Are Z lenses APO lenses?

Started 6 months ago | Discussions thread
LarsHP
LarsHP Contributing Member • Posts: 607
Re: Are Z lenses APO lenses?
6

as1mov wrote:

Hi,

are the Z lenses APO lenses in Leica's sense?

Thanks.

That depends on the definition, which Leica seems to hide or avoid ... !

What I am saying is that while Leica at one point did say what Jono Slack quotes (after reading the thread I link to below), including that color aberrations in the out of focus areas are eliminated, Leica removed* that description later from their website. That is a statement in itself, I think. The reason, I speculate, is that their "apo" lenses do not live up to that description, maybe with a few exceptions.

I asked about the "apo" designation in the Leica user forum in May 2021, which became quite a long thread:

https://www.l-camera-forum.com/topic/320955-90mm-apo-summicron-m-not-apochromatic

The thread includes several sample images shot with Leica "Apo-Summicron" lenses, showing LoCA (longitudinal chromatic aberrations).

The term apochromatic is a scientific one, which means that three wavelengths are fully corrected at the point of focus. Historically, the term was coined in relation to microscopes, where out of focus areas are of no interest. Lack of apochromatic correction will show up in high contrast scenes, typically as magenta fringing in reflections in metal (even when in focus).

Regarding your reference to Nikon lenses, Nikon (as well as Canon, Sony and Fuji for instance) don't use the "apo" designation. I think the reason for that is that most modern quality lenses qualifies as apochromatic lenses. Even if we think of the "apo" designation as Leica / Jono Slack use it, some of Nikon's lenses would be worthy of such a badge, for instance the F mount AF-S Nikkor 200mm f/2.0 VR / VRII.

I think that the Z Nikkor MC 105mm f/2.8 VR S lens is an apo lens in the extended sense of the term, but the Z 85mm f/1.8 S and Z 50mm f/1.8 S aren't, even though they are as well corrected as the Leica M "apo" lenses.

* Except for their Egyptian website, where it is still available for readers: https://leica-camera-eg.com/sl-lenses/

 LarsHP's gear list:LarsHP's gear list
Nikon Z7 Nikon Z6 Leica APO-Summicron-M 90mm f/2 ASPH Voigtlander 15mm F4.5 Super Wide Heliar Tamron SP 150-600mm F5-6.3 Di VC USD G2 +13 more
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