private void CMB_camera_SelectedIndexChanged(object sender, EventArgs e)
{
if (cameras.ContainsKey(CMB_camera.Text))
{
camerainfo camera = cameras[CMB_camera.Text];
num_focallength = (decimal)camera.focallen;
TXT_imgheight = camera.imageheight.ToString();
TXT_imgwidth = camera.imagewidth.ToString();
TXT_sensheight = camera.sensorheight.ToString();
TXT_senswidth = camera.sensorwidth.ToString();
}
doCalc();
}