I think Sigma lenses like the 35mm 1.4 Art II for ~1000€ would sell like crazy on the RF mount. So my guess would be that Canon is in fact asking for a licensing cut that is simply too greedy for it to be a profitable business proposition for Sigma.

I think currently the best mount is Z!
You can use Z, F, EF and FE!

And Sigma has already the data for the mount re-engineerered…. Go Sigma Go!!

justaCanonuser said:

According to CIPA, the RF version has a tad better IS, but in real life it shouldn't make any noticeable difference. I have the EF 600mm f/4.0 III, and I love this lens, its IS is quite impressive. Btw the mk II lens, which still was based on the conventional tele lens design with many big lens elements on the lens' front, is said to be a bit sharper. But it is heavier and on top more front heavy than the mk III lens, so shooting it hand-held is harder.

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My EF 800m f/5.6 gave great photos but due to the size I got rid of it (not helped with arthritis in my wrist). The big zooms are great for what they are but the majority of us can't afford them - I got a great deal on a 2nd hand 800mm, but have never seen the 600mm mkIII 2nd hand here in Oz so buying brand new is out of the window.

justaCanonuser said:

I have an RF 200-800, too, for occasions when I want a lighter lens and the flexibility of such a zoom. It is a real fun lens and sharper @ 800mm than I expected, but of course my 600mm prime is much sharper, even with 1.4x TC my EF 600mm f/4.0 III delivers noticeably sharper images @ 840mm. That said, in real life photography, what is more important than lab tests, the 200-800 performs very well, much better than its specs promise. There is only one drawback: from comments I learned that obviously lenses with different quality are out in the wild - I was lucky to get a really good copy that is quite sharp @ 800mm.

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I'm going to give the RF 100-500mm a try with the 1.4 extender and see how that goes. I think the 200-800mm is a great lens if you're happy to live with it's limitations (fantastic value for most). Agree that it seems there's a variance with the quality of the 200-800mm's out there, but unfortunately for it's price point that's one of the issues have to live with (if you get a good one then bonus).

justaCanonuser said:

One advantage of zooms is when you shoot birds in flight, you can catch it using a shorter focal length and then zoom to longer focal lenghts. With a about 800mm prime it is a real challenge to find the bird in the viewfinder.

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Zooms have so much more flexibility that if the image quality is at an acceptable level then would always go for them (of course primes still have their place). Having had a 800mm totally agree that's it's bloody hard to catch a BIF, unless it's far away which then defeats the purpose of having a large prime.

A couple of youtubers here in Oz took out the 200-800 for a spin when it first came out and did a great video on the benefits of the zoom. Yes, it needs a few turns to go from 200-800 but just the fact having the flexibility meant they could shot birds close up, but then catch BIF's at a greater distance.

AlanF said:

It’s not just the frame rate that Sony limits on Sigma and other makers but also it prevents the use of teleconverters.

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That's a key point, most users of a 600mm f4, want the flexibilty of a sharp and convienient (relatively) 800mm f5.6, ie popping on a 1.4x TC. If the native lens isn't particularly sharp wide open at 600mm, what's it going to be like with a 1.4x tc? I'd never buy lens like a 300-600mm and then prat around with it at the wide end becuase that's where it's sharp. Surely it's long end performance that matters.

jeff89 said:

I like many would buy the Sigma 300-600 f4 and personally, the Sigma 135 f1.4 Art (I have the EF 135, RF 135 and Sigma EF 135 Art) and would pair it with my Sigma EF 105.

I wouldn't pay Canon's price for the RF 100-300 f2.8 before the tariff increase, as I have the Sigma EF 120-300 2.8 and I won't pay for the Canon RF 300-600 f???, as is would be a want and not a need. I have 2 of the EF 200-400 f4 1.4x, the EF 300 f2.8 and the EF 400 f4 DO and I refuse to pay over $11,000 for a lens, but at $6599 for the Sigma, I would buy that, provided it integrates well. Sony limits the AF speed on it, so I won't buy the Sony version. In fact, I was seriously considering the Lumix S1 II, or maybe the S1R II given the alliance and the fact that it is optimized for the Lumix.

I will hold off for now, to see if they release it for the RF mount, if it doesn't happen, then I will buy a Lumix down the line and begrudge Canon for it.

Oh, and I know a retired Canon USA exec, I never asked for any scoops, I didn't think it was appropriate, but was told, "Pay attention to Canon Rumors." So you might have more pull than you know

​

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Wow! You have a lot of 135mm primes. Are they not suffient in some way or are you curating a personal collection? That's a lot of investment into a lot of very similar glass.
The RF 100-300/2.8 is vastly superior to the Sigma 120-300/2.8 OS in every regard. With both lenses, you are getting what you pay for. Please don't be deluded in thinking that your bargain Sigma is the equal to the Canon, it simply isn't.

It’s not just the frame rate that Sony limits on Sigma and other makers but also it prevents the use of teleconverters.

"The RF Mount is Complex" - i don't think that's the reason at all. Cannot be much different from RF-S (probably identical) and Sigma made lenses for that. I simply think they put some conditions on third party full frame RF licensing that takes longer or not worth it for Sigma.

mclaren777 said:

I would gladly buy the Sigma 300-600mm if they released it in either EF or RF mounts.

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Why? Because it's new? Sure it's kind of cheap. It looks a bit like an L lens but it doesn't perform like one. If the price point is your concearn and a 600mm f4 is your goal there are plenty of superior options.

Canon Rumors said:

I think it all has more to do with Sigma not being able to manufacture to the scale required. People grossly overestimate how many lenses SIgma sells.

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I'm not a buyer for this. No business would fail to enter a profitable segment because they were worried they might be too successful. Supply and demand will sort it out - if there's too much demand put the prices up until there's not. Over time increase your production capacity with the profits and cut prices.

Canon Rumors said:

We now know that it has nothing to do with Canon. There will still be the naysayers, but it doesn't matter what you tell some people.. the vacuum can be strong.

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I don't think we know that. We know that Canon say that they're not stopping third parties from making full frame RF lenses. That doesn't mean that they're not making it difficult in other ways - one example being in the way you describe of not giving them information about how to implement the RF mount. There's always more to these things.
My guess would be that the lenses that Sigma and Tamron have that are full frame are not suitable for some technical reason for a direct mount swap to RF - they need some sort of re-engineering. I'd guess they did the ones that were easier first, which is the APS-C lenses for some reason. Or perhaps they're the ones they thought they'd get more volume/profit from for some reason (maybe because Canon's lineup was weak, and because APS-C buyers might be seen as more price sensitive and so more inclined to buy third party).

dolina said:

Sigma lenses I'd want to see on RF mount

- 35mm f/1.2
- 15mm f/1.4
- 28mm f/1.4
- 135mm f/1.4 (I'd get this)
- 28-45mm f/1.8

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Sigma has so much great glass, and they just keep bringing out more. Sadly no 28/1.4 yet but recent patents for a 24/1.2 and 28/1.2 look interesting.

Tamron also have some amazing lenses in their lineup. Their 35-150/2-2.8 is a stunner of a lens. Their 50-400 is also great. Their f2.8 zooms are priced not much more than Canon's budget zooms but perform at 90% of L glass if not 95%.

jeff89 said:

The way it was presented was that Sony cut the AF speed and max frame rate for the Sigma lens (diabolical), keeping peak performance restricted to their GM lenses. Although, it may be in the secret sauce and Sigma has to backwards engineer it like with Canon, and they just couldn’t optimize for the Sony mount,, what the lens is capable of, like they can for Panasonic. With Sigma, Panasonic and Leica making up the L alliance, presumably Panasonic shares the recipe with Sigma, so the Lumix can take maximum benefit of the lens. Or as you suggested, provide the necessary juice with their batteries to drive the AF on the Lumix, like the new batteries required to take full advantage of the R5 II.

I like the idea of a 300-600 f4 in Africa or on the Amazon, especially on a 40-50 MP sensor. Apparently the AF is quicker on the Lumix S1 II, than the S1R II, so that was my reservation with limitation of 24 MP on the S1 II. My thought is by the time Lumix releases the S1R III, the AF and pre capture will be fast enough that I am the rate limiting step, not the camera, that’s where I think I am at with the R1 and R5 II.

The folks I was with, were shooting Sony A1 or A9, or Nikon Z8 or Z9, the Canon guys were shooting the R1 and R5 II. They were all doing better than me with the R3 and R5, particularly on the Amazon, small targets at a distance, locking AF was markedly better on my roommate’s R5 II.

I had just gotten the R5 II, but hadn’t used it, and prior experience heavily suggested that the first time shooting a camera is best not reserved for a trip, no muscle memory and searching the menu, because it is not like your other Canon results in a lots of missed shots for me. I love the R3, but the improved AF in the R1 and R5 II, and pre capture are game changers for wildlife as far as I am concerned. That’s why I want an R7 II, one of the prints from Africa that I printed for my living room went below the 300 dpi once I went above 24” x 36” and it’s on a wall were you can walk right up to it, so people aren’t standing the “proper” distance were everyone says 24MP is enough. I was interested in the rumored R3 II, which I was hoping would have more MP’s than the R3, and obviously the improved AF and pre capture. I got the R1 with Canon’s last trade-in opportunity, but haven’t used it yet, 2026 is all underwater for me with the R7.

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Sigma don't reverse engineer for Sony's emount, they have an emount licence in Sony provides them access to mount protocols.

I spoke to a Sigma UK rep a few years ago at a trade show and he told me that Sigma are waiting on licences from Canon and Nikon in order to release FF lenses on both RF and Z mounts. I heard another Sigma UK rep say the same thing at the same trade show last year because people are asking them this question directly. To my knowledge that is Sigma's policy that they will only release lenses for mounts when the OEM provides a licence to do so. Canon and Nikon have both granted Sigma licenses for APSC but not FF, everyone make of that what you will.

Canon Rumors said:

We now know that it has nothing to do with Canon. There will still be the naysayers, but it doesn't matter what you tell some people.. the vacuum can be strong.

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That is a MASSIVE overstatement.

If we assume the translation from the original Japanese to French was accurate (which given my over 30 years of business experience in Japan, is hilariously FAR from a given) then all he really says is that Canon will not comment on this, and that by extension the current views are based on an outside perspective. That's it. You cannot take his statement and invert it to conclude that he is also saying the opposite (that Canon has already allowed Sigma to make RF lenses but Sigma is not doing so.) This isn't math where you can say that because 2+3=5 that 5-3=2.

From a business perspective, of course Sigma would want to be making FF lenses on RF mount. Right now Sigma are almost entirely reliant on E mount sales to support their business. If something changed at Sony (such as a dispute between Sigma and Sony or a strategic change that resulted in Sigma no longer having an E mount license), it would tank most of Sigma's business. They have all their eggs in one Sony-sized basket, and that is NEVER something a company wants to be dealing with. Even if releasing FF RF lenses meant selling fewer E mount lenses due to production constraints, it would still be the smart business decision. Same goes for Z mount.

In the not so distant past, Sigma sold a truckload of ART, SPORTS, and Contemporary lenses for EF and F along with A and K. At the same time they started selling SLR designs with flange adapters onto E and L. And while doing all this, they were also developing new mirrorless-native designs for E and L. This all happened in an era where more cameras & lenses were sold than today. It's bizarre to think that Sigma is some tiny company that couldn't handle RF sales. They sold a lot more lenses in the past than they do today.

The only things we know for fact are:

1. Viltrox and Samyang released FF AF lenses for RF and Canon made significant enough legal threats to both companies that they not only removed the lenses from sale but they also completely removed all mention of them from their websites. They don't even officially provide support (firmware updates etc) for past RF lenses.

2. Currently there are exactly zero third party companies making FF AF lenses for RF. None. Not in China, not in Korea, not in Japan.

3. Both Tamron and Sigma sell RF-S lenses but neither has made any FF RF lenses. While you might say Sigma is a small family owned company (I disagree with the "small" part), Tamron is not. They are a publicly traded company that is already making FF lenses for Z mount.

That is all we know. The most reasonable conclusion from this is still the same conclusion people have drawn all along: Canon is not allowing third party AF glass onto FF RF mount.

Personally I don't think Canon will ever willingly allow FF AF glass onto RF.

Just collected my copy of the 14mm 1.4...quick brick wall test and can confirm (corrected) straight lines are very straight and corners look good at 1.4 (except for noise due to brightening of the corners via correction).

Flatter field and sharper corners wide open compared to my Sigma 14mm 1.8 (which itself was a very good copy tuned by a tech at Sigma Japan).

If only I had this lens when I went Aurora chasing in Norway end of last year lol.

Hopefully head out over the next few weeks to get some Milky Way shots if weather and time allows...

Have You tested the lens with TC on a DSLR? Might be a software problem EF/RF as the RF TC works without problems. And it is unlikely both EF-TC fail at the same time.

homebodyMacro2 said:

Looked up a 4TB crucial external drive I got about 6 months ago... it's cheaper than competitors still, but nonetheless roughly doubled in price since I bought it. Probably would have bought a 2nd at the original price.

But don't worry! Somewhere, right now, some executive is gloating about how AI is going to change everything, despite having exactly zero knowledge about what it does or doesn't do. And the 3 global memory manufacturers surely lament that there is infinite demand for memory for servers that aren't built yet, for datacenters that don't yet exist and for which no power generation is available, to run AI models that simply compress internet text with no system design intent, serious use case, or path to profitability.

All consumer electronics (cameras very much included) will be affected for years to come.

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I agree that CE will be affected for years, but for a different reason than the implied shortage. The continuation of the AI boom is dependent on continued financing and so far a lot of the money is flowing in a loop (or not flowing at all). Nvidia invests in an AI company and then the AI company agrees to buy Nvidia GPUs, but as you say, there is no power to run the beast. They hype causes gullible investors to throw money at the AI company and by association at Nvidia, which has a completely ridiculous market cap. The timeline is too long for investor patience to last, even if there is some magic application out there that could eventually produce enough revenue to fund the monster. When the house of cards collapses, the dot com bust will look like child's play and the ensuing recession will have an effect on CE for years to come. Take pictures and invest wisely.

Looked up a 4TB crucial external drive I got about 6 months ago... it's cheaper than competitors still, but nonetheless roughly doubled in price since I bought it. Probably would have bought a 2nd at the original price.

But don't worry! Somewhere, right now, some executive is gloating about how AI is going to change everything, despite having exactly zero knowledge about what it does or doesn't do. And the 3 global memory manufacturers surely lament that there is infinite demand for memory for servers that aren't built yet, for datacenters that don't yet exist and for which no power generation is available, to run AI models that simply compress internet text with no system design intent, serious use case, or path to profitability.

All consumer electronics (cameras very much included) will be affected for years to come.

Dragon said:

When you say "Sony limits the AF speed", is that a diabolical move on Sony's part or is the Sony system simply incapable of providing enough current to run the AF at full speed? I suspect that more often than not, the issues we discuss as if they were marketing decisions are actually engineering limitations. Much the same as the Canon "cripple hammer". A budget was set for a product, and engineering may well have done the best they could with that budget. We may not like the choice of tradeoffs, but the decisions may well have been as much or more engineering decisions as they were marketing decisions.

Click to expand...

The way it was presented was that Sony cut the AF speed and max frame rate for the Sigma lens (diabolical), keeping peak performance restricted to their GM lenses. Although, it may be in the secret sauce and Sigma has to backwards engineer it like with Canon, and they just couldn’t optimize for the Sony mount,, what the lens is capable of, like they can for Panasonic. With Sigma, Panasonic and Leica making up the L alliance, presumably Panasonic shares the recipe with Sigma, so the Lumix can take maximum benefit of the lens. Or as you suggested, provide the necessary juice with their batteries to drive the AF on the Lumix, like the new batteries required to take full advantage of the R5 II.

I like the idea of a 300-600 f4 in Africa or on the Amazon, especially on a 40-50 MP sensor. Apparently the AF is quicker on the Lumix S1 II, than the S1R II, so that was my reservation with limitation of 24 MP on the S1 II. My thought is by the time Lumix releases the S1R III, the AF and pre capture will be fast enough that I am the rate limiting step, not the camera, that’s where I think I am at with the R1 and R5 II.

The folks I was with, were shooting Sony A1 or A9, or Nikon Z8 or Z9, the Canon guys were shooting the R1 and R5 II. They were all doing better than me with the R3 and R5, particularly on the Amazon, small targets at a distance, locking AF was markedly better on my roommate’s R5 II.

I had just gotten the R5 II, but hadn’t used it, and prior experience heavily suggested that the first time shooting a camera is best not reserved for a trip, no muscle memory and searching the menu, because it is not like your other Canon results in a lots of missed shots for me. I love the R3, but the improved AF in the R1 and R5 II, and pre capture are game changers for wildlife as far as I am concerned. That’s why I want an R7 II, one of the prints from Africa that I printed for my living room went below the 300 dpi once I went above 24” x 36” and it’s on a wall were you can walk right up to it, so people aren’t standing the “proper” distance were everyone says 24MP is enough. I was interested in the rumored R3 II, which I was hoping would have more MP’s than the R3, and obviously the improved AF and pre capture. I got the R1 with Canon’s last trade-in opportunity, but haven’t used it yet, 2026 is all underwater for me with the R7.

Sigma lenses I'd want to see on RF mount

- 35mm f/1.2
- 15mm f/1.4
- 28mm f/1.4
- 135mm f/1.4 (I'd get this)
- 28-45mm f/1.8

Ran across this one in my archive. I've seen many GBHs, but not very many GBH tongues.

"Say Ahhhhhh"

EOS 1D X, EF 600mm f/4L IS II USM, 1/2500 s, f/10, ISO 8000

Great shots, ISv. I especially like the first one.

Sigma should also produce a few tiers of microphones, on-camera flashes, and dual chargers for Canon users alongside their lenses. Canon might even consider selling the R5 Mark III or R7 Mark III without accessories altogether. Maybe Sigma can finally free us from that thing called “Picture Style.”

jeff89 said:

I like many would buy the Sigma 300-600 f4 and personally, the Sigma 135 f1.4 Art (I have the EF 135, RF 135 and Sigma EF 135 Art) and would pair it with my Sigma EF 105.

I wouldn't pay Canon's price for the RF 100-300 f2.8 before the tariff increase, as I have the Sigma EF 120-300 2.8 and I won't pay for the Canon RF 300-600 f???, as is would be a want and not a need. I have 2 of the EF 200-400 f4 1.4x, the EF 300 f2.8 and the EF 400 f4 DO and I refuse to pay over $11,000 for a lens, but at $6599 for the Sigma, I would buy that, provided it integrates well. Sony limits the AF speed on it, so I won't buy the Sony version. In fact, I was seriously considering the Lumix S1 II, or maybe the S1R II given the alliance and the fact that it is optimized for the Lumix.

I will hold off for now, to see if they release it for the RF mount, if it doesn't happen, then I will buy a Lumix down the line and begrudge Canon for it.

Oh, and I know a retired Canon USA exec, I never asked for any scoops, I didn't think it was appropriate, but was told, "Pay attention to Canon Rumors." So you might have more pull than you know

​

Click to expand...

When you say "Sony limits the AF speed", is that a diabolical move on Sony's part or is the Sony system simply incapable of providing enough current to run the AF at full speed? I suspect that more often than not, the issues we discuss as if they were marketing decisions are actually engineering limitations. Much the same as the Canon "cripple hammer". A budget was set for a product, and engineering may well have done the best they could with that budget. We may not like the choice of tradeoffs, but the decisions may well have been as much or more engineering decisions as they were marketing decisions.

I don't know if @foda has success with the Orange-cheeked Waxbill but today I didn't (~40 min. searching). Took just few photos of House finch (two different males separable not only by the color: different amounts of dirt on the bill ! They did choose the same broken branch for posing. I still have no photo of House finch with yellow instead of orange/red colors on the head, despite seen few!

This is what shows up on my R1 with lens that forces distortion correction attached (not as obvious in the iPhone pic, but the Distortion correction option is grayed out):

AlanF said:

A Little Grebe was trying to swallow a fish that was too large. It bit off its head, a gull swooped to steal the fish, and the Grebe dived faster than a U-boat (R5ii + RF 200-800mm).

View attachment 228683View attachment 228684View attachment 228685

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Nice photos/story with happy ending . I don't like the gulls when they behave like kleptoparasites! On other hand I have a lot of fun watching videos of them stilling from people on the beech