When I was shooting film back in the 80's, I worked with avian researchers and rehabilitation centers to help me find nesting birds. These downy great horned owl chicks were a wonderful find. I used an on-camera flash because in those days, raising the ISO above 400 was just not feasible if you wanted high-quality transparencies. I shot this with a Mamiya RZ 67 medium format camera (meaning the slides or negatives were 2 1/4 x 2 3/4 inches or 6x7cm), a 350mm lens, and since the flash would sync at any shutter speed, I usually used 1/400th of a second. The flash was a large and powerful Metz CT-1 handle mount flash that I used on a modified bracket to invert the flash head so it was positioned directly over the lens axis. That allowed me to avoid unattractive black shadows just off to the side of the subject. I used a handheld Sekonic meter on flash mode to determine the exposure.