Review of the Ricoh GW-4 21mm Wide-Angle Conversion Lens for Ricoh GR III

Ricoh has made available a dedicated wide-angle conversion lens for the Ricoh GR III. It takes the standard 28mm lens to a wider 21mm. Here's how it works and what it does in real-world terms.

The Ricoh GR III has a fixed 18mm prime lens.1 On the GR III’s APS-C sensor, that’s the equivalent of around a 28mm focal length of a full-frame (35mm) camera. So it’s a medium-wide perspective.

While you can’t switch out the lens on the GR III—it’s fixed—there is a way to get a wider perspective. Ricoh makes a dedicated wide-angle conversion lens that clips onto the front of the camera. A few years ago, I reviewed the previous model for the GR II. There’s a new model just for the GR III—it’s the GW-4 0.75 Wide Conversion Lens.

This is with the GA-1 and GW-4 attached to a GR III but without the rubber lens hood.

This lens clips onto the front of the camera. It’s basically a hunk of glass—there’s no aperture, focusing, or other controls on the lens itself. You can often pick up conceptually similar lenses billed as wide-angle lenses very cheaply, and they’re often pretty terrible. But don’t let that put you off—Ricoh has made sure that this model is several steps up from those in quality. And, frankly, it’d want to be if only because it’s not cheap. Ricoh has set the MSRP at $250, and then you’ll need to spend another $50 on top of that for the adapter ring. So all up, you’re looking at $300. Which is not a lot for a good lens, but it is quite a lot for a lens like this that is just solid glass.

The GW-4 0.75x Wide Conversion Lens at left, with the GA-1 adapter at right.

It takes the camera’s standard 28mm perspective to a significantly wider 21mm perspective. I have some examples below on what that translates to in visual terms.

It just clips on the front of the camera. It adds quite a bit of size and weight to the GR III, so you’re probably not going to be able to just slip the camera into your pocket anymore. To switch between the 28mm and 21mm perspectives, you remove the lens; there’s not a more convenient way to switch between them.

I’ve been pleasantly surprised at the quality. Adding a thick layer of glass to the lens will undoubtedly have an effect—and typically a negative one—but the engineers at Ricoh have done a good job with this lens to make sure that the negative effects are minimized. The quality remains very good, and there’s a minimal amount of light dropoff. There’s not much in the way of lens distortion or bowing, the edges and corners are still quite sharp, and there’s not much in the way of chromatic aberration (purple fringing). I’ve included some practical examples below.

Essential Accessory: Ricoh GA-1 Lens Adapter

If you’re going to buy the GW-4, make sure you also buy the GA-1 lens adapter as well. You won’t be able to use the GW-4 lens without it.

The GW-4 is a lightweight plastic adapter barrel. It contains no glass and has only minimal electronics. It’s a multipurpose adapter in that it includes a traditional 49mm diameter filter thread (but a plastic one, so it’s not as robust as a metal film thread), so you can use it to attach regular screw-on filters (ideally, use 49mm ones, or you can use a step-up or step-down adapter.

It’s nearly entirely plastic. There’s a latch lock on one side to lock it into place, and some metal contacts on the other. There’s no glass—it’s just a spacer.

I don’t understand why Ricoh doesn’t include it with the GW-4. By all means, offer it as a separate accessory if you want—after all, it works with other Ricoh lenses, and it’s a common way to add filters to cameras like the Ricoh GR-III—but the GW-4 can’t work without it. It’s also overpriced—$50 for what is mostly some flimsy, lightweight plastic.

The GW-4 0.75x Wide Conversion Lens at left, with the GA-1 adapter at right.

21mm vs 28mm on the Ricoh GR III / With and Without GW-4 Wide-Angle Conversion Lens

Here are some side-by-side examples without and with the GW-4 lens.

[caption id="attachment_31101" align="aligncenter" width="678"] Without the GW-4.[/caption]

[caption id="attachment_31100" align="aligncenter" width="678"] With the GW-4 attached.[/caption]

[caption id="attachment_31103" align="aligncenter" width="678"] Without the GW-4.[/caption]

[caption id="attachment_31102" align="aligncenter" width="678"] With the GW-4 attached.[/caption]

[caption id="attachment_31105" align="aligncenter" width="678"] Without the GW-4.[/caption]

[caption id="attachment_31104" align="aligncenter" width="678"] With the GW-4 attached.[/caption]

[caption id="attachment_31099" align="aligncenter" width="678"] Without the GW-4.[/caption]

[caption id="attachment_31098" align="aligncenter" width="678"] With the GW-4 attached.[/caption]

Photos Taken with the GW-4 Wide-Angle Lens

Here are some real-world examples. These were all taken with the GR III and the GW-4 (and the GA-1, of course). They were shot in RAW (.dng). I’ve processed them in Lightroom, but I haven’t applied any of Lightroom’s sharpening, lens distortion, or chromatic aberration fixes.

You can click on each image for a full-size version for a closer look.

This shot, and the others on this page with the statue of Abraham Lincoln in golden sunlight, were taken at sunrise around the equinox. The golden light isn’t done in post-processing—it’s how it looks and these are directly out of the camera. I have more on these types of shots at the Lincoln Memorial and how to take them on my DC Photo Guide site.

I often shoot this scene to test lenses and cameras because it tests several things at once. The relevant ones here are sharpness at the edges and corners and chromatic aberration. I’m surprised at how sharp it remains at the corners and how little chromatic aberration (purple fringing) there is. I haven’t boosted sharpness in post or applied any chromatic aberration fixes.

This shot is closer than the other one like it on the page, but it’s due to moving closer to the scene, not any change in focal length.

Again, pretty straight lines even at strong angles to the corners.

Again, this scene is one I often shoot in part to test for chromatic aberration in the windows at the top. But there’s really not much here. There are also lights shining directly at the lens, but there’s no issue here with flaring.

Even from the corners, the lines remain impressively straight. I would have expected more bowing and distortion.

Lots of bright light sources that could provoke chromatic aberration. There’s a little in the spotlights at top, but it’s not bad. I haven’t made any fixes in post to correct for it.

You can see some bowing in the railing at the bottom of the frame, but it’s not as much as I would have expected.

Things Worth Knowing

The front of the lens has a screw-on filter thread. It’s a 72mm diameter, so you can use standard 72mm screw-on filters or a step-up/step-down ring. You can leave the rubber lens hood on, although it makes operating a circular polarizer difficult and gets in the way with a step-up ring.

Key Specs

Model GW-4
Compatibility For Ricoh GR III camera. Requires Ricoh GA-1 lens adapter. (NB. The GA-1 is sold separately)
Magnification 0.75x. On Ricoh GR III, it comes to around 21mm focal length (35mm equivalent).
Weight 8.5 oz / 241 grams
Filter Diameter 72mm
Filter Type Screw-on threaded
Lens Hood Soft rubber slip-on lens hood included.
Zoom? No. It’s fixed magnification.
Autofocus Compatible? Yes. Focusing is handled by the GR III’s built-in lens as normal.
Manual Focus Ring? No. Focusing is handled by the GR III’s built-in lens.
Aperture Ring? No. Aperture is handled by the usual in-camera controls.
Model GA-1
Compatibility For Ricoh GR III camera. Required for using GW-4 Wide-Angle Lens.
Filter Size 49mm
Filter Type Screw-on threaded
Weight 0.4 ounces / 11 grams

Where to Find Them

I bought mine at Amazon. You can also find them at B&H Photo.

And don’t forget to get the GA-1 lens adapter as well.

  1. The focal length self-reports in the EXIF information as 18.3mm.

Images and product information from Amazon PA-API were last updated on 2020-05-29 at 22:49. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon Site at the time of purchase will apply to the purchase of this product.

View Comments

  • Hello David,

    I am happy that it works and that you proofed it with a 72mm filter.
    That's fun,
    thank you very much,



  • Hi David,

    what size is the filter thread on the GW-4 or is it any filterscrew on it.
    Or say it so: Is it possible to put a filter on it. I love using black pro mist filters:-)



    • Hi Andreas. You can't attach a standard screw-on filter onto the lens itself. While they look like threads on the front of the lens ring, they're not. And the glass has a convex front that protrudes out and would prevent a flat filter from going on. You could probably find a way to attach an external filter holder, but I haven't tried any with this lens. The GA-1 adapter can be used to attach 49mm screw-on filters without using the wide-angle lens.

      • thank you,

        I read on B & H in a review on the GW-4 Adapter that we could now! use a 72mm filter thread in front of the lens. No idea how this works.



        • I stand corrected. Now that I've got it in front of me I've taken a closer look and it does indeed have a filter thread as well (just not the more obvious rings). And it is indeed 72mm--I've just screwed one on. So my apologies for my error, but thanks for the correction.