Mechanical shutters can wear out or break. They also limit shutter speeds when using a flash because of flash synchronization problems. Why not control exposure time electronically by turning the image sensor on and off? I am not talking about the mirror; I meant the shutter.
A lot of people think cost is the reason. I think that is very unlikely. An electronic shutter would require fewer parts, and should be cheaper.
I didn't mean to imply mechanical shutters are terribly unreliable. However, mechanical devices are usually less reliable than electronic ones. I've heard of shutter failures with DSLR's, and they seem to be one of the most common things to fail. I know shutters can last hundreds of thousands of cycles. I haven鈥檛 seen MTBF's officially published by manufacturers, but I've heard a typical MTBF for a lower end DSLR is around 50,000 cycles and perhaps double or a few times that for a professional DSLR. I think 50,000 or even 100,000 is a little low.
There must be some major advantage to mechanical shutters over electronic ones, or DSLR's wouldn't use them. because it would probably add $1000 to the price tag. Some fundamental principles of designing prducts is:
1. If it is proven in the field dont change it untill you need to
2. If it solves 80% of the problem you probably do not need to change it.
3. New designs cost a lot of $$$$$$$$$ to prove so stich with #1
4. Identify your target customes' needs. (mstly means stick with #2)
It usually is not a technical problem... It is mostly about money. Are you actually talking about a mechanical shutter? or are you talking about snapping the mirror out of the way? If you are really talking about the mirror - it has to go, or you can't have a "single-lens reflex" camera. Or, if you insist on a similar capability, you have to split the light between the focal plane sensor and the viewfinder - which decreases the light to the sensor -- a poor design. Why change something that works? From what i have seen in the camera field no Electronic shutter has yet to beat a mechanical shutter. My D200 shoots 5 frames a second and has a large buffer to keep shooting. Electronic shutters tend to lag and only have short burst modes. As far as wearing out or breaking I dont see how you can say that. I have a Rolliflex Twin Lens camera from 1939 that still works, I also have several 35mm bodies that still work that are about 20yrs old. Oddly, I have gone through 4 digital cameras that were all electronic. For flash sync, buy a real camera and elimnate that problem :) Backward compatibility with lenses from film SLR, for the most part. Cameras are cheap. Lenses are expensive. Easy. Most digital SLRs are not designed from the ground up for the job, instead they started their lives as a film design. It was less expensive to take a working system, like the Nikon or Canon, and figure out what it would take to make it digital.
Eventually all the major manufacturers will tilt to the digital side, so digital will dictate new design. One day Nikon is going to send out a release saying that they won't release a F7 or F8, and the next full pro machine will be 100% designed from the ground up to be digital. Maybe they you will start seeing some of the last mechanical systems disappearing. Maybe they get rid of the mirror and start showing LCD viewfinders, maybe they start using electronic shutters that actually last, etc.
I got a Nikon D50, and I love the shutter, it makes the camera feel like a real camera. All of my previous Sonys, as fantastic as they were, always felt like expensive toys. The Nikon feels like a tool. Just FYI:
I saw this question last night and it took me until now to find this (irrelevant) information, but I thought it was interesting, especially in light of the comment that the D50 shutter is rated at a duty cycle of 50,000.
In Pop Photo, January 2006, page 53, it says, "...the D200's shutter lifespan is rated at more than 100,000 cycles (compared to over 150,000 cycles on the D2s)." | 