I've been testing out my new flash and trying to figure out how to get slaves working with the popup flash, but the problem is whenever I trigger the external flash it makes the image a lot darker, I'm assuming it has something to do with the auto settings on my t2i(I'm in full manual mode, lighting optimizer off etc), so I'm not understanding what I could be missing, or if it's something else, or if the popup flash can't be used well as a slave because it auto adjusts itself.
I took a few photos to show:
I started off at f32, trying to get a dark image with the popup flash alone, then I would use the external flash on full power to have the largest difference, of course I realised that at f32 not much of the flash would get in afterwards and fixed that mistake
f32, 1/200th using the pop-up flash only:
f32, 1/200th using the pop-up flash and external flash:
At this point I thought that the shutter speed might be too fast for the flash, so I dropped it down to 1/10th. I also brought up the aperture so that more light from the external flash was getting in
f11, 1/10th using the pop-up flash only:
f11, 1/10th using the pop-up flash and external flash:
P.S. I'm not a 5 year old, as it would seem from the pictures, it's just old stuff I haven't gotten rid of.