I have just bought a new Canon EOS 4000D with an Apeman SL 450C speed light. When I take a photograph with the speed light switched off the photographs are a decent brightness. When I switch the speed light on the flash is activated (e.g. room lights up) but the photograph is very dark, much darker than when the speed light is switched on!

I've read the speed light instruction booklet but there's no troubleshooting for this type of problem. I have the speed light in 'TTL' mode which I figure means some type of automatic mode?

Any help for a newbie would be much appreciated!


Please find two pictures below to compare, the darker one is actually the one with the speed light!

With speed light Without speed light


Links to actual images;




Images properties. Image 28 is the one with speed light, image 29 is without speed light

Picture properties

  • 1
    What is your "Flash Exposure Compensation" setting when the speedlight is switched on? How is the flash being synced to the camera's shutter? Is the SL450C attached to the camera's hot shoe or are you using the flash off camera? If off camera. how are you attempting to trigger the flash?
    – Michael C
    Oct 22 '18 at 16:19
  • @MichaelClark the following is displayed on the speedlight screen when I take a picture "TTL f-4.5 zoom 24 mm". I have no idea how the flash is being synced to the camera's shutter, I have the camera on the 'Scene Intelligent Auto' mode. The SLC450C is attached to the cameras hot shoe. Thanks, Mike
    – Michael LB
    Oct 22 '18 at 16:44
  • As Wayne notes in his answer, this could simply be an underpowered flash issue. It could also be a technical issue. Or maybe a settings issue. Do you mind adding the image samples to your question so that some of these issue could be eliminated from the drawing board?
    – OnBreak.
    Oct 22 '18 at 17:36
  • 1
    What are the ISO, shutter time, and aperture of the image without flash? What are the ISO, shutter time, and aperture of the image with flash? When you put a camera in a fully automatic mode it (or more specifically, whoever wrote the program routine) has to guess at how you want the photo to look.
    – Michael C
    Oct 23 '18 at 1:32
  • @Hueco I have now added the images to the original question
    – Michael LB
    Oct 23 '18 at 15:53

I think that your camera and flash are incompatible. I ran into a similar problem when testing a non-Canon wireless (flash) transmitter. The Canon E-TTL system sends a pre-flash command before the mirror goes up, you can even see the light in the viewfinder ! The flash unit thinks that that is the only flash command. When a few ms later the actual flash command comes, it stays dark. Take a photo in a mirror to confirm that you are getting no flash light at all.

A used 430EX is not expensive, that's what I would buy. (I did, 3 !)

  • Unlikely that even the canon system sends a preflash command in a way that a non-dedicated hotshoe flash would misinterpret as a trigger - and the flash in question appears to be dedicated and compatible.... Dec 25 '18 at 5:49
  • This answer solved my problem, purchased a Canon Speedlite EL-100 and it works perfect out the box. May upgrade in the future but think this will do the job for us for now
    – Michael LB
    Jan 7 '19 at 14:33

Check your Exif data for ISO in the two pictures. With flash on, I think the Canon Auto ISO is reduced, 4000D manual says to ISO 800 (page 92).

Shutter speed too can change in Exif, probably to a Minimum of 1/60 second with flash.

So without flash, Auto ISO was high, and shutter speed could have been slower than 1/60, and room was brighter.

TTL is automatic flash, but with flash, lower ISO 800 and probably 1/60 second Minimum, so room goes darker. Flash power setting did not carry to furthest distance in room, so distance became dark. Using bounce flash indoors can help that range to light the whole (small) room, and is usually better lighting too.

The Exif will tell the tale.

  • Thanks for your input, I have added the photographs to the question to assist
    – Michael LB
    Oct 23 '18 at 15:54
  • It is exactly as I predicted. The picture without flash is ISO 3200 (high) and 1/25 second shutter (slow), so it is quite a bit of exposure. The one with flash (simply because flash was present) dropped ISO to 800 and increased shutter speed to 1/60 second, which dropped the ambient exposure more than 3 EV, which means pretty much black ambient. Idea is that the flash will contribute. But the flash somehow did not contribute. Flash mode must not have been TTL. If it fired, then probably Manual flash mode at very low power setting? The problem is the flash setup.
    – WayneF
    Oct 23 '18 at 17:28

Thank you so much for adding in the details! It's refreshing to see a question come together.

To boil it down, the shot without the flash has 2 extra stops from the increase in ISO and ~1 extra stop from the decrease in shutter speed. That's a total of 3 extra stops of light!

The question now becomes: can your flash make up for those 3 stops?

I think it can (note, I'm not familiar with your flash, but it's guide number from what I can find is higher than my 430EX, which I think would cover the 3 stop gap in that room with ease).

What I think happened is a metering issue. The window is causing a strong backlight, tricking the camera into thinking it needs to lessen the exposure. The flash is on TTL, meaning it's getting it's power instructions from the camera and the camera's meter. I doubt it popped with any power.

Now, what to do about it?

In strong backlit scenes, I think you should go full manual. Manual camera settings and manual flash settings. This way, you completely control how much exposure you're giving to the backlit window and how much for the interior.

If not using manual, and still going the TTL route, then make sure to use a spot or center-weighted metering and meter from within the room. Using the pattern metering mode, I'm fairly certain that the strong lit window caused the results that you got. Why the camera chose completely different exposures because of the flash? I have no idea - I just know that tricky lighting situations are the bane of auto-exposure modes.

  • Thank you so much for your help with this. Taking it one step further I manage an estate agents and we do photography in house (most of the time). We have a Canon 1200D with a speed light and we've always just stuck it in auto mode and it's worked perfectly. What we don't understand is why this Canon 4000D is behaving totally different in auto mode. I'll post some comparable pictures tomorrow with both cameras taking the same picture in auto mode with the same speed light attached.
    – Michael LB
    Oct 23 '18 at 17:04
  • @MichaelLB The software and algorithms used to figure out exposure based on a scene are probably different between the two cameras (there's ~4 years of R&D between them). We could speculate, but it wouldn't help anything except to satisfy our curiosity.
    – OnBreak.
    Oct 23 '18 at 17:50
  • @MichaelLB What kind of flash do you use with the 1200D?
    – Michael C
    Oct 23 '18 at 19:31

If you make a photograph with a flash, you are basically doing a double exposure. You have one exposure with the ambient light, and one exposure with flash light. Some basic info about this can be found here:

We know now why the ambient exposure got much darker when you turned the flash on, 2 stops darker due to lower iso, and about one stop darker due to the change in shutter time. Now the question is why is your flash is not giving much light. I found it has a guide number of 52, but it does not say 52 of what, meter, feet, inch or mm? A normal flash should have enough power to light up the room though. Can you also show the part of the EXIF file with the flash settings? Or maybe try the flash in manual mode if you can find it?

I think the first thing to check would be the FEC (flash exposure compensation). I have an FEC setting in the camera, but also on my flash, please check both of them. If they are set correctly, it may be some bug in the ETTL system. I don't think that is very likely though, the situation does not seem that unusual.


In addition to what the others have said:

Some third party flashes are known to have issues with not calculating enough power when used with Canon cameras with the E-TTL metering set to 'Evaluative'. This is the case particularly when the flash head is set in a "bounce" position.

Changing the menu item [Shooting (Red Tab with camera symbol) Tab 1→External Speedlite Control→ETTL II Flash Metering] from Evaluative to Average usually resolves the issue. You might also try switching main (ambient) metering to Center Weighted Average, Partial, or Spot metering modes rather than 'Evaluative'. (Main metering and E-TTL metering are two different settings in two different areas of the camera's memnu).

  • 1
    Ya know, this is a problem I didn't see coming. Yay for third party flashes?
    – OnBreak.
    Oct 23 '18 at 20:01

The hot shoe on 4000d has a missing centre contact so flashes won't work. Have a look at hotshoe and you will see black plastic where the round centre contact should be.

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