Already have the Canon EF-S 18-135mm f/3.5-5.6 IS that came with my 60D but also purchased the Canon EF 50mm f1.4 USM Lens only because I like this focal length and the speed of this lens. I am not thrilled with the budget EF-S 18-135mm and need something that is better quality and has more reach. The Canon EF 70-300mm f/4-5.6 IS USM Lens has good center sharpness wide open at the wide end. Center sharpness decreases slightly as the focal length is increased to its weakest at 300mm. The lens becomes soft beyond 200mm. Stopping down improves sharpness somewhat but it is still weakest at 300mm. Canon calls this the Canon EF 70-200mm f/4L IS II USM. EF: Electronic Focus, as all Canon's lenses have been since 1987. L: Expensive as L. IS: Image Stabilization. II: Canon's second version of this lens. USM: Ultrasonic Autofocus Motor. Optics. Canon EF 70-200mm f/4L IS II internal construction. Fluorite and UD elements. This better wide angle performance of the EF 24-70 comes at the cost of slightly lower 70mm MTF performance at wide aperture and slightly greater linear distortion and chromatic aberration. The EF 24-70mm f/2.8L is compared with the EF 24-105mm f/4L IS and the EF 28-135mm f/3.5-5.6 IS lenses here. Design: Canon L Series. The EF 85mm f/1.4L IS USM is rather squat, measuring 4.2 by 3.5 inches (HD) without the included hood attached; the hood adds about two inches to the height. It weighs 2.1 Canon calls this the CANON ZOOM LENS EF 11-24mm f/4 L USM. EF means "electronic focus;" there is an autofocus motor inside the lens. L means as expensive as L. USM (Ultra-Sonic Motor) means that the focus motor operates reasonably silently. Optics top. Canon EF 11-24mm f/4L internal diagram. Aspherical, Super UD Glass, UD Glass and glass. RF Version: Canon RF 70-200mm f/2.8L IS USM; Canon EF 70-200mm f/4L IS USM. Announced: August 24, 2006; Discontinued: September 2021; RF Version: Canon RF 70-200mm f/4L IS USM; Canon EF 70-200mm f/4L IS USM II. Announced: June 6, 2018; Discontinued: March 2021; RF Version: Canon RF 70-200mm f/4L IS USM; Canon EF 70-300mm f/4-5.6L IS USM 24mm. EOS 5D Mark IV/ EF24-70mm f/4L IS USM/ FL: 24mm/ Aperture-priority AE (f/11, 20 sec., EV-1.3)/ ISO 800/ WB: White fluorescent light. I often use a wide-angle focal length to capture a night shot of highway junctions because of their gigantic scale. With the EF24-70mm f/4L IS USM, a sharp image can be produced without aberration in the Canon calls this the Canon Lens EF 85mm f/1.4 L IS USM. EF: Electronic Focus, as all Canon's lenses have been since 1987. L: Expensive as L. IS: Image Stabilization. USM: Ultrasonic Autofocus Motor. Canon EF 85mm f/1.4 L IS USM. bigger. Optics. Canon 85/1.4 internal construction. Aspherical element. 14 elements in 10 groups. As I said the new lens is already out. the 24-70 f/4 IS. Supposedly Canon is preparing to switch over the kits using the 24-70 f/4 IS. And the 24-105 got kitted up in so many 5D3 and 6D packages that the market got totally swamped by split kit lenses that are for all intents and purposes, new. And the Tamron 24-70 VC came out as well. 69oQ4w.