Coming soon: RF15-30mm F4.5-6.3 IS STM and RF24mm F1.8 MACRO IS STM

pknittel wrote:

Sittatunga wrote:

But that also means that, while you lose some of the least important part of the image, it's probably a lot less than 15% of the whole image. I'll put up a proper illustration tomorrow, when I've finished tracing it.

For landscape shots, corners are not necessarily the least important part of the image. They can often be the most important parts of the image.

The issue I have is that when you correct for extremely heavy barrel distortion, you necessarily lose pixels and resolution. Your 45MP sensor becomes a 38.25MP sensor with a 15% loss.

The main reason why I have an issue with this is that this level of stretching should not come to a L lens, priced as expensive as it is. If I'm buying L lens on a high-resolution full-frame camera for landscape shots, you bet I absolutely want the best resolution possible, including at corners; and this lens fails to function as a "working" lens: it does not cover the sensor.

Read https://www.dpreview.com/forums/post/66332650 for some background to this post. This is a comparison of what correcting the wild distortion of the RF 16mm prime does compared with the mild distortion of the EF 16-35mm f/4 at 16mm, all 1:1 crops from two images taken at f/4 with different processing. I've Just shown crops from one end and one corner as that's where the differences you're worried about will show up most. The pebble-dash panel gives some fractal detail and the tiled columns show up any distortion better than a brick wall. Don't forget that the prime lens is a third of the price, size and weight of the zoom.

Original photo from the prime lens before distortion correction

EF zoom, top left, DPP4 with DLO & distortion correction

RF prime, top left, DPP4 with DLO & distortion correction

RF prime, top left, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, purple fringing correction and distortion correction, 3:2 crop

RF prime, top left, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, purple fringing correction and distortion correction, unconstrained.

RF prime, top left, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, purple fringing correction and Deep Prime, NO distortion correction

EF zoom, end, DPP4 with DLO & distortion correction

RF prime, end, DPP4 with DLO & distortion correction

RF prime, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, purple fringing correction and distortion correction, 3:2 crop

RF prime, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, purple fringing correction and distortion correction, unconstrained.

RF prime, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, purple fringing correction, NO distortion correction, unconstrained.

Yes, the car does look better with the barrel distortion left in, but thats what you get when you look at a bulbous object at the edge of an extreme wide-angle rectangular projection image. For completeness, here are the DxO end crops from the zoom.

EF zoom, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, NO distortion correction, unconstrained.

EF zoom, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, and distortion correction, unconstrained.

EF zoom, end, DxO PhotoLab5.3 with Smart Lighting, ClearView Plus, Deep Prime, and distortion correction, 3:2 crop.