Which Is Better Out of the Canon EF and RF 50mm f/1.8 Lenses

With many Canon photographers making the transition from the EF DSLR mount to the RF mirrorless mount, there are questions over whether it's worth adapting your current glass, or selling it and replacing it with the RF versions where possible. So, how do they compare?

Changing mounts is one of the most expensive transitions a photographer can make, and requires a lot of careful consideration and planning not to go down a large financial rabbit hole. I've only moved once, and I spent months spreading the change out to make sure I got the best deals for everything I bought and everything I sold. However, it worked out cheaper in some situations just to buy an adaptor for my old glass and use it on the new mount. There can be negative effects of this — there always some downsides — but it's often worth it when it comes to weighing the cost up against the benefits.

In this video, Alex Barrera compares the Canon EF 50mm f/1.8 STM with the new Canon RF 50mm f/1.8 STM using the Canon R5. The first thing to note is that these two lenses are about as cheap as brand new lenses can be, at less $200 even for the new RF mount 50mm. So, this isn't really that useful for helping you decide whether you should keep the EF version to save money, and more an interesting look into how different the adapter EF lenses are from the new RF versions in terms of results. I'll let the video speak for itself, but I must say, it's close. The RF does appear a little more on the nose wide open, but the differences are so slight that if you were going to buy an adaptor (or you already have one) then I wouldn't bother replacing the EF version. 

What are your thoughts? If you have Canon mirrorless bodies, are you going to adapt your old glass, replace the lenses with the RF versions, or a blend of the two?

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Robert K Baggs is a professional portrait and commercial photographer, educator, and consultant from England. Robert has a First-Class degree in Philosophy and a Master's by Research. In 2015 Robert's work on plagiarism in photography was published as part of several universities' photography degree syllabuses.

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The mirrorless DSLR form factor inherently lends itself to better lens design and image quality. With a mirrorless design, the back of the lens now sits much closer to the sensor. This frees up engineers from designing around a prism to funnel light the extra distance towards the senor once the mirror is out of the way. This alone will allow DSLR lenses to close the quality gap to more expensive cinematic lenses. I think the improved lens design/quality is the best reason to adopt a mirrorless system, though I have yet to switch myself in truth.

A technician from the famed camera manufacturer ARRI (the camera maker behind all of your favorite movies) explains this briefly in this video.

Thanks for starting the conversation.


Thank you very much. Great video.

I have been a Canon DSLR user and enthusiast nature photographer for the last twelve years and made feasible investments in their lenses. However, I was getting increasingly dissatisfied with this brand on multiple issues.

Now, I can happily concede that resentment has begun to soften up. The reason is attributable to Canon’s success in attaining seamless compatibility of their DSLR lenses with the mirrorless bodies through quality adapters. This prompted me, previously a mirrorless defiant, contemplate an MILC body sooner than later.

Well done Canon. I’m staying with you.

Actually I will also be adapting my R, FL and FD glass to the RF mount.
IBIS has given me the enthusiasm to do this along with my EF glass.
I am looking forward to using the FD L glass.

Indeed, FD glass gives great results, even without IBIS on the EOS R. I use the 85/1.2 L, the 7.5mm fisheye and the 35mm tiltshift. Maybe I find a 200mm f2.8 L version (I had the EF version, but rarely used it for being too big to carry around).

The EOS R cameras are the Canon FD lens adapters we didn't get before.

did all camera manufacturers took advantage of the move ro mirrorless to raise the $100 price of the old nify fifty to $200 for the new nify fifty ? (is there any reason that justify this doubling in price ? better optics ? better coating ? faster focus motors ?

No. Nikon even more than doubled its price - the Z 1.8 costs about 500 Euro whereas the 1.8 G is available for 200.-