Saturday, June 30, 2007





CAMERA LENS CAPABILITY—

The top photo is a view of my pond with the camera’s zoom lens set at
its widest angle of view; 18 mm. Note the brown soil in the middle of the picture. The bright speck at water level surrounded by the brown area is the pond’s spill pipe.

The middle photo was shot at the lens’ full telephoto setting of 200 mm. Note how much closer the spill pipe appears.

These focal lengths must be multiplied by 1.6 in order to know
the 35 mm camera equivalency. This is because the CCD device which captures the image in a digital camera is smaller than a 35 mm film negative. Thus, the second image above, for example, is the approximate equivalent of a 320 mm lens on a 35 mm camera.

In the bottom image, I replaced the zoom lens with my Meade ETX 90 telescope; attaching it to the Canon Digital Rebel XTi camera with adapters. The telescope has a focal length of 1,200 mm and was used without an eyepiece for this image.
The camera was in the same location for all three pictures.

With inexpensive, digital cameras your composition usually is limited to the range of the zoom lens built into the camera. The digital, single lens reflex, camera offers a nearly unlimited range of lens choices.

The extremes at the upper end, however, extract a toll in the form of price as well as size and weight, the latter of which become limiting factors in their portability.

Yet, as you can see, today’s technology offers the serious amateur photographer a wide range of optical tools.

No comments: