Focusing using colour

[Playdo]

Looking at Nikon's Autofocus system they use colour recognition via their SRS to track and produce accurate autofocus. I believe this might have only been about since the D3/700/300.

Scene Recognition System from Nikon

Does anyone know if Canon uses a similar method in any of their DSLRs? I was looking at the new iFCL system in the 7D but I'm not sure if this is similar. Please back your answers up with evidence if poss.

Thanks

 

[musicaleCA]

Nope. Don't think so. Nikon's AF is, generally speaking, quite superior to Canon's. Well, you get more AF points, but with Canon you get all cross points generally, as long as you have fast glass. Get down to f/4 and the cross points disappear.

 

[Playdo]

Yeah I did a little more research and I couldn't find anything like the Nikon system. I wonder if patents prevent other companies from developing similar colour information/AF technology?

Here's a nice interview with Hiroshi Takeuchi, lead SRS developer, if anyone fancies a read:

Nikon | Imaging Products | Scene Recognition System

 

[musicaleCA]

That's a possibility. Nikon's fast focusing motors (AF-S, is it called, yes?) in their lenses is actually based on (or is, I'm not clear on the specifics) Canon's USM technology. The fact that Canon is just now coming out with a metering system that uses colour to be "smart" like Nikon's matrix metering (with the 7D) may be because they didn't want to pay royalties to Nikon, or they were waiting for a patent to expire, or whatever. Neither company is very open about these things.

 

[Garbz]

Neither company holds the patents. You may see USM as something unique but it's a very common principle called Piezoelectric effect which was first turned into a motor in the 60s. USM or Silent Wave can't be patented because of the obvious application for a small motor in an autofocus system. (well knowing the American system it can be patented but no one would be stupid enough to take it to court)

Also the principles of autofocus haven't changed either. The novel thing is that Nikon uses the colour of the scene to recognise which part of the scene to focus on, like a soccer ball rolling away across the frame. The focus itself is still done by good old fashioned phase detection. Also as far as I've gathered this is still a greyscale system (surely that can't be right but I haven't seen much stating otherwise)