Not trying to hijack the thread...but can you explain that a little?
How do you get f/22 out of a fixed app lens?
It does sound wrong, and 'constant aperture' might be a better term. Fixed aperture used to mean fixed aperture. Now that fixed aperture doesn't mean fixed aperture, what do we call fixed aperture lenses? (Later edit, having read the recent posts: Fixed aperture lenses do exist, they are still manufactured, and they are quite common. There is no need for an adjustable aperture in many applications.)
Constant aperture zooms hold their f-number as the focal length is changed, so if you set f/4 at the wide end then zoom in you will still have f/4 at the long end. You can still change the aperture: the lens still has adjustable aperture blades.
Remember that the f-number (which can be written as 'f/') is the focal length of the lens divided by the diameter of the entrance pupil,
not the physical diameter of the aperture. The entrance pupil is the image of the aperture blades (I'll call the physical aperture the iris) you see when looking through the front of the lens - ie the image of the iris formed by the lens elements in front of it. It can be magnified or reduced.
As the lens zooms, the magnification of the iris will change. Lens designers can arrange things so that the magnification of the iris changes in proportion to the focal length of the lens, so that the ratio of focal length to entrance pupil diameter stays constant even though the diameter of the iris itself stays the same.
If you think about an 18 mm to 55 mm f/3.5 to f/5.6 zoom, the entrance pupil diameter must be 18/3.5 = 5.1 mm when the lens is wide open at 18 mm and 55/5.6 = 9.8 mm when the lens is wide open at 55 mm. The diameter of the iris has not changed, only its magnification. To maintain a constant aperture, the entrance pupil diameter would have to be magnified to 55/3.5 = 16 mm at 55 mm.
Best,
Helen