Alpha Silver Jubilee – 25 years 1985-2010

The AF mount

In January 1985, the Minolta 7000AF was launched on a completely unsuspecting photographic community. It had been one of the best-kept development secrets in Japan, something for which Minolta was never really forgiven. The 7000 Alpha as it was known in Japan hit the market running, earning the 1985 Technical Image Press Association (TIPA) Camera of the Year Award.It took the other camera makers two years to catch up and enter the autofocus era.

The original Alpha – a Japanese 7000 AF

For the Minolta Club, 1981 to 1984 had already been an exceptional period with the X-700 and X-500 attracting more users than ever. The AF system only added to this growth and by 1988 we had the largest number of members ever with almost 13,000 Minolta users.

There was much discontent over the change in the mount, not because it was autofocus but because the body thickness (back focus) remained the same as the earlier system. This meant there could never be a lens adaptor for manual focus lenses, and at the same time they were unable to fit the AF body directly.

The AF mount was made wider in diameter, allowing larger rear elements and reducing a design constraint. This was one difference which Canon followed in their EOS autofocus system, making the throat as wide as possible. Nikon, deciding to keep faith with existing users, designed their AF mount to fit manual F-mount lenses. This limited the optical design possibilities for Nikon, and has continued to do so ever since. In the end, they benefited as the narrower exit pupils tended to be more ‘telecentric’ to use a digital age term. This allowed many of their film-era lenses to outperform those from their great rival Canon when digital SLRs became the norm.

Minolta had created some very small and light MD lenses in the early 1980s. Experienced users knew that these were not in the same league as the late MC and early MD models with much larger filter threads. A good example would be the 20mm ƒ2.8 MD compared to the earlier 21mm ƒ2.8 MC – the 21mm is one of the best superwides ever made, the 20mm with its 55mm filter thread has strong vignetting and fails to deliver architecturally straight lines.

For the AF system, the lens designers stepped back ten years and added the latest developments. The new 20mm ƒ2.8 AF design resembled the old 21mm, not the tiny MD 20mm. In performance and drawing qualities it was midway between the two, but still much more akin to the classic design, sharing its 72mm filter thread. The new 24mm ƒ2.8 AF was treated the same way.

The 70-210mm f/4, a classic lens known today as the Beercan. That’s 580ml, not 440ml, by the way…

Some MD lenses were ‘ported’ almost unchanged to the AF system – the best known of these is the 70-210mm ƒ4, often called the ‘Beercan’. The final MD version was already an advanced internal zooming, constant aperture design derived from work Minolta had done with Leitz over the years. There was no need to go back to the drawing board, or look to an earlier generation, for this.

Other AF system lenses were revolutionary – a new breed of high performance standard zooms which eventually displaced the ubiquitous 50mm ƒ1.7 as the choice when buying a camera.

The 7000AF was launched with one, the 35-70mm ƒ4. This tiny lens used the world’s first commercially produced hybrid aspherical element, in which a layer of plastic is bonded to a glass lens to change its curvature. Though low in contrast and prone to flare when used against the light, the 35-70mm ƒ4 was stunningly high in resolution. New films had appeared at the same time as the AF system, with Fuji’s E6 slide films displacing older Kodak emulsions in popularity. The 35-70mm worked well with these bright, high contrast slide films.

The 9000AF was a truly professional camera with no built-in auto winder, instead a manual lever wind gave it a retro feel

All in all, the system was launched with 12 dedicated lenses including five entirely new designs. By 1988 – after only three years of real sales – the new ‘Alpha’ system included a professional body, the 9000AF also launched in 1985, as well as the original all-purpose 7000AF and dumbed down entry level 5000AF (1986). It also offered one of the first digital imaging backs – more accurately a still video back, capturing VGA resolution colour frames with a 2X crop factor and recording them on 2″ magnetic disks much like the Sony Mavica.

The first of the i generation, seen in Japanese livery

The first revision of the system came in 1988 with the Minolta 7000i, a far slicker and faster operating version of the 7000. It introduced Predictive Autofocus for the first time in any AF SLR, and the system of Creative Expansion Cards which were small ROM cards identical in form factor to the Sony MemoryStick Pro Duo. These cards added functions to the camera, and from the start there was the suspicion that functions might be removed from cameras in order to sell them as later add-ons.