Light Diffusion (Basics of Using an Umbrella & Reflector)


Using the on-camera flash can create a very harsh shadow as well as render the subject a little one-dimensional, as in the photo of a monkey's fist knot at the right. A significantly better photo can be crafted by moving the light source as well as softening it. This was shot at ISO 100, f5.6, 1/60 sec.

Searching on the web, I didn't have much luck finding any resources that detailed such basics so I decided to record my experiences for others to benefit.

All of these photos were shot with a Nikon Coolpix 5700 digital camera (mounted on a tripod), Nikon SB-28 flash, and the equipment detailed at each step. These photos haven't been retouched or had brightness/contrast corrections applied; aside from resizing and sharpening they're exactly as they came out of the camera. The monkey's fist is about 3 inches in diameter. Of course all of this applies equally to portraits or any other photos you might take.

The easiest way to eliminate the harsh shadow and breathe some life into a photo is going to be to shoot with natural light and a longer shutter speed, as I did for this photo. The problem becomes the required shutter speed: at ISO 100 and f5.0, this was a four second exposure. Aside from still life photos like this, thats an impossible shot--can you hold perfectly still for four seconds?

Regardless of shutter speed, the photo is more pleasing. This photo is a composite of the two above photos. Study the red circled areas: along the bottom, the harsh shadow is gone and within the two upper circled areas it's easy to see that more shadow exists in the naturally-lit shot, which gives the knot more texture and depth. So in the end, I want the knot to look more like the natural light, long-exposure shot but I want to use flash to accomplish this. All of the following shots were taken at ISO 100, f5.6 1/60 sec. exposures. Flash output was manually varied to get a pleasing exposure.

The first thing to do is move the flash. To do this I used an Nikon SC-17 TTL cable to control the flash (you probably need a different cable for your camera/flash), a lightstand, and a Photoflex MultiClamp. This photo was taken with the flash in the clamp on the lightstand at the same height and distance as it was when on the camera, only moved about 45 degrees to the left. The result is the hard shadow to the right, though there are some more subtle shadows to show the texture of the rope; as well the right side of the knot appears a little darker than the left side, giving the photo a little more dimension to better communicate the shape of the knot. I think it's a significant improvement over the first attempt with flash.

Next I want to soften the shadow from the flash. To do this I attached a PhotoFlex 30-inch white umbrella to the MultiClamp and fired the flash into it. The contrast in the texture within the rope is still very evident, but the shadow on the right and bottom are much more pleasing.

The reason the umbrella makes the light softer is simply that it is being spread out more. Rather than the burst of light coming from the small flashhead it appears to be coming from the large umbrella. The relationship between the size of the subject and the size of the lightsource determines the harshness of the shadows. Small lightsource and small subject equal harsh light; big lightsource and small subject equal soft light.

The big umbrella is a nice lightsource but I want to make the shadows even softer, so I need an even bigger light. Moving the umbrella and flash closer to the monkey's fist is an easy way to make the light appear bigger, as in this photo. This photo looks very nice to me. The rope still has lots of texture to it, and contrast varies across the knot. The shadow is small, which I like, but notice that it is darker than in the above shot.

I decided to try and lighten the shadow on the right side. To do this I used a PhotoFlex 22" MultiDisc Kit--a reflector to bounce some of the light from the righthand side back to the left. It was obviously effective as the shadow appears much lighter. I'm not sure it's an improvement over the previous shot, however, as much of the contrast across the knot has been removed, making the photo again look a little one-dimensional. I could back the reflector off a little more so that not as much light is relfected on to the knot. That would still have the effect of lightening the shadow slightly, but its effect on the contrast is unappealing to me. I prefer the previous shot.

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1. I just purchased a 35 mm canon rebelxt. I am trying to use the canon 420ex flash which I just purchased. None of the directions are in English! I went to canons site and found nothing. Where can I get directions on how to use it?

2. I am trying to get pictures of a stage which has only incandescent light in the room. All the pictures have a tan/brown look. We were told that the onboard flash was too small and that the 420 would solve the problem. It didn't. Is this a white balance issue? What is the best flash for live stage work? (I can move about and use flash, but disgression is in order)

1) I'd guess you bought a grey market flash? They often don't have English-language instructions. It looks like these guys will sell a copy of the manual.

2) Off color might be a white balance issue. How far away are you shooting from? Any more than about 25 feet--I think--and the 420EX won't be powerful enough to do the job. Personally, I believe in always getting the biggest flash you can because of its faster recycle time. The 580EX would put out more power--if you need it--and be ready for the next shot quicker.

I'm considering the purchase of a shoe mount clamp to use with my SB600 and I already have the SC-17 cable. How do you use the cable with the shoe mount since it already has a shoe mount on it? Thanks!

Hey, Thanks for the straight-forward explanation, and simple example photos. :)

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