Sony RX100 V Optics

Zoom
A shorter than average 2.9x zoom, with good far-field performance.

The Sony RX100 V is equipped with a 8.8-25.7mm lens, offering a fairly limited optical zoom ratio of about 2.9x, translating to a 35mm-equivalent focal range of about 24-70mm. The lens is however very fast (bright), with a maximum aperture ranging from f/1.8 at wide angle to f/2.8 at telephoto, which is excellent for low-light shooting and provides reduced depth-of-field for better subject isolation. As is often the case with fast compact lenses, though, maximum aperture does fall-off rather quickly as you zoom, already reaching f/2.8 somewhere between 28 and 35mm equivalent. The following table reflects the maximum and minimum apertures as reported by the camera at some popular focal lengths:

Far-field performance is quite good at f/5.6 as shown above, with very good sharpness and contrast across most of the frame, low chromatic aberration (the RX100 V's processor does a good job at suppressing it) though some softening and coma distortion can be seen in the corners at full wide angle. Performance at 50mm equivalent appears to be very good across the entire frame. Performance at full telephoto is also quite good with good sharpness and contrast across almost the entire frame, though some mild blurring and vignetting can be see in the extreme corners. The Sony RX100 V also offers Clear Image digital zoom at 2x, and standard digital zoom up to 4x magnification. Clear Image zoom is supposed to perform better than standard 2x digital zoom, but we didn't see much difference with this subject matter. (Both performed well, although magnification from Clear Image zoom was a bit lower.) 4x digital zoom was a bit soft, but it seemed to perform better than average for that much digital magnification.

See below for lab results on macro performance, geometric distortion, corner softness, etc.

Macro
A larger than average sized minimum coverage area, with very good detail. Flash throttled down well, but the lens casts a shadow at minimum distance.

The Sony RX100 V captured a larger than average sized minimum area measuring 3.83 x 2.55 inches (97 x 65 millimeters) at maximum wide angle. Sharpness over much of the frame is very good, but corners show quite a bit of softness even at f/8 (most lenses show some softening in the corners at macro distances). The flash did a good job throttling down, but the lens casts a bit of a shadow in the bottom half of the frame. You'll likely want to use external lighting for the closest RX100 V macro shots.

Geometric Distortion
Very low distortion in camera JPEGs, but very high in uncorrected RAW files at wide angle.

Thanks to in-camera distortion correction, there's almost no geometric distortion in the RX100 V's JPEG files. At full wide angle, we measured well under 0.1% barrel distortion. At full telephoto, barrel distortion is just over 0.1%. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

To see how much correction is taking place in the camera, we converted RAW files from the above shots with dcraw, which does not correct for distortion. As you can see at wide angle, barrel distortion is extremely high, at about 3.9%, while telephoto shows low but complex "moustache-shaped" pincushion distortion at about 0.3%.

We expect to see significant distortion in uncorrected RAW files in fast, compact lenses like the RX100 V's, as allowing this gives the lens designers greater flexibility in optimizing center sharpness and other aberrations, as well as in reducing cost, size, and weight. The downside is that the distortion correction contributes additional blurring to the corners of the frame where pixels are "stretched" during correction and where lenses are usually already a bit soft. Note that most RAW converters are capable of applying distortion correction automatically, as specified by the manufacturer in lens profiles embedded in RAW files.

Chromatic Aberration and Corner Sharpness
Very low to moderately low chromatic aberration in JPEGs. The lens produces some soft corners wide-open, though corner sharpness improves stopped-down.

Chromatic Aberration. Thanks to effective in-camera chromatic aberration suppression, there's moderately low to low C.A. to be seen in the corners at either wide angle or telephoto in camera JPEGs. As expected, though, uncorrected RAW files (see below) show much more C.A. than seen above.

Corner Softness. Wide-open at full wide angle, the lens in our sample showed a little decentering, with the left-hand corners showing more softness than the right-hand ones. The center is very sharp, and softness from the worst-case corner (upper left) doesn't extend very far into the frame. At full telephoto, it's the lower-right corner that is the softest when wide-open, and the softness extends far into the frame from the bottom (the top corners are much better). The center is slightly soft at full telephoto.

Vignetting. There's some mild vignetting (corner shading) at the telephoto end, as indicated by the darker corner crop compared to the center.

F5.6: Stopping down a few clicks improved corner sharpness, contrast and chromatic aberration slightly at wide angle, however corners were still much softer than the center. Sharpness in the center at wide angle remained about the same, however C.A. was reduced to almost nonexistent. Some corners improved at full telephoto when stopped down, but performance in the worse-case lower-right corner actually degraded a bit. Sharpness and C.A. in the center improved at full telephoto, though wide angle is still sharper. We can also still see some minor vignetting at full telephoto.

Chromatic Aberration Correction

As you can see in the crops from uncorrected RAW images on the right (taken from ARW files converted with dcraw), the RX100 Mark V's lens produces moderately high and bright chromatic aberration at both maximum wide angle and full telephoto. But the RX100 V's processor does a great job suppressing lateral chromatic aberration in camera JPEGs (crops on the left). Note that most RAW converters should also automatically suppress C.A. when converting the RX100 Mark V's ARW files.


Overall, good performance from the RX100 Mark V's lens, especially considering how fast (bright) and wide it is.

Coverage
Excellent accuracy from the LCD monitor and electronic viewfinder.

The Sony RX100 V's LCD monitor tested at 100% coverage at full wide angle and at telephoto, while the EVF tested at just slightly lower than 100% coverage. This is excellent performance, especially considering the amount of geometric distortion correction taking place at wide angle.