PhotoBanter.com

PhotoBanter.com (http://www.photobanter.com/index.php)
-   Digital SLR Cameras (http://www.photobanter.com/forumdisplay.php?f=21)
-   -   Why do digital cameras need shutters? (http://www.photobanter.com/showthread.php?t=57689)

Steve February 22nd 06 07:25 PM

Why do digital cameras need shutters?
 
I hope this isn't a silly question. Is it impossible or too expensive to
turn the sensor on and off or something instead of a mechanical shutter?
Just wondering.

Steve



Måns Rullgård February 22nd 06 07:31 PM

Why do digital cameras need shutters?
 
"Steve" writes:

I hope this isn't a silly question. Is it impossible or too
expensive to turn the sensor on and off or something instead of a
mechanical shutter? Just wondering.


It's possible, but slow and inaccurate. It is found on some cheap
(phone) cameras.

--
Måns Rullgård


Steve February 22nd 06 07:45 PM

Why do digital cameras need shutters?
 

"Måns Rullgård" wrote in message
...
"Steve" writes:

I hope this isn't a silly question. Is it impossible or too
expensive to turn the sensor on and off or something instead of a
mechanical shutter? Just wondering.


It's possible, but slow and inaccurate. It is found on some cheap
(phone) cameras.

--
Måns Rullgård


Thanks

How can it be inaccurate? Isn't there a processor clock that could time
"shutter speed"? Just wondering and stubborn, too.

Steve




PeterD February 22nd 06 08:57 PM

Why do digital cameras need shutters?
 
On Wed, 22 Feb 2006 13:25:30 -0500, "Steve"
wrote:

I hope this isn't a silly question. Is it impossible or too expensive to
turn the sensor on and off or something instead of a mechanical shutter?
Just wondering.

Steve


Another reason is that it protects the sensor from things like
accidental exposure to the sun, as even if the camera was off you
could accidently point it at the sun and damage teh sensor.

Tony Hall February 22nd 06 08:57 PM

Why do digital cameras need shutters?
 
Måns Rullgård wrote:

"Steve" writes:

I hope this isn't a silly question. Is it impossible or too
expensive to turn the sensor on and off or something instead of a
mechanical shutter? Just wondering.


It's possible, but slow and inaccurate. It is found on some cheap
(phone) cameras.


Not quite true. The Canon EOS1D used its CCD to control exposure while
the shutter was reduced to protecting the imager and keeping dust off,
it also meant you could use a 1/500th sec flash sync.

The MkII which replaced it (and MkIIN) use a CMOS imager so it's back to
using the shutter for controlling exposure, and sadly back to 1/250th
sec flash sync.

Cheers,
Tony
--
Newcastle upon Tyne, England

(Email address is valid ... for now)

Rich February 23rd 06 01:12 AM

Why do digital cameras need shutters?
 
On Wed, 22 Feb 2006 19:57:54 +0000, (Tony Hall)
wrote:

Måns Rullgård wrote:

"Steve" writes:

I hope this isn't a silly question. Is it impossible or too
expensive to turn the sensor on and off or something instead of a
mechanical shutter? Just wondering.


It's possible, but slow and inaccurate. It is found on some cheap
(phone) cameras.


Not quite true. The Canon EOS1D used its CCD to control exposure while
the shutter was reduced to protecting the imager and keeping dust off,
it also meant you could use a 1/500th sec flash sync.

The MkII which replaced it (and MkIIN) use a CMOS imager so it's back to
using the shutter for controlling exposure, and sadly back to 1/250th
sec flash sync.

Cheers,
Tony


Flash synch, 1/4000th of a second. Not a DSLR.
http://www.pbase.com/andersonrm/image/53920181

Alan Browne February 23rd 06 02:29 AM

Why do digital cameras need shutters?
 
Steve wrote:

I hope this isn't a silly question. Is it impossible or too expensive to
turn the sensor on and off or something instead of a mechanical shutter?
Just wondering.


In addition to the other replies I believe the camera manufacturers also
use the shutter as a black reference to measure sensor native noise.

The Nikon D70 "electronically" shutter flash syncs up to 1/500 which is
on the "closing" side of the cycle, and I think that should be standard
on all high end DSLR's.

Cheers,
Alan

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.

Jeremy Nixon February 23rd 06 02:49 AM

Why do digital cameras need shutters?
 
Rich wrote:

Flash synch, 1/4000th of a second. Not a DSLR.


Yeah, SLRs without electronic shutters can do that too. That's not really
flash sync.

--
Jeremy |

Jeremy Nixon February 23rd 06 02:50 AM

Why do digital cameras need shutters?
 
Alan Browne wrote:

The Nikon D70 "electronically" shutter flash syncs up to 1/500 which is
on the "closing" side of the cycle, and I think that should be standard
on all high end DSLR's.


You can only do that with a CCD sensor, not with a CMOS.

--
Jeremy |

Alan Browne February 23rd 06 03:26 AM

Why do digital cameras need shutters?
 
Jeremy Nixon wrote:

Alan Browne wrote:


The Nikon D70 "electronically" shutter flash syncs up to 1/500 which is
on the "closing" side of the cycle, and I think that should be standard
on all high end DSLR's.



You can only do that with a CCD sensor, not with a CMOS.


I didn't know that. Source?

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.


All times are GMT +1. The time now is 10:06 AM.

Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
PhotoBanter.com