Zoom zoom, tisk tisk

Early on our ride along the Pine Creek Rail Trail we stopped to watch a few Canada Geese as they began their day. I first viewed the distant scene with my D600 and realized immediately that the 24-85 mm zoom I had on wouldn’t get me close enough. I had also brought along the HX9V and its zoom (to an apparent 400 mm) brought me plenty close. When I got home however I was disappointed. I had been drawn by the Siren’s Song of digital zoom. Many of today’s Point-and-Shoot cameras boast both optical and digital zoom capability. Optical zoom results from the physics of light passing through three (and often, many more) pieces of glass the relative positions of which can be changed to create a lens with variable focal length. The latter has its effect through digital processing of the sort that used to be carried out in the dark room and which now may be achieved using any number of software packages available for image editing such as Adobe Lightroom for example. To create an image using digital zoom the firmware aboard your camera enlarges the center of the image and crops information at the periphery. The result gives the appearance of a photo taken with a very long lens. Images produced with digital zoom are lacking in quality because the digital manipulation enlarges the pixels themselves and adds interpolated information to fill newly-created spaces; together these effects reduce the image resolution and increase its grainy appearance. My Sony HX9V boasts a 16X optical zoom and, depending on the recording resolution, digital zoom capacity to more than twice that. It is important to remember that the two are not equivalent and a longer focal length isn’t necessarily better if you’re getting there through digital interpolation. When purchasing a Point-and-Shoot camera my recommendation would be to pay close attention to the amount of optical zoom and ignore digital zoom altogether. If you really want more zoom effect, this is easily created via post-processing.

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