Is the image circle of RF L lenses larger than any EF lens?

[dolina]

This would be one of the prerequisites for a medium format "0.79x crop" or "0.64x full frame" Canon RF body that is priced between $3.5-33k.

As Canon would prefer their medium format users to exclusively use RF L lenses then the image circle of RF non-L & RF-S glass can be limited to 35mm 1.0x full frame & 1.6x crop.

 

[Antono Refa]

This would be one of the prerequisites for a medium format "0.79x crop" or "0.64x full frame" Canon RF body that is priced between $3.5-33k.

As Canon would prefer their medium format users to exclusively use RF L lenses then the image circle of RF non-L & RF-S glass can be limited to 35mm 1.0x full frame & 1.6x crop.

I'm uncertain whether to note Canon could make a new mount with new lenses, or ask whether a driver's license would be a prerequisite to grandma having wheels.

 

[neuroanatomist]

As Canon would prefer their medium format users to exclusively use RF L lenses…

That’s an asinine statement for several reasons.

• Canon doesn’t have any medium format bodies
• We have no idea what Canon would prefer, but if Canon were to launch an MF line, then it’s far more likely that Canon would prefer those users to buy all new lenses for their cameras
• Of the RF lenses, only the white supertele primes would possibly have a large enough image circle, and those lenses would likely not be heavily used by MF shooters (the 28-70/2 has a relatively large image circle in the optical design, but there’s a rear baffle that cuts it off)
• The MF market remains a very small niche, the Northlight post you link mentions Canon thinking of MF over a decade ago, and goes on to argue that it’s far less likely to happen today with the current market conditions

 

[dolina]

I'm uncertain whether to note Canon could make a new mount with new lenses, or ask whether a driver's license would be a prerequisite to grandma having wheels.

The challenge of creating a new mount would be economies of scale. Would it sell at volumes Canon is accustomed to?

It is like R&D spend on the iPhone benefited Macs when they transitioned to Apple Silicon. Over 90% of the R&D spend has been subsidized by iPhone & iPad sales and the less than 10% spend would be covered for Mac-specific improvements. Apple Silicon would never happen if it dependent solely on R&D money from Macs.

Same logic applies here.

APS-C & Full frame revenue would pay for R&D spending of medium format without needing to retool as it is compatible for a medium format mount on day 1 of RF L lenses. Same reason why EF lenses works on both full frame & APS-C bodies but EF-S specific focal lengths were created for the price points of APS-C users.

Right now users of FujiFILM GFX medium format (crop) bodies are able to adopt EF L lenses with focal length of 35mm or longer without vignetting.

When a 0.79x crop medium format 100+MP Canon RF body comes out it would have me pre-ordering.

 

[LogicExtremist]

I suspect that EF format full-frame lenses would be insufficient for use on MF, and RF full-frame format would be a complete disaster.

Lenses are designed to provide adequate coverage across the sensor on their respective camera mount formats, producing a sharp image with minimal vignetting. Making the image circle much larger would cost more money for no gains, so camera companies avoid that, there's very little extra tolerance built in unless it's a tilt-shift lens which needs a larger image circle of decent quality to work properly.

The image quality and brightness of FF lenses drops off drastically beyond the 24×36mm sensor area, and to make matters worse the vignetting of RF lenses is way higher than on EF equivalents, it's a design limitation of the RF mount. Due to Canon being able to cut corners in optical design to a greater extent on the mirrorless format to save manufacturing costs and increase profits, quite a few entry level RF lenses can't even cover the whole FF sensor. The vignetting on many RF lenses is considerable, as I understand that's a result of the shorter flange distance - remember you can't get something for nothing in engineering, there's always a cost...

Whether the Canon lenses can resolve sufficient detail for high MP (such as 100MP) medium format sensors is another matter.
Almost half of Canon's older EF lenses were outresolved by the 5DSr and R5 camera body, and Canon released a list of lenses that were up to scratch.

The focal lengths of RF full frame lenses would be all wrong on MF too. The crop factor for a Fujifilm GFX system is 0.79. The focal lengths all change due to crop factor, so all the MF equivalents to their 35mm counterparts will be longer, a MF 110mm lens (87mm FF equivalent) is closer to an FF 85mm portrait lens.

The wide apertures needed on FF would be unnecessary and add extra cost for no purpose on lenses used on MF.

Also, Canon L series lenses are only a big deal in the stills photography works, and in amateur video, but relatively speaking they're a joke in the world of cine lenses where they have a different set of criteria to gauge what a decent lens is. Canon L glass is a master in its own domain, but not absolutely awesome (as marketing hype would have you think) that it can work effectively outside of that. Tools are designed and optimised for specific functions. In the same way that they don't compare to the cine lens range, they're most likely sub-standard for MF also.

Incidentally, the size of the MF sensor is a fair bit wider and taller than a FF, so a FF lens would need to project a decent quality of image 20% beyond its boundaries. Looking at lens MTF charts, the image quality of many lenses barely holds up on the FF sensor periphery.