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20D with 430EX?


I'm trying to get my 430EX speedily to work with my 20D.  I need to take some model photos for a friend.

In 430EX TTL mode, the speedlite flashes, but pictures are underexposed.

In 430EX manual mode it does not flash.

From what I read, the best to use the 430EX in manual mode.  The shutter speed can be 1/125 and adjusted to affect the ambient light only.  I have a diffuser for the 430EX I would like to use.

What mode should I set the 20D to?  I understand the 430EX set to 1-1 will give full output from it.

Should I use manual mode on the 20D, set the shutter to 1/125 and adjust aperture to give correct exposure?

Why is the 430EX not firing when it is set to manual mode?  Google says to make sure the flash function is turned on in the camera, but I don't see this in the menu.

Thanks Kevin





I suggest you locate a used copy of the late, great Speedlighters Handbook by Syl Arena. All will be explained.


I need to shoot Saturday.  This is a spur of the moment thing.  I've been reading, but my question is specific to the 430EX.  Why is it not firing in manual mode and what are the ca.era settings?  I have a degree in photography but it has been a while since I've used my equipment.


The manual does not help much, but it does have this odd note:


Make sure the speedlite is set to E-TTL Mode. A speedlite that is set to TTL will cause the speedlite to fire at full output ONLY. Old off the film TTL relied on light reflected off the film to end the flash duration. Digital image sensors don't work that way because digital image sensors and 35mm film have different reflectance. Therefor off the film TTL is incompatible with digital cameras. Digital cameras use a low powered pre-flash before the shutter opens. The camera then calculates how much flash power is needed for the correct exposure. What mode are you shooting in. E-TTL works differently depending on what mode your using. In Full Auto, P, Av, Tv & A-DEP Modes. The camera treats flash as fill flash. In Manual Mode the flash is treated as main light. E-TTL is adverse to blown highlights. With Canon E-TTL & TTL don't mean the same thing and they work completely differently.


Current Gear: EOS 5D Mark IV, EF Trinity, EF 50mm F/1.8 STM, EF 85mm F/1.8 USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM


The fact that you are seeing TTL and not E-TTL, and also not firing in Manual mode, suggests your flash is broken or unreliable. 

Seeing TTL can be an indication of a poor hotshoe connection, but then the flash would fire at full power and be overexposed, not underexposed. 

If you really need to do this shoot, I would get another flash. 

Mike Sowsun

My bad Mike,

I have E-TTL, not TTL.  I still can't get the flash to fire in "Manual" mode.

Will the speedlite work on a different camera.


Current Gear: EOS 5D Mark IV, EF Trinity, EF 50mm F/1.8 STM, EF 85mm F/1.8 USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM

Your flash is probably broken. I don’t think your main flash is firing. ETTL always fires a pre-flash. It sounds like the main flash is not being fired after the pre-flash. That would explain the underexpose in ETTL. 

Manual mode does not use a pre-flash. That would explain why you see no flash in manual. 

Mike Sowsun


The easiest way to use that flash is set to ETTL. The "mode" button is used to select that. It will toggle through Manual and TTL modes to ETTL.

Once that's done...

The camera set to "Manual" exposure mode will cause the flash to be treated as "Full" flash... as if it's the only light source (you still can vary the camera settings and flash exposure compensation to change the balance of flash vs. ambient light).

The camera set to any of the auto exposure modes (Av, Tv or P) will cause the flash to be treated as "Fill". Exposure will be set based upon ambient light, then the flash will fire at -1.66 stop output (you can override and tweak the camera's exposure setting with Exposure Compensation and/or override and tweak the flash's contribution to the image with Flash Exposure Compensation).

I think the 20D has a flash sync speed of 1/250 or slower. If you want to use faster shutter speed than that, you will need to set the flash to "High Speed Sync". This will allow you to use any shutter speed, but each step faster above 1/250 will reduce the reach of the flash a little more. (Alternatively, just set your ISO lower to be able to avoid shutter speed above 1/250.)

This full sun, semi-backlit image was done with 550EX FILL flash, without any compensation for either camera or flash and without any diffuser on the flash (i.e., direct flash). I used ETTL, Av, ISO 100, f/5.6, 1/320 (70-200mm lens at 160mm on APS-C camera, High Speed Sync selected on flash). 8315635848_2771d45384_o.jpg
















I think you will find it easiest just to use ETTL so long as this is the only flash you'll be using. You can take some test shots, using Exposure Compensation and Flash Exposure Compensation to adjust for the look you want.

The only time ETTL because a problem is if using multiple flashes with optical slaves. ETTL looks like a single flash, but it's actually two. The flash first fires a reduced power (1/64) pop that's used to measure the scene via the camera's metering system, then it fires the "real" exposure based upon the info gained with that first small exposure. This happens so fast you might not even notice. However, if you have add'l flashes setup and being triggered optically, they will go off too early. It's not a problem if using other methods of triggering the off camera units (radio, near IR, wired).

If you don't have them, the user manuals for the flash and camera are available to download from the support section here on the Canon USA website.

430EX user manual (not 430EX II or III or RT)

EOS 20D user manual


Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories