I have shot some video footage using two iPhones from two different vantage points for doing motion capture of a human figure. In order for this to work I need to do camera-matching in my 3D software. In order to do the camera-matching I'm searching for the following specs:
- iPhone 7's focal length (after cropping for stabilization)
- iPhone 7's sensor width and height (Update: 1/3" sensor = 4.80 x 3.60 mm)
Note that the iPhone 7 in question is not a Plus (so it has just one camera). Note also that this is for video footage, and that while shooting video the iPhone crops the frame slightly to compensate for stabilization. My understanding is that this results in a longer focal length. I've read that on iPhone 5 the result is a 4.1mm focal length instead of 4mm (or 4.027777~ to be precise… I think). Not sure if this is the same for iPhone 7.
So, I have the following specs for the iPhone 5, in case that helps determine those of the 7:
- iPhone 5's focal length: 4.1mm (after cropping for stabilization)
- iPhone 5's sensor: 4.54 x 3.42 mm
Thanks in advance for any help.
P.S. If you can explain how you found the answer that will be even more helpful than specs alone.
Best Answer
On the iPhone 6, I have found the video crop with stabilization activated to be 1.1x tighter than a still photo with stabilizer deactivated. The field of view goes from 63.9° to 58.1°, diagonally. The effective focal length changes from 4.2mm (29.3mm on full frame DSLR) to 4.6mm (32.3mm on full frame DSLR).
If you overlay a still image from the video footage and align it to a photo from the same position, you can see this crop in action.