14 May, 2012

Casio Exilim EX-ZR200 - Zoom

24 mm focal length
300 mm focal length

 24 mm focal length
63 mm focal length

24 mm focal length, 1/15 seconds shutter speed
 137 mm focal length, 1/8 seconds shutter speed
300 mm focal length, 1/8 seconds shutter speed
There's a rule of thumb that says at focal length x mm, the slowest shutter speed you can use is 1/x seconds before the image starts to blur. Yet this image looks ok. I think at low shutter speeds, the camera makes use of its high speed by taking several pictures and combining them, instead of one long exposure. I think this was taken in Premium Auto mode.

24 mm focal length
68 mm focal length
300 mm focal length

One of the features of the ZR200 is Multi Frame SR Zoom, which is like an advanced digital zoom. There's a difference between digital zoom on camera and on computer - on camera, the interpolation can be done before the image is compressed, so the image is potentially better. If you don't take pictures at full resolution, you can use digital zoom without losing quality. The camera increases the limits of SR zoom at lower resolutions.

24 mm focal length
151 mm focal length
300 mm focal length. This is the limit of optical zoom.
I think this was at 33.8x or 811 mm focal length, the limit of single frame SR zoom, where the camera only takes one picture.
I think this was at 45x, or 1080 mm focal length, the limit of multi frame SR zoom. Beyond this the ZR200 only has digital zoom.

Updated 8 July 2012
Ok! I finally got around to taking some pictures to test the zoom.
I took 3 pictures using the different zoom levels: only optical zoom, single shot SR zoom and multi shot SR zoom. The maximum zoom level in SR zoom depends on the resolution, and whether it's single or multi shot. For 5 MP, single shot SR zoom goes to 33.8x and multi shot goes up to 45x. All pictures were taken with ISO 200 and tripod.
However, this picture is not enough to compare, since the text is readable using only optical zoom. So I took another picture from further away:
Only using optical zoom
Comparing optical zoom and multi SR zoom. Multi SR zoom seems less noisy, but I'm not sure if that's due to processing. To me, multi SR zoom seems a little bit clearer.

Still figuring out how to test the stabilisation effect of combining pictures.

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