Pentax MX-1 Review

Image Quality

We realize that this is the page that you've likely skipped to, and we're pleased to offer an in-depth evaluation of the Pentax MX-1's image quality.  We're also happy to say that in this area, the MX-1 fares very well!

The MX-1 features a bright 6-24mm F1.8-2.5 lens, which has a field of view of 75 degrees diagonally (or 65 degrees horizontally) at the wide end, and about 20 degrees diagonally (or 16 degrees horizontally) at the tele end.  It corresponds to a 28-112mm lens on a full-frame camera, which means that it has a very convenient zoom range.  The lens is what's allows the MX-1 to capture sharp images!

Sharpness

It turns out that the MX-1 has a rather sharp lens. We'll start off with a 100% crop of a tree about 100 feet away:

As you can see, there's a great deal of detail in this photo.  Carefully exemining some sharpness test charts leads to some very positive findings.

Both sets of test charts suggest that sharpness peaks just below the maximum aperture, and that severe diffraction sets in at F8, resulting in much lower resolution.  The main thing to take away from these tests is that the MX-1 can comfortably be used wide-open!  At 24mm, the lens was sharp enough wide-open to provoke moire around the test chart!

Diffraction

Diffraction (severe loss of sharpness due to small aperture) is only an issue at F8.  The real-life 100% crop samples below illustrate this.

	F5.6	F8
6mm
24mm

Noise

Generally speaking, the MX-1 handles noise very well.  We found that the JPEG files remained usable up to ISO 1600.  Starting with ISO 3200, color noise started being introduced, suggesting that this and all higher ISO settings are beyond the sensor's native sensitivity range.

Please refer to the full-size files to gauge the MX-1's noise levels.  The RAW files shown have been sharpened and de-noised using Adobe Camera Raw.  We recommend always shooting RAW above ISO 1600, as that's where the difference between RAW and JPEG starts becoming significant.

As is evident from the above JPEGs, the MX-1 applies a fairly strong noise reduction algorithm to all of its JPEG files at high ISOs.  It is not possible to disable or adjust this noise reduction.  We've found that at high ISOs, the in-camera noise reduction algorithm is rather poor, as it sacrifices a great bit of detail, as can be seen in the comparison below.

Overall we're pleased with the noise performance of the MX-1; one can't expect much more from a 1/1.7" sensor.

Vignetting

The lens produces a very slight amount of vignetting at both the wide and the tele end.  However, we don't believe that the vignetting will ever have a negative impact on real-life photos.

Vignetting at 6mm

Vignetting at 24mm

Distortion

The MX-1 has a significant amount of barrel distortion at the wide end, but almost none at the tele end.  Fortunately, the camera does feature a built-in distortion correction option which does a great job of eliminating distortion.  The only bad news here is that for RAW shooters, a correction profile is needed, as the distortion is complex.  We were unable to fully correct the distortion using Adobe Photoshop without a profile (the Pentax desktop software can be used instead).  In the table below we summarize the amount of distortion found at each zoom setting based on Photoshop lens corrections:

As the numbers indicate, the lens quickly switches from exhibiting barrel distortion to pincushion distortion, and the pincushion distortion is minimal.

In the comparative images below, the uncorrected file is developed from a RAW corresponding to the in-camera-corrected JPEG.  Please disregard all differences in color/exposure. 

6mm (28mm eqv):

12mm (56mm eqv.):

24mm (112mm eqv):

Because the camera does such a good job of correcting distortion in JPEGs, and because distortion is minimal beyond the 9mm setting, we conclude that distortion isn't a major issue with the MX-1.

Flare and Aberrations

The MX-1's lens is subject to lens flare, which is very easy to provoke when shooting at night, as the lens has no hood.  This is the MX-1's biggest weak point.

The lens does a good job of controlling chromatic aberration, though you will sometimes see slight green or purple fringing around your highlights.

Exposure, Color, and White Balance

We did not perform a comprehensive test of the MX-1 auto exposure, though overall, we found it to be accurate.  During night city shooting, the camera tended to overexpose slightly, which is why we recommend using RAW for this purpose.

Color reproduction is good in JPEG mode, but shooting RAW will of course give you the most control in this area.

Overall, the MX-1's auto white balance is accurate, but it can be overriden manually at any time.

Macro Mode

We did not perform a formal image quality test in 1cm macro mode.  We did observe, however, that in this mode, the lens is not as sharp, and that there is a significant loss of sharpness in the corners.  Refer to the sample photos page for an example of this.

Bokeh

The MX-1 has smooth and pleasing bokeh overall, though you generally have to be in macro mode in order to see it.  The lens's aperture diaphragm (leaf shutter) appears to be hexagonal.

Image Quality Verdict

The MX-1 takes excellent pictures.  The fact that the lens is sharp wide-open is one of the MX-1's key advantages.  Of course, enthusiast compacts with larger sensors will exhibit less noise and better colors, but considering that it only has a 1/1.7" sensor, the MX-1 performs extremely well, especially in terms of sharpness. If you are looking for a "prosumer" compact camera and image quality is your top priority, then the MX-1 may be for you.

We find that the camera only really struggles with low-light shooting, for which the small sensor is to blame.  The sensor-shift shake reduction system in the MX-1 isn't quite as effective as in Pentax DSLRs, and we'd like to say that it compensates for about two stops of camera shake in practice, meaning that very slow shutter speeds should be avoided when without a tripod.  The JPEG noise reduction algorithm starts smearing details at and above ISO 3200, so RAW should be used at night whenever possible.  In addition, auto ISO mode always tends to select the highest ISO at night, so we recommend limiting the ISO to 1600 and perhaps underexposing a bit when appropriate.