Canon
RF 800mm F5.6 L IS USM
Canon RF Mount
RF 800mm F5.6 L IS USM — 800mm f/5.6 for Canon RF, a popular choice in the canon lineup.
$16,999
Launch priceReleased Feb 2022
Tamron
28-75mm F2.8 Di III VXD G2
Sony E Mount
An incredibly popular third-party zoom updated with vastly improved sharpness and autofocus.
$899
Launch priceReleased Aug 2021
RF 800mm F5.6 L IS USM is 7 months newer.
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Wins
RF 800mm F5.6 L IS USM
Wins
28-75mm F2.8 Di III VXD G2
TL;DR — Key differences
- ARF 800mm F5.6 L IS USM has higher OIS effectiveness (4.5 stops vs 0 stops)
- B28-75mm F2.8 Di III VXD G2 has lower Min focus distance (18 cm vs 400 cm)
- B28-75mm F2.8 Di III VXD G2 has lower Weight (540 g vs 3140 g)
- B28-75mm F2.8 Di III VXD G2 has lower Length (118 mm vs 432 mm)
- B28-75mm F2.8 Di III VXD G2 has higher Max magnification (0.37 × vs 0.14 ×)
Key specs at a glance
Size and weight, to scale
RF 800mm F5.6 L IS USM
⌀140 × 432 mm
3140 g (6.92 lb / 110.76 oz)
Credit card
85.6 × 54 mm
for scale
28-75mm F2.8 Di III VXD G2
⌀76 × 118 mm
540 g (1.19 lb / 19.05 oz)
RF 800mm F5.6 L IS USM is 314mm longer and 64mm wider than 28-75mm F2.8 Di III VXD G2.
RF 800mm F5.6 L IS USM is 2600 g heavier than 28-75mm F2.8 Di III VXD G2.
Diameter (⌀) is the maximum barrel width; length is measured from the mount to the front of the lens.
Use-case scoring
Which one for what?
Algorithmic scores from verified specs · 10 = best in class
Why pick one over the other
Reasons to choose the RF 800mm F5.6 L IS USM
- ✓
Special elements
Adds 2 Fluorite, 2 Super UD, 1 UD
- ✓
OIS effectiveness
4.5 stops vs 0 stops — higher is better
- ✓
Optical stabilization
Only RF 800mm F5.6 L IS USM supports it
- ✓
Control ring
Only RF 800mm F5.6 L IS USM supports it
Reasons to choose the 28-75mm F2.8 Di III VXD G2
- ✓
Special elements
Adds 2 LD, 2 GM
- ✓
Min focus distance
18 cm vs 400 cm — lower is better
- ✓
Weight
540 g vs 3140 g — lower is better
- ✓
Length
118 mm vs 432 mm — lower is better
- ✓
Max aperture (Wide)
f/2.8 vs f/5.6 — lower is better
- ✓
Max aperture (Tele)
f/2.8 vs f/5.6 — lower is better
- ✓
Diameter
76 mm vs 140 mm — lower is better
- ✓
Max magnification
0.37 × vs 0.14 × — higher is better
Shared specifications
Internal focus
Both support internal focus
Weather sealing
Both support weather sealing
Custom function button
Both support custom function button
Pros & cons at a glance
Editorially curated highlights and trade-offs.
RF 800mm F5.6 L IS USM
Pros
- ✓Prime design typically delivers strong sharpness and lighter weight
- ✓Built-in optical image stabilization
- ✓Weather-sealed construction for outdoor shooting
Cons
- –Premium price point
- –Relatively heavy for extended handheld use
- –Slower maximum aperture limits low-light performance
28-75mm F2.8 Di III VXD G2
Pros
- ✓Superb value for money compared to first-party options
- ✓Excellent sharpness throughout the range, even at f/2.8
- ✓Very lightweight and compact (only 540g)
- ✓Fast VXD linear motor focus drive
- ✓Customizable lens functions via Tamron Lens Utility software
Cons
- –Starts at 28mm instead of the wider 24mm standard
- –Slightly weaker corner sharpness at 75mm wide open
- –Weather sealing is basic compared to Sony GM lenses
Decided which one is right for you?
Compare live prices for the RF 800mm F5.6 L IS USM and 28-75mm F2.8 Di III VXD G2 at major authorized retailers.
Canon RF 800mm F5.6 L IS USM
Tamron 28-75mm F2.8 Di III VXD G2
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Full specifications
✓ = category winner
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed June 2026.