450D won't take underexposed image when in manual mode

[James Adams]

I was recently shooting using external flashes and I had my camera (Canon Rebel Xsi/450D) set to manual mode (I forget the settings but probably something like f8.0 + 1/120s + ISO 200) and the camera would not take the photo, no matter how many times I pressed the button. The room was dark and the exposure meter in the viewfinder showed it pegged to the left, way underexposed without using a flash. I was using two Canon 580EXII flashes and some wireless triggers, and the camera settings were set for a correct exposure with the flash. So I turned on the overhead light in the room and with this additional light I could then get the camera to click again. My understanding was that when you have the camera set to manual mode then you as the photographer are making all the decisions as to the exposure and that the camera shouldn't be preventing you from taking an image which is under or over exposed, but it seems like that is what was happening -- it thought that the exposure was way too low (not factoring in the light which would be coming from the external flashes) so it prevented me from taking the photo. Is this indeed what was happening and if so is there a setting that I can make which tells the camera to let me make the exposure settings as I like in manual mode and not prevent me from taking what the camera assumes are under or over exposed photos? Or maybe there's something else afoot that I need to learn about? Perhaps there's something wrong with one or more pieces of my equipment?

Thanks in advance for your feedback/thoughts/insight!

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[Brian D. Schneider]

I was recently shooting using external flashes and I had my camera (Canon Rebel Xsi/450D) set to manual mode (I forget the settings but probably something like f8.0 + 1/120s + ISO 200) and the camera would not take the photo, no matter how many times I pressed the button. The room was dark and the exposure meter in the viewfinder showed it pegged to the left, way underexposed without using a flash. I was using two Canon 580EXII flashes and some wireless triggers, and the camera settings were set for a correct exposure with the flash. So I turned on the overhead light in the room and with this additional light I could then get the camera to click again. My understanding was that when you have the camera set to manual mode then you as the photographer are making all the decisions as to the exposure and that the camera shouldn't be preventing you from taking an image which is under or over exposed, but it seems like that is what was happening -- it thought that the exposure was way too low (not factoring in the light which would be coming from the external flashes) so it prevented me from taking the photo. Is this indeed what was happening and if so is there a setting that I can make which tells the camera to let me make the exposure settings as I like in manual mode and not prevent me from taking what the camera assumes are under or over exposed photos? Or maybe there's something else afoot that I need to learn about? Perhaps there's something wrong with one or more pieces of my equipment?

Thanks in advance for your feedback/thoughts/insight!

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

--What was your focus setting? In one shot the shutter wont fire if focus is not achieved. Was the flash focus aid on?
Brian Schneider

 

[Lemming51]

The shutter will trip regardless of exposure. But in autofocus modes One Shot or AI Focus the shutter will not trip if the camera cannot confirm focus on something. I suspect this is what you ran into in the dark room. If one of the 580EX II speedlites is mounted in the hotshoe, make sure the AF Assist light is functioning. Or switch the lens to manual focus.

I was recently shooting using external flashes and I had my camera (Canon Rebel Xsi/450D) set to manual mode (I forget the settings but probably something like f8.0 + 1/120s + ISO 200) and the camera would not take the photo, no matter how many times I pressed the button. The room was dark and the exposure meter in the viewfinder showed it pegged to the left, way underexposed without using a flash. I was using two Canon 580EXII flashes and some wireless triggers, and the camera settings were set for a correct exposure with the flash. So I turned on the overhead light in the room and with this additional light I could then get the camera to click again. My understanding was that when you have the camera set to manual mode then you as the photographer are making all the decisions as to the exposure and that the camera shouldn't be preventing you from taking an image which is under or over exposed, but it seems like that is what was happening -- it thought that the exposure was way too low (not factoring in the light which would be coming from the external flashes) so it prevented me from taking the photo. Is this indeed what was happening and if so is there a setting that I can make which tells the camera to let me make the exposure settings as I like in manual mode and not prevent me from taking what the camera assumes are under or over exposed photos? Or maybe there's something else afoot that I need to learn about? Perhaps there's something wrong with one or more pieces of my equipment?

Thanks in advance for your feedback/thoughts/insight!

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[fotog400d]

The camera will also refuse to shoot if you are too close to a subject, closer than the lens is capable of. In this case, the lens/camera cannot achieve focus.

If this is the case, try going to manual focus. This will allow the camera to shoot even for out of focus subjects.

 

[James Adams]

I was recently shooting using external flashes and I had my camera (Canon Rebel Xsi/450D) set to manual mode (I forget the settings but probably something like f8.0 + 1/120s + ISO 200) and the camera would not take the photo, no matter how many times I pressed the button. The room was dark and the exposure meter in the viewfinder showed it pegged to the left, way underexposed without using a flash. I was using two Canon 580EXII flashes and some wireless triggers, and the camera settings were set for a correct exposure with the flash. So I turned on the overhead light in the room and with this additional light I could then get the camera to click again. My understanding was that when you have the camera set to manual mode then you as the photographer are making all the decisions as to the exposure and that the camera shouldn't be preventing you from taking an image which is under or over exposed, but it seems like that is what was happening -- it thought that the exposure was way too low (not factoring in the light which would be coming from the external flashes) so it prevented me from taking the photo. Is this indeed what was happening and if so is there a setting that I can make which tells the camera to let me make the exposure settings as I like in manual mode and not prevent me from taking what the camera assumes are under or over exposed photos? Or maybe there's something else afoot that I need to learn about? Perhaps there's something wrong with one or more pieces of my equipment?

Thanks in advance for your feedback/thoughts/insight!

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

--What was your focus setting? In one shot the shutter wont fire if focus is not achieved. Was the flash focus aid on?

Thanks Brian. I always use auto-focus, and my subject was about 6-8 feet away. Both of my flashes were off-camera -- would this prevent the flash focus aid from functioning (i.e. does a flash need to be mounted in the hotshoe for the focus aid to be useful)? The transmitter for my wireless triggers was attached to the hotshoe, maybe this is enough to tell the camera that there's a flash involved in the equation?

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[James Adams]

Thanks for your responses.

My flashes were both on light stands but my wireless trigger transmitter was mounted in my hotshoe. I'm not sure if the AF assist light was turned on but I will certainly remember to enable that in the future after this learning experience.

I was about 6-8 feet from my subject which is above the minimum focus distance for both lenses I was using (it happened with both lenses), which were Canon f4/24-105mm and f1.8/50mm lenses.

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[WilbaW]

Thanks for your responses.

My flashes were both on light stands but my wireless trigger transmitter was mounted in my hotshoe. I'm not sure if the AF assist light was turned on but I will certainly remember to enable that in the future after this learning experience.

If the wireless transmitter was a Canon ST-E2, I'd expect AF assist to fire (they support all functions as if the flash was mounted on the camera, don't they?), but if it was a Chinese cheapie it would only fire the flashes.

 

[Yaamon]

Just make sure in the camera custom function menu that flash auto focus assist is enabled.

Once enabled the camera with a external flash can take pictures in a completely dark room. My daughter has done this many of times.

You can tell by the flash red light on the subject, did you notice that ?

Good luck next time.
--
Canon 5D II, 50D, & XSI, Fuji 31fd

 

[CityLights]

Both of my flashes were off-camera -- would this prevent the flash focus aid from functioning (i.e. does a flash need to be mounted in the hotshoe for the focus aid to be useful)?

Yes, flash must be mounted to camera for flash focus aid to work.

The transmitter for my wireless triggers was attached to the hotshoe, maybe this is enough to tell the camera that there's a flash involved in the equation?

Flash was involved for exposure no problem, but not for flash focus aid.

Camera did not achieve focus lock and refused to shoot. Achieve autofocus lock, or put the lens in manual focus and it will shoot.

--
CityLights
http://www.pbase.com/citylights
.

 

[CityLights]

Flash focus assist will not work unless the flash is mounted to the camera.

--
CityLights
http://www.pbase.com/citylights
.

 

[Yaamon]

I know that was why I said and a external flash guess I should have said mounted on top of the camera.
--
Canon 5D II, 50D, & XSI, Fuji 31fd

 

[WilbaW]

Thanks for your responses.

My flashes were both on light stands but my wireless trigger transmitter was mounted in my hotshoe. I'm not sure if the AF assist light was turned on but I will certainly remember to enable that in the future after this learning experience.

If the wireless transmitter was a Canon ST-E2, I'd expect AF assist to fire (they support all functions as if the flash was mounted on the camera, don't they?), but if it was a Chinese cheapie it would only fire the flashes.

Der. Of course the ST-E2 has its own AF assist lamp.

 

[James Adams]

Thanks a lot, that explains everything.

What's my work around if I don't want to use manual focus (almost invariably the camera's auto focus is more accurate than I am)? Can I rig up some sort of AF assist of my own which won't throw unwanted light onto my subject when shooting in a dark setting?

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[James Adams]

Thanks for the clarification/education!

(BTW excellent shots on your pbase page)

--James
--
http://www.pixeljuju.com
http://www.flickr.com/photos/buddhafinger/

 

[WilbaW]

What's my work around if I don't want to use manual focus (almost invariably the camera's auto focus is more accurate than I am)? Can I rig up some sort of AF assist of my own which won't throw unwanted light onto my subject when shooting in a dark setting?

Shine a light on the subject to achieve focus, then turn the light off and take the shot. You must be using your flashes in manual mode (since your not using an E-TTL triggering system - right?), so the light on the subject during the shutter button half press won't disturb the exposure.

 

[graphikal]

Move AF off the shutter button, which will allow you to take a picture even if the camera doesn't think it's achieved a lock.

Honestly, I think your whole situation is sort of strange and not something most people would want. Who would want to take a picture with little chance that the camera has achieved correct AF?

 

[Roonal]

What's my work around if I don't want to use manual focus (almost invariably the camera's auto focus is more accurate than I am)?

In your original post you said you turned on the overhead light to get the camera to take a shot.

Well one work around would be to again turn on the overhead light,

• half-press the shutter button to engage the auto-focus,
• once focus is achieved take your finger off the shutter button,
• on the lens flip the AF-MF switch to MF,
• turn off the overhead light.

Perhaps another possible work around might be turn on the overhead light and leave it on, and to set your exposure settings on camera and flashes such that the ambient light doesn't efect the image.

Have you tried shooting at a very fast shutter speed with your flashes in high speed sync mode (FP Mode)?

Can I rig up some sort of AF assist of my own which won't throw unwanted light onto my subject when shooting in a dark setting?

Is your subject moving or your camera position changing such that you would need to focus more than one time?

Simple focus assist light would be a spotlight lighting your subject with an on/off located by you - turn it on to focus, turn it off prior to taking the shot (change auto focus to the back button so that you're not having to keep the shutter button half-pressed with one hand while turning off the spotlight with the other).

The spotlight could be in the form of a flashlight, a desk lamp, etc.

--
Good Day,
Roonal

'Money doesn't buy happiness, but it makes for an extravagant depression' by golf tournament sportscaster

 

[fenderplay]

Just make sure in the camera custom function menu that flash auto focus assist is enabled.

Once enabled the camera with a external flash can take pictures in a completely dark room. My daughter has done this many of times.

You can tell by the flash red light on the subject, did you notice that ?

Good luck next time.
--
Canon 5D II, 50D, & XSI, Fuji 31fd

Yes sir! I agree with you, either use manual focus(which is impossible because its hard to see if the subject is in focus since its dark) or enable the flash assist

 

[Bill-NM]

I know this is a really ancient thread, but with my M50, changing from servo to single shot AF makes the camera fire more often in a dark environment, or also, when using exposure settings that would otherwise result (without a flash) with a very under-exposed image.