RF-S Lenses on Full Frame EOS R Bodies

[Bbarn]

Has anyone used one of the new RF-S lenses on an EOS R series full frame body?  I'm wondering how the IS and Focus/Control ring functions are controlled with no switches on the lenses. Doesn't seem clear in the full frame body manual since it's a new scenario (since all the FF lenses have lens switches).

[amfoto1]

The R10 and R7 crop sensor cameras, for which the RF-S lenses are designed, have the AF/MF switch on the body instead of the lens. Using the RF-S lens on a full frame R-series camera will need to enable a means of AF/MF control in the camera's menu. This is already there, since some of the full frame RF lenses also don't have an AF/MF switch. 

The control ring function assignment will simply need to be disabled if these lenses are fitted to any of the full frame cameras. Note that at least two of the full frame capable RF lenses... the 16mm and the 50mm f/1.8... have a control ring that becomes a manual focus ring at the switch of a button. Using those lenses in MF mode must also disable the control ring function in the camera.

User control of Image Stabilization also is in the menu of the crop sensor cameras, so will need to be there in the full frame cameras too, if these lenses are attached to the FF camera.

BUT IT MAKES LITTLE SENSE to use the RF-S lenses on any of the full frame R-series cameras. It's possible to do so, but the camera will "self crop" to APS-C format, which hugely reduces camera resolution. For example, the highest resolution R5 will be reduced to 17MP in APS-C mode, compared to 45MP in full frame. The low resolution R6 with only 20MP full frame will be reduced to less than 8MP when cropped to APS-C! 

It would be a big waste of those full frame cameras' capabilities to use them with an APS-C crop lens.

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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & ZENFOLIO 

[Tronhard]

Alan, agree with you - your latter point was one I also made and that alone, to me, precluded any idea of putting an APS-C lens on a FF body, especially given the availability of comparable FF lenses that will do the job and retain the sensor capacity.

At this time, the only two APS-C lenses available are :
18-45, and the 18-150 - one of which at least the OP is considering attaching to their FF body.   
The actual Field of View of these lenses, as they combine with the crop sensor, will render 28.8 - 72mm, and 28.8 -240mm respectively.   Considering there are FF lenses of 15-30mm, and 24-240 that will render those exact focal lengths and not cause the camera to go into crop mode, thus keeping the original sensor capacity, it beggars belief that anyone would want to consider this!  I have the 24-240 and it's an excellent lens, and I have used it on my R5 with decent results.

As people consider crop R-series bodies as an alternative to the M-series platform, they likely look at the two most popular lenses: the 15-45 and 18-150 lenses and are attracted to roughly the same range on the R-series bodies.  However, there is no RF-S15-46, only a 18-45.  Given that even if there was, it would render an FoV of 24-72mm, thus the 24-240 will cover both this range and that of the 18-150 lenses in one unit.  That is one lens the OP should consider. 

If they want to vlog (which I suspect is the purpose), then the RF 15-30 would be the way to go and it has a manual focus control ring, and switches for that and IS! See that HERE 

The OP is obviously blind to the points you, I, and others have tried to make here.   This is why I make an effort to explain crop factor and its implications.  It wasn't an issue with Canon EF and EF-S lenses before, but it sure is now.  I have come across this in a couple of my classes in various guises, and this is the first time I have seen it on this forum, but I fear we will encounter it more frequently in the future - it's a trap for young players...

[Bbarn]

In this thread, almost all the answers and comments were to questions I didn't ask. So, asking the original three questions in this community was a waste of time. None of the answers addressed the three specific questions in the OP.

I had to contact Canon directly to get answers to the lens ring (control/focus) and IS function questions.  I posted their answers to those two questions in this thread several days ago.

As far as the foolishness of using of RF-S lenses on FF bodies, Canon themselves suggest just that crop mode possibility in their RF-S lens marketing.

[Tronhard]

I think the issue for us is that you were asking the wrong question and you weren't listening to the advice from multiple sources that you were given in good faith. Still, it's your money...

[Bbarn]

Perhaps you are right. I came here asking specific questions regarding camera functionality in hopes of getting concrete answers. In the future I'll limit any questions I submit here to those asking for opinions or advice.

[Tronhard]

That was not actually my point.   If you had asked the question about a result  you wanted to achieve, such as "I want to vlog with my Canon R5, and I looking at the RF-18-45 lens", and not made the leap to a very specific technical question, - which BTW is answered in the manual.   The assumption that this lens was the right choice was what we questioned for you own good, but you took umbridge at that as if we were insulting you - we weren't we were trying to get you to consider points that you may not have.

The point we have all been trying to make to you is that while the RF-S 18-45 might be a great lens paired with the crop-sensor R7 or R10 body, it will massively reduce the performance of your sensor's output.   If that is something you already had taken into account, all you had to do was say so, but instead your seemed to ignore the good and sincere advice, and hurl abuse at us. 

The people who have been trying to help you are excellent and experienced photographers and deserve a bit more respect than that - at least consider the information we have given you.

Have you considered the RF 15-30mm IS STM lens, which is going to cover much the same range - and more at the wide end, and has switches for both IS and Focus?   It is not insignificant that the lens was released around the same time as the 18-45, unit because it is the more suitable for your camera body - given both the focal range and the inclusion of switches that are not necessary on the 18-45 because the R7 has an AF/MF switch on the body.

[Bbarn]

If you believe my questions are answered in a full frame R series body manual, please indicate in which manual, and where.

I submit the issues prompting my questions are not addressed in the full frame R-Series manuals, and that if you believe they are, you still don't truly understand my original questions.

It's too bad that my questions led many to believe I was ignorant regarding the downsides of using APS-C lenses on a full frame body. That is not true. For some of my uses, the reduced pixel density is more than adequate for my needs, and I would welcome the greatly reduced size and weight these APS-C zooms offer compared to several of the larger full frame RF lenses I already own.

I have considered the RF 15-30 but will probably pass since I already have the RF14-35. If it were significantly smaller than the RF24-105 IS STM, I might consider it. But it's almost exactly the same size.

Had I known so many would presume I was ignorant, I would have offered my reasons for considering those new lenses. But since my reasons for considering the lenses had no bearing on my questions, I didn't consider it necessary to provide them.

[Tronhard]

When we are not aware of your background or intent, context is critical.  We often get people here who are not technically inclined or experienced asking questions that are very specific, but not necessarily what they want, or more importantly need to know.    Given the detail of the question you were asking and because of its extremely unusual and unlikely nature (let's face it the vast majority of people would not willingly crop down their sensor capacity to such an extent ), it was suggestive of someone who had been directed to this lens for whatever purpose (although most would use this for vlogging), via Canon marketing or third-party advice.  

We try to respect people who seek information of us, but I think it is fair to say that we were all aghast at the idea you were proposing and without the context you suggest we were doing our best to provide information as to why this choice was a bad one, and to suggest viable alternatives.  Our desire to help pointed us to wonder why you would have come to the conclusion upon which the very specific question you asked was based.  With no further clarification, we were left to conclude that you had no answer to that.

Right now, I am still not sure what your intent as regards to purpose or use, but to me it makes most sense that you are considering video applications, where both IS and AF may not be desirable.  However, for most purposes I would have thought that given the RF 15-30 would be a better match: it is light, has a good spread at the wide end that the 18-45 does not have, and of course is fully compatible with the sensor, add to that it has switches for AF and IS - which directly relates to your original question, as long as one is willing to look at the result rather than the specific lens questions itself.   

As to your comment about references.  I would have suggested that two things would answer this: one is the spec of the 18-45 lens, that shows it has no switches, which logically means that any such controls must remain in the camera.  That takes us to the advanced user camera manual, where on P451, there is a section that refers to using full-time manual focus and there are further references on P924.  Frankly, it seems a bit of a hack to me and not an elegant solution.

To me, the design of the R5 is precluded on the premise of users utilizing lenses not designed for the APS-C cameras.   This perception is enhanced further by the fact that the R7 and R10 units have a manual focus switch built into the body, thus relieving the lens of the need to have such a switch. The DoF preview button, in the centre of this switch may be customized to allow one to turn off IS - I don't have this body and the manual is hard to read in that respect.

For whatever reason you are using this lens, I hope it works out for you.

[Bbarn]

Nevermind.