Cameras Ranked

100–400 Canon RF 100-400mm F5.6-8 IS USM vs 75–300 Canon RF 75-300mm F4-5.6

Canon RF 100-400mm F5.6-8 IS USM vs Canon RF 75-300mm F4-5.6: our pick for most people is the Canon RF 75-300mm F4-5.6. Pick the Canon RF 100-400mm F5.6-8 IS USM if you want more reach at the long end, or your body has no in-body stabilization or you shoot handheld video (focal length: 100-400 mm vs 75-300 mm; stabilization: 5.5 stops vs No). Pick the Canon RF 75-300mm F4-5.6 if you carry it all day or travel light, you shoot in low light or want a blurrier background, you want a wider view at the short end, or you want cheaper filters (weight: 635 g vs 507 g; widest aperture: f/5.6-8 vs f/4-5.6; focal length: 100-400 mm vs 75-300 mm; filter thread: 67 mm vs 58 mm).

To one scale. Canon RF 100-400mm F5.6-8 IS USM: length 164.7 mm, diameter 79.5 mm, filter thread 67 mm; Canon RF 75-300mm F4-5.6: length 146.1 mm, diameter 71.2 mm, filter thread 58 mm.164.7 mmø79.5Canon 100–400635 g146.1 mmø71.2−18.6 mmCanon 75–300507 g
Both to one scale, from each maker's length and diameter, the filter thread in yellow. The rings are drawn, not measured.
To one scale. Canon RF 100-400mm F5.6-8 IS USM: length 164.7 mm, diameter 79.5 mm, filter thread 67 mm; Canon RF 75-300mm F4-5.6: length 146.1 mm, diameter 71.2 mm, filter thread 58 mm.164.7 mmø79.5Canon 100–400635 g146.1 mmø71.2−18.6 mmCanon 75–300507 g
Both to one scale, from each maker's length and diameter, the filter thread in yellow. The rings are drawn, not measured.

The pick, in points

Lead for a pick: 1

Canon 100–400

3points

Wins on focal length (longest) and optical stabilization.

Canon 75–300

7.5points

Wins on weight, widest aperture, focal length (widest) and filter thread.

Each real difference scores its importance for the side that wins it; a lead under 1 is “it depends”. How the weights work

The Canon 75–300 on its ownThe Canon 100–400 on its ownAll Canon RF lenses

Where they differ

7 of 20 specs

Each bar is the gap as a share of the smaller value, on one scale from 0 to 100%; an arrow end is a gap past 100%. The dashed tick marks where a gap starts to count.

  1. Widest aperture

    Importance 3

    Canon 100–400f/5.61Canon 75–300f/42

    1.6 apart (40%), to the Canon 75–300

    3points

  2. Weight

    Importance 2

    Canon 100–400635 g3Canon 75–300507 g4

    128 g apart (25.2%), to the Canon 75–300

    2points

  3. Focal length (longest)

    Importance 2

    Canon 100–400400 mm5Canon 75–300300 mm6

    100 mm apart (33.3%), to the Canon 100–400

    2points

  4. Focal length (widest)

    Importance 2

    Canon 100–400100 mm5Canon 75–30075 mm6

    25 mm apart (33.3%), to the Canon 75–300

    2points

  5. Optical stabilization

    Importance 1

    Canon 100–400Yes3Canon 75–300No

    Only the Canon 100–400 has it

    1points

  6. Filter thread

    Importance 0.5

    Canon 100–40067 mm3Canon 75–30058 mm4

    9 mm apart (15.5%), to the Canon 75–300

    0.5points

  7. Closest focus, wide end

    Importance 1

    Canon 100–4001.2 m3at 100mmCanon 75–3001.5 m4

    0.3 m apart (25%), not counted: compared only between lenses of the same focal length (widest)

    0points

Also different, no weight reads them7

  1. Widest aperture at the long end

    Canon 100–400f/81Canon 75–300f/5.62

    2.4 apart (42.9%)

    Not weighted

  2. Length

    Canon 100–400164.7 mm3Canon 75–300146.1 mm4

    18.6 mm apart (12.7%)

    Not weighted

  3. Diameter

    Canon 100–40079.5 mm3Canon 75–30071.2 mm4

    8.3 mm apart (11.7%)

    Not weighted

  4. Maximum magnification, wide end

    Canon 100–4000.09x3at 100mmCanon 75–3000.06x4at 75mm

    0.03 apart (50%)

    Not weighted

  5. Maximum magnification, long end

    Canon 100–4000.41x3at 400mmCanon 75–3000.25x4at 300mm

    0.16 apart (64%)

    Not weighted

  6. Elements

    Canon 100–400123Canon 75–300134

    1 apart (8.3%)

    Not weighted

  7. Aperture blades

    Canon 100–40093Canon 75–30074

    2 apart (28.6%)

    Not weighted

Side by side, to scale

Focal length on one log scale

Focal length on one log scale: Canon RF 100-400mm F5.6-8 IS USM: 100 to 400 mm; Canon RF 75-300mm F4-5.6: 75 to 300 mm.Canon 100–400Canon 75–300+100 mm−25 mm5085135200400
The focal lengths each maker states.

Specifications

SpecificationsCanon RF 100-400mm F5.6-8 IS USMCanon RF 75-300mm F4-5.6
Focal length100-400 mm575-300 mm6
Widest aperturef/5.6-81f/4-5.62
Closest focus1.2 m at 100 mm, 1.05 m at 400 mm31.5 m4
Maximum magnification0.09x at 100 mm, 0.41x at 400 mm30.06x at 75 mm, 0.25x at 300 mm4
Stabilization5.5 stops3No
Weight635 g3507 g4
Length164.7 mm3146.1 mm4
Diameter79.5 mm371.2 mm4
Filter thread67 mm358 mm4
On sale fromOct 20217Not stated
Elements123134
Aperture blades9374
Weather sealedNot statedNo4
Focus motorNano USM3DC motor4
HoodET-74B (sold separately)3ET-60 (sold separately)4
ExtendersExtender RF1.4x, Extender RF2x3Not stated

Same on both

  • Mount Canon RF3
  • Covers Full frame
  • Type Zoom
  • Groups 93

Full specifications, side by side†

Show all 10 rows
Full specifications, side by sideCanon 100–4003Canon 75–3004
Lens construction9 groups, 12 elements9 groups, 13 elements
Diameter and length79.5 mm × 164.7 mm (Approx.)71.2 mm × 146.1 mm (Approx.)
Drive systemNano USMDC motor
Filter size67 mm58 mm
Minimum aperture32 - 4532 - 45
Diaphragm bladesDiaphragm blades: 9Number of diaphragm blades: 7
Weight635 g (Approx.)507 g (Approx.)
Included lens capLens Cap E-67 II & Lens Dust Cap RF (included)Lens Cap E-58 II & Lens Dust Cap RF (included)
Lens hoodLens Hood ET-74B (sold separately)Lens Hood ET-60 (sold separately)
Lens caseLens Case LP1224 (sold separately)Lens Case LP1019 (sold separately)
Rows only one maker lists: 14

Also on the Canon RF 100-400mm F5.6-8 IS USM spec page3

Diagonal angle of view24°00′ - 6°10′
Horizontal angle of view20°00′ - 5°10′
Vertical angle of view14°00′ - 3°30′
Closest focusing distance1.2 m / 3.94 ft (at 100mm)
Closest focusing distance0.88 m / 2.89 ft (at 200mm)
Closest focusing distance1.05 m / 3.44 ft (at 400mm)
Max magnification0.09x (at 100mm)
Max magnification0.41x (at 400mm)

Also on the Canon RF 75-300mm F4-5.6 spec page4

Diagonal angle of view32°11′ to 8°15′ (Diagonal)
Horizontal angle of view27°00′ to 6°50′ (Horizontal)
Vertical angle of view18°11′ to 4°35′ (Vertical)
Closest focusing distance1.5 m / 4.92 ft
Max magnification at 75mm0.06x (f=75mm)
Max magnification at 300mm0.25x (f=300mm)

How the pick works

  1. Widest aperture3

    Lower wins once they are 0.3 apart.

  2. Weight2

    Lower wins from a 12% gap.

  3. Focal length (longest)2

    Higher wins from a 15% gap.

  4. Focal length (widest)2

    Lower wins once they are 2 mm apart.

  5. Optical stabilization1

    Having it wins.

  6. Closest focus, wide end1

    Lower wins from a 15% gap. Compared only between lenses of the same focal length (widest).

  7. Filter thread0.5

    Lower wins once they are 5 mm apart.

  8. Lead for a pick1

Our pick or our take adds up the importance of each real difference, with these importances and thresholds: a gap smaller than its row's threshold is too close to call and counts as the same. They are our editorial choice, not a measurement, the same on every page, and they never read prices, sales or who sells it.

Paid placements0

How we rank, in full

Sources

  1. Wikidata: Canon RF 100-400mm F5.6-8 IS USM, checked Oct 9, 2026 (CC0 1.0)
  2. personal.canon.jp, cited by Wikidata for Widest aperture (Wikidata checked Oct 9, 2026; we didn't read this page)
  3. Canon product specifications: Canon RF 100-400mm F5.6-8 IS USM, checked Oct 6, 2026
  4. Canon product specifications: Canon RF 75-300mm F4-5.6, checked Oct 6, 2026
  5. www.canon.at, cited by Wikidata for Focal length (Wikidata checked Oct 9, 2026; we didn't read this page)
  6. Wikidata: Canon RF 75-300mm F4-5.6, checked Oct 9, 2026 (CC0 1.0)
  7. global.canon, cited by Wikidata for On sale from (Wikidata checked Oct 9, 2026; we didn't read this page)

Worked out by code, not stated by a source

  • Read from the lens name: each maker marks the sensor size a lens covers (Sony FE/E, Canon RF/RF-S, Nikon DX, Tamron Di III/Di III-A, Sigma DG/DC); every Fujifilm X lens is APS-C and every Micro Four Thirds lens is Four Thirds.
  • Prime or zoom, read from the focal length in the lens name.
  • Read from the lens name: Sony marks optically stabilized lenses OSS, Canon IS, Nikon VR, Fujifilm OIS, Panasonic O.I.S., Tamron VC and Sigma OS; a lens from these makers without the mark has no optical stabilization.

Each value is checked automatically against the source it links, on the date shown. How we build these pages

† The makers' own tables, row by row, with labels in our plain words (translated where the maker's page isn't in English); each row's numbers are checked against the page it links.

What we don't know yet

  • On sale from for the Canon RF 75-300mm F4-5.6: our sources don't state it yet.
  • Weather sealed for the Canon RF 100-400mm F5.6-8 IS USM: our sources don't state it yet.
  • Extenders for the Canon RF 75-300mm F4-5.6: our sources don't state it yet.

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