Minolta's 'weak lenses' - facts, not bias! The real truth!

From: David Kilpatrick
Date: 2000-02-23 13:11:05 (david@maxwellplace.demon.co.uk)

There was that question...
>
> 3. I've seen Minolta slammed in some places as having
> "weak glass." Any comments--yea or nay?
>
Only a comment made by people who like wiry, contrasty simple lenses - typically, press photographers and sports photographers for whom a bright cartoon image is better than a highly detailed, subtle image. You'll notice that Minolta is preferred by landscape, portrait and wildlife/natural history photographers. The more fluid tonal rendering of the best current Minolta lenses, and their classic 60s-70s glass, is often mistake by fast film users for 'softness' - their film can't resolve what the lenses are doing, so they can't see it. Nikon has always been top with these guys because they like 'bite'. Canon falls in between and it's an easy choice to make. Really discerning news and sports pros who work with slow films and aim for top grade repro often pick Minolta - or Leica, or Contax. But it's an eccentric choice when Canon and Nikon hire stock is so easily available.

One of Minolta's best points has been their use of lens coatings to keep colour balance equal between many different lenses. In some makes, the wide angles produce pictures which look different from the teles - more contrasty, or warmer, or cooler, etc. Minolta generally try to keep the contrast, colour and 'feel' unusually well-matched. This is one reason why Minolta owners don't enjoy mixing one Sigma (for example) with two or three Minolta optics - the Sigma pictures never look the same. It also means that some lenses are 'toned down' - after all, it's very easy to design ultra high contrast into a moderate wide angle like a 28mm f2.8, and very difficult to get it in a 100-400mm zoom. If you want the lenses to match you have to produce a 'controlled' wide angle and an extremely good zoom!

Minolta have done this for longer than anyone else. Back in the 1960s, they were the first company to use two or more layers of mag.fluo lens coating in different deposit thicknesses. Their first innovation was called
'Achromatic' coating, and this just meant they could vary the thickness of one layer, which allowed them to fine-tune colour transmission. After this came 'Double Achromatic' coating (I think around 1965-6) which was a two-layer coating, and gave them even greater control. They used it in combination with single coatings, depending on the lens type. Then, at the same time that Pentax licensed OCLI's 'multicoating' technology and called it SMC, Minolta advanced to Super Achromatic coating which was much the same
- not entirely, and the huge colour swings present in Pentax lenses of the first generation (they just coated to achieve maximum contrast, and didn't care about colour) were absent from Minolta's designs. However, the Minolta lenses were not as radically flare-free, and very few lens testers used colour film in the mid-1970s (sounds crazy, but true), so the SMC lenses got a higher 'rating'.

Canon, who had suffered from the worst flare-proneness of all makers in the 1960s and never had a double layer process, introduced this ten years after Minolta with SC (Spectra Coating) which as the name implies was intended to allow colour balancing. It was not very successful, partly because the FTb of the time also had a very low contrast viewfinder which suffered from flare itself. They were almost the last firm to have true multicoating when most lenses went SSC (Super Spectra Coated). In the meantime, Fuji had pipped everyone at the post by managing to devise a coating just as flare-killing as Pentax SMC, but actually rather better at colour balance - EBC (Electron Beam Coating). Combined with new glasses and the first computer design, Fuji released a true five-element EBC Fujinon 55mm f1.9 lens and an unusual f2.2 budget version, when most other makers were using six elements. They were not the first - Wray's British Unilite (1948, thirty years ahead of its time) has only five elements yet was a 50mm f2. However, it was only required to cover 24 x 32mm - the same 'short 35mm' format which Minolta first used for their rangefinder Model 35 Leica copy. This camera had a 45mm f2 Rokkor which appears to have a large blue copyright symbol next to the name - actually, this symbol, a C in a circle, refers to Coating
- the first of the coated postwar Minolta optics.

Much of the superficial opinion of lenses comes from people who look through the viewfinder and judge that way. Minolta's Acute Matte focusing screen does few favours to edge detail - it appears to spread outwards - and Minolta's prism oculars sometimes introduce apparent barrel distortion. The cause of this is to increase brightness (at the expense of accurate image detail) and to make the camera more compact. Examination of an actual negative shows that impressions given by the finder can be wrong.

One of the greatest advances in the use of coatings has been the extension of multicoating to the prism, screen/condensor/fresnel lenses, and the eyepiece optics. All the major makers now do this. However, Minolta (like some others) now use porroprisms, hollow mirror assemblies, instead of solid glass in low-end cameras. These are less contrasty than glass prisms as well as dimmer. But of course, this does not affect the final image, and with AF you only really need the finder to be a viewing aid, not a focusing device.

History lesson over. But remember, Minolta lenses are not exactly the same as Canon, Nikon, Pentax or Sigma. All these companies have access to similar computers - many actually use the same methods and designs - and they don't aim to produce 'worse' lenses than the competition. Minolta has a very holistic philosophy - colours which match, contrast which matches, lenses which make a certain kind of image (hence the switch to circular apertures, and the creation of some very odd things like the STF 135mm). I have no idea why they have always been this way inclined, instead of just going for ZAP! quality at enprint size, but that's the way they are.

'Weak glass' this is not! Different glass it certainly is. It's like choice in music. Personally I'm happy to let Nikon do the heavy metal rock anthems, Canon do the hip-hop and rap with its hat on backwards, while Minolta buggers off and plays its own mixture of jazz, classical and New Age ambient in a quiet corner. With all this lot going on you can hardly hear the Leica baroque chamber orchestra or Zeiss's Kraftwerke...

David Kilpatrick

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