Okay, I know this is beating a dead horse as a matter of fact, the horse has been beaten to death, dragged off, and turned into glue already. But when I saw this patent application from Sigma today, and tossed it over to Craig, his response was “Well, don't expect Canon to ever do a lens like that” to which I agree. Canon has an aversion to doing nice things for APS-C and seems to think that high-end lenses for APS-C should be rare things that happen once a decade if not longer. For example, Canon did exactly one high-end lens the EF-S 17-55mm F2.8 in 2003 and followed it so quickly that it stunned the industry with an EF-M 32mm F1.4 in 2018.
When I was rocking the EOS-M my portrait lens was not Canon, but Sigma. The 56mm was a stunning lens that Canon had no answer for and didn't consider the APS-C platform worthy of such a lens. Even with the RF-S system, if you want a small portrait lens, use the 50mm F1.8 and consider yourself lucky, peasant. Don't expect Canon to release lenses specifically tailored to your system – expect to have to compromise, but that's not necessarily a bad thing, especially for longer focal lengths.
I would be remiss if I didn't mention that small full-frame lenses that use digital image stretching to fit a full-frame image circle are usually very good on APS-C, perhaps even better than on full-frame cameras because they don't have to do as much digital manipulation. So I have to be honest here, lenses like the 16mm F2.8, 24mm F1.8, and 28mm F2.8 are uniquely suitable for the RF-S platform, and lenses like the 35mm F1.8 and the 50mm 1.8 find new uses on the RF-S platform from their traditional use cases on full frame.
So it's not all doom and gloom for RF-S users, however, in total Canon practice, Canon does a very bad job of explaining this to novices. Instead of selling kits with these lenses or even a white paper or video, etc. Canon is mute on this and there's a segment of the user base that doesn't read this article (shocking, I know) or online reviews that would detail this (and most reviews don't detail or suggest using these lenses primarily for APS-C either, users are assumed to know this fact because we are all old boomers that cut our teeth on EF-S.
As a step-up system, RF primes are a unique way to transition from cheaper RF-S systems to a full RF mount full frame system. So this needs to be explained better. But to be fair, the crop factor gets in the way, and even Canon's widest cheap prime the 16mm F2.8 is 26mm on a Canon RF-S camera.
So why am I griping about a Sigma Patent Application then? Well, this Sigma patent details 10mm F1.4 lens. This is a lens that would never be done by Canon for RF-S and a 6mm F2.8 full-frame lens would be both ridiculously large (if it's even possible) and insanely costly. Is this an APS-C lens that Sigma will develop? It has all the hallmarks of a lens that most certainly Sigma will develop for the Nikon, Sony, and Fuji mount since Sigma already has a wide array of F1.4 APS-C lenses. This would make it 3 prime lenses that are wider than any Canon prime for APS-C (10, 16, and 23mm), and RF lenses with those equivalent full frame focal lengths, would be prohibitively more expensive than APS-C counterparts. We won't even get into their nice compact APS-C 10-18 F2.8 and 18-50mm F2.8 either.
Now there are rumors that Canon is relenting with Sigma and Sigma is expected to come out with lenses for the RF mount “soon™“, but there's no communication from Sigma and no communication from Canon still on how or when this is to occur.
Here is hoping that Canon ends this silence during CP+ or sometime shortly as it serves no purpose to Canon and creates more uncertainty about the future of the platform. Canon's EF mount enjoyed a vast array of third-party lenses, RF needs to follow. With recent Sigma announcements, I have slowly turned my eye back to Fuji's APS-C line-up to see what is happening over there, even though I have a very high degree of resistance to any camera not made by Canon. I know that some readers will state that this subject has been talked about for the past 2 or so years, but that's part of the problem. We users have been doing the talking, no one else is filling in the details.
Canon sliding to 2nd in mirrorless in Japan, and not even placing in the top 3 of lens sales in Japan indicates that even though Canon may enjoy a fantastic market share and excellent profits, that can quickly turn on them – ask Nikon about that.