Minolta glass vs Sony

[artington]

I remember buying my first Minolta camera, the SRT101b, because I had read about the supposed superior qualities of Minolta glass and had also heard vaguely about links with Leitz, which seemed to put Minolta on a different plane from the other Japanese manufacturers. Today, Minolta glass seems to be regarded with awe in some quarters and one reads comments about "Minolta colour" or "extra-dimensionality" (rather like Leica glass in that respect). Certainly I have noticed the latter in my 85/1.4 G when wide-open but this may just be a DOF effect (although with my Leica lenses there often does appear to be an almost 3D effect which I am sure is not in my imagination). I have recently been pondering the merits of the 100/2.8 macro. I have rather assumed that the Sony version is an up-dated clone of the Minolta version, yet it can now be bought more cheaply than the latter. While I believe the design is the same this set me wondering whether Sony glass is the same as Minolta glass. I recall (possibly incorrectly) that Minolta made their own glass but I presume that Sony sources from Hoya or someone like that. Has anyone been able to compare Sony and Minolta versions of the same lens to see whether there are different performance characteristics? Or is the legend of Minolta glass just that - a romance?

[David Kilpatrick]

It all mattered a lot more with film, where the colour rendering and contrast were more or less fixed - especially by transparency film. Minolta never really 'made' their own glass, they melted their own mixtures using raw glass supplied by Hoya, Scott, Pilkington and others - just the same way Hoya themselves make different glasses. But they did this in-house, unlike the other camera makers who had the glass blanks made to their specs. They also did have a fairly unique approach to lens design, glass formulation and coatings which made the colour and contrast very consistent over a wide range of lenses including zooms.

I imagine that some Minolta lenses - probably the ones we still have under the Sony name - used glass types which are readily available. Others, maybe, used glass which was produced in-house. Some will definitely have used components like cadmium which are no longer permitted in lenses, which is why they will never be produced again. I suspect that designs like the 100mm f/2 and maybe even the discontinued 85mm f/1.4 G used glasses with environmentally unfriendly additives, and one reason for replacing the 85mm with a Zeiss was probably that it had to be reformulated.

This is definitely the case with Nikon, a whole range of classic fast manual/early AF lenses can not be re-introduced because they use glass types no longer available.

David

[01af]

I'd say when you're dealing with melted glass then you're making your own ... no matter whether you start with sand and quartz and minerals, or with raw glass purchased elsewhere. Insofar, Minolta really did make their own---but they stopped that, I think, in the late '80s, or maybe even earlier. Maybe the abandonment of the Rokkor name in 1980/81 had to do with this. The discontinuation of Minolta glass forced other lens makers to re-calculate some of their designs (notably Leitz), so obviously Minolta glass was truely unique.

Regarding the current AF Macro 100 mm lenses ... I don't know if the SAL Macro 100 mm 1:2.8 is an exact copy of the Minolta AF Macro 100 mm 1:2.8 (D) ... I guess it is ... but the SAL Macro 100 mm and the first-generation Minolta AF Macro 100 mm 1:2.8 from 1986 definitely are different. At far distances and wide apertures, the Sony is the better performer, and the focal lengths differ by half a millimeter so the optical designs are (similar but) not identical.

-- Olaf

[youpii]

They probably used glass that is no more available because of the new environment regulations.
But I find it hard to believe that adapting these designs for different glasses is impossible.
Cosina did it recently for the ZF Distagon 18/3.5.

[sparaxis]

I work in the electronics industry, and we have the same issues. I.e. "lead free solder" etc.

I spent some time doing research when the new rules went into effect a few years ago. (June 2006, note the date, it is significant)

Some key points:

-Practically ALL older lenses include lead bearing elements.
-The only way to continue selling a lead-bearing design was to get a waiver. You could not get a waiver for a new product.
-The Alpha range was launched after the law went into effect, thus ALL lenses had to be compliant, Nikon Canon and others could apply for waivers to continue selling old designs.
-Manufacturers had about ten years warning so could start designing compliant products from the late 1990s
-This probably explains the survival of "odd choices" like the STF and the 24-105, which were designed late enough to not include lead.
- I suspect Minolta and KM started reworking their designs over a period of time as they made new batches. I.e the "new" 35 f1.4, the "new" 50 f1.4, and the 28mm f2.8. This last lens had disappeared from the listings prior to the cessation of business only to re-appear in Sony guise.
- The major difference between leaded glasses and their replacements is the relationship between refractive index and dispersion.
- Some leaded glasses can be directly replaced with lead free equivalents.
- Some equivalents are close enough that a small change to element curvatures, thicknesses and spacing can compensate.
- Some high index exotic glasses have no direct replacements, thus requiring extensive redesign if possible, or otherwise it may not be possible to manufature the lens at all.

Speculation: The 85f1.4 could not be made as originally designed with new glass. Thus the short lived "limited" experiment. The final re-design may have been something like the current Zeiss.

We should not read too much into Zeiss "Re-introducing" old designs. The 85 f1.4 planar in ZF mount is quite different from either of the Contax versions, and different to the Sony version. The 18mm may be a similar marketing trick. Old reputation, substantially new lens.

Interesting observation: the 16-25 Zeiss design looks a lot like the Tamron 11-18 and 17-35 formulas and nothing like anything Zeiss ever offered before. Who really designed it? Tamron, Zeiss copying Tamron, Sony copying Tamron, or even Konica Minolta Opto Inc, which still makes a LOT of lenses on an OEM basis for all sorts of applications?

[youpii]

Speculation: The 85f1.4 could not be made as originally designed with new glass. Thus the short lived "limited" experiment. The final re-design may have been something like the current Zeiss.

We should not read too much into Zeiss "Re-introducing" old designs. The 85 f1.4 planar in ZF mount is quite different from either of the Contax versions, and different to the Sony version. The 18mm may be a similar marketing trick. Old reputation, substantially new lens.

I'd say that redesign is better than substituting glass: 85/1.4 ZA & 300/2.8 SSM are a step above the older versions.

Interesting observation: the 16-25 Zeiss design looks a lot like the Tamron 11-18 and 17-35 formulas and nothing like anything Zeiss ever offered before. Who really designed it? Tamron, Zeiss copying Tamron, Sony copying Tamron, or even Konica Minolta Opto Inc, which still makes a LOT of lenses on an OEM basis for all sorts of applications?

Yes, the DNA of the ZA lenses is indeed strange.
David, do you know if Sony bought the Minolta lens design team of if they had to start a new one?

[David Kilpatrick]

It is known that 'engineers' transferred to Sony from KM lens design/production. However, whether they were designers or not, I am not sure. I imagine that KM kept the computer systems and key staff for optical design, as they already had contracts for all kinds of optical units ranging from photocopiers and scanners to video cameras and (I am fairly sure) companies like Tamron and Nikon who use their hybrid aspherical technology.

I think you can assume that even if some staff remained with KM and some transferred to Sony, the genetics of the current lenses are not much changed - some added Zeiss input, but any maker could go to Zeiss and get lens design work done (and still can). Paying for the name is another matter. Zeiss, like KM, will make glass elements for anyone willing to pay and they will provide computer design services too.

David