summilux.net

Ayant un Summicron 35mm f2 version II, je voudrais me laisser tenter , juste par curiosité, par la version III du même objectif.
Mes recherches sur la toile parlent de l'existance de la même formule optique pour les deux objectifs II et III du Summicron 35mm f2.

Voici mes questions:
1- Comment expliquer l'existançe des deux objectifs ayant la même formule optique?
2- Deux formule identique signifie deux objectifs identiques?
3-En termes de rendu, les deux objectifs produisent le même rendu?

Merci pour l'aide. M6Leica

ce qui peut vous guider peut être:

source: http://www.kenrockwell.com/leica/compar ... rpness.htm

en gros:
le II, III et IV sans comparables, le nombre de lamelles changent, le bokeh très peu ( même du IV, appelé "king of bokeh" par un journaliste un jour, mais on s'aperçoit qu'il n'a pas de joli bokeh plus que ça, puis il est devenu objet des vendeurs et acheteurs aimant la spéculation), la version I à 8 lamelles et les versions modernes sont les plus performantes.

on trouve plus bas sur ce site:

The SUMMICRON-M (7-element, 1979-1996)

This is the lightest lens of these four. It's a swell lens, but sells used for the same price as used ASPH.

Its bokeh is the same as the rest, as I'll show shortly as soon as I can crunch the data (I've already returned all of these lenses back in December 2010).

This version picked up a false aura when a magazine article in 1997 (back when this was LEICA's newest SUMMICRON) claimed it had great bokeh, but that article was talking about bokeh at f/8, which is meaningless. Even at f/2, there isn't much out-of-focus with a 35mm lens, and as I've seen, this lens' bokeh is pretty crummy at f/2, as it is with all these four lenses.



The SUMMICRON (6-element, 1969-1979)

This is LEICA's least-loved SUMMICRON, however even in these looking-too-close tests, the 6-element lens from 1969-1979 works great.

If you're on a budget, these work 99% as well as the other SUMMICRONs, but people on a budget don't shoot the LEICA, which is why these are in so little demand.

The advantages of this lens is that it's lighter than all but the SUMMICRON-M (1979-1996), and has higher contrast at f/2 in the center than the previous 8-element version. It's a tiny, high-performance lens.



The SUMMICRON (8-element, 1958-1979)

This original SUMMICRON works great. In fact, it's the sharpest in the corners wide-open, except for the ASPH, and the sharpest in the center. At most apertures, it's actually the sharpest lens here! It has slightly less contrast on digital at f/2, but on film it looks spectacular at every aperture.

The other lenses have similar color rendition, however the B&W-optimized coatings of this version give it a very slightly more cyan cast than the others.

This first SUMMICRON comes both with or without viewfinder optimization optics as shown above.

Both versions work perfectly on every LEICA M today.

Giacomelli, merci maintenant c'est claire! Excellente réponse. M6Leica.

Ceci est également intéressant à lire
http://www.antiquecameras.net/35summicronmlenses.html

Merci jml. Demain je vais le lire. M6L