rf 16mm 2.8 - Raw Images (Normal Distance + Closeup)

Karl_Guttag wrote:

crusliq wrote:

Hi,

I just shot some images of a wall with a lot of detail to see the sharpness level of each aperture. I also did this closeup with minimum focus distance (13cm).

The pictures are shot with my EOS R.

https://1drv.ms/u/s!Ap8Y3G8kon1Zgo52hcV6f4EDNVItyQ?e=Npt5wu

I dont't know if its normal that you have this black circle vignette at closeup distance?

My opinion so far:

- heavy barrel distortion

- sharp corners around f5.6 at normal distances

- good closeup sharpness in the center area

Thanks for giving links to the RAW files!!!

My impressions:

• The RF16mm barrel distortion looks nearly identical to the amount of barrel distortion the RF24-240 has at 24mm. I compared the curvature of the top of the wall versus mine of a test chart (after scaling my R5 shot), both using Adobe RAW with correction disabled. I also looked at the RF15-35, and it is vastly better (as one should hope with an L lens - some barrel but much, much less).
• The "normal" photo looks about like I would expect with that much distortion. You will lose about 1/2 the resolution for the pictures in the corners due to the amount of correction required.
• I notice there is very little improvement in sharpness in the corners with the "normal" distance photo between F2.8 and f8. I notice this with the RF24-240 as well. With that much image correction in the corners, the distortion and not focus is the main limiting factor.
• I did notice a big difference in illumination uniformity between f2.8 and f8. And yes, I double-checked, and DPP4 had peripheral illumination correction on, but in both cases, I used the "default" amount, and obviously, the f2.8 needs more.
• Wow, the closeup picture looks horrible from about 1/2 way out from the center. You don't even have to look at the picture magnified to tell it is a mess. It might be "field curvature," as in that focus varying from the center to the outside. It would be interesting to see what happens if your focus point was in one of the corners. Seeing this, I ran a quick check on my RF24-240, and when focused at the minimum focus distance and 24mm, and sure enough, it too looks horrible compared to "normal" distance shots. If the RF24-240 at 24mm focuses in the corner, the corner looks much better, but the center gets blurry. Probably best not to use either lens for closeups.

In Lightroom, use the RF 24-240 lens profile for the RF 16mm. It works quite well.