Here is a Canon RF 100-400mm f/5.6-8 IS review. One of the less expensive lens…
At a glance:
- EF-Mount/Full-Frame Format
- Maximum Aperture: f/4-5.6
- One Ultra Low Dispersion Element
- NANO USM Autofocus System
- Optical Image Stabilizer
- Lens Information Display
- Full-Time Manual Focus
- Rounded 9-Blade Diaphragm
All images below © Lensrentals.com, used with permission.
LensRentals‘ Roger Cicala and Aaron Close took the new Canon EF 70-300mm f/4-5.6 IS II and opened it, tore it down to all its components.
In the conclusion they write:
[…] Canon [is] great at optomechanical engineering, and the Canon EF 70-300mm f/4-5.6 IS II is no exception. And unlike some of their cameras, they don’t seem to have a problem putting all the right features in their consumer grade models. We were impressed by the numerous elements that could be optically adjusted, by the metal collars and rollers, pleasantly modular and robust construction, and the efficient layout.
The new motor is tiny. By claim, it is both fast and accurate, and it appears it will be replacing the STM type motors for use in a lot of lenses. […] I saw nothing about the motor that made me think ‘this is going to fail.’ It’s a real USM with no gear train and by our examination, no glued together pieces that might separate.
Be sure to head over to LensRentals for pictures and step by step description of the teardown.