Medium format quality? Test results: Leica M10P vs. Leica M10M vs Sony a7r4 vs Phase One IQ4 with optimum lenses by Onasj (see all previous posts by Onasj):
Leica’s new M10 Monochrom (M10M) has been touted by multiple reviewers as offering image quality rivaling that of medium-format. And Sony explicitly claims that its a7riv camera rivals medium-format cameras. In this test, I compare side-by-side the Leica M10P (24 MP, color) with the M10M (41 MP, monochrome), the Sony a7riv (61 MP, color), and the “full-frame medium format” (54 x 40 mm sensor) Phase One IQ4 (151 MP, color), currently the largest and highest-resolution imaging sensor available to most photographers. (Note that the 102-MP Fuji GFX-100 has a cropped (44 x 33 mm) version of the Sony-manufactured sensor In the IQ4.) For each camera, I used the very best available lens at the best-quality aperture and at base ISO.
Test conditions:
Leica M10P + Leica APO 50 Summicron at f/5.6, ISO 100
Leica M10M + Leica APO 50 Summicron at f/5.6, ISO 160
Sony a7riv + Sony 85/1.4 GM at f/5.6, ISO 100
Phase One IQ4 + Rodenstock HR90 at f/9, ISO 100 (yes, the base ISO of the IQ4 is 100, not 50).
Shooting the IQ4 at f/9 gives a comparable depth of focus as shooting the other cameras at f/5.6. I know from my other tests, and from discussions with Phase One dealers, that at f/9 diffraction is not limiting in practice for the IQ4 sensor (though it can be limiting at apertures smaller than f/9).
Everything was shot on a tripod with 2-3-second release delay to avoid shake, at subject distances to give similar subject size and position. Note that the aspect ratio of the IQ4 sensor is 4:3, rather than 3:2 like the other sensors, so I used frame width to match framing. Since I was shooting the IQ4 on a technical camera, all four cameras were mirrorless, with no risk of mirror slap vibrations spoiling sharpness.
Raw files were exposure-matched and converted to monochrome using Capture One 20. Then each converted max-quality JPEG was auto-bicubic-scaled in Photoshop to either 7864 pixels wide (the width of native M10M images) or to 14204 pixels wide (the width of native IQ4 images).
You can download all the raw files and full-resolution max-quality JPEG files here.
A tiny 100% crop from near the center of the 14204 pixel-wide images was composited into a matrix for comparison, attached to this post. Click on the image to see the comparison full-size. I choose to use the scaled-up 14204-pixel-wide images since one goal of this test is to determine if any of these imaging systems can approach medium format quality, not to test if they can approach down-sized medium format quality. You can build analogous matrices from the smaller images as well using the files in the above link if you would like.
Summary of findings:
1) As expected, all of these four imaging systems with optimum glass, ISO, and aperture produce excellent images at their native sizes.
2) The Bayer CFA-less M10M does indeed punch above its megapixel weight. With respect to capturing subject details, I found the M10M (41 MP) and Sony a7riv (61 MP) to be virtually identical. In fact, to my eye the M10M+50 APO was able to capture slightly more details than the a7riv+85 GM—compare the lint on the upper grey band of the vessel in the attached matrix.
3) The Phase One IQ4 eats all the competitors for lunch if you compare image quality at 100%. But a 14,204-pixel-wide image printed at 200 dpi is 6 feet wide (!). At any practical viewing distance (assuming you don’t need to crop heavily), I would say that the IQ4, M10M, and a7riv are actually quite similar, even when scaling up the latter two images to the 14,204 pixel width of the IQ4 image. Which is pretty cool.
4) The M10P, as you might expect for a 24-MP camera thrown into a resolution and sharpness gunfight, lags well behind the others, but even so, once I view the M10P image at about 50% magnification it begins to look quite similar to the other images.
5) In terms of bang for the buck, Sony offers outstanding value, as usual. The Sony a7riv + 85 GM lens costs ~$5,200. Either Leica body + the 50 APO costs ~$17,000. And the Phase One IQ4 + Rodenstock HR90 costs around $55,000. And the Sony is the only one of the four tested systems that offers autofocus.
So can the Leica M10M or the Sony a7riv offer image quality rivaling that of state-of-the-art digital medium format systems? Yes, at practical viewing sizes and distances, when using optimal glass. But if pixel peeping or (very) large prints are your target application, then medium format, for now, has no peer.
