If I shot a video with lots of markers to be tracked, I know I could get the lens data in the Camera specs sheet, BUT, when using this point and shot camera, even though the lens cannot be removed, you can still zoom in and out, so…it’s not like the camera stores data on how far it zooms in or zooms out so assuming I zoomed a little, how do I know the exact Focal length of the lens ?
1: Does zooming in and out of the G7X Mark II change what I need to put inside the Focal Length in Blender ?
2: Does zooming in and out of the G7X Mark II change what I need to put inside the Sensor Width data ?
3: Does zooming in and out of the G7X Mark II change what I need to put inside the Sensor Pixel Aspect Ratio ?
Sterling !
The zoom is not changing during the shooting because I know that would render tracking impossible.
Say it was zoomed in BEFORE pressing the record button, so how do one retrieve the NEW focal length ? Since the video don’t store that data, thanks !
If you shoot a still image before or after recording the video you can get the focal length from the image exif data.
Even knowing the focal length, it is still worth also using refine for the focal length in the tracker.
Do you think the exif data store the “generic” focal length data or it actually stores the new focal length of the len as in taking into considering current zoom ?
Yes, as SterlingRoth pointed out, it should store the camera settings (ISO, shutter speed, aperture, focal length, etc) for that particular image.
You can try doing some tests by photographing the same scene at different zoom levels, then compare the exif data for the saved images. It should save different focal lengths for different zoom levels.
Ok I just took a picture using my G7X Mark II with zero zoom and here is the data when I right click->information:
F-Stop: 1.8
Exposure: 1/100 Sec
ISO: 640
Focal Length: 9mm
Max Aperture: 1.6875