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Old May 6, 2006, 1:22 PM   #1
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For those of us who grew up using 35mm cameras and lenses, it is helpful to know the equivalent 35mm focal length on digicam lenses. In 35mm photography, we learn which lens lengths are good for certain situations, and it becomes easy to pre-select a focal length prior to taking the picture. Of the FZ series cameras, only the FZ-30 simplifies the task by putting the 35mm equivalent numbers right there on the zoom ring. The rest of the cameras in the series give you only the vague "X number" in the viewfinder -- 1x, 2x, 3x and so on -- so that it is difficult to know "which lens" you are using at the moment.

However, it is easy to construct a chart that will translate zoom magnification numbers into useful 35mm equivalent values. You can either print it out (small) and stick it on the bottom of the cam for reference, or like I do, memorize the numbers (it is no more difficult than memorizing a multiplication table like you did in primary school).

Here goes...

The base focal length (full wide angle) for most of the FZ series (FZ7, FZ20 etc) is 6mm. Because of the relationship of the lens image to the sensor size, the equivalent 35mm camera focal length is 36mm. The chart is worked out by simply multiplying 36 times each whole number zoom position.

1X = 36mm
2X = 72mm
3X = 108mm
4X = 144mm
5X = 180mm
6X = 216mm
7X = 252mm
8X = 288mm
9X = 324mm
10X = 360mm
11X = 396mm
12X = 432mm

You will notice some values close to those of traditionally favorite lenses along the way, like 70mm (2X), 100mm (3X), 180mm (5X), 280mm (8X), and 400mm (11X). It can be helpful to pre-select a zoom number in order to emulate the characteristics of a particular lens value.

Also notice that zoom lenses give a dramatic amount of change in the low ranges (the move from 1X to 2X doubles the magnification of the lens), but there is little relative change between each "X" step the higher up you go (you must go from 6X all the way to 12X to double the magnification). So, each zoom number between 6 and 12 gives just a small increment of change.

Some of the FZ cameras (FZ5 etc) use a starting equivalent focal length of 35 instead of 36. Practically speaking, there isn't much difference, but if you like you can use a calculator to work out the exact focal lengths -- 35 x 1, 35 x 2, and so on.

-- PK

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Old May 7, 2006, 10:06 AM   #2
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Old May 7, 2006, 9:59 PM   #3
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Old May 7, 2006, 9:59 PM   #4
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