We did a quick review on the 'Voigtlander 28 f/2 Ultron' a couple of weeks back. Here is a quick comparison against the 'Leica 28mm f/2.8 Elmarit-M' Connor grabbed these 2 frames on our way to lunch (both at f/2.8). The two files bellow are just strait out of the camera, below that are two 100% cropped section of the eyes. I just tried to match the exposure visually in Lightroom as best I could for this DIY comparison. A little less exposure bouncing of the wall to camera right on the Voigtlander, you still get the basic idea for this post.
The lenses both have a great feel of their own, the Leica is obviously the sharper lens as it should be at almost 3 times the price. The Voigtlander does a commendable job indeed, so hats off to Leica's well priced 'country cousin'.
Finally, both images processed in Adobe Lightroom using a strait VSCO Preset, not certain which one I used so my apologies. We did not set out to right a complicated post, just a quick DIY reference point for those interested. Both images are at f/2. I think if we did some 'street' images stopped down to f/5.6 or 8 it might be a much harder task to spot the differences. What is apparent is that once the images are processed (all be it quickly) and adjusted for the web, there really is not much in it.
The comparison becomes a bit more interesting when your hip pocket is the base decision maker. The latest incarnation of the Leica 28mm f/2.8 Elmarit-M NEW has a street value of $2481 the Voigtlander 28 f/2 Ultron $745. If we look online at some earlier versions of the Leica you should be able to grab yourself a much larger saving at around $1013 (eBay Gumtree) give or take a few dollars.
Whats clear is that either lens are a worthy choice depending on your hip pocket and or level of PIXEL PEAKING necessity of your final image. If Flickr or Facebook is your outlet of choice grab the Voigtlander, if 10 foot gallery prints are your thang ... the Leica.
Source (Leica lens image http://us.leica-camera.com/)