As demand for lightweight and accessible super-telephoto zoom lenses grows across full-frame mirrorless camera users, Sony's recently announced ‘FE 100-400mm F5.6-8 OSS’ and Canon’s proven bestseller ‘RF 100-400mm F5.6-8 IS USM’ are going head-to-head in the entry-level and hobbyist market.Both manufacturers have adopted a variable aperture (F5.6-8) strategy to maximize portability and affordabi..