The rules behind the answers. These are the details that cause most wrong purchases.
Canon LP-E17
Canon compact 7.2V battery used by EOS R8, R10, R50 and smaller DSLRs.
- Not interchangeable with LP-E6-family bodies (R5, R6 Mark II, R7).
Source: Canon EOS R8 specifications
Canon LP-E6 family (LP-E6 / LP-E6N / LP-E6NH / LP-E6P)
Canon 7.2V battery family for mid/high-end EOS bodies; newer packs are backward compatible.
- LP-E6NH is backward compatible with cameras that use LP-E6 and LP-E6N.
- In-camera USB PD charging works only with LP-E6NH (and newer) in compatible EOS bodies, not every body.
- LP-E6P is designed for the EOS R5 Mark II's higher current draw; older bodies may need a firmware update to use it without limitations (e.g. EOS R6 firmware 1.9.0).
- Check each camera's spec: e.g. EOS R5 and R6 Mark II list LP-E6NH/LP-E6N; EOS R7 lists LP-E6NH/LP-E6N/LP-E6.
Source: Canon LP-E6NH Battery Pack (Canon UK store)
Fujifilm NP-W126S
Fujifilm compact battery for the X100 series and smaller X bodies.
- Does not fit NP-W235 bodies (X-T5, X-S20, X-H2).
Source: Fujifilm Li-ion Battery NP-W126S
Fujifilm NP-W235
Fujifilm high-capacity battery for X-T5, X-S20, X-H2/X-H2S and several GFX bodies.
- About 1.5x the capacity of NP-W126S; the two are not interchangeable.
Source: Fujifilm Li-ion Battery NP-W235
Nikon EN-EL15 family (EN-EL15 / 15a / 15b / 15c)
Nikon battery family for full-frame Z bodies and many DSLRs; EN-EL15c is the current pack.
- Z8, Z6III and Z f ship with EN-EL15c; EN-EL15b and EN-EL15a also work but give fewer shots per charge.
- Only EN-EL15c and EN-EL15b can be charged in-camera over USB; original EN-EL15 and EN-EL15a cannot.
Source: Nikon USA - How to Charge a Nikon Z series Mirrorless Camera Using USB
Nikon EN-EL25 / EN-EL25a
Nikon compact battery for DX Z bodies (Z50, Z50II, Z fc, Z30).
- Z50II ships with EN-EL25a and also accepts EN-EL25.
- Does not fit EN-EL15 bodies.
Source: Nikon Z50II product page
OM System BLX-1
OM System battery introduced with the OM-1.
- Not the same as the older Olympus BLH-1 used by the E-M1 Mark II/III.
Source: OM System OM-1 product page (box contents)
Panasonic DMW-BLK22
Panasonic LUMIX battery shared by S5/S5II/S9 full-frame and GH5/GH6/GH7/G9 Micro Four Thirds bodies.
Source: Panasonic DMW-BLK22 product page
Sony NP-FW50 (W-series)
Sony W-series 7.4V battery used by older/compact APS-C Alpha bodies and the ZV-E10.
- Does not fit NP-FZ100 bodies (A7 IV, A7C II, A6700, A1, A9 III).
Source: Sony NP-FW50 product page
Sony NP-FZ100 (Z-series)
Sony Z-series 7.2V battery used by full-frame Alpha bodies and the A6700.
- Not interchangeable with the smaller NP-FW50: the A6400 and ZV-E10 use NP-FW50 while the A6700 uses NP-FZ100.
Source: Sony NP-FZ100 product page
CFexpress Type A
Small CFexpress card used by Sony; Sony bodies put it in combo slots that also take SD.
- Not interchangeable with CFexpress Type B (different size).
- In Sony combo slots (A7 IV slot 1, A1, A9 III) you can use either a CFexpress Type A or an SD card.
Source: Sony ILCE-7M4 specifications
CFexpress Type B
Larger CFexpress card used by Canon, Nikon, Fujifilm and Panasonic high-end bodies.
- Not interchangeable with CFexpress Type A.
- Nikon Z8 and Z6III CFexpress slots also accept XQD cards.
Source: Canon EOS R5 specifications
microSD / microSDHC / microSDXC (UHS-I slot)
microSD card slot (used as the second slot on the Nikon Z f).
- Full-size SD cards do not fit a microSD slot.
Source: Nikon Z f product page
SD / SDHC / SDXC (UHS-I slot)
Standard SD card slot with a single row of pins (UHS-I bus).
- UHS-II cards fit and work in UHS-I slots but only at UHS-I speed.
Source: SD Association - Bus Speed (UHS-I uses one row of pins; UHS-II adds a second row)
SD / SDHC / SDXC (UHS-II slot)
SD card slot with the second row of pins for UHS-II speeds.
- UHS-I cards work in UHS-II slots at UHS-I speed; high-bitrate video modes may need a V60/V90 UHS-II card.
Source: SD Association - Bus Speed
XQD
Older card format that shares the physical size of CFexpress Type B; accepted by some Nikon CFexpress slots.
- Only some CFexpress Type B slots accept XQD (Nikon Z8, Z6III do); Canon/Fujifilm/Panasonic CFexpress slots are not listed as XQD-compatible.
Source: Nikon Z 8 product page
Canon EF mount (DSLR)
Canon's DSLR lens mount; EF lenses fit EOS DSLRs natively and EOS R bodies via the EF-EOS R adapter.
- Requires Mount Adapter EF-EOS R on any RF-mount camera.
Source: Canon Mount Adapter EF-EOS R product page
Canon EF-S mount (APS-C DSLR lenses)
Canon APS-C DSLR lenses; usable on EOS R bodies only through the EF-EOS R adapter.
- Requires Mount Adapter EF-EOS R on RF-mount cameras.
- On full-frame EOS R bodies expect an APS-C crop, as with RF-S lenses.
Source: Canon EOS R8 specifications (EF and EF-S lenses via Mount Adapter EF-EOS R)
Canon RF mount
Canon EOS R mirrorless lens mount; full-frame and APS-C EOS R bodies all use it.
- RF-S (APS-C) lenses mount on full-frame EOS R bodies, which automatically switch to 1.6x crop mode.
- EF and EF-S lenses only work on RF bodies through a Canon Mount Adapter EF-EOS R (or the Control Ring / Drop-In Filter versions); they do not mount directly.
- EF-M lenses and CN-E cinema lenses cannot be used via the EF-EOS R adapter.
- EOS R50 excludes the RF 5.2mm F2.8L DUAL FISHEYE lens.
Source: Canon EOS R8 specifications (Canon Europe)
Canon RF-S (APS-C RF lenses)
APS-C lenses that use the RF mount; designed for EOS R7/R10/R50-class bodies.
- On full-frame EOS R bodies, RF-S lenses automatically enable 1.6x crop mode.
Source: Canon RF-S18-150mm F3.5-6.3 IS STM product page
Fujifilm X mount
Fujifilm APS-C mirrorless lens mount used by X-T, X-S and X-H bodies.
- Fixed-lens X100-series cameras (e.g. X100VI) cannot take X-mount lenses.
- Fujifilm GFX medium-format cameras use the G mount, not X mount.
Source: Fujifilm X-T5 specifications
L-Mount (Leica / Panasonic / Sigma alliance)
Full-frame mirrorless mount originated by Leica and used by Panasonic LUMIX S and Sigma bodies and lenses.
- Sigma lenses come in L-Mount and Sony E-mount versions that are not interchangeable; check the mount on the box.
Source: Panasonic DC-S5M2 Operating Instructions - Specifications ("Leica Camera AG L-Mount")
Micro Four Thirds mount
Open lens mount shared by Panasonic LUMIX G and OM System/Olympus bodies.
- Sigma and other third-party lenses are sold in several mounts; buy the Micro Four Thirds version.
Source: Panasonic LUMIX DC-GH7 Features and Specifications
Nikon F mount (DSLR)
Nikon's DSLR lens mount; F lenses work on Z bodies only via the FTZ/FTZ II adapter.
- About 360 AI-type-onward NIKKOR F lenses support AE on the FTZ II, but only ~94 AF-P/AF-S/AF-I lenses support AF; non-AI and some older lenses are incompatible.
Source: Nikon Mount Adapter FTZ II
Nikon Z mount (FX and DX)
Nikon mirrorless lens mount shared by full-frame (FX) and APS-C (DX) Z bodies.
- F-mount NIKKOR lenses need the Mount Adapter FTZ or FTZ II; Nikon notes restrictions may apply.
- Through the FTZ II, autofocus works only with AF-S, AF-P and AF-I lenses; screw-drive AF/AF-D (Type G and D AF NIKKOR) lenses are manual focus only.
- DX lenses on FX bodies use the DX (24x16) image area, reducing resolution.
Source: Nikon Z 8 Online Manual - Specifications
Sony E-mount (FE full-frame and APS-C E lenses)
Sony mirrorless lens mount shared by full-frame (FE) and APS-C (E) bodies and lenses.
- APS-C "E" lenses (e.g. E 18-135mm, SEL18135) mount on full-frame bodies but the camera records an APS-C crop, so you lose resolution and field of view.
- FE (full-frame) lenses work on APS-C bodies with a ~1.5x narrower field of view.
- Third-party lenses (Sigma, Tamron) are sold in separate mount versions; buy the Sony E-mount version.
Source: Sony E 18-135mm F3.5-5.6 OSS specifications (APS-C format, E-mount)