# Why is a Shutter needed for Digital Cameras? **URL:** \ **Category:** Factual Questions\ **Created:** [April 23, 2003, 4:42am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530 "2003-04-23T04:42:40Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 23, 2003, 2:41pm UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/21 "2003-04-23T14:41:01Z")
> [@](#): > > \*Originally posted by Earthling \* > \*\*[hijack] > > Hey **Padeye** , is your camera noisy? I have a Dimage 7i, and the images I get appear to be noisy (or grainy), even when I use the lowest ISO speed, put the camera on a tripod, and crank the aperture down to about f/8. > > [/hijack] \*\* No, it’s not as clean as a DLSR with a much bigger CCD but I don’t consider it noisy at all. What kind of images are you looking at? Blue skys are a problem with most cameras. What settings? I only ever shoot in fine JPG or raw. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 23, 2003, 2:46pm UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/22 "2003-04-23T14:46:12Z")
> [@](#): > > \*Originally posted by bcullman \* > \*\*Is everyone in here that says they have a shutter, sure that is what it is, and not a lens cover? I’ve seen plenty of digital cameras with lens covers (powered and unpowered) but none with a shutter. \*\* You’re unlikely to see the shutter unless you take the camera apart. A shutter is typically inside the lens or in the case of DSLRs like the Nikon D1 or Fuji S2 at the CCD. Earthling, FWIW mine is an original Dimage 7 with the firmware upgrade that makes it _almost_ a D7i. Email me offline if you want and we’ll see if we can get your noisy images under control. [padeye@padeye.net](mailto:padeye@padeye.net) ---
**Author:** ![aeropl](https://avatars.discourse-cdn.com/v4/letter/a/f05b48/32.png) [@aeropl](https://boards.straightdope.com/u/aeropl)\ **Post date:** [April 24, 2003, 12:51am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/23 "2003-04-24T00:51:53Z")
> [@](#): > > \*Originally posted by bcullman \* > \*\*Is everyone in here that says they have a shutter, sure that is what it is, and not a lens cover? I’ve seen plenty of digital cameras with lens covers (powered and unpowered) but none with a shutter. \*\* The one I see is inside the camera, behind the lens. So it’s not a lens cover. It’s about 1 or 2 mm in diameter. I’m pretty sure its a shutter. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 24, 2003, 1:07am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/24 "2003-04-24T01:07:16Z")
> [@](#): > > \*Originally posted by aeropl \* > \*\*The one I see is inside the camera, behind the lens. So it’s not a lens cover. It’s about 1 or 2 mm in diameter. I’m pretty sure its a shutter. \*\* Does it in fact close all the way when you take a picture? You may be looking at the aperture iris, not the shutter. ---
**Author:** ![Doc\_Nickel](https://avatars.discourse-cdn.com/v4/letter/d/5fc32e/32.png) [@Doc\_Nickel](https://boards.straightdope.com/u/Doc_Nickel)\ **Post date:** [April 24, 2003, 1:13am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/25 "2003-04-24T01:13:24Z")
I used to have an older Nikon Coolpix- I forget the number- that split apart, and the images were read directly off the camera body when it was inserted in a PCMCIA slot on a laptop. It was pretty lo-res, but functional. The interesting thing was it appeared to have zero shutter speed. I could take a photo- non-flash even- of the chuck of my lathe doing about 600 rpm, and the resulting image was as crisp as if the thing hadn’t been turning at all. It made no sound whatsoever when it took a photo, other than the slight “poof” of the flash and a light ‘click’ from the shutter button’s mechanical contacts. Nowadays I have an Olympus D360R, which is a 1.3Mp, and definitely has a mechanical shutter. It’ll blur just about anything in a reduced-light shot, if you’re not holding it dead steady. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [April 24, 2003, 2:13am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/26 "2003-04-24T02:13:00Z")
> [@](#): > > \*Originally posted by Padeye \* > \*\*Does it in fact close all the way when you take a picture? You may be looking at the aperture iris, not the shutter. \*\* The two functions are often done by one component, an iris that works fast and closes all the way. For exposure it opens up partway and closes again. This is why some cameras have strange restrictions on what aperture you can use for certain shutter speeds, like the maximum speed only being available at small apertures. I may have been a bit misleading about the smearing issue. Cameras designed for video are optimized for shutterless operation, and there is minimal smearing. But such detectors sacrifice efficiency and pixel count. If the detector doesn’t need to perform well for shutterless operation (i.e. if you don’t mind some smearing, or if you always use a mechanical shutter), you can make it more efficient and cram more pixels onto the same size CCD. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 24, 2003, 5:15am UTC](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530/27 "2003-04-24T05:15:05Z")
> [@](#): > > \*Originally posted by Doc Nickel \* > **It was pretty lo-res, but functional. The interesting thing was it appeared to have zero shutter speed. I could take a photo- non-flash even- of the chuck of my lathe doing about 600 rpm, and the resulting image was as crisp as if the thing hadn’t been turning at all.** Not even digital cameras can cheat the laws of physics. You have to expose the CCD or film to light for a finite amount of time to get enough photons to make an image. A 600rmp chuck is fast to our eye which does not take discreet frames bus a 1/1000 second shutter speed is very reasonable in good light and only results in about 3.6º of movement. Little enough to seem like a true freeze frame at typical digicam resolution. [Previous page](https://boards.straightdope.com/t/why-is-a-shutter-needed-for-digital-cameras/170530.md?page=1)