Ricoh GR III Flash: GF-2, P-TTL Options and Best Settings

That last line matters more than it looks. At f/2.8 the shutter tops out at 1/2500 sec, and you only get the full 1/4000 sec from f/5.6. For daylight fill flash, stopping down a little gives you more room before highlights clip.

If a body flash is a deal-breaker, the GR II still has one, and our GR II buying guide explains when that older camera makes sense.

The flashes that work on the GR III

Ricoh lists four flashes on its GR III/GR IIIx accessory page, and its firmware notes name two more Pentax units for P-TTL. These are the ones worth knowing:

Flash	Guide number on GR III	Power	Status (Ricoh, Oct 2026)	Best for
Ricoh GF-2	3 (ISO 100, m)	Built-in Li-ion, USB-C	Current	Street, parties, pocket carry
Pentax AF180FG	18 (ISO 100, m)	2x AAA	Current	Events, bounce
Pentax AF201FG	20 (ISO 100, m)	2x AAA	Discontinued	Used market only
Pentax AF540FGZ II	35 (ISO 100, m, 28mm zoom)	4x AA	Discontinued	Overkill on a GR

The firmware notes also list the AF540FGZ, AF360FGZ and AF360FGZ II as P-TTL compatible, which helps if you already own a Pentax kit.

Our pick: the GF-2 for almost everyone. A GR is a pocket camera, and the GF-2 is the only option here that keeps it that way. Buy the AF180FG only if you shoot events indoors and want to bounce light off a ceiling.

The Ricoh GF-2: specs and what changed with firmware 2.10

Ricoh announced the GF-2 alongside the GR IV. According to photoscala's launch report of August 28, 2025, which quotes Ricoh's specifications:

GF-2 spec	Value
Guide number	3 (ISO 100), 6 (ISO 400)
Weight	About 19 g
Flashes per charge	About 270
Recycle time	About 2 seconds
Charging time	About 2 hours, over USB-C
Coverage	Optimized for an 18mm focal length; vignettes with the GW-4 wide converter
Launch price	Around 100 euros

At launch, the GF-2 was not a full partner for the GR III. Photoscala reported that on GR models other than the GR IV it only fired in full-discharge mode, because the flash contacts are laid out differently, and that a firmware fix was planned for October 2025.

That fix arrived on October 23, 2025: firmware 2.10 for the GR III, Street Edition, Diary Edition and HDF, and 1.60 for the GR IIIx, Urban Edition and GR IIIx HDF. Both add a new exposure mode, GF-2 Flash Mode. Ricoh's notes describe how it works:

• The camera "automatically calculates the appropriate exposure value before shooting, based on the subject distance measured by autofocus or the distance set manually via manual focus."
• It is available when the mode dial is on P, Av, Tv or M, and can be assigned to the ADJ lever or an Fn button.
• It does not work for video or with Snap Distance Priority.
• The camera waits for the flash to recharge before each frame, so continuous and bracket shooting slow to about one frame every two seconds.
• With a fixed ISO, Ricoh warns that the camera's ability to adjust exposure is limited and frames may come out over- or underexposed.

The GR IV page adds a detail that explains that last warning: with ISO Auto, the system adjusts both the flash output and ISO to the distance; with fixed ISO, it can only change the flash output. A guide number of 3 leaves very little room, so give the camera ISO as its second lever. If you also shoot a GR IV, our GR IV accessories guide covers which flash and hot shoe gear carries over.

How far a small flash really reaches

Guide number divided by aperture gives the maximum flash distance in meters. Every two stops of ISO doubles the guide number. Applied to the GF-2:

ISO	Effective GN	Range at f/2.8	Range at f/5.6	Range at f/8
100	3	About 1.1 m	About 0.5 m	About 0.4 m
400	6	About 2.1 m	About 1.1 m	About 0.75 m
1600	12	About 4.3 m	About 2.1 m	About 1.5 m
3200	About 17	About 6 m	About 3 m	About 2.1 m

Two practical conclusions. First, the GF-2 is a close-range tool: people at arm's length to a couple of meters, not a whole room. Second, the classic street setup of f/8 and a fixed snap distance needs ISO 1600 or more to light a subject at 1.5 meters. That is normal for night street flash, and the GR III's sensor handles it, but it is why ISO Auto matters in GF-2 Flash Mode.

The AF180FG's guide number of 18 at ISO 100 reaches about 6.4 m at f/2.8 before you even raise ISO, which is the whole case for carrying it.

Best GR III flash settings

These are our starting points. Save the one you use most to a custom slot, as explained in our U1, U2, U3 guide, so the flash setup is one turn of the dial away.

Direct flash on night streets (GF-2)

Setting	Value
Exposure mode	GF-2 Flash Mode (assigned to Fn)
Aperture	f/5.6
ISO	Auto, upper limit 3200
Focus	Manual, about 1.5 m
Flash exposure compensation	-0.7 to start
Image Control	Ilford HP5 B&W

Manual focus at a fixed distance replaces Snap Distance Priority, which the mode does not support, and gives the camera a known distance to calculate from. If you usually zone focus, our snap focus guide explains which distances keep a street in focus at each aperture.

Fill flash in daylight (GF-2)

Setting	Value
Exposure mode	GF-2 Flash Mode
Aperture	f/5.6 or smaller, so the full 1/4000 sec is available
ISO	Auto
Focus	AF, subject within 1 m
Flash exposure compensation	-1.0 to -2.0
Image Control	Portra 160

Dragging the shutter at a party (P-TTL flash or GF-2)

Setting	Value
Exposure mode	Av
Flash mode	Slow-speed Sync
Aperture	f/2.8 to f/4
ISO	800 to 1600
Flash exposure compensation	-0.7
Image Control	Kodak Gold 200

Slow-speed Sync lets the background lamps register while the flash freezes your subject, and the warm Kodak Gold rendering suits the mix of tungsten and flash. For low-light work without any flash, our night photography guide has the ambient-only settings.

Flash and film recipes

Flash changes how a recipe reads. Direct flash gives hard shadows and bright, near subjects against a falling-off background, so recipes with strong contrast exaggerate it. That is exactly why Ilford HP5 B&W, built on Hard Monotone with high contrast and strong grain, is our pick for flash at night: the look is meant to be harsh. For color, presets with a fixed white balance, such as Kodak Gold 200 (6900K) or Portra 160 (Shade), keep skin tones consistent from frame to frame, where Auto white balance can shift between a frame lit mostly by flash and one lit mostly by streetlights. Indigo Film 800 is built for neon and ambient night light; with flash at full strength it loses the cinematic glow it is designed for, so use it without flash.

Mistakes we see all the time

• Skipping the firmware update. Without GR III 2.10 or GR IIIx 1.60, the GF-2 has no dedicated mode on the camera.
• Fixing ISO at 200 in GF-2 Flash Mode. With a guide number of 3, the flash runs out of power past about a meter. Leave ISO on Auto.
• Using the GW-4 with the GF-2. The flash is optimized for an 18mm focal length and vignettes with the wide converter.
• Expecting bursts. The camera waits about two seconds between flashed frames. Time your shot instead of holding the button.
• Fighting over the hot shoe. A flash, an optical finder and a thumb grip cannot all sit there. Choose the one you need tonight.
• Full-power flash in daylight. Fill flash should be felt, not seen. Start at -1.0 EV of flash compensation.

In short

The Ricoh GR III has no built-in flash, and the right add-on for most owners is the 19 g GF-2 with firmware 2.10, used in GF-2 Flash Mode with ISO on Auto. Keep subjects within about 2 meters, or carry a P-TTL Pentax AF180FG when you need real reach or bounce. If you shoot the longer lens, the same firmware logic applies, as covered in our GR IIIx guide.

For a flash look that is meant to be gritty, get the Ilford HP5 B&W recipe, or pair flash with warm skin tones through the Kodak Gold 200 recipe ($1.99). Shooting black and white most nights? The B&W Masters bundle collects our monochrome recipes in one purchase.