Curious what the experts here think regarding the feasibility of making something like this:
teleconverter for crop bodies (1.6 ex) that allows a 300 f/2.8 lens to be converted to an equivalant say 200mm f/2. My thinking is that by "using all of the glass" to fill the crop sensor, you would essentially be making the lens more "wide"- like if it were on a FF camera. The extra light gathered on the sensor should translate into a faster lens right? I know it would not be a "true" 200mm f/2 but would add a lot of versatility to this and other lens.
Probably missing something obvious but thought I would throw it for comments.