Fujifilm X20 Review
Before we get into the tests we will show a sample image that illustrate the excellent image quality of the X20.
|12.7 mm (50 mm eqv.), F4, ISO 100|
|Click for 100% crop|
Sharpness, Contrast and Diffraction
The test chart below were shot at ISO 100 and focal lengths of 7.1 mm, 12,2 mm, and 28.4 mm (28 mm, 50 mm, and 112 mm eqv.). The magnification was kept constant at all three focal lengths which allows for direct comparisons of resolution and contrast not only within the same focal length but also between the focal lengths. In the drop down we show 100% crops from JPG fine originals.
The test charts suggest that sharpness peaks at F2.8 and F4 at all focal lengths. The X20 has an excellent lens, it's only a pity that these best apertures cannot be used outdoors in sun shine since the shutter speed cannot go as high as required.
Our findings on resolution and contrast are summarized as follows:
|Focal length||Our findings|
|7.1 mm (28 mm eqv.)|| |
|12.2 mm (50 mm eqv.)|| |
|28.4 mm (112 mm eqv.)|| |
Bottom line is that this lens is sharp from wide open to F5.6. F8 is useable except at the long end (due to low contrast), and F11 should be avoided at any focal length.
For the example below we shot at close distance in macro mode. Again diffraction sets in at F8 (albeit ever so slightly) and really takes its toll of the image quality at F11. F11 should be avoided whenever possible. At close distance we found that the image quality is at its best from F4 to F5.6 with F2.8 right behind. The images were shot at a focal length of 17.3 mm at ISO 100 and the 100% crops below are from this scene:
The level of detail at F4 and F5.6 is impressive for a 12 MP sensor this small and is probably to be attributed to the lack of a low pass filter.
Super Macro Mode
Super macro mode focuses as close as 1 cm but is only available at the widest focal length (28 mm eqv.). This means that the magnification isn't a large as one might think. Anyway, we gave this mode a try. We used autofocus and a sensitivity of ISO 400. The light source was one halogen lamp. Click a thumbnail to browse or the link below the thumbnail for the full size original.
|Distance: 2 cm. F5.6. Click thumbnail to browse||Distance 1 cm. F7.1. Click thumbnail to browse|
|Click here for full-size version (3 MB)||Click here for full-size version (3 MB)|
There is significant barrel distortion in super macro mode due to the short focal length and auto white balance is off, but other than the results are excellent.
Finally we show a crop of an image shot at 5 cm distance of our HO scale model, ISO 400, F5.6. Click the image for the 100% crop.
|Distance 5 cm, cropped to 2000 x 1300 (crop includes about 1/4 of the original). F5.6, ISO 400|
Barrel distortion isn't an issue at this distance.
To test high ISO noise we took some night shots at the same scene we used in our Pentax Q and Olympus E-PL3 in-depth review. The images were shot in JPG since the X20 doesn't allow the full ISO range in RAW (tops out at ISO 3200 in RAW), another undocumented "feature". Noise reduction was set to "0" (standard).
Note how much detail is lost at high ISO (watch the gate in the lower right hand side disappear at high ISO). With that said, we find the results up to ISO 800 clean and perfectly usable, ISO 1600 is very good, ISO 3200 is good, ISO 6400 borderline acceptable, whereas ISO 12,800 is for emergency use only. Not much detail is left at that high sensitivity. For a relatively small sensor we find the performance excellent.
Vignetting is a non-issue with this camera. Even wide open and at all focal lengths tested (28, 50 and 112 mm eqv.) the light falloff in the corners is imperceptible.
Distortion is not an issue at 112 mm eqv. At 28 mm eqv. and at 50 mm eqv. there is some visible barrel distortion. At 28 mm eqv. the distortion is much less than what we have seen with other small-sensor cameras. Perhaps the X20 employs software correction of the optical distortion, but there is no indication as to such a feature neither in the documentation nor in the menu system. We were surprised to find almost the same level of barrel distortion at 50 mm eqv. as present at 28 mm eqv. Usually zoom lenses have the least distortion at the middle of the zoom range, but that's not the case here.
The distortion is the same in RAW and JPG. Adobe Photoshop does not have a profile for the X20, but +3 and +2 in the generic lens correction in Photoshop CS6 takes care of the modest distortion at 28 mm eqv. and 50 mm eqv., respectively.
|Wide angle (28 mm eqv.)|
|Normal angle (50 mm eqv.)|
|Telephoto (112 mm eqv.)|
Flare and Aberrations
The X20 is extremely flare resistant. We did several test shots with the sun in or near the frame and we were not able to provoke any ghosting. The below samples where we managed to get a star reflection from the diaphragm and some faint flare and the night shot were our most "successful" tests. Click any thumbnail to browse:
|7.1 mm (28 mm eqv.) F4.5, EV comp +1||11.7 mm (50 mm eqv.) F4.5, EV comp +1|
|28.4 mm (112 mm eqv,) F4.5, EV comp +1||F5.6, ISO 800|
Chromatic aberration is also not an issue with the X20's lens/sensor combination. We took several backlit shots at various focal length and only in the one example below can one perhaps detect a tiny bit of chromatic aberration.
|The scene. Click image to download the full size original (4 MB file)|
This aberration test illustrates the excellent result than can be achieved when a quality lens and sensor can be designed to work together, something that cannot be achieved with an interchangeable lens camera.
Exposure and White Balance
White balance is accurate, we left it on auto and did not have to make any adjustments.
Exposure is accurate for most scenes, but the matrix metering didn't always do a good job of determining where to meter a scene:
|Matrix metering got fooled|
Some of our close-ups of flowers benefitted from a -0.3 EV correction to get more texture in the petals. But we didn't see significant clipping of the yellow and reds with exposure correction off as is otherwise typical of many sensors. Overall an excellent performance.
Bokeh and Blur Control
The focal length of the lens is very short due to the small sensor and this makes the depth of field quite large. Unless you're shooting in macro mode there is not much out of focus blur (bokeh) to speak of.
Oftentimes the large depth of field is a benefit (typical landscape shots), but if you want to isolate a subject from the background you cannot just achieve this by opening the lens up to a large aperture and get a narrow depth of field as you can do with your DSLR.
With the X20 technology comes to the rescue in the form of what Fuji calls "Pro Focus" which is a feature you can assign to the "Adv" position on the mode dial. Exposure mode is automatic and the camera will artificially blur what it deems to not be the main subject. If the camera cannot detect a main subject then a warning is displayed on the screen. There are three softness settings to chose from, that's about the level of control you have. In the example below the camera set the aperture to F5 and we did the same manually for the comparison shot. We also tried F2.2 for comparison but that got us a severely overexposed image. We thus learned the hard way that the shutter speed tops at 1/1000 s at that aperture. Some compact cameras have a built-in ND filter to solve that situation, but that's not the case with the X20. And there is no filter thread on the lens (an optional combined hood/adapter is available that allows for a filter to be mounted).
Click any thumbnail to browse.
|Pro Focus setting 1, F5||Pro Focus setting 2, F5|
|Pro Focus, setting 3, F5||Comparison shot, normal autofocus, F5|
The X20 does an admirable job of isolating the subject, much better than what we found the Pentax Q capable of doing. The artificial blur doesn't have the smoothness of a top notch DSLR lens, but on the other hand it isn't harsh either like often seen on inexpensive DSLR zoom lenses. We deem this feature absolutely useable on the X20 and it is easy to engage.
As mentioned above, in macro mode the depth of field narrows and lens bokeh can be evaluated. The focal length was 21 mm and ISO was 100. Click any thumbnail to browse larger images.
The bokeh is good for a zoom lens, not super smooth, but not harsh either except perhaps at F11.
The dynamic range is somewhat limited compared to what we get with our DSLR. Not much detail can be recovered from the shadows.
Crop to the area outlined above:
|As shot||With shadows brightened in Photoshop|
Image Quality Verdict
The image quality is excellent for a compact camera. The only negative is heavy diffraction at F11 and at the long end of the zoom range also F8. There are no other optical flaws to be concerned about: no vignetting, no distortion, the lens is quite flare resistant and it is sharp already from wide open.