Canon EF and RF Lenses – All Autofocus Motors

Lens Cost, Value, and Rental Ecosystem

• Canon glass and bodies are seen as excellent but very expensive; Sony, L‑mount and Micro Four Thirds are noted as more attractive for indie filmmakers and YouTubers.
• Several commenters justify Canon L‑series prices via longevity (10–30 years of use) and image quality; “buy the glass, rent the body” is still common wisdom, though bodies are now cheap enough to upgrade often.
• Local rental shops are reported to be disappearing, replaced by online rentals and informal “renting” via big retailers’ lenient return policies, which some see as unethical and harmful to local businesses.

Build Quality and Tradeoffs

• Users praise Canon L lenses for ruggedness, weather sealing, fast and sharp optics, and broad selection, but criticize their size and weight, which demand sturdier tripods and make outdoor shooting less pleasant.

Mount Compatibility and Legacy Systems

• Canon EF is praised for ~30+ years of near‑seamless electronic compatibility between late‑80s film bodies and modern DSLRs; EF lenses can also adapt well to other mounts.
• Nikon’s F mount offers much longer physical continuity (1950s onward) but with a confusing matrix of partial compatibility (AI/AI‑S, AF‑D screw‑drive, G, E, AF‑S, AF‑P) and missing features on many bodies and adapters.
• Mirrorless transitions (Nikon Z, Canon RF) complicate reuse of older glass; third‑party adapters with screw‑drive motors are emerging to fill gaps.

Autofocus Motors, Algorithms, and Control

• The article’s breakdown of USM, STM, Nano USM, and voice‑coil motors prompts discussion of open‑ vs closed‑loop focusing: bodies close the loop on “sharpness,” but lens position is not repeatable to sub‑step precision, which matters for calibration and machine‑vision uses.
• Distance encoders and EXIF focus distance are described as approximate. Focus‑by‑wire implementations on modern lenses are criticized for lag and coarse stepping versus older ring‑USM full‑time manual feel.
• Autofocus subject selection has evolved from single‑point / nearest‑subject heuristics to AI‑based eye/face/animal tracking running on dedicated processors, enabling extreme frame rates with continuous AF.

Third‑Party Lenses and Canon RF Lock‑In

• Canon’s blocking of third‑party autofocus RF lenses elicits strong backlash: users report buyer’s remorse, praise Sigma/Tamron EF options, and say they’re switching to Fuji or Nikon.
• Some argue Canon needs lens revenue for survival; others think the policy hurts reputation and accelerates customer flight. RF lens optical quality is viewed as mixed, especially for ultra‑wide zooms.

Article and Site Feedback

• The autofocus‑motor deep dive and companion articles are widely lauded for clarity and graphics, likened to high‑end technical explainers.
• Some report scrolling issues tied to the cookie banner and note a non‑compliant color scheme for consent buttons; the author acknowledges and adjusts.