EOS R6 Mark II firmware version until 1.5 limits aperture range on Speedlite EL-5

[Ccming]

I use Fv with auto ISO, auto aperture, auto shutter speed and ETTL flash.

before Feb, include Feb, the auto f stop can be correctly set as f2.8 automatically.

but from Mar, it always set f4 as priority, and ISO often go to 6400.

today, 2024-Aug-07, I went to a shop to try another two R6 Mark II,

what I found is, if the firmware version is 1.1, auto aperture works normal, but if the firmware version is 1.4, the auto aperture will be f4 for most of the situation, except very low light, it can be f2.8

[deebatman316]

Yes that's exactly how E-TTL works. It always Fill Flash when the camera is NOT set to Manual Mode. In Manual Mode its treated as Main light.

[Ccming]

Thanks Brian,

Let me demonstrate my concern in another way,
Say I have an EOS camera body, mine is R6 Mark II, but for others model like R3, R1, R52, R7, R8, R10, R50, because they all have digital contacts, so I think they may have the same behavior, if someone has it, thanks to test it.
Any RF lens which has aperture more than F4, like F2.8, F2, F1.8, F1.4, F1.2, all OK to test, I don’t have F1.4 and F1.2, thanks if someone can help test.
The last device is the EL-5 speedlite,

Engage the three devices,
Test at night, some environmental light but not very strong, like desktop light, building light far away,
Flash mode: ETTL
E-TTL Balance: Standard
E-TTL II meter: Eval(FacePrty)
Continuous Flash Control: E-TTL 1st shot
Slow Synchro: 1/250 - 30sec. auto
Shutter synchronization: First-curtain synchronization
AF operation: SERVO
Subject to detect: people
Eye detection: Auto

First test,
A+ mode,
No matter enable flash nor disable flash, camera always set an aperture which is bigger than F4, like f2.8 or f1.8

Fv mode,
Disable flash, camera always set an aperture which is bigger than F4, like f2.8 or f1.8

Fv mode,
Enable flash, camera always set aperture f4 as priorities even the auto iso go to 6400, I think this is a defect of the logic of the firmware, anyone any idea how do you think about it?

Regards,

Haiming

[deebatman316]

All EOS R series cameras work that way it’s normal. EOS DSLRs locked AUTO ISO to ISO 400. But the EOS R series will push the ISO to ISO 6400. EF vs RF lenses also make a difference too. So does the AF mode One Shot vs Servo AF. One Shot locks the exposure but Servo AF doesn’t. Also the AF Assist Beam is DISABLED in Servo AF and FEL (Flash Exposure Lock). The flash algorithm is better than in the EOS R series vs EOS DSLRs. EOS DSLRs usually set ISO 400, 1/60th, F/4. The EOS R series will open the aperture up and change settings as needed. Instead of locking in a fixed value.

[Ccming]

thanks Demetrius,
you didn't explain, why program does not choose ISO800_f1.8 instead of ISO6400_f4 in Fv mode,
but A+ mode does.
it's not reasonable that program set ISO6400 when f1.8 option is available.

P.S. Mirrorless camera should be more smart than a DSLR. each time I have to set f1.8 manually, but the environment always changing, manual is not effeciently.

[deebatman316]

I will say how the EOS R Series handles flash is much better than DSLRs. In Program mode it’s trying to maintain enough depth of field. F/1.8 has paper thin depth of field that’s why it’s not being used.

[Ccming]

if f1.8 is paper thin, how about f1.4 even f1.2, and there is another option there, it's f2.8, it's normal for portrait shooting, and in A+ mode with/without flash, or program mode without flash, all works reasonably well. a good program should balance the ISO and aperture, should not use a fixed f4 aperture all the way, can't say that is smart. if the ISO is too high, it should has the ability to adjust aperture larger.

[deebatman316]

P Mode works differently with the aperture because some EF & RF lenses have apertures smaller than F/4. DSLRs almost always set the aperture to F/4 in P Mode. Now EOS R series cameras I haven’t seen this behavior where the camera always sets F/4. You actually use less flash power at a higher ISO. That’s the reason it uses a higher ISO. Setting a low ISO will require more power. 

[Ccming]

Hello Demetrius, you always mention DSLR, now I'm talking about Canon EOR R6 Mark II, the latest and most modern model for the time being, it even can't compare with EOS R5, R5 don't have the digital contacts, so it can't use EL-5 directly.

EL-5 has a powerful battery, I can use it two days continuously without re-charge, why I worry this? it's weird.

why you always suppose Canon is correct and perfect, it's quite easy to judge which one is good which one is bad. I have the examples link below.

it must be one of the two possibilities, first, I do some wrong setup to forbid f4 go to larger, second, firmware has defects. it force aperture prefer f4. the firmware of body or of flash.

https://flic.kr/p/2qCYWQD

https://flic.kr/p/2qD1838

[deebatman316]

Doesn’t matter if the camera has a multi interface shoe or not. This behavior dates back to the original R. There’s a reason Canon designed the flash system that way.

[p4pictures]

Hi Haiming,

I have EOS R6 Mark II with firmware 1.5.0, so I tried your test above using RF 28-70mm F2 and also Speedlite 600EX II-RT. I did not have Speedlite EL-5 to test.

1. A+ mode with flash - shutter speed is minimum 1/60, aperture opens up to f/2 in very low light, and ISO mostly limited to 1600. 

2. Fv mode with flash and using one-shot AF or servo AF - shutter speed is limited to 1/60 as the slow sync setting does not apply to Fv mode, only Av and P modes. Aperture usually f/4, but sometimes f/2.8. Not seen f/2. ISO can go higher but not over 6400. 

3. Fv mode without flash and using one-shot AF OR servo AF - shutter speed as low as 1/15 aperture at f/2 and ISO over 128000 in very dark conditions. 

For situation 1, the camera recognises that it cannot balance the flash and the ambient light, so it choses minimum shutter speed of 1/60 and ISO up to 1600 max, aperture may open as much as lens can do. In brighter ambient light the camera sees that it can balance flash and ambient light, so it choses settings to make the balance work. You have no control over when the camera does a balance of only cares about flash exposure. 

For situation 2, the camera is trying to balance flash and ambient light and maintain a reasonable depth of field while minimising camera shake. Minimum shutter speed is 1/60, aperture often closed by 1-stop, sometimes more, so my lens is f/2 and I get f/2.8 or f/4. ISO can go quite high, it's a different calculation than A+ mode and is allowed to go up to ISO 6400 with RF lenses and only ISO 1600 with EF lenses. No AF assist light or intermittent flash firing when using servo AF.

For situation 3, the camera is working with the ambient light only, so ISO can go to the max allowed on camera 25,600 in my case, aperture is wide open at f/2 and shutter speed is 1/15. 

For what you want to do, I really suggest you try one of these alternative ways to work.

• With Fv mode select the aperture you want to use, easy with the main dial next to shutter button. Shutter speed is still limited to min of 1/60, and ISO with flash will be under ISO 6400. 
• Use Av mode, and auto ISO set the slow synchro to the default 1/250 to 1/60. You change the aperture value with the main dial next to shutter button. ISO with flash will be under ISO 6400. 
• Change the range of AUTO ISO settings, from the default 100 - 25,600 to maybe 100 - 3200 or less. This limit applies to bother ambient auto ISO and flash in Fv or Av mode. If this limitation bothers you, then why not use a custom shooting mode C1 configured to your choice of Fv or Av mode and restrict the auto ISO for the custom mode. Now you know that C1 will be your choice for flash photos. It is even possible to link the C1 mode on the EOS R6 Mark II with the Speedlite EL-5 custom modes.

Lastly I tested the same sequence on an older EOS R6 (original version) and achieved the same results as for the EOS R6 Mark II. If there has been a change in the way the EOS R6 Mark II works post firmware 1.1.0 then it is probably to correct operation to match other EOS cameras.