there is some prime I am overlooking that handles the high res better. People say the zoom is great but is it actually sharp corner to corner at f/8? Or should I just suck it up and carry a couple of primes to get the most out of this body... what are you guys actually using that doesnt fall apart at the edges?

69Battle · Accepted Answer

Honestly, I was in your exact shoes last year before a trip to Glacier. I was so worried about the R5 sensor showing every little flaw in my older EF glass, especially since I print large too. I ended up pulling the trigger on the Canon RF 15-35mm f/2.8L IS USM and Ive been incredibly satisfied. It is a bit of a chunky lens, but the contrast and color are just on another level compared to the mark II. I shot a bunch of wide mountain vistas and the edges are actually really clean once you hit f/8. A couple of quick things that helped me:Use the 2-second self-timer because that 45MP sensor is way more sensitive to tiny vibrations than the 5D ever was.Stay around f/8 for peak sharpness; you start to see diffraction earlier on this body than you might expect. The Dolomites are gonna look insane through that glass... totally worth it for the peace of mind.

Mashaelam7297 · Answer

Unfortunately, I had issues with the corner performance on the expensive zooms too. They were not as good as expected for professional prints. To fix this:

Use the Canon RF 14-35mm f/4L IS USM for more consistent edge sharpness.

Stop down to f/8 or f/11 for landscapes. Its frustrating that the R5 reveals so many flaws, but the f/4 version is actually the better deal.