hdrpano, © Kilian Eisenegger 2023, info@hdrpano.ch, 3283 Kallnach, Switzerland

### Focal length and image size

First we have to choose a focal length based on the image
size. The smaller the focal length the less images we have to
create for the panorama. The image will be smaller accord-
ingly. If we want to create the largest possible image, we have
to move the focal length to the telephoto range. If we have
chosen the focal length, the corresponding image angle in x
and y has to be calculated.
We have to calculate the diagonal of the CCD chip. For a Sony
Alpha 77 we have 23.5mm x 15.6mm. The factor on full
format is 1.5 35mm x 24mm. The diagonal of the CCD chip is
28.21mm.
Viewing angle from lens
Focal length
With a focal length of 16mm, the viewing angle is 72.59° in
width and 51.98° in height.
### Image overlap

The average image overlap for panoramas is 30%. Now we
have to reduce the angle by 30% according to the focal
length to get an optimal overlap of the images.
The angles will change to 55.83° x 39.98°
### Panogear Software

The software of my Panogear calculates these values auto-
matically. The result can be displayed in a simulation before
taking the pictures
With the Sony Alpha 77 the following resolution at 7x5
images results with a focal length of 19mm:
At 35mm focal length 12x9 images:

In the software you can choose between different cameras.
Depending on the CCD chip size and focal length, the grid
changes.