mechanical shutter vs electronic shutter

macgregor

macgregor

Veteran
Why is there a need for a mechanical shutter for taking photos on DSLRs? I could imagine that we must have one in order to give the mirror time to go up and down. But while being in Live view or shooting a movie, the shutter still needs to close-open-close to take a photo.

If i´m not wrong, the GH1 does not have a shutter in front of the sensor (is it built in the lens?). I remember shooting with an old olympus DSLR that had the option of shooting with mechanical shutter and and electronic shutter. In the user manual you could read that using the electronic shutter would result in photos with less quality (and so it was).

Maybe Barry or some tech freak could answer this. :beer:
 
mechanical shutter protects the sensor when changing the lens i believe? coz it's closed
mechanical shutter makes an awesome noise
no jello/rolling shutter issues in photos
on my film slr you don't need a battery for 1/90th coz it's all manual. but the other speeds are apparently electronically controlled. and there's something to do with flash syncing as well...
that's all i know :)

btw i only own a film slr :beer:
 
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The GH1 does have a mechanical shutter.

The CMOS cameras need shutters because they would otherise prove useless for flash photography! :) So as I understand it, they go into a shutterless "mode" for stills; the chip itself doesn't use the rolling shutter at all, it relies on the physical shutter to expose it.
 
CMOS is too slow to turn on and off for say 1/4000 of a second, so the shutter does that. That's also why you get rolling shutter. CCD is fast, which is why the Canon 1D (Original) has a maximum shutter speed of 1/16000 and every 1D or 1Ds since then has a maximum shutter speed of 1/8000. CCD isn't used in still cameras any longer because of atrocious battery life and the now superior performance of CMOS sensors. The 1D had a battery life of 500 shots or less, and some people complain of being able to take less than 50 shots, while the 1D II and it's CMOS sensor easily takes 1000 shots on a charge.
 
Barry_Green said:
The GH1 does have a mechanical shutter.

The CMOS cameras need shutters because they would otherise prove useless for flash photography! :) So as I understand it, they go into a shutterless "mode" for stills; the chip itself doesn't use the rolling shutter at all, it relies on the physical shutter to expose it.
Click to expand...

so its global shutter on stills?
 
i see.

I think i remember reading an interview somewhere a panasonic jap rep talking about their next m43 something like not having that much drastic change in features and they are currently looking into eliminating the mechanical shutter... which i am just now realizing what he meant

cant wait to see these new implementations like the backlit sensors and etc.
 
Barry_Green said:
The GH1 does have a mechanical shutter.
Click to expand...

Is it located inside the lens or in front of the sensor?



Vascilli said:
CMOS is too slow to turn on and off for say 1/4000 of a second, so the shutter does that..
Click to expand...

Nah, not really. The 5D itself can reach 1/4000th of a sec. A phantom HD camera can go quite faster than that and uses a CMOS and electronic shutter.

I knew the point that by using the mechanical shutter they avoid the skew on the stills (i´d like to know the speed of a mechanical shutter vs the speed of the reading in a rolling shutter CMOS though, because a curtain shutter can show skew too).

But my question was towards what are the quality improvements when using the mechanical shutter because photos with mechanical shutter look better than the ones with electronic shutter and i´m not talking about skew artifacts. I believe it has to do with something about charging and de-charging the sensor at slower speeds...
 
also - and I dont know too much about this - but a mechanical shutter is used to create a 'black reference'

ie the digicam takes a photo
then takes a photo of black

and somehow merges them together to cancel out some noise in the digital file

you will be aware of this occurring if you take some long exposures (in stills mode)

say you shoot a 4 second exposure, the camera wont allow another frame to be taken for a further four seconds - because it is writing that black file for the duration of the actual exposure

S
 
dcloud said:
i see.

I think i remember reading an interview somewhere a panasonic jap rep talking about their next m43 something like not having that much drastic change in features and they are currently looking into eliminating the mechanical shutter... which i am just now realizing what he meant

cant wait to see these new implementations like the backlit sensors and etc.
Click to expand...
In what is being billed as another sizeable revolution in the camera world, Panasonic is set to unveil a shutter-less DSLR. Billed as a ‘global shutter’ and marketed as HD Progressive, Panasonic will for now reserve this feature only for their high end range of camcorders and the GH2.

Panasonic is set to release the LX4 and G2 in February, but the GH2 will wait until the 2nd half of 2010 according to my source in Asia. Rather than do a yearly update of the GH line, Panasonic want to bring a greater incremental step to the ‘luxury’ line.“,,,”The global shutter also creates the possibility of an entirely silent camera. Goodbye shutter click. On a DSLR a global shutter requires greater power demands and causes the sensor to run hot, but Panasonic were able to develop one because their modern CMOS processing plant can shrink a chip below 35 nanometers, which coupled with the relatively small (in DSLR terms) sensor size of the Micro 4/3rds format allows the chip to run cooler.“
http://43rumors.com/ft2-panasonic-gh2-to-be-first-shutter-less-camera/

i cant say if the details of the rumors are true but from what i remember, i did read sometwhere about the shutterless camera. and now heres a rumor about it.

and i also like the gh2 being the high-end cam line (hopefully bigger gh1 with proper avchd & less aliasing)

gh>g>gf
 
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