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02-19-2009, 05:20 PM   #16
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I imagine that the physical shutter as opposed to electronic, to some degree, plays a role in preventing dust from depositing on the sensor, seeing as it spends a significant amount of its time separating the sensor from the world outside.

Besides, I'll be damned the day that my camera has to make cheesy shutter noises through a speaker to compensate for it's lack of mechanism.

02-19-2009, 05:47 PM   #17
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How does the shutter on cellphone cameras work then?
I'm sure there is no mechanical shutter (the audible mechanical 'shutter' sound in cellphones is a legal requirement in some countries, I believe).
02-19-2009, 06:03 PM   #18
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QuoteOriginally posted by Blue Quote
Why are some pentax bodies designated in the specs to have electronic vertical run shutters such as the k2, SuperProgram, K200d and K20d?

Edit: The K1000 and KX has mechanical horizontal run shutters for example.

Edit: Edit: Then there's the LX with the hybrid electronic-mechanical horizontal run shutter . . .
Peter is correct, vertical run shutters have shorter travel, and higher flash sync. For pentax the champ was the PZ-1 and PZ-1p which had 1/8000 shutter speed and 1/250 sync. the "electronic" part of older shutters comes from the timing mechanisms being electronically controlled as opposed to the wonderful clock work shutters like in the KX
dont confuse these "electronic" shutters with a true electronic shutter that has no moving parts
02-19-2009, 06:36 PM   #19
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Physics

Mechanical shutter play the same role as the aperture, which is to cut excessive light which the imager actually cannot handle - flooding of charge.

Video is a different thing than still picture taking, which each frame taken is "rough" and somehow fast (but not very fast, normally - 25 to 30 fps). Still, mechanical aperture is required to control the light.

QuoteOriginally posted by denisv Quote
I always thought it had to do with the sensor heating up or something, but with the release of the 5DII and D90 that shoot video by keeping the shutter open and sampling, I've come up with the question why do DLSRs still have mechanical shutters?

Why not just flip up the mirror and sample the sensor electronically on exposure? It'd allow lighter, smaller, quieter, more reliable cameras and faster "shutter speeds" (1/250000 anyone?).


02-19-2009, 06:50 PM   #20
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QuoteOriginally posted by RiceHigh Quote
Mechanical shutter play the same role as the aperture, which is to cut excessive light which the imager actually cannot handle - flooding of charge.

Video is a different thing than still picture taking, which each frame taken is "rough" and somehow fast (but not very fast, normally - 25 to 30 fps). Still, mechanical aperture is required to control the light.
RH
\
A little too simple. Apature varries the Amount of light a lens passes on a continual basis, as well as changing the optical characteristics of the lens (depth of field and to a lesser extent sharpess) the shutter limits the Time the sensor (or film) is exposed to the light let through by the lens, and has the ability with fast shutters to "freeze" teh action, or slow shutter to let it blurr.

While both limit light, their function is very different
02-19-2009, 07:19 PM   #21
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QuoteOriginally posted by Lowell Goudge Quote
RH
\
A little too simple. Apature varries the Amount of light a lens passes on a continual basis, as well as changing the optical characteristics of the lens (depth of field and to a lesser extent sharpess) the shutter limits the Time the sensor (or film) is exposed to the light let through by the lens, and has the ability with fast shutters to "freeze" teh action, or slow shutter to let it blurr.

While both limit light, their function is very different
In *this* case, they do the same thing.
02-19-2009, 07:58 PM   #22
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QuoteOriginally posted by Camera lucida Quote
How does the shutter on cellphone cameras work then?
I'm sure there is no mechanical shutter (the audible mechanical 'shutter' sound in cellphones is a legal requirement in some countries, I believe).
Cell phone cameras are not known for their quality. It's strictly electronic.
02-19-2009, 08:21 PM   #23
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A simple explanation how a DSLR is different from a compact camera.

PENTAX digiich

A photo of a K10D shutter mechanism made by Copal.
Since Copal produces practically all shutter mechanisms, for Pentax to attain a higher fps for it's future cameras, it all boils down to the design engineers to specify and procure one.

[IMG][/IMG]

03-05-2009, 06:57 PM   #24
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QuoteOriginally posted by creampuff Quote
A simple explanation how a DSLR is different from a compact camera.

PENTAX digiich

A photo of a K10D shutter mechanism made by Copal.
Since Copal produces practically all shutter mechanisms, for Pentax to attain a higher fps for it's future cameras, it all boils down to the design engineers to specify and procure one.

[IMG][/IMG]
Interesting. I just picked a Ricoh Singlex from the early '60s that uses a similar shutter from Copal.
03-05-2009, 07:37 PM   #25
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QuoteOriginally posted by denisv Quote
Don't DSLRs with video capture already have this? What about the K20D with 21fps burst mode? Or, uhm, any DSLR with live-view?
No. Look at videos taken with the D90 of objects moving quiclky sideways or panning the camera. The bottom of the picture lags behind the top showing the camera can't read a frame at a time, but a row, or pixel, at a time. That means there's no side-pixel where brightness is stored for future reading.
03-05-2009, 08:50 PM   #26
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QuoteOriginally posted by MrEspie Quote

Besides, I'll be damned the day that my camera has to make cheesy shutter noises through a speaker to compensate for it's lack of mechanism.
I'm sure the Samsung NX will have that option
03-06-2009, 02:09 PM   #27
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Originally the shutters moved horizontally with fabric curtains. Once manufacturers managed to have metal blades, they introduced vertical shutters. For shutter speeds quicker than flash synch, only a partial slit is open. However, the whole photo takes at least the length of the flash synch, even if each part is only exposed for a fraction of the time.

Note that the flash synch time is when the leading curtain is fully open and the trailing curtain has not yet moved. The actual flash can be of the order of 1/25000 sec, even if the synch is 1/250 sec. Ever seen a flash photo taken with a faster than flash synch speed? only part of the photo is exposed.

While technically you can achieve fast shutter speeds with a horizontal curtain, the vertical curtain was introduced to increase the flash synch speed from 1/60 to presently 1/250 or 1/125
03-06-2009, 10:29 PM   #28
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I wish the k-m had an electronic shutter to get me super high sync speeds I would sync up to 1/2000 on my uncle's D70 haha
03-07-2009, 05:01 AM   #29
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It would be a nice option but the D70 is a little odd ball camera that has a feature it's newer and "better" brothers don't even have. Now that it's discontinued, I bet it will gain an even more cult status with flash shooters.
04-05-2009, 01:48 PM   #30
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QuoteOriginally posted by Ben_Edict Quote
There were only very few DSLRs with an electronic shutter (Nikon D70, I think), simply because the mechanical shutter has some real-world advantages. An electronic shutter needs loads of space on the sensor.*The old interline transfer chips are the prototypical example, where each pixel row had a secondary transfer row, which transports the electrical charge out of the pixel to the electronics. This read-out process can be used as the shutter. But nevertheless, even if the "shutter is closed", i.e. during read out, light falls onto the sensor (without the mechanical shutter) and this can lead to blooming,colour and brightness shifts.

A mechnical shutter completely blocks light during the read-out phase of the sensor and thus prevents any detrimental effects by strong light on the already captured image.
The Nikon D1 had Single-blade mechanical shutter. And the D1x had Charge-coupled electronic and mechanical shutter. They could go up to 1/16,000 sec. With flash sychronization up to 1/500 sec

The D2x had electromagnetically controlled vertical-travel Focal-plane shutter. And could “only” go to 1/8000 sec. With flash X-Sync: 1/250 sec
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