This 35mm APO lens from Light Lens Lab looks very similar to the original Leica lens. However, their optical designs are different: it has 11 elements in 6 groups, while the Leica lens has 10 elements in 5 groups.
I have a 35mm F2 eight-element lens from the LLL series. I’m very satisfied with both its optical quality and mechanical construction. Here are some photos taken using this lens for your reference: https://www.fredmiranda.com/forum/topic/658112/1746#17089910
Even if a lens had the exact same elements and groupings, exact same dimensions, my understanding is that the glasses used will typically be very different, such that light rays will not use the same 'transport routes' to the sensor.
You would need to duplicate the exact refractive indexes and Abbe numbers of the glass. It might be akin to two men of the same height and weight, but you can't call them identical. But even Leica does not do that in their revisions, designers are always looking for improvements in some aspect or another.
Google AI: .You cannot produce an exact optical copy. Even if two different glass stocks share the exact same refractive index and primary Abbe number - their partial dispersions across individual wavelengths will differ because their internal chemical compositions are unique.'
The only two serious makers doing this are Thypoch and LLL, and it's a bit of a tightrope walk, I'm sure. We see small shape variations and very often quite different glass types. For example, the Simera 35/1.4 has no APD glass, but the (probable) source 2022 Summilux uses 'several elements with anomalous partial dispersion'.
Optical science is messy, 2nd and third order aberrations etc. They always look to improve.
david6908 wrote:
This 35mm APO lens from Light Lens Lab looks very similar to the original Leica lens. However, their optical designs are different: it has 11 elements in 6 groups, while the Leica lens has 10 elements in 5 groups.
I have a 35mm F2 eight-element lens from the LLL series. I’m very satisfied with both its optical quality and mechanical construction. Here are some photos taken using this lens for your reference: https://www.fredmiranda.com/forum/topic/658112/1746#17089910
Light Lens Lab is claiming it will perform similarly to the Leica overall, and actually better in the corners. As far as rendering and actual axial CA control, only a comparison can say for sure.
