Tags

, , , ,

But first, check out THIS must-have item…

Probably a bit chunky for tight pants (not that I ever wear tight pants, but just sayin’)—I’ll wait for the slim-line, water-proof cased model that—no doubt—is on its way. I shall be looking at passers-by more carefully from now on wherever I am, you can be sure. Adds a whole new dimension to being aware.

Now, to the subject of today: Miss O an I have been looking at footage out of the Panasonic HMC-152 cameras. For those whose eyes glaze over re. matters technical, you might want to skip ahead, but if you are still here, the video images out of these cameras  is designated ‘p’, for ‘progressive scan’—this jargon means that all frames are complete image frames. Any frame of video can be used as a still image. Shooting at 25 frames per second means that, potentially, thousands of useable images in any clip.

Digging deeper, the frame size of the 720p setting is 1280 pixels on the long side, and 720 on the vertical; accordingly, just under 1MP total pixels (921, 600). What does this mean for the size of an image?

Well, it all depends: if we use 72ppi (pixels per inch, or a standard PC screen display resolution, then a single frame from a video will display almost 18″ across; bigger than most displays. If printed at the standard setting of 300ppi, the same images will print at just over 4″ on paper—and that’s big enough to see plenty of detail, but you couldn’t get a cover image from it. On the other hand, if we select a printing resolution of 180ppi, that same image can print at 7″ on the long side, almost twice the size.

What’s the point? For our kind of books and products, it may mean that we do not need to shoot stills, from now on: we will record a workshop, for example, and simply scan through the footage for the stills we need. Scanning can happen as quickly as you need, too, with QuickTime, the viewing utility I use (the footage moves as fast as you move the cursor). Will these pulled-from-video images look as good as purpose-shot stills—no, but probably good enough for the purpose. As a commercial photographer for 30-odd years, I realises that—today—I have been overly concerned with visual technical quality.

Now to the last part of today’s post: I used the HMC-152 as the exemplar—but from now we will be shooting on the two NEX 6 bodies—and it has “true HD”: 1080p. This video is also progressive scan, but at a larger frame size: 1920 x 1080, or 2,138,400 pixels, almost 2.5 times the area of the Panasonic cameras. As well, the shallower depth of field for any given aperture (a function of the focal length and aperture) means that the larger sensor on the NEX 6 will yield more ‘film-like’ images in any case, and all the fast, old, and cheap manual focus lenses that I own can be used, too, for their own rendering style.

Doing the same calculations on the 1080p frame dimensions yields:

Display (on screen) image sizes: @ 92ppi, almost 21“; at 72ppi, almost 27″

Print size (for a print on demand book, for example): @300ppi, 6.4″ (so, 50% larger than the 720p video frames) and @180ppi, 10.6″, large enough for a cover.

Of course, if I were shooting a cover, I would shoot the stills as still, and at the full resolution of the sensor (16Mp), but the take-home message from today’s post is that not only are pro video cameras dead, but pro stills cameras are too, for certain kinds of work.