topic Re: Eh? Confusing Myself - R5 and Setting Aperture Range in EOS DSLR & Mirrorless Cameras

Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 13:30:04 GMT

My 70-200 f2.8 L IS is not performing at it's best at f2.8. Needs a service... I shoot in Manual most of the time while doing low-light events. I just assumed I could set the Aperture Range on my R5 to Minimum and Max values for this event. e.g. I'd say Max aperture was f3.2 and Minimum say f8 (unlikely to work higher than f5.6 anyway). When I toggle the C.FN 2 settings that max aperture jumps from f2.8 to f4. Offering nothing imbetween. In the other modes I can, of course, set aperture to whatever I want f3.2 f3.5 yada yada.

What am I doing wrong, or is this just a peculiar limitation of the system?

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

SignifDigits — Fri, 20 Mar 2026 13:44:52 GMT

For us to answer your question it would be helpful to know what 70-200 f/2.8 L lens you are using. There are three generations of the EF lens and two versions of the RF that I'm aware of. If you're using EF, then please also share the make/model of the converter. I am guessing that it is possibly a function of the lens you're using and its' communication with the camera rather than something in the camera.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 13:55:15 GMT

It is an

EF70-200mm F2.8L IS USM via a Canon Mount adapter. Same aperture range display limitations on my 5D MK IV too. They are the fixed f-stops, so perhaps it just defaults to those, even though we can shoot at interval f stops.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 13:56:03 GMT

5d MK IV tested regardless of lens attached.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

deebatman316 — Fri, 20 Mar 2026 13:56:50 GMT

@richclark Welcome to the forums. Which exact EF version are you using. Canon has made 7 different versions in the EF Mount. Between F/2.8 & F/4 version. They’ve also made 3 versions in the RF Mount too. So a Full and Complete name is needed. So we can assist you. Note older lenses have hardware limitations making some features of your camera unavailable.

EF 70-200mm F/2.8L USM
EF 70-200mm F/2.8L IS USM
EF 70-200mm F/2.8L IS II USM
EF 70-200mm F/2.8L IS III USM
RF 70-200mm F/2.8L IS USM
RF 70-200mm F/2.8L IS USM Z
EF 70-200mm F/4L USM
EF 70-200mm F/4L IS USM
EF 70-200mm F/4L IS II USM
RF 70-200mm F/4L IS USM

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 14:01:56 GMT

See Above.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

deebatman316 — Fri, 20 Mar 2026 14:08:57 GMT

@richclark Do you have your camera set to whole stops, 1/2 stops or 1/3 stops. I believe older lenses have aperture limitations. Like the widest aperture setting is NOT possible when the aperture range is limited. Newer EF lenses are more optimized for video. They’re usually designed with a stepless aperture. They smoothly change between apertures for video work. While older ones just jump from setting to setting. New RF lenses offer 1/8th stop or even 1/32nd stop aperture options for video mode.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 14:17:53 GMT

Both bodies are set to 1/3 stops for Exposure Level Increments but that does not impact the Aperture Range in CFN2. I guess it is just default settings.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

deebatman316 — Fri, 20 Mar 2026 14:21:02 GMT

What lenses are you using that’s causing this? Older lenses have limitations such as not supporting step-less aperture motors. They’ll just jump from setting to setting.

Re: Eh? Confusing Myself - R5 and Setting Aperture Range

richclark — Fri, 20 Mar 2026 14:56:13 GMT

After more testing it is less about the lenses and more about the functionality within the bodies. With or without a lens makes no difference. I can access all apertures in varying modes when working. It was just about not being able to set a custom range from 3.2 on a specific lens that is poorer at 2.8.