There is "External flash control" section in the camera's menu. However it is not accessible if you have no external TTL flash on hand.

How can I find out is there ability to change the output power or ratio for different groups of flashes (A, B, C) remotely via camera menu?


Page 117 of the XSi's manual says that the settings available are dependent on the flash and indicates to look at the documentation for the flash.

Generally speaking, the settings you are talking about can be controlled from the camera menus when using flashes that support them, but check the documentation of the flash you intend to use first.


In order for the 450D to control a flash via E-TTL, an E-TTL compatible flash or transmitter needs to be physically connected to the hot shoe either directly or via an off-shoe cable or external wireless trigger that is E-TTL compatible. Until the recent release of the 600EX-RT the Canon wireless system was an optically controlled one that uses pre-flashes to meter and communicate with any off camera flashes. A few recent bodies with built-in flash (beginning with the 7D) can control off-camera slave flashes optically using the built-in flash. Earlier Canon bodies with built-in flash, such as your 450D, do not have this feature. The only option for radio control of a Canon flash was to use a third party wireless trigger system that is E-TTL compatible and allows communication in both directions between the camera and flash unit. For optical control either a 'Master Capable Flash' or 'Master Transmitter' must be used with the 450D. The 600EX-RT now has radio, as well as optical, capability when paired with another 600EX-RT or when using an ST-E3-RT radio transmitter mounted on the hot shoe. The older ST-E2 wireless transmitter is only capable of optical control.

Beyond that, what functions your camera can control are dependent upon the capabilities of the connected E-TTL flash unit. Since your EOS 450D/Rebel XSi is a Type-A camera that can use all the features of EX-series Speedlites, it supports any camera controllable E-TTL feature if the attached flash is capable of that feature (See ppg. 117, 166-67 of the EOS 450D/Rebel XSi user manual). If the external flash is capable of manual output power then power output will be controllable via your camera's menu. If the flash is not capable of manual adjustment, then that function will not be available to you in the camera's menu.

If the flashes are capable of being used in groups and ratios, then your camera can control them via the menu. With multiple flashes, a 'Master Capable Flash' such as the 580EX II or "Master Transmitter" such as the ST-E2 must be connected via the hot shoe (directly, cable, or wireless trigger). The others may be either 'Master' or 'Slave Only' capable.

Here is a chart that outlines how the optical control process works.

Optical wireless E-TTL sequence

  • Oops! I just noticed your question says, 'ratio control' rather than 'radio control', as I originally read it.
    – Michael C
    Sep 18 '13 at 7:54

Without an eTTL-II capable flash, as you've noticed, it's hard to tell, since that menu selection remains grayed out. But, basically, it depends upon the flash, and whether or not it can communicate via the camera menu.

In terms of Canon's speedlites, the following models can be controlled via the camera menu:

  • 600EX-RT
  • 580EXII
  • 430EXII
  • 320EX
  • 270EXII
  • 90EX

Earlier models, like the 580EX, 550EX, and 430EX cannot be controlled through the camera menu, and that selection in the camera remains grayed.

There are also a number of 3rd party flashes that can be controlled via the camera menu, and the first way to find out whether or not is to look at reviews and specs of the flash. This feature may not be listed in the specs, however, so you may also need to go on a google search for user reports; "menu control" is a good phrase to search on along with the flash model name, and the PoTN forum, which is Canon-centric, has a bunch of flash gurus who could probably tell you definitively.

One additional note. A number of cheaper radio triggers (e.g., YN-622C, Phottix Odin, Pixel King, etc.) are now hitting the market that allow for TTL communication over radio, and they can take advantage of the menu control protocol to give you remote ability to change flash settings via the camera menu. This feature now has a lot more convenience than simply keeping you from having to remember custom function codes, or having to use the flash LCD menus.


The 450D does not have a built in wireless flash controller - also, even if you had a flash controller all the controlled flashes need to be compatible ETTL flashes - so, if you don't have an all-ETTL setup this is basically not relevant for you.

To remotely control flash power from the camera menu you need:

  1. An ETTL flash controller unit (ST-E2 or ST-E3-RT) or an ETTL flash with a controller (580EX, 580EX2 or 600EX-RT)

  2. All your flashes (in all groups) must be ETTL flashes (430EX, 430EX2, 580EX, 580EX2 or 600EX-RT)

I listed only Canon original models, you can find cheaper 3rd party alternatives of varying quality and compatibility

I also didn't list flash units designed for the EOS-M system simply because I don't know much about them.

  • The 450D does have a built-in flash contoller, it just isn't a wireless one. If any E-TTL capable flash is connected to the hot shoe (directly or via off-shoe cable) the 450D is perfectly capable of controlling any features which that flash is capable. When a master flash unit (i.e 580EX II) is attached the 450D can controll groups and ratios via the master flash.
    – Michael C
    Sep 18 '13 at 8:11
  • The 320EX is also capable as a slave in multiple groups. And though designed for the EOS-M system, a camera mounted 90EX is capable of performing as an optical Master Flash to control groups of E-TTL slaves when mounted on any EOS hot shoe that is E-TTL compatible.
    – Michael C
    Sep 18 '13 at 8:23
  • "... so, if you "have no external TTL flash on hand" this is basically not relevant for you." Maybe he wants to confirm he can control them with his 450D before he purchases one or several E-TTL compatible flashes?
    – Michael C
    Sep 18 '13 at 8:26
  • @MichaelClark - it's pretty obvious I have offended you with my "this is basically not relevant for you" remark - I really didn't mean to be offensive, I myself don't have the budget for the nice Canon flashes I want so I got cheap Chinese units instead - and that means that some features I would like but are not must-have went into the "not relevant for me" category. the asker uses a 450D, this is a 5 year old entry level model and that implies the asker is, like me, also on a limited budget and so also has things that go into the "not relevant for me" pile.
    – Nir
    Sep 19 '13 at 22:16
  • E-TTL compatible flash doesn't necessarily mean expensive. YongNuo makes the E-TTL compatible YN-468 that sells for less than $100 US on amazon.
    – Michael C
    Sep 19 '13 at 23:30

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