Any way to change iOS camera settings?

The camera image when captured through Vuforia is cropped compared to an image taken from the same vantage point through the system camera app; that crop factor appears to be nearly identical to what would happen when the 4:3 image is cropped to 16:9, then cropped again back to 4:3 when running on iPad (our target platform). This is fairly unfortunate; presumably Vuforia is requesting a 16:9 format image from the camera, and then cropping it again to fill the screen.

Is it possible to set Vuforia to request a different resolution from the camera, ideally with an aspect that matches the display? Or, barring that, in the app we're developing we are fine with getting a "letterbox" effect (as that area is covered over by our own UI anyway) and we just need as much horizontal resolution as possible; can we configure Vuforia to shrink-to-fit the image (with letterboxing) rather than crop-to-fit?

Thanks.