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.

15 thoughts on “Zoom zoom, tisk tisk

    • Hey Seonaid! Glad to see your smiling Gravatar once again. I’ve been reading your posts from Venice with envy! Such a wonderful opportunity in so many ways. Thanks for responding to say that this post about zoom was helpful. I am glad. D

  1. Such clarity! Good to know about the optical part being more important than the zoom part. Will remember that next time I buy a camera. But all that physics? It’s above my head. Never took it in HS or college!

    • It’s optical you want … over digital. Not optical over zoom. Both optical and digital are TYPES of zoom. Whatever. Really warm, humid, and very, very sticky here. Really looking forward to fall and, would you believe it, winter. D

      • I told you it was over my head! Agreed that the cooler fall tempts greatly outweigh the heat/humidity of summer. Last night it was in the 50’s and Wednesday is forecasting temps near 90!

        • We have had 90s the last couple of days and near 100% humidity. Really uncomfortable. We had some rain and a few thunder storms this evening, so hopefully that’ll mean an end to this nasty stretch. D

    • I know what you’re saying about typos. I have found, with increasing frequency, that today’s computer are programmed to think that they know more about what we’re trying to say than we, ourselves, do. The darn things try to complete my words for me. I have to proof very carefully to find words that the software has inserted that I never intended. Thought again about you yesterday as I removed wool from fence lines. You are correct in that it is a tedious job – but very, very, necessary nonetheless. Say ‘Hi’ to your daughter from me. D

      • Auto-correct and auto-fill will be the end of spelling ability in this and future generations. What will replace the spelling bee? I told Audrey hello from you and she said, “I don’t want to I don’t want to I don’t want to.” No offense, that is her current response to everything.

        • I wish we could share a meal with you and Robb. Although our lives are very different, I think they are very similar in many ways (that is, believe it or not, we are all facing many of the same ‘challenges’). It would be nice to talk even if for nothing else other than mutual support and encouragement. Be tough, and be good. You know you and I have our own, adult, ways of expressing “I don’t want to I don’t want to I don’t want to.” Give the kid a break. D

  2. The physics teacher inside of me is pleased to see a life-scientist applying physics to his everyday life 🙂 On a somewhat sad note, geometric optics is very much downplayed in K-12 physics education and that’s a real shame as the topic lends itself well to everyday life. What’s more the teaching techniques are very much hands-on and appropriate for school-aged youngsters.

    • Thanks Maurice … I’ve got to reply to your lengthy reply to my comment on 10,952 which was, by the way, very kind. By the way … did you ever receive the link to the BBC piece about ‘connectivity?’

    • I agree with you, Maurice – it is great to see physics applied to everyday life. But it’s sad that it is not (anymore?) an important part of the curriculum – I was a geometric optics fan and remember the projection experiments I did myself as a child with lenses from old glasses.
      I wonder if the generation of digital natives then probably believes that “anything can be fixed with software”? “Digital zoom” should be called an oxymoron really.

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