# Gordon Liang review RF 16mm f/2.8



## Chaitanya (Nov 16, 2021)




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## koenkooi (Nov 16, 2021)

The big takeaway: the mechanical vignetting is worst at MFD, gone at infinity.


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## neuroanatomist (Nov 16, 2021)

koenkooi said:


> The big takeaway: the mechanical vignetting is worst at MFD, gone at infinity.


Focus breathing. That’s why I raised the issue in the other thread, and why I tested distortion correction of the RF 14-35 by filling the frame with the side of a 9-story building, not a test chart or brick wall a few feet away.


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## Frodo (Nov 20, 2021)

Very positive review. Similar sharpness to RF14-35mm, even in corners, but not quite as good as RF15-35mm. Coma didn't seem to be a big issue. It annoys me that the lens is USD 490 in New Zealand.


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## Frodo (Dec 17, 2021)

I bought an RF 16mm. Here are my observations following some testing:
- Sample variation can be significant. I shot jpgs with two RF 16mm's in the shop and compared the jpgs on my laptop. One was noticeably sharper than the other across the frame at f/2.8 and f/4. I looked more closely when I got home using a split screen on my monitor and this confirmed what I'd seen on my laptop in the store. There did not appear to be any inaccurate focusing in the softer lens. I experienced the same comparing two RF 50mm f/1.8 lenses.
- Raw files converted in DPP and imported as tiffs into Lightroom are significantly sharper than in-camera jpgs imported into Lightroom. For critical subjects its worth processing in DPP.
- I shot some test charts on the side of my house. There is a noticeable improvement stopping down to f/4. F/5.6 is still a little sharper.
- I compared the RF 16mm against my fully manual Samyang EF 14mm f/2.8. The Samyang is noticeably sharper and has noticeably less colour fringing than the RF lens. The difference is (not surprisingly) greatest in the corners. The RF 16mm stopped down to f/4 is still not as good as the Samyang wide open.
- I tried to manage my expectations, but I had hoped that the RF 16mm at f/4 would match the Samyang at f/2.8. That is clearly not the case. It remains to be seen if the RF16mm is usable as an astrophotography lens. I might be able to test this tonight as we will have clear skies, but an almost full moon. I am particularly interested in coma.
- As you will already know, the RF lens is much, much smaller and lighter than the Samyang, especially with adapter. It also focuses much closer. See the photo of an isopod on our beach.
- So overall, I am sure that the RF 16mm will get a lot more use than the Samyang 14mm. It is a perfect complement to my RF 24-105 f/4L, especially when I go hiking. But it looks like I will be keeping the Samyang for astro photography.


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## gruhl28 (Dec 17, 2021)

Frodo said:


> I bought an RF 16mm. Here are my observations following some testing:
> - Sample variation can be significant. I shot jpgs with two RF 16mm's in the shop and compared the jpgs on my laptop. One was noticeably sharper than the other across the frame at f/2.8 and f/4. I looked more closely when I got home using a split screen on my monitor and this confirmed what I'd seen on my laptop in the store. There did not appear to be any inaccurate focusing in the softer lens. I experienced the same comparing two RF 50mm f/1.8 lenses.
> - Raw files converted in DPP and imported as tiffs into Lightroom are significantly sharper than in-camera jpgs imported into Lightroom. For critical subjects its worth processing in DPP.
> - I shot some test charts on the side of my house. There is a noticeable improvement stopping down to f/4. F/5.6 is still a little sharper.
> ...


I bought one too. I haven't had a chance to shoot much yet, but I agree that, despite what we've seen in resolution charts in some reviews, the corners do get noticeably sharper as you stop down. All the talk about the corners staying the same because they are "made up" data or because of the distortion correction are incorrect. Maybe at very close distances the corners don't sharpen much, I haven't tested that yet, but at longer distances they do sharpen up. I did a quick comparison to the 10-22 APS-C lens at 10mm f/3.5 and they seem roughly comparable, but I need to compare more carefully to be sure of the results.


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