Originally Posted by
Manfred M
Marianne - I see very little difference in the quality of light between the first image and the subsequent three images. It looks to me like you have a small, camera mounted softbox, so far as I can make out when I look at the reflections in the last image. How large is your soft box? I suspect it is fairly small as it produces "green eye", which tells me it was sitting quite close to the optical axis of your lens. By the way, "red eye" occurs in humans, not in dogs and cats (I have read that blue-eyed cats do show the red-eye effect).
The quality, i.e. softness of the light does not come about from the use of a softbox, but rather from the size of the light source relative to the size of the subject. A general rule I was taught when I took a studio lighting course was that in order to get good quality light from your key light, it had to be located no more than about twice the diagonal (on a rectangular softbox) or twice the diameter (on a circular softbox or umbrella), the light becomes hard quite quickly. A camera-mounted softbox is generally only good for closeup work of a small subject.
When I look at the images, the top one looks properly exposed, but the next three look a bit underexposed.
When it comes to shutter speed, so long as you are at or below the camera's synch speed, the actual shutter speed is not all that important in a fairly dark environment. The light from the flash is usually in the order of less than 1/1000th second, so the flash should freeze all motion.
How are you determining the correct power settings for your flash? Which flash unit are you using? I generally use a flash meter when using off-camera flash and use TTL metering when using bounce flash (i.e. having the flash reflect from a light coloured wall and / or ceiling). That turns those surfaces into large reflectors that will generally give you a very pleasing light, as long as they are not too far from the subject. Based on the four images you have posted here, an umbrella would have worked just fine as you can light the area where the cat is sitting. When I shoot with an umbrella, I generally shoot 100% manual mode. My large studio flash units have to be shot in manual mode. I don't use softboxes with Speedlights as they tend to absorb too much light with all the baffles inside them, although I know some people that do, but they generally use multiple Speedlights inside a larger softbox.