What is the maximum aperture at 400mm on the Canon RF 100-500mm f/4.5-7.1L IS USM?

SecureGSM · Jul 14, 2020

Yeah.. as in camera displays / reports the aperture being f/5.6 as a rounded number while in reality it would be at f/6.3 Right?

sleepylamp · Jul 14, 2020

SecureGSM said:
Yeah.. as in camera displays / reports the aperture being f/5.6 as a rounded number while in reality it would be at f/6.3 Right?

Feels like that is the case. Someone will test and calculate the T stop, which will be a better indicator.

juststeve · Jul 14, 2020

In reality, it likely means real, physical aperture is something like F6 or 6.1. When in third top mode the nearest number to round to is 6.3. In half stop mode, it is 5.6.

SecureGSM · Jul 14, 2020

sleepylamp said:
Feels like that is the case. Someone will test and calculate the T stop, which will be a better indicator.

A bit like wide end forced distortion correction on the RF 24-105 STM. You won’t know unless you are really looked for it

Sharlin · Jul 14, 2020

SecureGSM said:
Yeah.. as in camera displays / reports the aperture being f/5.6 as a rounded number while in reality it would be at f/6.3 Right?

They're both rounded, obviously. The apparent aperture size varies continuously and not in any sort of increments.

SecureGSM · Jul 14, 2020

Sharlin said:
They're both rounded, obviously. The apparent aperture size varies continuously and not in any sort of increments.

Yup, the Next half stop after f5.6 is f/6.7. Sooo... f/6.0 or f/6.1 could be the number that being rounded down to f/5.6 going in half stops and rounded up to f/6.3 if going in 1/3 of a stop. With f/6.1 being the likely real number. Not bad though. Not bad at all.

Steevo · Jul 14, 2020

Didn’t Gordon Laing do a video with this lens? It was 5.6 at something like 360mm? I’d imagine it isn’t a great loss in reach with that aperture considering you now get an extra 100mm on the long end. It seems a relatively small compromise to get the RF benefits too.

CJudge · Jul 14, 2020

Is Canon Rumours Guy being sarcastic with that last bit about changing settings? It’s hard to tell with text.

Because surely, when it comes to max aperture on variable aperture zooms, the number reflected in the metadata is always a rounded figure. The aperture isn’t mechanically clicking into different positions during the zoom... it’s simply the calculated value based on the entrance pupil in relation to the changing focal length. Right?

bbasiaga · Jul 14, 2020

The thing to remember is the 100-400 isn't exactly 5.6 at 400mm either. IN fact I think that lens isn't actually 400mm, but I can't recall which variation. Might have ended at like 380mm in actuality. All camera lenses are approximate stops near the ends of their ranges. This is why, as I understand it - and I may not have all the right understanding - cinema lenses are listed in T stops instead. You can take two lenses and know you are getting the same transmittence/light flux on both of them.

SecureGSM · Jul 14, 2020

bbasiaga said:
The thing to remember is the 100-400 isn't exactly 5.6 at 400mm either. IN fact I think that lens isn't actually 400mm, but I can't recall which variation. Might have ended at like 380mm in actuality. All camera lenses are approximate stops near the ends of their ranges. This is why, as I understand it - and I may not have all the right understanding - cinema lenses are listed in T stops instead. You can take two lenses and know you are getting the same transmittence/light flux on both of them.

Around 386mm on top of my head..

SecureGSM · Jul 14, 2020

bbasiaga said:
The thing to remember is the 100-400 isn't exactly 5.6 at 400mm either. IN fact I think that lens isn't actually 400mm, but I can't recall which variation. Might have ended at like 380mm in actuality. All camera lenses are approximate stops near the ends of their ranges. This is why, as I understand it - and I may not have all the right understanding - cinema lenses are listed in T stops instead. You can take two lenses and know you are getting the same transmittence/light flux on both of them.

What it means to me though is that the lens is not a f/6.6 rounded down to f/6.3 but f6.1 rounded up to f/6.3 when going in 1/3 of a stop. Good.

AlanF · Jul 14, 2020

SecureGSM said:
Around 386mm on top of my head..

But what on your camera?

AlanF · Jul 14, 2020

Steevo said:
Didn’t Gordon Laing do a video with this lens? It was 5.6 at something like 360mm? I’d imagine it isn’t a great loss in reach with that aperture considering you now get an extra 100mm on the long end. It seems a relatively small compromise to get the RF benefits too.

Here it is again as it is most pertinent.

Billybob · Jul 14, 2020

What it means to me is that the 100-500 will be slightly darker than the 100-400 at 400mm. With the high DR of modern cameras, this is totally irrelevant to me. I shoot RAW, and it's rare that I don't tweak good shots in post. Although I wish that Canon had been more upfront that the light transmission is slightly lower at 400mm, for me it is a reasonable tradeoff if I'm getting equal or better IQ and an extra 100mm of reach in roughly the same-size package. I hear some grumble about not getting 600mm and 6.3 at the long end, but I don't want the extra weight and bulk that's required for those specs when I'm traveling or when I want to do close-up photography. What the extra $700 buys you over the $2000 super-tele-zooms is flexibility (100mm versus 150-200 at the short end), compact size and weight (1.5-2.5lbs saving), closer focusing, and hopefully better IQ throughout the range. For me, these are great benefits.

SecureGSM · Jul 14, 2020

AlanF said:
But what on your camera?

EF 100-400 II L if that’s what you were asking?

Skyscraperfan · Jul 14, 2020

It would be nice if Canon finally released the manuals of the R5 and R6. Do they expect people to order those camaras without having read the manual? Then we would know how easy it is to change from 1/2 to 1/3 increments and back.

FamilyGuy · Jul 14, 2020

Skyscraperfan said:
It would be nice if Canon finally released the manuals of the R5 and R6. Do they expect people to order those camaras without having read the manual? Then we would know how easy it is to change from 1/2 to 1/3 increments and back.

My sarcasm detector is buzzing a little. Manuals would be nice, sure, but for that reason?

bbasiaga · Jul 14, 2020

Skyscraperfan said:
It would be nice if Canon finally released the manuals of the R5 and R6. Do they expect people to order those camaras without having read the manual? Then we would know how easy it is to change from 1/2 to 1/3 increments and back.

I mean, i feel like the acronym RTFM was created precisely because people don't...well...read the manual. LOL