Image Quality – Sharpness
If you’ve read other reviews of this lens, you might know what’s coming here. The lens has been universally praised for its resolving ability. My findings are the same. This is quite possibly the sharpest lens I have ever owned, for any camera system. Wide open it’s already sharper than most lenses at their sweet spot, and stopped down it is absolutely staggeringly sharp, all the way into the very extreme corners. I have never seen a lens with such uniformly stunning sharpness across the entire frame. I think it is safe to say that it is likely outresolving the 16MP sensor of the OM-D quite handily.
Take a look at the 100% crops below. These are taken from the full shot at the right. The shot below and left is a 100% crop from the center of the image, while the crop on the right is from the very extreme lower right corner. Click on the images for full size. I think you’ll agree that they are quite incredible for 100% crops, especially in the corners.
Image Quality – Bokeh
For a wide aperture longer focal length lens, the quality of the blur produced by the lens is extremely important. A lot of the use of this lens will come in for tight portraits with very blurred backgrounds, and how the lens performs in these situations is critical. One problem that can happen occasionally with extremely sharp lenses is that bokeh often suffers. It’s the rare lens that has truly exceptional bokeh and is very sharp. The good news is that the Olympus 75mm is one of those lenses. In the vast majority of cases, bokeh is extremely smooth, with evenly illuminated specular highlights. The lens has a 9-bladed circular aperture and maintains circular highlights even stopped down. At further focus distances, a hint of green bokeh fringing can sometimes be seen, but it can usually be corrected in a program such as Lightroom 4.1. Overall, I’m very pleased with the performance in this department. The best part is that wide open, the lens produces creamy background blur while retaining biting sharpness at the focus point. Click on the image to the left for a larger view to see what I mean.
Image Quality – Chromatic Aberration, Color, Flare and Distortion
If you’re thinking this is a 100% positive review so far, well, you’re right. But the lens isn’t perfect. The lens does have one weakness, though it’s admittedly minor. The 75mm f/1.8 can exhibit some minor purple fringing wide open on high contrast subjects. It also is not immune to longitudinal chromatic aberration, which shows up as a magenta fringe in the foreground out of focus areas and as a green fringe in background out of focus areas. The good news is that compared to most fast lenses, it’s relatively well controlled and can either be completely corrected, or is minor enough to not impact the photo. In most situations, it doesn’t rear its head at all, but you can see some effect (with some detriment to the bokeh) as the green rings in the background of the shot on the right. Lateral chromatic aberration is extremely well controlled, and I didn’t see any at all in my testing.
The colors the Olympus 75mm f/1.8 produces are rich and saturated. Combined with the sharpness and bokeh, the overall rendering is quite beautiful. The lens is relatively resistant to flare. Even without the hood, images with the sun just out of frame retained good contrast (also seen in the shot at the right). The lens exhibits essentially no visible distortion.