EOS R6 Mark II firmware v1.4 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

[kvbarkley]

What is the problem?

[Ccming]

The logic how program to set f stop is not reasonable, it should take big aperture as priority when shooting indoors

[deebatman316]

It was common for DSLRs when set to P or A+ Modes. To set exposure settings to 1/60th F/4 ISO 400. If the lens had a maximum aperture of F/5.6 it would just change the aperture to that. But the camera uses Fill Flash in those modes. So all the camera did was adjust flash output in E-TTL Mode regardless of the aperture set.

[p4pictures]

Older versions of the firmware for EOS R6 Mark II did not support the Speedlite EL-5. Support was added with firmware 1.1.1

Here is the notes for camera firmware v1.1.1

Changes in version 1.1.1:
1. Adds supports for the Speedlite EL-5.
2. Reduces start-up time when the camera's Bluetooth setting is enabled.
3. Allows FTP/FTPS/SFTP transfers to be completed when using an IPv6 setting.
4. Fixes minor issues.

[Ccming]

Thanks Brian

I just checked my history photos, I take two photos as examples, the first one took at Jan-28 15oclock, firmware version is 1.3, auto aperture is f2, it’s fine. 

[Ccming]

The second one took at Jun-2 20 o’clock, firmware also 1.3, it’s unreasonable to set f4 + iso6400

[p4pictures]

From your two images you shared, there is a difference in the lenses, and also the available light. First one appears to be in daylight in the mid of the afternoon and used EF 50mm f/1.8 or EF 50mm f/1.8 II though you also show a screen capture with RF 50mmF1.8 STM. The second taken at night one uses the RF 35mm F1.8 MACRO IS STM. The camera behaviour with auto ISO and flash will change due to this.

With RF lenses the auto ISO range can vary from 100 - 6400. For many older EF lenses AUTO ISO with flash is limited to ISO 100 - 1600.

You can find the list of lenses that are NOT compatible with the extended range of ISO AUTO with flash on the Canon website https://cam.start.canon/en/H001/supplement_0210.html 

If you want to place an upper limit for ISO AUTO then change the default upper limit from 6400 to 1600 in the ISO settings menu.

[deebatman316]

Hi Brian, I would like to add the camera also factors in the focal length of the lens too. The camera will shoot 1/ focal length x crop factor rule. So to the OP the focal length does matter the camera will change the aperture to use an appropriate F/ stop. I DO NOT believe the OP's camera is malfunctioning. When flash is always used the camera stops down the aperture when shooting in a mode that controls the aperture.

[p4pictures]

Hi Demetrius,

I also just realised the time of the two pictures is also important - and revised my post above. 

First one is taken mid-afternoon with an EF lens. With Fv mode and auto shutter speed, auto aperture and auto ISO the camera will likely choose different settings as the ambient light is higher, before flash is considered. Canon E-TTL considers the ambient before thinking about flash.

Second image is taken at 8pm, it's a dark night scene. With the camera controlling the three parameters it raises the ISO to allow some of the dark night to be rendered, and since it's an RF lens that ISO can go to 6400, with such a setting the camera can opt for f/4 to achieve good depth of field too, and then it thinks about flash.