Focus Pattern Instruction

I believe the best focus pattern is the Sieman's Star: a radiating pattern of black and white wedges each 5 degrees wide. It is easy to see in or out-of-focus even with camcorder view finders which have awful resolution. They are useful to check if a zoom lens holds focus at different focal lengths. The star is especially useful with wide-angle and fish-eye lenses to check focus distance. It is also useful with wide-angle adapters on professional video zoom lenses when the back focus or macro feature is adjusted to accommodate the wide angle adapter. Your view finder will not resolve as well as film or a video recording chip will. but you can easily see the points of out-of-focus when you "rack through" perfect focus. To "rack through" focus you split the difference by feel as you see the image go out-of-focus on each side of perfect focus. Down load some of these patterns for the future or make some high contrast copies.

Here are letter-sized Focus Patterns for download in various formats:

PDF Format 11k (Recommended)
EPS Format 84k
GIF 300dpi 147k
GIF 75dpi 53k

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