Saturday, December 12, 2009

Motion Blur, Shallow DOF

Originally uploaded by scott.jantzen

I created this image using natural light from a window to camera right. I took several images with flash, but didn't like how the flash stopped the wheel. I wanted the pottery wheel to be blurred, creating a sense of motion and I liked the shallow depth of field.

Introduction to Off Camera Flash (OCF)

This past week I took a series of photographs to demonstrate how using off camera flash can be used to create much more dynamic and interesting lighting for portrait photos.The first photo was of Bailey, sitting in a stairwell with cool, late afternoon light coming through the windows and harsh fluorescent lighting from above. I took the photo on program mode where the camera chose the shutter speed and aperture. As you can see the shutter speed was too slow resulting in a slightly blurred image.

The second shot, was again on program mode, but this time with the little pop-up flash on the top of the camera. Notice how the image looks very flat and two dimensional. I then switched to manual mode and took several test photos at 1/200th of a second and an aperture of f/2.8 to underexpose the image so that the fluorescent lights were pretty much killed. We then started adding flash to build the light back up to where we wanted it.

This next shot was taken with one flash, but with no light modifier or diffuser, pointed from camera right at about a 40 degree angle. Note how the exposure is at the right level and we are getting some more dynamic shapes and shadows, but the light is too harsh and the squiggly shadow to the right of Bailey's eye and the shadow to the left of her mouth are very distracting.

I then shot the flash through a white umbrella, to create a much bigger light source. (OCF Principle #1: The bigger the light source, the softer the light) Note how the shadow from the arm of Bailey's glasses is reduced and the light has softened and is much more flattering. Much better.

The next photo in the sequence was taken with a second flash, located right behind Bailey. I like the result, but the backlighting is a bit too "hot".

For the last shot in the sequence, I moved the backlight flash, off to the side, still behind Bailey, but out of the frame to camera left, so that we would still get some highlights on Bailey's hair but that it wouldn't be overpowering. I then moved off to the side to get some of the stair railing in the background.

After the photo shoot I uploaded the photos into Lightroom and did some minor cropping and editing. You can see the final edited photos here. Thank-you David Hobby and Strobist. You've taught me everything I know about OCF.

Which lens to take to Africa?

I recently had a friend ask me this question. She is going to Malawi to work with girls and women, helping them with their education needs. She wants to take her camera to document her travels and is totally torn between purchasing a 31 mm f/1.8 or a 50 mm f/1.4. She needs a fast lens, meaning that it will have a large aperture to let in lots of light (ie. small aperture guide number f/1.4 as opposed to f/4.5) because many of her photos will be taken in dark huts. This situation and the need to travel light pretty much rules out any reasonably inexpensive zoom lens in the f/3.5 - 4.5 range. Following is the email I sent to her.

I've been thinking about your lens situation. I don't know what your equipment budget is, but I think you would be very happy if you could have both the 31mm and the 50mm. You could use the 31 for tight quarters where you want to take a photo with some context ie. mother with children, children playing, women working, etc. Then you'd use the 50 for when you want to get in for close portraits and catch the look in their eyes and totally remove the person from their context by blurring out the background. The two lenses have different purposes. You are taking your camera to Africa to tell a story and to bring the story of these women back to Canada. I think the 31mm lens might be the better choice for that purpose. Context is important to storytelling.
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