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Canon RF – why choose original optics?

The RF bayonet is your gateway to the enormous possibilities that the new mount brings to the Canon EOS R system. See why choosing original optics is so important to get the most out of your camera.

Almost exactly 30 years after the first introduction of the EF mount, Canon introduced a new bayonet and a new communication standard between the body and separate optics. With the development of digital technology, the needs of photographers have changed, but above all, new, fascinating opportunities have appeared for more efficient and comfortable work.

In this article, we look at the key aspects of RF mount design and the new solutions used in original Canon lenses – not only professional lenses, but also compact and affordable models that still have no equivalent on the market.

RF system wide port

The Canon RF mount has the same 54mm diameter as the EF mount, but the absence of a mirror chamber on the EOS R cameras allowed the focal plane to be much closer to the matrix. The distance between the mount and the matrix has been reduced from the EF standard 44 mm in the case of RF mounting to 20 mm. Thanks to this, the lenses can be not only smaller (or brighter while maintaining the same dimensions), but also optically more complete – the larger diameter of the rear element means smaller light refractions and thus less aberration and better sharpness also in the corners and edges of the frame.

Bayonet RF is a 12-lane highway

The RF lens has 12 bayonet communication pins (8 on EF models), which allows for significantly faster data transfer and greater data transfer. Above all, however, it enabled the introduction of new functions, such as a programmable ring or correction of optical defects in real time, i.e. DLO (Digital Lens Optimisation). Knowing the special features of a specific lens well and relying on the extensive data stream flowing through the RF bayonet, the camera’s processor is able to correct, for example, distortions or vignetting during image processing – also in burst mode and without affecting work efficiency.

RF bayonet is faster tracking

After all, effective communication is a faster focusing system, which is a key consideration for most photographers. The latest Canon EOS R bodies focus in less than 0.05 seconds, but only show their full potential with Canon’s original RF optics. For example, with the zoom Canon RF 70-200 mm f / 2.8L IS USM, which is the manufacturer’s first construction equipped with two Nano USM motors (each of which moves a different lens group) or the RF 400 / 600 mm f / 2.8L IS , with also innovative, 2x more efficient autofocus for the first time.

New solutions are also designed with the constantly growing group of photographers in mind. The Nano USM motor combines the speed of USM technology with the silent and very smooth operation of the STM motor. It’s worth mentioning here that the aperture value of the RF lenses can be changed in 1/8 EV increments (rather than 1/3 EV as usual), which means a smoother depth-of-field function, but more importantly, it minimizes brightness jumps during shooting. Fast communication with the camera’s processor also enables the electronic correction of the breathing phenomenon (the change in the angle of view of the lens during focusing). In the case of classic film lenses, the correction is performed mechanically, which forces the optical systems to be much larger.

The RF bayonet means better stability

Another technology that is highly dependent on fast and efficient data transfer between the lens and the body is of course the image stabilization system. Even in cameras without an in-sensor stabilization system (IBIS), the sensor collects and the processor sends to the lens with the IS system information about low-frequency vibrations (such as heartbeats or breathing) to increase the effectiveness of optical stabilization (Dual). Sensing IS) by at least 1/2 EV. The ideal situation is, of course, a stabilized tandem, where the lens stabilization system complements the microshift technology of the sensor (the first is most effective for long focal lengths, the second is ideal for wide-angle optics).

Closed means reliable

A topic often discussed in online forums and social media is why Canon does not allow third parties to design lenses compatible with the RF mount. We think the answer is very simple. Because it could not guarantee its customers that all the functions described above are still available and implemented correctly (especially after subsequent software updates). The strength of the Canon EOS R’s closed system is, after all, the reliable cooperation of all its elements, where the optics are as important as the camera itself.

The RF system consists of completely redesigned lenses

When designing new versions of lenses for the EOS R cameras, Canon engineers did not limit themselves to changing the mount. Almost every RF model means better optical performance, but also additional functions and new possibilities. Importantly, in addition to the expensive, top-of-the-line “L” lenses, affordable consumer models at popular focal lengths have also been renewed. A good example is the Canon RF 35 mm f / 1.8 IS STM Macro, which has small dimensions and weight, but with 5-stage stabilization and a significantly shortened focusing distance (Macro).

Also, the RF 50mm f/1.8 STM, a new version of one of the most popular lenses in history, now includes an additional PMO optical element in addition to a better construction and performance ring. The super-bright RF 50mm f/1.2L model, on the other hand, is not only much faster and lighter, but thanks to a richer structure (instead of 8 elements in the EF, 15 and even 10 film plates) it improves optical properties. performance and offers a shorter focusing distance. The real showpiece, however, is the RF 70-200mm models, which in the new version are so small they’re not much different from a regular or wide-angle f/2.8 zoom.

Cross-section of the RF 70-200mm f/2.8 lens. The RF version is 25% shorter and as much as 33% lighter than the classic EF model

LOW BUDGET? It is okay!


One of the most interesting lenses in the compact RF line. It’s perfect as a lightweight (165g!) travel companion and a great complement to a standard zoom. The aspheric PMo lens offers excellent colors and the STM motor provides very fast and quiet focusing – so it’s also perfect for vlogging!

CANON RF 15-30MM f/4.5-6.3 IS STM

For landscapes, interiors and architecture, but also for reportage and vlogging – the light and compact Canon RF 15-30 mm is a very versatile zoom with an optical IS stabilization system, a fast and quiet STM motor and a short minimum distance. focus (28 cm), so that at 15 mm the mapping scale is already 1:2 macro!


The classic “fifty” is usually the first lens to complete our standard series. It works great for wider portraits (the RF version gets you closer), but the natural angle of view also makes it an ideal lens for everyday photography. Especially since it only weighs 160 grams. The redesigned design also includes a function ring and additional lens in the optical system to minimize staining.

A few more reasons why you should choose native glass

  • Exemplary cooperation Only original system optics can guarantee that we use all the features of our body. This mainly applies to focusing functions (such as eye and object detection, tracking in movie mode), optical stabilization (which works with matrix stabilization) or system correction of optical defects, which is performed so well because the camera knows the lens. own pocket.
  • Investment of years One of the main advantages of original optics is its longer service life. System models are replaced much less often with successive generations, so they stay up-to-date longer and practically do not lose their value in the aftermarket. Canon lenses are also known for their durability. We can be sure that even in hard professional work, they will serve us for years.
  • quality guarantee No two copies of the same design are ever exactly alike. In the case of the original optics, we can be sure that the performance differences are marginal and reduced to the level of statistical error. In the event of a factory defect, which unfortunately can never be ruled out, we can also rely on the support of the manufacturer’s authorized service service.
  • Uncompromising quality Although third-party lenses are getting better and better these days, original lenses are still unmatched. These are precisely refined optical instruments that – in the case of professional models – usually do a good job in all aspects of image reproduction.
  • Sophisticated structures Finally, we get to the heart of the matter, the simple fact that for many original designs we simply cannot find a suitable alternative: lenses equipped with an AF system with f / 1.2 light, advanced AF systems with separate motors for different groups of lenses or ultra models – compact zooms such as Canon RF 70-200mm f/2.8L IS USM and RF 70-200mm f/4L IS USM. RF lenses also offer unique features, such as the ability to control spherical aberration in the Canon RF 100mm f/2.8L Macro IS USM camera. And these are just a few aspects where the budget competition still can’t compete.

The article was commissioned by Canon Polska

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