Westcott
Westcott FJ400 Strobe 400Ws with AC/DC Battery
$349.45Cheaper
Best Studio Strobes · head-to-head
Westcott FJ400 Strobe 400Ws with AC/DC Battery vs Paul C. Buff Einstein E640 Flash Unit
A sourced, side-by-side comparison. Westcott FJ400 Strobe 400Ws with AC/DC Battery is cheaper at $349.45. Every spec and price links to its source.
Paul C. Buff
Paul C. Buff Einstein E640 Flash Unit
$529.95
Which is better: the Westcott FJ400 Strobe 400Ws with AC/DC Battery or Paul C. Buff Einstein E640 Flash Unit?
On the specs we track, they're closely matched. The Westcott FJ400 Strobe 400Ws with AC/DC Battery is the cheaper at $349.45.
See Westcott FJ400 Strobe 400Ws with AC/DC Battery on Amazon See Paul C. Buff Einstein E640 Flash Unit on Amazon
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Westcott FJ400 Strobe 400Ws with AC/DC Battery | Paul C. Buff Einstein E640 Flash Unit |
|---|---|---|
| US price | $349.45 | $529.95 |
| Brand | Westcott | Paul C. Buff |
| Released | — | — |
| Power output ws | 400 | 640 |
| Flash duration t01 | Normal mode 1/280-1/3000 sec; Freeze mode 1/280-1/7000 sec | 1/568 sec at full power (Constant Color mode, t0.5 1/1600 sec); as fast as ~1/2000 sec (t0.1) at half power in Action Mode |
| Recycle time s | 0.05-0.9 | 0-1.7 |
| Ttl hss support | TTL; HSS to 1/8000s; Rear Curtain Sync | Manual only — no TTL, no camera-side HSS. Fires via CyberSync radio triggers or optical slave; Action Mode shortens flash duration for motion-freezing rather than providing sync-pulse HSS. |
| Modeling lamp (W) | 20 | — |
| Color temperature k | 5500 | 5600 |
| Power source | Removable 14.8V/4400mAh lithium-polymer battery (480+ full-power flashes) or AC power | AC only (100-240V, 3-wire grounded, auto-sensing with IEC connector); no battery option |
Sources — Westcott FJ400 Strobe 400Ws with AC/DC Battery: fjwestcott.com (verified 2026-08-09). Paul C. Buff Einstein E640 Flash Unit: s196259524.onlinehome.us (verified 2026-08-09).
What's the difference between the Westcott FJ400 Strobe 400Ws with AC/DC Battery and Paul C. Buff Einstein E640 Flash Unit?
Where the two actually differ on the specs we track (6 of 7). Matching specs are omitted.
- Power output ws: Westcott FJ400 Strobe 400Ws with AC/DC Battery 400 vs Paul C. Buff Einstein E640 Flash Unit 640
- Flash duration t01: Westcott FJ400 Strobe 400Ws with AC/DC Battery Normal mode 1/280-1/3000 sec; Freeze mode 1/280-1/7000 sec vs Paul C. Buff Einstein E640 Flash Unit 1/568 sec at full power (Constant Color mode, t0.5 1/1600 sec); as fast as ~1/2000 sec (t0.1) at half power in Action Mode
- Recycle time s: Westcott FJ400 Strobe 400Ws with AC/DC Battery 0.05-0.9 vs Paul C. Buff Einstein E640 Flash Unit 0-1.7
- Ttl hss support: Westcott FJ400 Strobe 400Ws with AC/DC Battery TTL; HSS to 1/8000s; Rear Curtain Sync vs Paul C. Buff Einstein E640 Flash Unit Manual only — no TTL, no camera-side HSS. Fires via CyberSync radio triggers or optical slave; Action Mode shortens flash duration for motion-freezing rather than providing sync-pulse HSS.
- Color temperature k: Westcott FJ400 Strobe 400Ws with AC/DC Battery 5500 vs Paul C. Buff Einstein E640 Flash Unit 5600
- Power source: Westcott FJ400 Strobe 400Ws with AC/DC Battery Removable 14.8V/4400mAh lithium-polymer battery (480+ full-power flashes) or AC power vs Paul C. Buff Einstein E640 Flash Unit AC only (100-240V, 3-wire grounded, auto-sensing with IEC connector); no battery option