Sunday, August 30, 2015

Faux Fish Eye: Wrong Body, Right Lens

ISO 800, 1/25, F 8.0
Hurry, hurry, hurry. I was late for a swearing in ceremony of some new American Citizens at the San Bruno Public Library. I quickly grabbed a camera body from my bag and attached my 11-16mm DX format Tokina wide angle lens. I set the camera to ISO to 800, and made a quick sample shot to see how if I needed to change the ISO setting. I was stunned when I saw the clipped corners of the image. I took a while to realize that I had put a DX (a.k.a. APS format) lens on my full frame  D600 body. The Tokina wasn't designed for use with the larger format, so the physical edge created by the lens was clearly visible. I did manage to re-install the lens onto my D7000 body, and put my favorite 24-70 2.8 on the D600.

David Hobby blogged about using one particular APS lenses on a full-frame body. While his experience should have been identical to mine, he did point out the Nikon's APS 1.8 35mm lens would barely cover the full frame sensor when used wide open. Certainly the situation would be aggravated as soon as the lens was stopped down, but wide open and a centrally located subject, the sharpness of the lens could be fully utilized. I was unable to locate Mr. Hobby's  original post, but his use of this unusual lens/body combination is documented in his "Lighting In Layers" DVD set. The blog image created by this apparent miss-match can be seen here.

Nice Recovery! To illustrate the point, I simulated the limited area covered by the APS-sized sensor on the full-frame exposure. This approximates what the photo I would have made had I mounted the lens on my D7000 with its appropriate sensor.

Based on a liberal interpretation of the word "acceptable", this image could have been submitted on its technical merit. It's reasonably sharp and properly exposed, and assuming that the word "Return" was the center of attention, properly focused on the areas of greatest importance. It all reinforces a photographic truism: a technically marginal photo of a critical moment is better than a technically excellent photo that doesn't illicit viewer interest.

This is the photo I finally submitted. I thought it spoke to the importance of earning one's citizenship, and the flag in the lapel leaves no doubt as to where this new citizen's loyalties lie. It was never published.

That Kiss Of Light

"Kiss of Light" is a (Joe)  McNally-ism. Simply stated, it's light that doesn't dominate the image, gently supports the existing light. It should not cast a shadow of its own.

This photo was a cull* from a series of photographs from the Obon festival I made here in San Mateo.These shots, made in open shade, weren't worth considering for publication. However, when discussing exposure problems with a former student who was also there, I used some of these images to illustrate some potential exposure problems. I liked this particular shot well enough to make it the subject of this brief post. Two of these shots were labeled to be simplify identification in an e-mail message.

Open Shade: Besides a bluish tint. This can normally be corrected by selecting the cameras Open Shade white balance preset. Open shade also tends to be flat lighting with no sharp-edged shadows.

Imagine, if you will, an environment where light is coming from the left and right sides, as well as from above.  I was standing in front of a large building when I made this photo. This prevented any skylight from landing on the front of my subject's face. You can see that the cheeks and the forehead are lit, but the region below the chin, the eyes, and the teeth are not.

Front Light: This shot, also made at 1/1000 of a second, F 4.0, and at ISO 800, had a full blast from an shoe-mounted SB-900 speedlight. Just so that you know, the D7000 body was set to allow High Speed Flash Synchronization, so I wasn't limited to the normal ceiling of 1/250 of a second. The flash output was set manually because I couldn't rely on the camera's ability to properly render an image when the foreground subject occupied such a small percent of the total image area, as it did here. At full power, all existing facial shadows are essentially obliterated, and any sense of three- dimensionality removed from my subject's face.

Low Output Fill: The lead shot was made with the flash power turned to a much lower output level. A couple of  things are happening here. First, the flash now serves as a "fill" light, putting light in the subject's eyes, teeth, and neck. Second, the flash, which normally produces the equivalent of a Daylight white balance preset, is warmer when compared to the camera's Open Shade setting. This warm wash of light, when added to the cooler ambient lighting, gives the subject a healthier glow. And third, the flash introduces "catchlights", or glare spots, on any reflective surfaces.

How Much Is Too Much? During this experiment, I dialed the power up and down, chimping all the while, until I got something that I liked. I did not record my settings, so I would have to repeat the process if the distance between my camera and my subjects changed significantly.

Fill Light: By definition, Fill Light brightens the shadows, but does not eliminate them. We can see the details in the neck, along with the proverbial sparkle in my subject's eyes. Notice that when using the flash fill close to the lens axis, the catchlight will always appear at the point closest to the camera.The catchlights might seem a little low in this photo, but if you think of the eye as the reflective sphere that it actually is, the position is exactly where you'd expect them. Then too, humans are "hard wired" to assume that light comes from above, like sunlight. These low catchlights just aren't right.

I can't explain why there's a catchlight on my subject's teeth. I suppose I could have cloned it out in Photoshop, but I didn't bother for these samples. I do hope that this illustrates how a small "kiss of light" can add a little sparkle to an otherwise flat, open shade image.

*There are a number of reasons why the lead image wasn't considered for submission. First, the composition doesn't include the drummer's left hand, and cuts off the tips of the drum sticks. The subject is positioned in front of a background that is much brighter than the foreground/subject, which tends to draw the viewer's eye away from the main subject. And last, the image really isn't that compelling.