Waldemar
Enthusiast
Jan 9, 2005, 7:32 PM
Post #2 of 3
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Re: [jerry] Avoid eye blur and how to fix in post?
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This is a bit of a long winded answer.
Yes, the camera's autofocus mechanism is trying to focus on the hands moving in the forground. The eyes look blurry because the aperture is very wide and the camera has chosen a focus plane about 10 inches in front of the eyes. Stopping DOWN to a smaller aperture/higher number may improve things.
The general rule of thumb in people photography/videography is to keep the eyes in focus because that will hold attention.
Aperture numbers refer to the ratio of the diameter of a lens to its focal length. The smaller number means a larger diameter iris. Each subsequent setting will have a larger number but is actually a smaller diameter. Additionally, each setting represents a reduction in light passing through the lens by half. From widest aperture to smallest aperture the numbers typically are:
1.4, 2.0, 2.8, 4.0, 5.6, 8.0, 11.0, 16.0, 22.0. 1.4 is the largest aperture. 22 is the smallest. The direction from 1.4 to 22 is referred to as STOPPING DOWN, and f22 is a lower aperture, not a higher one.
As one stops DOWN TO A LOWER, not higher, aperture, the depth of field starts to increase. This gives one the IMPRESSION of sharper focus in objects receding away from the photographer towards infinity.. There is in fact only one plane of focus in any given image (wherever you chose to focus), and the apparent depth of focus will be approximately be from a point 1/3 in front of your actual focus plane and another point 2/3 behind the actual focus plane. Manual focus 35mm camera lenses have scales on them that give you guidelines relating to depth of field.
There really is no way to improve an out of focus image. If you can afford to shoot the sequence again, do so. However, with the use of "sharpen filters" you may be able to bring the image into a zone of visual acceptability.
Hope this has helped.
G5 1.8. Final Cut/QT Pro/iMovie/Still Life. GL1. XL1-s
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