topic Re: EOS RP continuous auto focus when filming with EF adapter in EOS DSLR & Mirrorless Cameras

EOS RP continuous auto focus when filming with EF adapter

MillenniumSnake — Fri, 01 Aug 2025 13:53:39 GMT

Hey there! So I have a small Youtube Channel about my reptiled and other critters, almost reached monetization (woohoo!) so I film 80% of the time. My old camera ( Canon 70D) just died on me and I wanted to upgrade to 4K anyway, but I am now stuck at making a decision what my next camera will be. All my lenses are EF and EF-S so I am probably stuck using an Adapter either way.
I am currently looking at the Canon EOS RP and a Sony Alpha 7 III for it's low-light capabilities. Most of my critters are more chill with little light, but all I keep reading is that continuous autofocus is an issue with adapters. Now I am stuck. I can't afford a new camera AND new lenses. But I am also not really sold on the EOS RP yet. Would love to hear your insights!

Re: EOS RP continuous auto focus when filming with EF adapter

stevet1 — Sat, 02 Aug 2025 00:37:17 GMT

MillenniumSnake,

I don't think continuous autofucusing is an issue with your adapter.

In still shooting, you have the ability to turn your continuous AF on or off in your menu settings.

In movie mode, it's called Movie Servo, which again, you have the ability to turn on or off in your menu settings.

I personally find Continuous Autofocus to be a nuisance in still shooting, so I have that disabled, but I like Movie Servo when shooting video, so I have enabled that.

Steve Thomas

Re: EOS RP continuous auto focus when filming with EF adapter

shadowsports — Sat, 02 Aug 2025 04:01:52 GMT

Greetings,

In order for us to make meaningful suggestions, we need to know what gear you own now. I understand the 70D is done. Tell us about your lenses? We also need to know your budget.

The RP and A7 III are both full frame. If you go this route, you may want to consider parting with your EF-S lenses. With the right camera, I think your EF lenses could perform admirably adapted. Happy to discuss further with your input.

🐍

Re: EOS RP continuous auto focus when filming with EF adapter

JeffXB — Sat, 02 Aug 2025 09:53:40 GMT

I’ve used an old EF 24-105mm f/4 L and a 70-200mm f/4 L (both purchased around 2007-2008) on my R6 M2 with an adaptor. The only difference I noticed when it came to autofocus was that it wasn’t quite as fast or “snappy” as it is using the same RF version lenses. Otherwise it worked fine.

Since your budget is tight, perhaps have a look at purchasing a used camera from a reputable dealer? You might be able to get more bang for your buck and have enough $ left over for an RF lens that would suit your individual needs.

Re: EOS RP continuous auto focus when filming with EF adapter

Waddizzle — Sat, 02 Aug 2025 11:45:57 GMT

“ Most of my critters are more chill with little light, but all I keep reading is that continuous autofocus is an issue with adapters. “

I don’t know what you may have read or heard. You didn’t describe the source. Be careful with anecdotal reports of camera performance, both good and bad. There’s a lot of content out there that is posted by individuals who don’t have a clue, as well as individuals who just want to spread disinformation.

There is a significant difference between Continuous AF when shooting stills compared to capturing video. The most obvious difference is frame rate, which has nothing to do with the mount adapter and everything to do with the lens. Don’t get me wrong. There are some bad third party adapters out there, so stick with a Canon model.

Just because a given lens is great for capturing stills doesn’t mean that it’s also great for capturing video, particularly with older EF mount lenses. Most were not designed for video. Most were designed for shooting stills at up to 10-15 fps, if that fast. Many have noisy AF motors, which doesn’t matter much when shooting stills. Many DSLRs weren’t capable of continuous AF capturing video because of the lenses.

But an even bigger problem is how many DSLR lenses have noisy aperture blades. The popular EF 24-105mm f/4 IS USM is a good example of a lens that’s great for stills, but not so great for video. Most DSLR users never notice the noisy aperture blades because it’s drowned out by the mirror slap. Try shooting a video clip that fades to black by stopping down the aperture.

Canon introduced Dual Pixel AF in 2009, and then spent the next few years introducing new lenses that didn’t have the same issues capturing video as their older lenses. Canon released Mark II versions of nearly every L Series lens and a lineup of STM lenses for the consumer market.

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others have pointed out the potential for issues with using crop sensor lenses on full frame mirrorless bodies. Be prepared to not be able to use any of them on a full frame sensor body. You would have to switch the body to crop mode, which would negatively impact capturing video. I am not sure if 4K video modes would still be available.

If you can find a 90D, then I recommend that. Or, you could upgrade to an R50 or R10. You could still go with a full frame sensor body, too. You might not be able to use all your current lenses.