Saturday, June 26, 2010

iPhone 4 video frame difference

One surprising thing I've noticed about the iPhone's camera; the camera's framing for video is very different from the still camera's framing; and it's NOT just the top and bottom crop to fit the 16:9 aspect ratio.

I first noticed it when switching between camera and video mode; the video image jumps in noticeably. Taking a video and a still, and overlaying the 1280 x 720 video frame on the 2592 x 1936 still frame (below) you can see that it's significantly cropped on the sides. I thought that maybe the crop size would be the equivalent of 2560 x 1440 (double the 1280 x 720 size.) I was wrong.

Since I took the pictures while hand holding the camera, the alignment/scale is approximate. But doing a rough calculation, the area covered is about 2120 x 1190 which isn't close to being double 1280 x 720.

Is this important? Well, no, but it is kind of curious.

Overlay of iPhone video frame over iPhone still frame

1 comment:

Arlen said...

Hmm, think about when you shoot video on a DSLR. The camera might be capable of taking still pictures that are 8,000 pixels across. But that doesn't mean the camera can shoot in video at half that resolution (in this example, 4K). Though it would be sweet if it did...