Inventor Hiroshi Terada has filed a patent
for what he describes as a “movie image shooting mode
” for digital single-lens reflex (DSLR) cameras. The patent details a system whereby a 30FPS film mode could be added to consumer grade digital SLR cameras, bringing a feature more associated with point-and-shoots to a higher level.
The main reason DSLRs don't already have a movie mode – aside from the fact that the people likely to be lugging such a beast around with them aren't the ones who want a VGA resolution movie of their family waving from a boat – is due to the way the mirror works. The mirror reflects the light from the lens to the viewfinder and, more importantly, the auto-focus sensor. When you take a shot, the mirror hinges out of the way to allow the light to fall on the sensor and the image to be captured: it's this motion that makes the tell-tale 'clunk' of an SLR. In order to take movie footage, the mirror would have to move in and out of the path of the light thirty times a second – a recipe for a great deal of noise and a rapidly deflating battery.
The patent details a novel solution to this problem: a mirror which is partially translucent. The idea is that the mirror will allow 70% of the light to pass through it, and 30% to be bounced to the auto-focus sensor. This means the mirror can stay in place when the camera is in movie mode, and still hinge away when required for high-quality still shooting.
The patent also details solutions to other technical speedbumps such as a much faster auto-focus mode when shooting video, a wider field of focus, and a cropping system to prevent the field of view chancing during focussing.
It's not a function that you're likely to see on the professional – or even 'pro-sumer' – end of the spectrum, but if the technology works as well as detailed in the patent it's quite likely we'll see the system picked up by at least one of the camera manufacturers as a way to tempt people to DSLR from compact cameras – and thus into the market for lovely high-margin lenses.
Something you'd like to see on your next DSLR purchase, or is video shooting something best left to dedicated devices and toy point-'n-shoot cameras? Share your thoughts over in the forums