I recently purchased a Summicron 28mm Aspherical 6 Bit and will be comparing it to the Voigtlander 28mm Ultron M (I’ve had for a few months) On my reviews we like to compare sharpness, color and ergonomics. There are much more aspects like type of Bokeh, Flare Resistance, Color Cast, etc… But I usually compare the first mentioned. The Voigtlander 28mm Ultron M, specially at f/4 and beyond has been good to me. At f/2 it is soft, but a bit of sharpen mask usually renders good results. But after looking at what the Summicron can do at f/2 I may have gotten a new respect for the cron.
In the left section I add Sharpen Mask to both images from each lens. If I add it only to the Voigtlander then we get close to the unprocessed straight DNG file from the Summicron but as soon as we add a bit of sharpening to the Summicron file, you can see the clear winner.