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A used Canon Speedlite or Nikon Speedlight can be excellent value on the secondhand market — until you discover, mid-shoot, that the in-camera flash menu is grayed out, the radio group won't fire, or the whole unit does nothing but sit there as an expensive paperweight. Every Speedlite and Speedlight covered in this guide is now out of production as a new item, which means most buyers are pairing one with a camera body it was never designed to talk to.
That gap matters because Canon and Nikon didn't just build different flashes — they built entirely different communication protocols. Canon's E-TTL/E-TTL II and Nikon's i-TTL under the Creative Lighting System (CLS) share a physical hotshoe and a center sync pin, but the data pins that carry exposure information are wired differently between the two systems. Add Canon's multi-function accessory shoe on recent EOS R bodies, and Nikon's silent-shutter and menu-visibility quirks on Z-series cameras, and "does this flash work on my camera" stops being a simple yes-or-no question.
This guide breaks down five specific units — Canon's 430EX II, 600EX II-RT, and 320EX, plus Nikon's SB-700 and SB-800 — against current DSLR and mirrorless bodies, and lays out exactly what functionality survives, degrades, or disappears when you mix generations or brands. Specs, wireless behavior, and every compatibility caveat below reflect verified compatibility data, not assumptions.
It's written for two overlapping readers: someone weighing a used flash purchase against a specific camera, and someone who already owns one of these units and is trying to figure out why a feature stopped working after a body upgrade.
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Quick Reference — What Works Where
| Flash | Protocol | Wireless | Mount type | Current status |
|---|---|---|---|---|
| Canon 430EX II | E-TTL / E-TTL II | Optical slave only | Standard hotshoe, unsealed foot | Discontinued — used market |
| Canon 600EX II-RT | E-TTL / E-TTL II | 2.4 GHz radio + optical | Weather-sealed foot | Discontinued — used market |
| Canon 320EX | E-TTL / E-TTL II | Optical slave only | Standard hotshoe, unsealed foot | Discontinued — used market |
| Nikon SB-700 | i-TTL (CLS) | Optical commander/remote | Standard hotshoe | Still cataloged, in stock |
| Nikon SB-800 | i-TTL, D-TTL, film TTL | Optical commander/remote | Standard hotshoe | Discontinued — used market |
How Flash Compatibility Actually Works
Canon's E-TTL II and Nikon's i-TTL are the exposure-metering languages each brand's cameras and flashes use to negotiate power output in real time. They are not interchangeable: the hotshoe's center pin (which fires the flash) is standardized across brands, but the surrounding contact pins that transmit distance, aperture, and ISO data are laid out completely differently. Put a Canon Speedlite on a Nikon body, or vice versa, and the flash fires — but only as a dumb manual or sync flash, with no TTL metering, no high-speed sync, and no menu control.
Two numbers matter most when comparing units: Guide Number (GN), which measures maximum flash reach in meters or feet at ISO 100, and zoom range, the focal-length coverage the flash head can match to a lens (24-200mm on the 600EX II-RT versus 24-105mm on the more modest 430EX II and SB-800). Higher GN means more usable distance and headroom for bounce flash or diffusion.
The other axis is the physical mount. Canon's legacy hotshoe — used by all five flashes in this guide except in edge cases — differs from the newer multi-function accessory shoe found on EOS R3, R6 Mark II, R7, R8, R10, R50, and R5C. Weather-sealed flash feet (like the 600EX II-RT's) don't seat correctly on this newer shoe without Canon's AD-E1 adapter; unsealed feet (430EX II, 320EX) slide in without issue. On the Nikon side, every flash here works physically and electrically on Z-series mirrorless bodies via the standard hotshoe — the friction points are software-level, not mechanical, and are covered body-by-body below.
Canon Speedlites — Fit and Function by Body Generation
Canon Speedlite 430EX II
The 430EX II is E-TTL/E-TTL II with a Guide Number of 43m/141ft at ISO 100 and 105mm, a 24-105mm zoom range (14mm with the pull-down wide panel), and bounce/rotation of 90° up and 90°/180° left-right. It's optical-slave-only — no radio — and its recycle time is roughly 20% faster than the original 430EX, largely silent in operation. The foot is unsealed metal with no weather protection.
That unsealed foot is actually an advantage on current mirrorless bodies: Canon's own community support confirms full E-TTL functionality and in-camera flash-menu control on the EOS R6 Mark II, with the flash seating directly into the multi-function shoe without an adapter. The one caveat that carries across every EOS R body: the 430EX II's IR autofocus-assist beam does not function on mirrorless cameras, which fall back to intermittent-flash AF assist instead.
- Specs: GN 43m/141ft @ 105mm · 24-105mm zoom · optical slave · 4×AA · unsealed foot
- Fits: All EOS DSLRs; EOS M and R-series via standard or multi-function shoe (no adapter needed)
- Loses on mirrorless: IR AF-assist beam only
- Perfect for: Canon shooters who want full E-TTL on a DSLR or EOS R body without paying for radio wireless they don't need
Canon Speedlite 600EX II-RT
Canon's former flagship carries the highest output in this lineup — GN 60m/197ft at ISO 100 and 200mm — with a 20-200mm zoom range and full tilt/rotation articulation. It's the only flash here with built-in 2.4 GHz radio, controlling up to 5 groups and 15 units at roughly 30m/98ft range, alongside optical wireless. Its radio system talks natively to the 600EX-RT, 430EX III-RT, and ST-E3-RT transmitter, and it's optically backward-compatible with older units going back to the 580EX/II and 320EX.
The weather-sealed foot that makes this unit rugged also makes it awkward on the newer multi-function shoe: it requires Canon's AD-E1 adapter to seat correctly on R3/R6 II/R7/R8/R10/R50 bodies. Some owners simply remove the rubber weather seal to make it fit flush, trading sealing for convenience. One recurring reliability concern from Canon's own community forums: first- and second-generation 600EX-RT units have been reported to drop radio connections over extended use, with no official fix — part of why some professionals migrated to third-party radio systems or studio strobes instead.
- Specs: GN 60m/197ft @ 200mm · 20-200mm zoom · 2.4GHz radio + optical · 5 groups/15 units · 4×AA · weather-sealed foot
- Fits: All EOS DSLRs; EOS R bodies with AD-E1 adapter for full weather-seal fit
- Loses on mirrorless: IR AF-assist beam; requires adapter for a flush, sealed mount
- Perfect for: Multi-flash off-camera setups where radio range and group control matter more than mount convenience
Canon Speedlite 320EX
The compact option in Canon's lineup pairs a modest GN of 32m/105ft (at 50mm, ISO 100) with a genuinely useful extra: a built-in LED video light rated at 75 lux, 4500-6500K, good for 180-1000 flashes or roughly 3.5 hours of continuous light. Flash coverage switches manually between 24mm and 50mm settings by extending or retracting the head, and wireless is optical-slave-only (3 groups, 4 channels), plus a wireless shutter-release function compatible with Canon's RC-series remotes.
The LED is genuinely dim for anything beyond casual use — Canon's own spec puts usable range at about 1 meter at f/5.6 and ISO 3200, more comparable to a small utility light than a dedicated video panel. There's no LCD screen and no on-flash manual power mode, which frustrates anyone wanting direct manual control rather than camera-menu or wireless adjustment. Compatibility covers EOS 5D Mark II and later natively, with firmware updates extending support to the EOS-1Ds Mark III, 1D Mark III, 40D, 50D, and Rebel XS.
- Specs: GN 32m/105ft @ 50mm · 24mm/50mm manual coverage · built-in 75-lux LED · optical slave · 4×AA
- Fits: EOS 5D Mark II and later natively; older bodies via firmware update
- Trade-off: No on-flash manual mode, no LCD; LED light is a convenience feature, not a real fill-light substitute
- Perfect for: Hybrid shooters who want a compact flash plus a small modeling/AF-assist light in one unit
Nikon Speedlights — Fit and Function by Body Generation
Nikon Speedlight SB-700
The SB-700 is Nikon's current mid-range Speedlight, optimized for the Creative Lighting System with a Guide Number of 28m/92ft at ISO 100, 35mm FX, and 39m/128ft at ISO 200. Its 24-120mm FX zoom (12mm with the wide panel) auto-detects FX or DX sensor format, and it offers standard, even, and center-weighted illumination patterns. As an optical CLS commander it can control two remote groups across four channels, though it has no radio. It's compatible with essentially every CLS-era Nikon body — FX and DX DSLRs excluding the D1 series and D100, the F6 film body, and select COOLPIX models — and mounts and fires correctly on Z-series mirrorless via the standard hotshoe.
Two things trip up new owners moving to Z-series bodies. First, the in-camera Flash Control menu appears grayed out on Z8, Z9, and similar bodies — this is normal and by design: only the SB-500 and SB-5000 support camera-side menu control, so the SB-700 has to be configured on the flash unit itself. Second, if the flash refuses to fire at all, the near-universal cause is silent or electronic shutter mode being enabled on the camera; disabling it restores normal flash operation. Against its predecessor, the SB-700 also has improved thermal protection, slowing recycle time under heavy use rather than cutting out entirely.
- Specs: GN 28m/92ft @ 35mm FX · 24-120mm zoom · optical CLS commander (2 groups) · 4×AA · recycle ~2.5-3.5s
- Fits: All CLS-compatible Nikon DSLRs (except D1 series/D100), F6, select COOLPIX, and Z-series via hotshoe
- Common confusion on Z bodies: grayed-out flash menu (normal) and no firing in silent shutter mode (disable it)
- Perfect for: Nikon shooters on current DSLR or Z-series bodies who want a fully supported, still-in-production Speedlight
Nikon Speedlight SB-800
The SB-800 is the most backward-compatible flash in this guide by a wide margin. Beyond i-TTL, it supports D-TTL for the D1 and D2 series and D100, film TTL for the F5, F100, N80/N75/N65, and FM3A, plus auto-aperture, non-TTL auto, and full manual — a spread of protocols Nikon's later SB-900 dropped entirely. Output runs from GN 38m/125ft at 35mm up to 56m/184ft at 105mm, ahead of the SB-700, with 24-105mm auto zoom (down to 14mm with the wide adapter dome). As an optical CLS commander and legacy SU-4 slave, it remains fully usable as a wireless master. Measured trigger voltage sits at a safe 3.63V on the X-sync contact — well within tolerance for any modern camera, including a manual-only pairing with a Canon body.
On Z-series cameras it behaves exactly like the SB-700: i-TTL metering works over the hotshoe, but the in-camera flash menu is grayed out (again, only the SB-500/SB-5000 get that control), and silent shutter mode blocks firing entirely. A very common first-time question — "why does my SB-800 flash three times before the real exposure?" — is simply i-TTL's monitor pre-flashes doing their metering job; switching to non-TTL auto or manual removes them. Compared to the newer SB-900, the SB-800 also lacks the aggressive thermal cutout that frustrated many owners, slowing gracefully instead of shutting down.
- Specs: GN 38-56m/125-184ft (35-105mm) · 24-105mm zoom · i-TTL/D-TTL/film TTL/manual · optical CLS commander · 4×AA (+optional 5th cell) · X-sync 3.63V
- Fits: All i-TTL Nikon DSLRs and Z-series; also legacy D-TTL and film bodies that no current Nikon flash supports
- Trade-off: Discontinued with no first-party stock — used/third-party only
- Perfect for: Nikon shooters who need one flash to bridge modern digital bodies and older D-TTL or film cameras
Mixing Canon and Nikon Flashes — What Actually Happens
The single most common cross-brand question is whether a Canon flash can be used on a Nikon body, or the reverse. The center sync pin that physically fires the flash is shared across both systems, but the surrounding data pins — which carry aperture, ISO, and distance information for TTL metering — are wired to completely different specifications. The result: a Canon Speedlite on a Nikon body (or vice versa) fires only in manual or basic sync mode. There is no TTL metering, no high-speed sync, and no menu-based control, regardless of how modern either unit is.
Voltage is the real safety question, and it's a lower risk than most shooters assume. Nikon's own documentation specifies its Speedlight circuits around 12V, and warns that voltages above 250V applied to a camera's sync terminal risk damaging the sync circuit — a legacy concern from older studio strobes and vintage flashes, not modern Speedlites or Speedlites. Measured trigger voltage on units like the SB-800 (3.63V) sits comfortably below any threshold that would harm a Canon body electrically. In practice, mixing brands is safe voltage-wise but functionally crippled — for anyone who actually needs cross-brand triggering, a radio system built for both ecosystems (Godox, PocketWizard) is the practical fix, not the flash's native protocol.
It's also worth retiring a related myth: newer doesn't automatically mean more compatible. The SB-800, despite being the oldest Nikon unit here, out-compatibilities the newer SB-900 by retaining D-TTL and film TTL. On the Canon side, the older, unsealed-foot 430EX II slides onto EOS R-series multi-function shoes more easily than the weather-sealed 600EX II-RT, which needs an adapter to seat flush.
Specifications Comparison
| Model | Guide Number | Zoom range | Wireless | Power | Mount notes |
|---|---|---|---|---|---|
| Canon 430EX II | 43m/141ft @105mm | 24-105mm (14mm w/ panel) | Optical slave only | 4×AA | Unsealed foot; fits EOS R multi-function shoe directly |
| Canon 600EX II-RT | 60m/197ft @200mm | 20-200mm (14mm w/ panel) | 2.4GHz radio + optical, 5 groups/15 units | 4×AA | Weather-sealed foot; needs AD-E1 on EOS R multi-function shoe |
| Canon 320EX | 32m/105ft @50mm | 24mm/50mm manual | Optical slave, 3 groups/4 channels | 4×AA | Unsealed foot; built-in LED light, no manual power dial |
| Nikon SB-700 | 28m/92ft @35mm FX | 24-120mm (12mm w/ panel) | Optical CLS commander, 2 groups | 4×AA | Standard hotshoe; menu grayed out on Z bodies |
| Nikon SB-800 | 38-56m/125-184ft | 24-105mm (14mm w/ dome) | Optical CLS commander + SU-4 slave | 4×AA (+5th cell option) | Standard hotshoe; also D-TTL/film TTL for legacy bodies |
Which Speedlight Should You Choose?
Canon DSLR or EOS R shooter wanting straightforward E-TTL, no radio: the 430EX II covers the fundamentals at a lower entry point and mounts directly on multi-function-shoe bodies without an adapter.
Canon shooter running multi-flash, off-camera lighting setups: the 600EX II-RT is the only unit here with native radio, controlling multiple groups at real working distance — worth the adapter step on newer EOS R bodies for that flexibility.
Content creator who wants flash and a modeling/AF-assist light in one unit: the 320EX's built-in LED is a genuine convenience, though it's not a substitute for a dedicated LED video panel if continuous output quality matters.
Nikon shooter on a current DSLR or Z-series body: the SB-700 is the only flash in this guide still in first-party production, with the most straightforward long-term support.
Nikon shooter who also shoots film or older D-TTL bodies: the SB-800's protocol range — i-TTL, D-TTL, and film TTL in one unit — has no current equivalent in Nikon's lineup.
Frequently Asked Questions
Q: Can I use a Canon Speedlite on a Nikon camera, or a Nikon Speedlight on a Canon body?
Only as a manual or basic sync flash. The center sync pin is shared, but the surrounding data pins that carry TTL exposure information are wired differently between the two systems, so no autoflash, high-speed sync, or menu control will work across brands.
Q: Why is my Nikon Speedlight's flash menu grayed out on my Z-series camera?
This is expected behavior, not a fault. Only the SB-500 and SB-5000 support in-camera flash menu control on Z-series bodies; every other Speedlight, including the SB-700 and SB-800, must be configured directly on the flash unit itself.
Q: My flash won't fire at all on my mirrorless camera — what's wrong?
The most common cause on both Canon and Nikon mirrorless bodies is silent or electronic shutter mode being enabled. Switching to a mechanical or electronic-first-curtain shutter mode typically restores normal flash firing.
Q: Does a weather-sealed Canon Speedlite fit directly on newer EOS R bodies?
Not flush. Weather-sealed feet, like the one on the 600EX II-RT, need Canon's AD-E1 adapter to seat properly on multi-function-shoe bodies such as the R3, R6 Mark II, R7, R8, R10, and R50. Unsealed-foot flashes like the 430EX II and 320EX mount directly without an adapter.
Q: Why does my Nikon SB-800 fire three quick flashes before the actual shot?
Those are i-TTL monitor pre-flashes used for exposure metering — normal behavior, not a malfunction. Switching the flash to non-TTL auto or full manual mode removes the pre-flashes entirely.
Q: Is it safe to trigger a Nikon flash from a Canon body, or vice versa, voltage-wise?
Generally yes. Modern Speedlites and Speedlights from both brands operate at low trigger voltages (in the low single-digit volts), well under the levels that risk damaging a camera's sync circuit. The limitation is functional, not electrical — you lose TTL and automation, not safety.
Conclusion
Every flash in this guide can still do useful work today, but only if it's matched to a camera that speaks its protocol and, in Canon's case, its mount generation. The 430EX II and 600EX II-RT cover Canon's budget-to-flagship range, with the sealed foot on the 600EX II-RT being the one real mounting friction point on newer EOS R bodies. The 320EX trades power for a built-in light source that's better as a convenience than a primary tool. On the Nikon side, the SB-700 is the safer buy for anyone on current gear, while the SB-800's unusual backward compatibility with D-TTL and film cameras makes it worth seeking out specifically for that use case.
None of this compatibility logic changes if you're building out the rest of a lighting kit — the same protocol and mount considerations apply when pairing a flash with modifiers, triggers, or a dedicated video light for hybrid work. For a broader look at current speedlight options beyond these five discontinued units, the best speedlights and external flashes guide covers what's actively shipping today.
The short version: check your camera's mount generation and protocol before buying used, not after — a flash that fires isn't the same as a flash that works the way you expect it to.
