Canon 850D Exposure Preview Does Not Function When Attached to External Flash

[ld899651]

Hi,

I use a Canon 850D for macro photography. When dealing with macro lenses, subjects are initially very dark before the flash, due to the low amounts of light that go into the lens at magnification. I have an external flash that I use to get more light when working with subjects, and I often use it in the slave function. For this, it works fine, and the exposure preview functions well. However, when I put the external flash directly on top of the built in to use in its place, the exposure preview does not function, so the viewfinder is essentially pitch black. Is there any way I can get the exposure preview to function without using the built in flash? If it makes a difference, I am planning to upgrade to a speedlite in place of my original external flash.

[stevet1]

Ld899651,

How does Live View behave?

Steve Thomas

[deebatman316]

The EOS 850D aka Rebel T8i in North America is a DSLR camera. So the viewfinder only shows the ambient lighting through the lens.

[deebatman316]

Exposure Simulation does NOT work with flash photography for a reason. The camera can't predict how the picture will turn out. This is due to the camera not knowing if the flash is direct, bounce or off camera. Therefor Exposure Simulation IS DISABLED.

[stevet1]

Demetrius 

Thank you. I didn't know that.

Steve Thomas

[deebatman316]

The same thing applies to mirrorless cameras. They will show the ambient lighting just like a DSLR camera would. Or the camera can be set to display the highest brightness if set.

[ld899651]

Thanks for the response! Why does exposure preview work with the built in flash? Is there any way for me to manually set the brightness of the viewfinder?

[deebatman316]

No not with a DSLR only mirrorless cameras. I also believe Exposure Simulation doesn't work with the built in flash either. Exposure Simulation is grayed out on my camera with the built-in flash enabled.

[ld899651]

That's odd... When I use the built in flash, it is distinctly brighter. When I close the built in and switch to the external, the exposure simulation greys out and the screen goes dark.

[deebatman316]

My camera will cause "Exposure Sim" to blink if the built-in flash is up. My old camera is 13 + years old. Things may have changed. I will have to pull up the manual for your camera.