RE: Movement of 'smudges' on a windscreen
I'm sorta embarrassed to post this - maybe I'll redo it later - but here's a rather crude preliminary look at the behaviour of objects stuck on a
A few notes..
The main things you are looking at here are small but deep stone chips on the windscreen.
Why? Well, I had guessed that the 'smudge' might have been in the order of 1" in diameter, so I took along a round piece of orangish paper and some
sticky tape (3/4", 19mm). However, when I tried it, it was way too big (I had to bring the camera too far back, and the object was too
well-focused). I roughly ripped it way down in size, and then I stuck it (a bit low) on the windscreen. While moving the camera round, I noticed
that the stone chips were working admirably, so i thought what the heck, and just went with them instead. If you look carefully you will see that
sticky-taped bit of paper low down in some of the images.
The camera was an (old) Sony DSC-P73 5mp camera, lens set to widest (approx 39mm equiv - iphone is about 37mm equiv), and manually set to f2.8 (same
as iphone). I chose that camera as it was my nearest match to the iphone. The sensor is likely larger, meaning that the objects in my image would be
little more out-of-focus than on the iphone.. maybe - I'd have to research that further. Camera was handheld about 1-2" (25-50mm) or so from glass,
and was moved over a range of less than 3" (~75mm).
The images were taken at full resolution (and are available if anyone wants them, but I'd suggest that if you really want that, let me re-do it a
little more professionally!). The ONLY alterations to them were to align the backgrounds as closely as possible, and resize down to make the gif.
There was NO other resizing or angling or distortion of the original images to get them to match. In fact you can see very slight mismatches due to
the camera being handheld, which meant that its angle varied slightly between each shot. In hindsight, I probably should have labelled each mark so
you can tell which is which, but I think you'll work it out.
It is VERY clear that the background scene is almost completely unchanged, yet by very small movements of the camera I could place the stone chips and
sticky-taped paper all over the place, wherever I wanted.
It is also very clear the blurring effect of the objects looks rather similar (but exaggerated by the larger sensor size on my camera) to the images
being discussed. If I had used a small round object as I first intended, the match would be much closer.
Finally, I would re-iterate that the blurring of the object/s in the original pics is evenly distributed around the object. It is NOT motion blur.
Motion blur looks quite different. Therefore, either the object looks like that
or it is close to the lens and out of focus. And you'll notice a
few 'orbs' and streaks - the windscreen was pretty dirty and I decided to leave it like that.
Questions and criticisms welcome..
PS - where's firemoon?
[edit on 27-3-2010 by CHRLZ]