ChrisLeong
Active member
Just when my EFS17-55F2.8 broke down, this news is like music to my ears..
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Sigma RF-S lenses
- Thread starter Henri P
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2ndact scene1
Veteran Member
Early this year, I had an R50, which I really liked. But I needed lenses with faster apertures than the nascent RF-S portfolio offered and I could not get comfortable with the age, and weight of the EF-S 17-50mm f/2.8 (apologies if I am a little off on the focal lengths). For a number of reasons, I ended up going to Olympus, which I am pretty happy with. If the Sigma APSC lenses for the RF mount been announced a year ago, I might have invested more in the R series crop sensor line of cameras.
Ironically, I just bought the Sigma 56mm f/1.4 lens for the micro 4/3 mount. I am delighted with the image quality but on my first two outings, autofocus has been a little slow. I am also seriously considering the Sigma 16mm f/1.4. So all I can say at this point is that Sigma can produce high quality crop sensor lenses. The advantage of the M4/3 mount is that once a company joins the M4/3 governing organization, they get access to all electronic and physical aspects of the mount. I asume the L mount is similar. In contrast. CANON, NIKON AND Sony have proprietary mounts and Sigma has to negotiate agreements with each and then work on adaptability. Results are therefore not as predictable.
R2D2
Veteran Member
Yup, it's all a game of Leap-Frog! Sometimes immediate needs outweigh the long-term.
Hmmm, interesting to hear. My Sigma EF-M 56mm f/1.4 (as well as my EF-M 16mm f/1.4) are very good AF performer on my M6 Mark II. May be a different design entirely tho.
I do suspect that AF on these Canon bodies might be better however.
But that's exactly what Sigma just did with Canon. I suspect/expect they'll perform up to their full potential.
We'll just have to see.
R2
Steve Balcombe
Veteran Member
Had an email from my local bricks-and-mortar today - if I still want the Sigma 18-50 they've got them in stock. July 11, bang on time! So I pootled down on my bike and picked it up, a much nicer experience than waiting in for a delivery.
I have one on pre-order so I'll be able to add my less-qualified comments soon. Sigma has published a launch date of July 11, but when I enquired at the end of last week my supplier here in the UK didn't have a delivery date as yet.
First impression is great. Zoom action is nice. Manual focus is fly-by-wire obviously, but the feel is OK with just enough damping. And image quality looks fine but I won't be able to test it properly until next week.
An issue which hasn't come up in the discussion is that there is no AF/MF switch. This is fine on the R7 because there's a switch on the body, but (while I haven't checked) I don't think the other 'RF-S' bodies have one. (Edit: Correction, the R10 has one, but the R50 and R100 don't.)
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2ndact scene1
Veteran Member
They simply 'outsourced' the development of lenses for the aps-c rf cameras.
Why should they restrict anything.
Canon's company camera strategy is to obvious.
I’ve just watched the Damien Bernal video - an interesting point is made at 3:30. It is possible to set the FOCUS ring to control EXPOSURE via the camera menu (AF TAB 6). So if you’re using AF and don’t need MF adjustments, you can effectively have a control ring with exposure compensation instead. This replaces a focus/control switch on the lens and may be useful for bodies with fewer controls.
He also shows that focus breathing correction for this lens can be turned on for video. Another useful feature I don’t think any of the English speaking reviewers have commented on.
He also shows that focus breathing correction for this lens can be turned on for video. Another useful feature I don’t think any of the English speaking reviewers have commented on.
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R2D2
Veteran Member
I have a friend who is champing at the bit to get that Sigma 56! If it's anything like the EF-M lens, it'll make a much better portrait lens than the Canon RF 50/1.8 IMHO.
R2
Yes I saw this too. This confirms the extent of Sigma's compatibility with the R mount.
Other reviewers focus more on handling and IQ, which of course is useful, but concerns only this specific lens. Damien's report is more general, and indeed good news for Canon R users. He is an excellent reviewer, borrows his gear from a reseller, so he has no affiliation to any brand and can speak freely (and I'm not saying others can't). I recommend him to those who understand French. Maybe Google can subtitle his videos in English.
Now I wonder if there will be a way to convert existing Sigma EF lenses to RF. This should be technically possible, if only to get rid of the adapter. Sigma claimed that you could change the mount on their lenses, but this was at the time of DSLRs.
Can you develop?
Sittatunga
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I wouldn't want to; there would be no size saving over keeping an adapter on the lens, the conversation service costs around there times the price of the plain adapter (1½× the price of the control ring adapter) and (for my country at least) takes weeks as it's done in Japan. Of course, it would also rule out the use of the rear filter mount adapter on my only Sigma lens. That's important to me because that lens won't take front mounted filters.
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It also means that either Sigma have given their lenses’ optical characteristics data to Canon, or that Canon have measured them, in order to apply optical and focus breathing corrections. This shows close collaboration and bodes well for future RF mount lenses from Sigma.
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Sigma RF-S 18-50 IQ comparisons now on Canon R7 (previously on Sony only). I was interested to compare to the RF-S 18-150 which I have. My conclusion - Canon at 18mm f3.5 vs Sigma f2.8 or f4, the Canon is slightly better at peripheries. From f8 both similar. At 35mm, Canon at f5 markedly softer, little improvement at f8, Sigma very good at f2.8 and much better at f8. No other directly comparable focal lengths unfortunately.
Also comparing the Sigma on R7 vs Canon EF-S 17-55/2.8 on 7D2, though a different image scale, the Sigma appears significantly better at every setting.
Also comparing the Sigma on R7 vs Canon EF-S 17-55/2.8 on 7D2, though a different image scale, the Sigma appears significantly better at every setting.
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That makes sense...
R2D2
Veteran Member
Thanks for this. Do you know if corrections were applied to the Sigma images? I'd think that they would be to the Canon.
R2
He doesn’t say specifically. But I think we’ll see an updated review for the Sigma on a Canon body, and Canon does provide in-camera corrections (in the menu) for the Sigma. Brian Carnathan does respond to emails so it may be worth asking.
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Sittatunga
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I don't think they do, by now the corrections are generally stored in the lens so that the cameras don't need to be updated every time Canon bring out a new lens. Sigma had to do a lot of reverse engineering around 2015-16 to get rid of those concentric rings that appeared with some of their lenses when Peripheral illumination correction was enabled. Canon may well have told Sigma how to encode the in-camera corrections properly now, but I'm sure those corrections are provided by Sigma, not Canon.
R2D2
Veteran Member
Lens correction data sits on the lens, so the collaboration here is same as that for AF. Sigma know what to do (as part of whatever spec/protocol they have been privy to as part of the deal with Canon) and they are doing it as part of their product development
See https://www.canon-europe.com/pro/infobank/in-camera-lens-corrections/
Sigma did the same in their more modern EF lenses, only that time they had to reverse engineer the lens correction data, and was limited to basic distortion correction only
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