Plexi Head
Active member
Sigma's primes should work with AF and they have a dock for firmware upgrades when Canon goes and messes with their AF programming. Every lens, including Canon's, acts differently in terms of how the AF engages so some pull focus more naturally than others. Tokina's zooms all use a screw drive AF that is pretty loud. They also don't have full time MF override so you have to engage the AF whenever you want to use it an then disengage it if you want to do any manual focusing.
Basic AF works with 50mm Sigma Art series prime. Face recognition does not, tracking does not - terrible breathing - footage unusable for broadcast. Sigma 50mm Art series prime to me is the best looking lens I have ever used on C300MKII. I own and use the 18-80 servo but not in the same league as Sigma 50mm prime for locked off shots e.g. interviews etc. I also own the Zoom Primes and many, many Canon zoom and prime lens but none produce the magic (in very specific environments) that the Sigma 50mm is able to produce. Just my opinion.