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Canon RF 100–300mm F2.8L IS USM vs Canon RF 45mm F1.2 STM

Every spec side by side, from each maker's published figures.

Better figure, where one is clearly better

CanonRF 100–300mm F2.8L IS USMCanonRF 45mm F1.2 STM
Overview
ReleasedMay 2023November 2025
Optics
Lens typeZoomPrime
Focal length100–300 mm45 mm
Maximum aperturef/2.8f/1.2
Minimum aperturef/22f/16
Optical constructionTwenty-three elements in eighteen groupsNine elements in seven groups
Special elementsOne fluorite, four UD and one glass-moulded aspherical elementOne plastic-moulded aspherical element (Canon USA)
CoatingsSuper Spectra, ASC and fluorine coatingsSuper Spectra coating
Aperture detailConstant maximum f/2.8; minimum f/22f/1.2–16
DiaphragmNine bladesNine aperture blades
Angle of viewFull-frame diagonal 24°–8°15′; horizontal 20°–6°50′; vertical 14°–4°35′43°35′ horizontal, 29°50′ vertical and 51°20′ diagonal on full frame
Mount and compatibility
MountsCanon RFCanon RF
Image circleFull frameFull frame
CompatibilityCanon RF mount for full-frame and APS-C EOS R camerasCanon EOS R cameras; full-frame image circle
Teleconverter supportRF 1.4× gives 140–420 mm f/4; RF 2× gives 200–600 mm f/5.6Canon RF extenders not compatible
Focus and stabilisation
AutofocusYesYes
Minimum focus distance1.8 m0.45 m
Maximum magnification0.16×0.13×
Optical stabilisationYesNo
Autofocus detailTwo Nano USM motors independently drive the electronic floating-focus groups; full-time electronic manual focusGear-type STM autofocus with magnetic focus-position detection; full-time electronic manual focus
Focus distance detail1.8 m minimum focus throughout the zoom range; limiter selects full range or 6 m–infinityMinimum focusing distance 0.45 m; Canon does not separately specify AF/MF distances
Magnification detail0.06× at 100 mm and 0.16× at 300 mm–
Stabilisation detailCanon rates lens optical IS at 5.5 stops under CIPA conditions, and coordinated IS at up to 6 stops with EOS R5 and compatible bodiesNo optical image stabilisation (Canon USA)
Design
Dust and moisture resistantYesNo
Filter diameter112 mm67 mm
Maximum diameter128 mm78 mm
Length323.4 mm75 mm
Weight2,590 g346 g
ControlsSeparate focus, zoom and clicking control rings; front lens-function buttons and focus-preset controlsSeparate focus and clickable control rings; AF/MF switch; no iris ring or lens function button (Canon USA)
Zoom designInternal zoom maintains barrel length–
Filter detail112 mm front screw-in thread; no rear drop-in filter67 mm front screw-in filter thread
Weather resistanceDust- and moisture-resistant construction with heat-blocking white paintNo dust or weather resistant construction (Canon USA)
Dimensions detail128 mm maximum diameter × 323.4 mm lengthApproximately 78 mm maximum diameter × 75 mm length
Weight detailApproximately 2,590 g, as listed by Canon UK, Canon Japan and Canon Camera MuseumApproximately 346 g lens
Tripod mountRotating tripod collar with support foot–
Lens hoodET-124 includedOptional ES-73B hood and LP1116 case; E-67 II front cap and Lens Dust Cap RF listed by Canon
In the boxLens, E-112 front cap, RF dust cap, ET-124 hood, LS100-300 soft case and user manualFront and rear lens caps (Amateur Photographer); hood not included
Release detailMay 2023 first release confirmed by Canon's June 2023 retrospective announcement and Camera MuseumCanon Japan's 14 November 2025 notice confirms first sale on 28 November 2025; Photography Blog instead reports availability from 20 November without a matching regional maker day, so no UK date is inferred

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