Im in a lighting techniques class and one of the assignments is fill flash. Either im dense or when the teacher explained how to do this it didnt sink in. I think he expects us all to use light meters or something. I just dont get it. the first part of the assignment is to have the light source *sun* 90 degree's to the camera, so to the side of the object. This should make one side bright and the other side dark, of the object. the 2nd part is to use the flash to fill in the darker area, so that its 1 or 2 stops less than the bright side. For the first part I used something like F8 @ 3 seconds. I used a regular 60 watt house light that was right next to the object. *the object was a carebear stuffed animal* the 2nd part, the camera/flash was 5 feet from the object, doing the math, the aperature I should use is F22 since the GN is 110 and the distance is 5' using the formula: aperature = GN / distance But this is for when the flash is the main source of light, so the ambient light shouldnt interfear with the exposure. But I just want the flash to be "fill". So what I ended up doing was changing the flash from full power to 1/4 power, and bracketed for +/- 1 stop. But I dont like the guess work and would like to know how to do this properly, with out a hand held light meter and with out using the light meter on the flash to control how much light hits the subject. Does anyone know how to do this, and explain it so a 5 year old could understand? hehe.