For the past year or so my go-to lens has been a Cosina Voigtlander Nokton 50mm f1.1. It's a very fast but very large lens in the world of Leica M-mount glass.
It's been a great lens, but I just couldn't quell that desire for an authentic Leica lens. I wanted to know if I was missing something.
I had a 50mm Summicron DR f2 on my M3, but it wasn't getting much use and because of its design, the DR can't be used on digital Ms. That's a shame because the DR is really one of the most solid and beautifully engineered lenses I've ever handled. With a tear in my eye I traded it in on a vintage Leica 50mm Summilux f1.4. It was not only faster glass, but I could also use it on my M8.
You're probably thinking, shouldn't the Nokton be compared against Leica's Noctilux? Yes and no. Yes, it's more similar in design to the Noctilux. However, it's much closer to the price range of the Summilux, which is the biggest determining factor for poor photographers like myself. I spent $800 on the used Nokton, but then another $150 having the backfocus problem fixed by DAG. The used Summilux came in at $1500. (I previously owned the Nokton 40mm f1.4, which is a much cheaper lens but found the 50mm f1.1 to be a much better lens and sold the 40mm.)
So how does what could be considered an antique lens stack up against a modern apsherical lens like the Voigtlander Nokton 50mm f1.1?
First, there's size.
Although they weigh about the same, the Summilux is a good deal smaller than the Nokton and doesn't block the viewfinder. The Summilux also has a longer throw on the focus ring.
During back lit situations the Nokton has a tendency to put a purple fringe and a green fringe around the edges of the back lit objects, so my first shot before I decided to drop any money on the Summilux was to test it with some back light.
There was still some purple fringing around the door frame and window sticker, but there was no green fringing. Score one for the Summilux.
Once I decided I would trade in on the Summilux, I began some highly rigorous scientific tests. These included shooting a pirahna and a Diet Coke can with both lenses set to f1.4.
Summilux 100% Crop
Nokton 100% Crop
While the color rendering is almost the same, the Summilux proved to be noticeably sharper with better contrast.
Summilux 100% Crop
Nokton 100% Crop
With the backlit Diet Coke can the Summilux again came out on top when pixel peeping for a look at sharpness and contrast.
So the last question remained, what about the areas in a photo that are out of focus? I turned to a string of Christmas lights to answer that question.
Summilux Bokeh f1.4
Nokton Bokeh f1.4
Nokton Bokeh f1.1
At f1.4 the Summilux bokeh tended to be oval shaped with an outline. It wasn't terrible, but it's not the prettiest I've ever seen. However, at f1.4 the Nokton's bokeh was octagonal, not good at all. Once again the pre-ASPH Summilux, despite having been designed in 1969, came out on top. BUT the Nokton had that extra stop, so I couldn't just act like it didn't exist. At f1.1 the Nokton had very pleasing bokeh, which I liked better than the Summilux.
I was pleased with the test results because I had already spent the money on the Summilux, but I was really expecting the ashperical design of the Nokton to be sharper. It turns out, I have been missing something. Those Leica engineers knew what they were doing even way back in the 1960s. I can't imagine how great the modern 50mm Summilux ASPH with a floating lens element must be, but it's still well out of my price range at $4,000.
So now the question remains, does that little edge in sharpness and constrast matter at all if you're not making large prints? Is it worth paying more for an old lens versus a new lens with a warranty?
To me, it's worth saving a little more to buy the Summilux, but I have a really nice Nokton for sale if you're interested.