Leica Interesting Article Comparing Top SLR 50s and Leica M Mount 50s at LensRentals.com

[Amin]

Roger Cicala did some very interesting testing of some top performing SLR 50s and several current production Leica M mount 50s.

As expected, all of them are great. Still interesting to see the differences.

Link: Comparing Rangefinder and SLR 50mm Lenses. (Version 0.7)

 

[asiafish]

Most impressive to me was how well the under $1000 Sigma Art and 35-year-old (non-APO) Summicron performed.

 

[Amin]

I was surprised to see the much better edge performance of the Summicron compared to the Planar ZM. How can the Summicron have identical center and edge sharpness at f/2? Has to be a mistake, no?

 

[Brian]

This test shows how good the 50/1.1 Nokton is- a real "Rodney Dangerfield" lens. It and the 35/1.2 Nokton are bargains.

 

[asiafish]

The whole thing was proof that specs mean very little. Look how poorly the Sonnar did, and yet its the most interesting of the group.

 

[Brian]

The Sonnar has a high degree of field curvature- so it's difficult to measure it's "real world" resolution using flat targets. This is the "plastic" look of the Sonnar.

 

[Amin]

Brian, based on the information Roger provided, the MTF50 data provided in the tables shouldn't be affected by field curvature. Only the MTF curves shown further down on the page would reflect field curvature.

One point I want to make clear is the testing methods differ – the MTF50 tests are done at ‘best focus for that point’. In other words the bench individually focuses at the center, mid point, and edge to generate the highest possible numbers. With the MTF tests we’re showing here, the bench focuses in the best position for the center of the lens and all other measurements are done at that focus. So field curvature will affect these graphs, but not the MTF50 tests done earlier.

 

[asiafish]

I still love my Sonnars

 

[Brian]

Brian, based on the information Roger provided, the MTF50 data provided in the tables shouldn't be affected by field curvature. Only the MTF curves shown further down on the page would reflect field curvature.

I missed that, makes sense. The older tests done with resolution charts would not do this.

To put in it perspective, at F1.5 the Sonnar resolves 840 lp/image height, 840/24, or 35lp/mm. A good match for the M9 and M8 with the Color array.