Sony
Alpha 7S III
12MP low-light video specialist with 4K 120p, 16-bit RAW HDMI, and excellent autofocus.
$3,499
Launch priceReleased Sep 2020
Sony
FX3
Compact full-frame cinema line camera with S-Cinetone and pro video ergonomics.
$3,899
Launch priceReleased Feb 2021
FX3 is 6 months newer.
Affiliate disclosure: As an Amazon Associate, Cameraegg earns from qualifying purchases. Cameraegg may also earn commission from B&H links, at no extra cost to you.
Wins
Alpha 7S III
Wins
FX3
12 categories tied
Which would you choose?
TL;DR — Key differences
- AAlpha 7S III has higher AF points / zones (759 vs 627)
- AAlpha 7S III has higher Battery life (CIPA) (600 shots vs 580 shots)
- AAlpha 7S III has lower Weight (699 g vs 715 g)
Key specs at a glance
Size and weight, to scale
📸 Snap this size diff to shareAlpha 7S III
129 × 97 × 81 mm
699 g (1.54 lb / 24.66 oz)
Credit card
85.6 × 54 mm
for scale
FX3
130 × 78 × 85 mm
715 g (1.58 lb / 25.22 oz)
Alpha 7S III is 1mm narrower and 4mm thinner than FX3 but it is also 19mm taller.
Alpha 7S III is 16 g lighter than FX3.
Depth (front-to-back): 81mm Alpha 7S III · 85mm FX3
Back view, to scale
Width × Height — same proportions as the front of the body.
Alpha 7S III
129 × 97 mm
Credit card
85.6 × 54 mm
FX3
130 × 78 mm
Top view, to scale
Width × Depth (front-to-back) — see which body is chunkier on the table.
Alpha 7S III
129 × 81 mm
Credit card
85.6 × 54 mm
FX3
130 × 85 mm
Sensor size, to scale
Alpha 7S III
35.6 × 23.8 mm · Full Frame
847 mm² area
FX3
35.6 × 23.8 mm · Full Frame
847 mm² area
Lens ecosystem
Native lens selection
Alpha 7S III
✓ more lensesSony E
350+
native lenses available
FX3
✓ more lensesSony E
350+
native lenses available
Counts include current first-party and major third-party native autofocus lenses.
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
Alpha 7S III
Dimensions (W×H×D mm)
Adds 128.9, 96.9, 80.8
AF points / zones
759 vs 627 — higher is better
Battery life (CIPA)
600 shots vs 580 shots — higher is better
Weight
699 g vs 715 g — lower is better
Reasons to choose
FX3
Dimensions (W×H×D mm)
Adds 129.7, 77.8, 84.5
Both cameras share
- ✓Resolution — Both 12.1 MP
- ✓AA filter — Both support aa filter
- ✓ISO min (native) — Both 80
- ✓ISO max (native) — Both 102,400
- ✓AF frame coverage — Both 94 %
- ✓Eye AF — Both support eye af
Pros & cons at a glance
Editorially curated highlights and trade-offs.
Alpha 7S III
Pros
- ✓Best-in-class low light
- ✓4K 120p
- ✓Full-size HDMI
- ✓Strong IBIS
Cons
- –12MP stills limit
- –Older generation now
- –No 8K
FX3
Pros
- ✓Cinema form factor
- ✓S-Log3 / S-Cinetone
- ✓Compact for gimbals
- ✓Full-frame sensor
Cons
- –No EVF
- –Still photo ergonomics limited
- –Single card slot
Decided which one is right for you?
Compare live prices for the Alpha 7S III and FX3 at major authorized retailers.
Sony Alpha 7S III
Affiliate disclosure: As an Amazon Associate, Cameraegg earns from qualifying purchases. Cameraegg may also earn commission from B&H links, at no extra cost to you.
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for travel, Alpha 7S III or FX3?
Alpha 7S III scores 6.5/10 versus 6.0/10 for FX3 — 699g — manageable for travel.
What's the resolution difference between the Alpha 7S III and FX3?
Both cameras share the same 12.1 MP resolution.
Do the Alpha 7S III and FX3 have in-body image stabilization?
Alpha 7S III has 5.5-stop in-body image stabilization, while FX3 has 5.5-stop in-body image stabilization.
Which shoots faster bursts — the Alpha 7S III or the FX3?
Alpha 7S III reaches 10 fps electronic. FX3 reaches 10 fps electronic.
What's the weight difference between the Alpha 7S III and FX3?
Alpha 7S III weighs 699 g and FX3 weighs 715 g, so the Alpha 7S III is 16 g lighter.
Do the Alpha 7S III and FX3 record 4K video?
Alpha 7S III: 4K up to 120p. FX3: 4K up to 120p.
Are the Alpha 7S III and FX3 weather sealed?
Alpha 7S III: Yes. FX3: Yes.
Which has better battery life?
Rated battery life is 600 shots (CIPA) for the Alpha 7S III and 580 shots for the FX3, giving the Alpha 7S III the edge.
How much does each cost?
Alpha 7S III launched at $3,499 and FX3 at $3,899. The Alpha 7S III is $400 less.
Can't decide between two? Compare a third camera.
Add any camera to get a three-way Alpha 7S III vs FX3 vs X comparison.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed July 2026.
Product images courtesy of Sony press materials.