Video: A take a look at Canon’s 40-year-old AF lens, the FD 35-70mm F4 AF: Digital Images Assessment


These days, it is easy to take autofocusing lenses as a right. Nevertheless, within the grand scheme of images’s historical past, autofocus is a comparatively current innovation. In Canon’s wealthy photographic historical past, the EF mount launched in 1987 seemingly stands out as the start of autofocus for the corporate. Nevertheless, Canon’s earlier FD mount had a particular lens amongst its handbook focus optics, the Canon FD 35-70mm F4 AF, which was initially launched again in 1981.

In a brand new video from Kai W, he goes hands-on with the Canon FD 35-70mm F4 AF tailored to a Sony A1 mirrorless digital camera. It is fairly the mix of outdated and new. What’s maybe most attention-grabbing in regards to the video is how uncommon the Canon FD autofocus lens is. It would not appear to be some other lens I’ve seen.

The lens features a ‘Stable State Triangulation’ autofocus mechanism. This was added to the present FD 35-70mm F4 lens that got here out in 1979. As Canon writes, ‘The incorporation of this perform into the best-selling FD35-70mm F4 (June 1979) interchangeable lens led to automation of focusing for SLR cameras.’

How does SST work? Canon writes:

‘The SST technique is a system through which data on the photographed object that enters the sensor by two mounted mirrors is transformed into an electrical sign and distance is measured by a microcomputer, with focusing carried out by transferring a distance ring with a motor. The newest mounted imaging machine CCD (charge-coupled machine) know-how is adopted to offer excessive decision and a broad dynamic vary in a position to detect low to excessive luminance, making it much less vulnerable to the distinction and sample dimension of the photographed object and enabling extremely exact autofocusing. Additionally, because the SST technique doesn’t have a movable part within the distance measuring mechanism, no vibration or electrical noise is brought on, which offers excessive reliability becoming of a high-end SLR digital camera.’

Sure, you have learn that excerpt appropriately, a CCD. The lens has digital imaging know-how to drive autofocus. Given the constraints of the FD mount, the lens required its personal energy supply, which is a pair of AA batteries.

Utilizing the lens has some quirks. The FD system was not designed for autofocus, so it’s essential to use a button on the lens itself to set off autofocus. The autofocus system covers the place the zoom ring is situated on the non-AF model of the FD 35-70mm F4 lens, so there is a small lever on the underside of the AF system element that permits you to modify zoom. Aperture is manually managed through an ordinary aperture ring close to the bottom of the lens.

As you’ll be able to see in Kai’s video, the AF efficiency is surprisingly good. It isn’t the quickest lens, in fact, however it’s neat to see a blast from the previous carry out effectively sufficient on a contemporary digital camera. To see extra movies from Kai W, go to YouTube.


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