Dive light buying guide: torch vs primary vs video

Why four different lights exist

A dive light has to balance three things: brightness, beam shape, and burn time. You can’t optimise all three at once. So different lights have evolved for different jobs.

You can carry two devices that each do two jobs (a primary with adjustable beam can stand in for video work; a backup can stand in for a pocket light). But the dedicated tools each work better at their job.

Lumens — useful, but not the whole story

A 3,000-lumen flood light spread over 120° is dimmer at any single point than a 1,000-lumen spot beam at 8°. Lumens measure total light output; lux measures concentration. Cave divers want lux. Photographers want lumens spread evenly over a wide angle.

Rough lux benchmarks for spot beams:

• Below 4,000 lux at 1m: insufficient for night-dive primary
• 4,000–10,000 lux: standard rec primary
• 10,000+ lux: tech / cave grade

Manufacturers don’t all publish lux numbers. When they don’t, you’re stuck comparing lumens — but the same lumen count in two different beam patterns produces very different underwater experiences.

Backup torch — the one you always have

If you do nothing else, own a backup torch. Carry it on every dive. Day dives included — you’ll find yourself shining it under ledges constantly once you have one.

The pick: Scubapro Nova 850 Wide. 850 lumens, USB rechargeable, ~5,000 THB / $140. Burns 90 min on high, 4 hrs on low. Compact enough to clip to a BCD pocket.

Cheaper alternatives:

• Tovatec Mera 1050: ~3,000 THB / $85. Slightly bigger, similar performance.
• Mares EOS 5RZ: ~3,500 THB / $95. Push-button only (no twist), some find that less reliable on cold hands.
• Light & Motion GoBe Nightsea 700: ~5,500 THB / $150. Smaller, well-built, runs on AA cells.

Budget option: Generic 1,000-lumen torches off Lazada or Amazon for ~1,500 THB / $40. They work. They also flood within a few months. If you’re certifying and need a torch for one course, fine. For a torch you’ll use for years, don’t.

The non-negotiable specs for a backup:

• IPX8 rated to at least 100m (most claim more; verify the actual depth rating, not just “waterproof”)
• Push-button or twist switch that doesn’t accidentally engage in your BCD pocket
• Lanyard attachment point — you will drop it

Primary light — for night, wreck, cave

The primary is the workhorse. Night-dive briefings expect you to have one. If you’ll do any wreck penetration or overhead environment, the primary is critical, not optional.

Beam angle for primary should be a tight spot — 8° to 12°. A flood beam doesn’t punch through dark water; it lights up the particles between you and the subject (backscatter) and washes out your night vision when others look at it.

The pick: Big Blue VL10000P. 10,000 lumens, 12° spot, ~22,000 THB / $620. Sounds excessive — it isn’t. The headline number runs the light at full power for short bursts; cruising at 30% gives 4+ hours burn time. Burst lumens on big lights are for signalling and emergencies.

Strong mid-tier options:

• Scubapro Nova 4000 SF: 4,000 lumens, ~12,000 THB / $340. Reliable, well-built, available globally.
• Light & Motion Sola Dive 2500 S/F: 2,500 lumens spot + flood switchable, ~14,000 THB / $390. The switchable beam is genuinely useful.
• Big Blue AL5000WP: 5,000 lumens, ~9,000 THB / $250. Best value at this brightness.
• Mares EOS 32RZ: 3,200 lumens, ~10,000 THB / $280. Compact for the output.

Tech-grade primary (worth it only if you do tech):

• Dive Rite EX-35: ~25,000 THB / $700. Canister-style with separate battery pod connected by cable. The standard for cave diving.
• Light Monkey 32 Watt LED: similar segment, around $1,200.

Burn time matters more than peak lumens. A 3,000-lumen light that lasts 90 minutes on full beam is a 60-minute usable light on a 75-minute dive once you account for safety stops and ambient time. A 5,000-lumen light at 50% for 3 hours is more useful underwater.

Video light — for photography and video

A video light is a continuous wide flood, evaluated on colour rendering (CRI) and colour temperature (K°). Strobes don’t help video — you need continuous light.

CRI matters. A high CRI (90+) renders colours close to natural sunlight. A low CRI (70s, typical of cheap lights) makes reds and oranges look brown and corals look grey. You can’t fix this in post.

Colour temperature for underwater video: 5,000–5,500K is the sweet spot. Daylight balance. Some lights run 4,000K which looks warm but unnatural for blue water.

The pick: Light & Motion Sola Video Pro 12000. 12,000 lumens, 80° flood, CRI 92, 5,800K. ~38,000 THB / $1,100. Premium price, but the standard professional video light for a decade.

Strong mid-tier:

• Big Blue VL10000P-MS (mini broad): 10,000 lumens, 120° flood, CRI 80+, ~22,000 THB / $620.
• Bigblue VTL5500P: 5,500 lumens, switchable wide+narrow, ~15,000 THB / $420. Best value.
• Kraken Hydra 4000WSR: 4,000 lumens with built-in red and UV modes, ~18,000 THB / $500. Useful niche for fluo and reef macro.

Budget video lights to consider:

• Lumens like Big Blue AL2600XWP: 2,600 lumens flood, ~6,500 THB / $180. Limited for serious video but works on a GoPro for casual use.
• Generic “5000-lumen” Chinese brands on Amazon for $40–80: low CRI, short burn times, fail at depth. Avoid.

Pocket light — small spotlight for daytime

Once you’ve owned a small pocket torch you’ll wonder how you dove without one. It lives clipped to your BCD shoulder D-ring or in a chest pocket. You pull it out to look under a ledge, into a swim-through, into the eye of a moray, into the gills of a frogfish. Daytime use, mostly.

The pick: Light & Motion GoBe Mini 500. 500 lumens, 8° spot, ~3,000 THB / $85. AA-battery, no charging cable to carry.

Alternatives:

• Scubapro Nova 250: small, runs on a single AA, ~1,500 THB / $40
• Bigblue AL450NM-II: 450 lumens, USB rechargeable, ~2,000 THB / $55
• Many divers use a high-end EDC flashlight (Fenix, Olight) in a dive-rated housing — Olight Perun 2 with the right o-ring is rated to 100m and is bright. Some divers swear by it; others prefer purpose-built.

The battery question

For a primary light that will travel on liveaboards: lithium-ion 18650 cells are the standard. Buy spares (~$10 each, Panasonic NCR18650B or Samsung 30Q are the go-to). Bring at least 3 cells per light if you’ll do 4 dives a day. Charging on a liveaboard is fine but slower than at home.

Travel rules: Lithium cells must fly in carry-on, not checked. IATA limit is 100 Wh per cell, 2 spares per passenger uninstalled. An 18650 is ~12 Wh, well under. A canister battery may exceed the limit — check before booking flights with one.

What to actually buy at each budget

Minimum setup, ~5,000 THB / $140:

• One Scubapro Nova 850 ($140). It’s a backup-grade light used as your only one. Works for day diving and signalling. Skip night dives until you upgrade.

Recreational, ~13,000 THB / $370:

• Backup: Scubapro Nova 850 ($140)
• Primary: Bigblue AL5000WP ($250)
• That’s it. Two-light setup covers night dives reliably.

Enthusiast, ~25,000 THB / $700:

• Backup: Scubapro Nova 850 ($140)
• Primary: Big Blue VL10000P ($620) — overkill, but a primary you won’t outgrow
• Pocket: Light & Motion GoBe Mini 500 ($85)

Photographer-enthusiast, ~50,000 THB / $1,400:

• Backup: Scubapro Nova 850
• Primary: Bigblue AL5000WP ($250)
• Video: Bigblue VTL5500P x 2 ($420 each)
• Pocket: GoBe Mini ($85)
• Total: ~$1,425

Pro/tech, ~100,000 THB / $2,800+:

• Backup x 2 (always two on tech)
• Primary canister-style Dive Rite or Light Monkey ($700–1,200)
• Video Sola Video Pro 12000 x 2 ($1,100 each)
• Pocket-mounted focus light
• Total: $3,000–4,000

What to check before you buy

Five questions for any light:

1. Real-world burn time at the brightness you’ll actually use — not just on the high setting they advertise
2. Beam angle — published spec, not marketing copy
3. Depth rating — match it to where you’ll actually dive (rec to 40m is fine; tech needs 100m+)
4. Battery replacement availability — proprietary batteries become unobtainable in 3–5 years
5. Warranty + repair network — Light & Motion, Scubapro, Bigblue have global service; some smaller brands don’t

Maintenance — keep the light working

• Rinse in fresh water after every dive, especially the switch and o-ring
• Replace o-rings annually with the manufacturer’s spec parts
• Lubricate o-rings with silicone grease — not petroleum-based
• Charge before storage, but don’t store fully charged for long periods (lithium batteries prefer 40–60% for storage)
• Store with batteries removed if not used for >2 months

A light that floods because of corrosion or a perished o-ring is the most common dive-light failure. None of it is from defects; it’s from skipped rinsing. Five minutes of care per dive trip extends the light’s life by years.