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Specific image quality issues

As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don't show up in the tests. The Leica Macro-Elmarit 45mm F2.8 OIS proved be to a capable, unfussy performer, consistently producing good quality images. One important observation from 'real world' shooting is that image stabilization appears to work much better when set to mode 1 (i.e. always on) on Panasonic bodies.

Flare

Like many lenses with a relatively narrow angle of view, the 45mm isn't at all happy when bright light sources are directly in shot - then again there aren't that many pictures you'd want to take with it where this is the case (sunsets maybe). The results aren't pretty at any aperture, but as usual multicolored flare patterns become ever more pronounced the further you stop down.

Move the sun even slightly out of the frame, though, and the results improve substantially. Even shooting into the light in very bright conditions we saw few problems with flare, and nothing that really spoiled any shots. However small flare spots did occasionally show up in images, indicating that the shallow lens hood is not as effective as it should be.

F2.8, Panasonic G1 F8, Panasonic G1
F22, Panasonic G1 F6.3, Panasonic G1

Background blur ('bokeh')

One genuinely desirable, but difficult to measure aspect of a lens's performance is the ability to deliver smoothly blurred out-of-focus regions when trying to isolate a subject from the background, generally when using a long focal length and large aperture. The 45mm F2.8 macro is capable of delivering quite reasonable background blur; with its 16mm entrance pupil, it offers similar depth of field characteristics to a 60mm F3.5 lens on APS-C, or a 90mm F5.6 lens on full frame.

When used for close-up shooting, bokeh is attractively blurred, with a smooth fade-off into out-of-focus regions. We'd expect that from a macro lens, but perhaps more impressively distant bokeh is also very smooth, with no hint of hard-edged character to out-of-focus highlights. At F2.8 it also has an appealing, 'swirly' character with a "cat's eye" effect towards the edges - a consequence of physical vignetting by the lens barrel design (and a reflection of the small diameter of that front element).

Close-up Bokeh
Distant Bokeh
F2.8, Panasonic G1 F2.8, Panasonic GF1
50% crop 50% crop

Chromatic aberration

If you use a Panasonic camera, lateral chromatic aberration is corrected in software when shooting either in JPEG, or raw with a fully compatible converter (e.g. the supplied SilkyPix, or Adobe Camera Raw or Lightroom). However if you use this lens on an Olympus E-P1, or convert Panasonic raw files with converter which doesn't understand the embedded correction data, you'll see a hint of fringing. It's testament to how little lateral CA there is that we hand to hunt far and wide for a 'real world' shot that showed this - even then it's really nothing you'd worry about unless you're making really large prints.

Perhaps due to the relatively modest maximum aperture, longitudinal chromatic aberration is also next-to-nonexistant on this lens. If you really look for it you can find it, in the form of slight fringing around highlights that is magenta in front of the plane of focus, and green behind. But it's most unlikely to be a significant problem in normal shooting.

Lateral CA
Longitudinal CA
Panasonic G1, F6.3, raw + dcraw Panasonic GF1, F2.8
100% crop, lower right 100% crop, in front of focal plane
100% crop, camera JPEG (corrected) 100% crop, behind focal plane

Diffraction softening at small apertures

One aspect of lens performance that's literally impossible to get away from is the gradual softening of the image due to diffraction at small apertures. The 45mm F2.8 macro stops all the way down to F22, which may not sound too bad until you realize that this gives similar results to F28 on APS-C, or F44 on full-frame - all of which will be very soft at the pixel level. Of course this comes with the very real benefit of increased depth of field, so the trade-off can sometimes be worthwhile (especially when shooting closeups). But it's important to appreciate just how much the image degrades in the plane of sharpest focus.

The example below illustrates this much-misunderstood effect, looking at the depth of field of the picture as a whole alongside the pixel-level sharpness of 100% crops from the indicated regions. Stopping down brings progressive benefits in terms of depth of field, but detail in the region of sharpest focus is visibly softened at F11, and heavily blurred at F22 (all the sharpening in the world won't bring it back). Against that, though, detail at the top of the shell is most defined at F22, at which point it's coming close to that in the plane of focus.

F2.8 F5.6 F11 F22

The choice of aperture for any specific shot is dependent upon both the desired aesthetic, and the final output size. The F22 shot here would look fine in a 6" x 4" print, for example, but visibly lack detail at 12" x 8". For most purposes we found F11 to give the best compromise between fine detail and overall depth of field. It's also important to understand that diffraction isn't a specific flaw with this lens (or indeed any other), but simply a direct consequence of the immutable laws of physics.

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