madmaxmedia
New member
Since most all lenses are softest wide open, I wonder how lens makers arbitrarily draw the line at what the max. aperture is for a lens.
For example, in C-mount there are a few lenses that come in f/1.5 and f/1.9 apertures (or other numbers, but half to one stop apart.) Is there that much difference in the lens designs, or is it mainly just that the blades on one lens opens a little more than the other?
Or perhaps 2 different such lenses could have the same basic design, but the tolerance for the glass elements and overall manufacturing is tighter for the faster lens. Because of this the wide open fast lens is similar in image quality to the wide open slower lens.
For example, in C-mount there are a few lenses that come in f/1.5 and f/1.9 apertures (or other numbers, but half to one stop apart.) Is there that much difference in the lens designs, or is it mainly just that the blades on one lens opens a little more than the other?
Or perhaps 2 different such lenses could have the same basic design, but the tolerance for the glass elements and overall manufacturing is tighter for the faster lens. Because of this the wide open fast lens is similar in image quality to the wide open slower lens.