Steve Spencer
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 p.92 #17 · Light Lens Lab (LLL) replica lenses discussion & image thread | |
philip_pj wrote:
'Maybe my expectation was just too high...'
It's an eleven element lens inside nine groups, so plenty can go wrong in fabrication and assembly - aspherics are diabolical to align, according to no less a figure than Iain Neil.
Everyone claims they have new tech to produce them, so it appears to be a moveable feast. My experience is the same as Fred's in that my 35/2 is pretty much free of CA, but the 50/2 does not like ocean waves.
Cosina is more 'small general enthusiast market' than vintage-oriented, low volume LLL, maybe another factor here. APOs are always going to receive close scrutiny, aren't they? Two of Cosina's better APOs (my opinion) do without aspherics at all, the 110/2.5 and 50/3.5. Their 90/2, 90/2.8 and 75/2.8 also lack aspherical surfacing too, so that shows a clear trend for them. ...Show more →
I don't think there is any relation between using aspherical glass and quality of Voigtlander APO lenses. Here is the current list of Voigtlander full frame APO lenses:
28 f/2 Lanthar (M, E, & Z mount)
35 f/2 Lanthar (M, E, & Z mount)
50 f/2 Lanthar (M, E, & Z mount)
50 f/3.5 Lanthar (M mount only, at least so far)
65 f/2 Macro Lanthar (E, & Z mount)
75 f/2.8 Skopar (M mount only, at least so far)
90 f/2 Ultron (M mount only, at least so far)
90 f/2.8 Color Skopar (M mount only, at least so far)
90 f/4 Lanthar (announced but not yet produced)
110 f/2.5 Lanthar (E mount only)
Here are the ones with Aspherical elements
28 f/2 (2)
35 f/2 (2)
50 f/2 (2)
65 f/2 (1)
Here are the ones without Aspherical elements
50 f/3.5
75 f/2.8
90 f/2
90 f/2.8
110 f/2.5
We of course don't know what the design of the 90 f/4 will be yet (we will likely find out in the next month or two, but I would bet a lot that it won't have aspherical elements either).
What do we see in theses lists? It seems pretty clear that wider lenses and wider aperture lenses and especially when those two things are combined predicts the use of aspherical elements. If you look more broadly that is true of Voigtlander lenses in general and pretty much true of every manufacturer. Wider lenses and faster lenses predicts the use of aspherical elements if the lenses are going to be corrected for aberrations and aren't designed to display those aberrations.
My own sense is that all these lenses are at least excellent, but I would rank them after using almost all of them as follows in terms of aberration correction
Truly Outstanding:
28 f/2 Lanthar (I have used one copy in E mount)
50 f/2 Lanther (I have used 3 copies 2 in E mount and 1 in M mount and all three were truly outstanding)
65 f/2 Lanthar (I have used 2 copies in E mount and both were truly outstanding)
110 f/2.5 Lanthar (I have used 1 copy in E mount)
Excellent
35 f/2 Lanthar (I have used one copy in E mount)
90 f/2.8 Color Skopar (I have used one copy which was of course in M mount). Of the APO designated lenses, this was clearly the weakest in my experience despite still being excellent.
From Fred's reviews but not from my own experience I would also rate the 50 f/3.5 Lanthar, 90 f/2 Ultron, and 75 f/2.8 Color Skopar as truly outstanding, and we will have to see about the 90 f/4 Lanthar.
So from my experience there are only two lenses that Voigtlander designates as APO that I consider a bit weaker and one has aspherical elements and one doesn't.
I have also used four lenses that Voigtlander has designated at APO that I consider to be truly outstanding and 3 of those have aspherical elements and 1 doesn't. If we add the three that Fred has reviewed that look to me like they are truly outstanding in his reviews it evens out but I really don't see any relation between quality of the lenses and the use of aspherical elements.
The relation between aperture and focal length and the use of aspherical elements, however, is obvious. As is the use of abnormal partial dispersion elements--all these lenses have more of those elements than other lenses of the same focal length that Voigtlander makes.
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