Re: Prime lenses

I actually don't know of a website, but I can tell you that the 12 x 4.8 that you refer to is the standard structure for a zoom lense specification.

The first number is the zoom factor. The lense you reference has a zoom factor of 12x, a lense with a zoom factor of 17x zooms farther, and for many professional sports like football, the networks utilize lenses that are as much as 70x or 77x (or more).

The second number, in this case 4.8, refers to how wide the lense can get at the extreme wide angle. 4.8 would be very wide for an EFP zoom lense. In earlier posts in this string, lenses were mentioned that had wide angle specs of 8 or 9. These lenses can't get as wide as a 4.8. More common specs for the widest point of a zoom lense are 6.7, 7.0, 7.3, etc. The smaller the number, the wider the shot at the widest setting.

The zoom factor isn't the only thing that indicates image magnification. A 17x lense that has a wide setting of 4.8 will not yield as "tight" a shot from a given position as a 17x with a wide angle of 9. The zoom has to be taken into account along with the wide angle number.

For most production people, the wide setting is the important factor. Very few of us in production need a lot of zoom on a regular basis. News videographers need zoom often as they may be held back from the image they need to shoot and need the "reach" to get the shot.

I'm sure there is other wisdom around here. Just a couple of observations.

-Tim Kolb