I suck at cameras
June 23, 2010 1:12 PM
Extreme photography noob question: I have a canon powershot sd880. Why do photos becomes incredibly blurry when I turn off flash (but not when it's on autoflash and the flash doesn't go off)?
I have a canon powershot sd880. Whenever I turn the flash off, the photos tend to be very blurry. Flash on: no such problem. Even if it's on autoflash, but the flash doesn't engage, the photos are fine. It's just when I manually turn off the flash. Why does this happen? At this rate, I'll never win a Pulitzer.
I have a canon powershot sd880. Whenever I turn the flash off, the photos tend to be very blurry. Flash on: no such problem. Even if it's on autoflash, but the flash doesn't engage, the photos are fine. It's just when I manually turn off the flash. Why does this happen? At this rate, I'll never win a Pulitzer.
When you turn off the flash, the shutter stays open longer (lets in more light). Which means that it's recording the image for a longer time, and your shaky hand is causing the blur. If the autoflash doesn't engage, it means there's enough light to take a faster photo...and no blur.
I like to use no flash and a tripod, but that's not always practical.
(On preview: yep, what FLT said.)
posted by JoanArkham at 1:18 PM on June 23, 2010
I like to use no flash and a tripod, but that's not always practical.
(On preview: yep, what FLT said.)
posted by JoanArkham at 1:18 PM on June 23, 2010
Most modern cameras increase the exposure time to accomodate lower light so that your subject will be visible in the photo. Fancier cameras will let you configure all of the variables yourself.
The longer the exposure time, the more subtle movements of your hand are picked up. If the flash is on, there is tons of light, and the exposure time is near-instantaneous, so no subtle movements are picked up, if you're on autoflash and the flash doesn't trigger, that means there is enough light to get a sufficiently short exposure time.
The solution is to get a tripod.
posted by coryinabox at 1:19 PM on June 23, 2010
The longer the exposure time, the more subtle movements of your hand are picked up. If the flash is on, there is tons of light, and the exposure time is near-instantaneous, so no subtle movements are picked up, if you're on autoflash and the flash doesn't trigger, that means there is enough light to get a sufficiently short exposure time.
The solution is to get a tripod.
posted by coryinabox at 1:19 PM on June 23, 2010
When there's less available light and the flash is off, the shutter has to stay open longer for enough light to get to the sensor. Your hand shakes slightly, and if the camera moves while the shutter is open, you get a blurry photo.
If autoflash is on, but the flash doesn't engage, that means there was enough light in the first place (by your camera's standards) for the shutter to stay open a short enough amount of time for any camera motion to be negligible. When the flash, er, flashes, that adds to the amount of available light so the shutter can be quicker.
Quicker shutter = sharper picture = darker (i.e., less light exposure).
posted by supercres at 1:19 PM on June 23, 2010
If autoflash is on, but the flash doesn't engage, that means there was enough light in the first place (by your camera's standards) for the shutter to stay open a short enough amount of time for any camera motion to be negligible. When the flash, er, flashes, that adds to the amount of available light so the shutter can be quicker.
Quicker shutter = sharper picture = darker (i.e., less light exposure).
posted by supercres at 1:19 PM on June 23, 2010
The camera sensor needs to receive a certain amount of light to create an image. That amount is determined by the size of the aperture allowing light in, and the length of exposure time. When the light is low, the camera compensates by enlarging the aperture and increasing the exposure time, but beyond a certain length of time you cannot hold the camera completely still for the entire exposure, so you get a blurry picture from the camera moving. When the autoflash is on the camera detects whether there is enough light and will not use the flash when not necessary. If you were to place the camera on a tripod or steady surface you could probably take crisp (but dark) pictures in low light without flash.
posted by ghharr at 1:22 PM on June 23, 2010
posted by ghharr at 1:22 PM on June 23, 2010
Basically in order to expose the photo receptor in your camera you'll need some minimum level of light. If the scene is very bright, this level is reached very quickly - in hundredths of a second. The shutter opens only very briefly and therefore the chance that the image will move across the receptor is small.
If, however, the amount of light in a scene is low, then the shutter needs to be open for a relatively long period of time (up to perhaps half a second or even longer) in order to expose the receptor. The longer the shutter is open, the bigger the chance that the image on the receptor will change - either because you move the camera, or the scene in front of the camera changes, or both.
In order to minimize this possibility, you can use a flash to temporarily brighten up a scene in order to help decrease the amount of time that the shutter needs to be open. So your camera has a light meter (auto-flash) inside it to detect whether or not you need to use the flash. If you have the auto-flash on and the flash does not go off, then the camera has determined that there is ample light and the shutter opened only very briefly and therefore you probably have a nice crisp image.
If you turn the flash off, however, the camera will still be automatically setting the shutter speed for you based upon what the light meter detects. Unless the scene is very bright then the shutter will have to be open for a relatively long time in order to get exposure and hence blurry pictures. So when the flash doesn't go off and auto-flash is on, then you can infer that the scene was pretty bright and the shutter was fast. If you have the flash off, you can make no such inference, and it is much more likely that the shutter was open for a long time, and hence it is therefore also more likely that your pictures will come out blurry.
If you want to keep the flash off, you have basically two options. Option 1 is to try to hold the camera very still, or use a tripod. Option 2 is to see if you can set the shutter speed manually, as well.
posted by ChasFile at 1:26 PM on June 23, 2010
If, however, the amount of light in a scene is low, then the shutter needs to be open for a relatively long period of time (up to perhaps half a second or even longer) in order to expose the receptor. The longer the shutter is open, the bigger the chance that the image on the receptor will change - either because you move the camera, or the scene in front of the camera changes, or both.
In order to minimize this possibility, you can use a flash to temporarily brighten up a scene in order to help decrease the amount of time that the shutter needs to be open. So your camera has a light meter (auto-flash) inside it to detect whether or not you need to use the flash. If you have the auto-flash on and the flash does not go off, then the camera has determined that there is ample light and the shutter opened only very briefly and therefore you probably have a nice crisp image.
If you turn the flash off, however, the camera will still be automatically setting the shutter speed for you based upon what the light meter detects. Unless the scene is very bright then the shutter will have to be open for a relatively long time in order to get exposure and hence blurry pictures. So when the flash doesn't go off and auto-flash is on, then you can infer that the scene was pretty bright and the shutter was fast. If you have the flash off, you can make no such inference, and it is much more likely that the shutter was open for a long time, and hence it is therefore also more likely that your pictures will come out blurry.
If you want to keep the flash off, you have basically two options. Option 1 is to try to hold the camera very still, or use a tripod. Option 2 is to see if you can set the shutter speed manually, as well.
posted by ChasFile at 1:26 PM on June 23, 2010
If you have it on autoflash, but the flash chooses not to go off, it means you are in a situation the camera (correctly) has judged to have enough light.
Enough light = the shutter can open and close more quickly and still get a decent picture.
If you're in a low light situation without using a flash, the shutter has to stay open longer to compensate. That extra time it's open allows time for subject movement or camera shake to blur the resulting photo.
posted by Ouisch at 3:07 PM on June 23, 2010
Enough light = the shutter can open and close more quickly and still get a decent picture.
If you're in a low light situation without using a flash, the shutter has to stay open longer to compensate. That extra time it's open allows time for subject movement or camera shake to blur the resulting photo.
posted by Ouisch at 3:07 PM on June 23, 2010
(Also, if you're manually turning off the flash and getting blurry pictures as a result, it means you're not yet a good judge of whether there is enough light present for the camera to engage at a faster shutter speed. Practice, and maybe fooling with manual shutter speed settings, will correct this in time.)
posted by Ouisch at 3:08 PM on June 23, 2010
posted by Ouisch at 3:08 PM on June 23, 2010
What everybody else said, but you don't necessarily HAVE to get a tripod. Other things that may help include
- bracing your elbows against your body
- bracing your forearm(s) against nearby surfaces
- putting the camera on a flat surface and pressing the button
- putting the camera on a flat surface and using the self timer
- getting a Gorillapod
posted by emilyw at 3:21 PM on June 23, 2010
- bracing your elbows against your body
- bracing your forearm(s) against nearby surfaces
- putting the camera on a flat surface and pressing the button
- putting the camera on a flat surface and using the self timer
- getting a Gorillapod
posted by emilyw at 3:21 PM on June 23, 2010
This can be confusing because our eyes are so good at dealing with a very wide range of illuminations that it is sometimes not intuitive why a camera has trouble when it still seems perfectly bright. For an example, the illumination outdoors on a clear day is over a million times brighter than a well-lit room at night.
posted by Nothing at 5:46 PM on June 23, 2010
posted by Nothing at 5:46 PM on June 23, 2010
Yeah, like all the other posters have said, the blur is motion blur from the relatively long exposure -- it may be only a fraction of a second, but may be still long enough for the motion of the subject or the shake of your hands to blur the image.
So really I'm just commenting to second emilyw's excellent suggestions for sucessful low-light photography without a tripod. I love an empty wine or pint glass, myself, for photos of dim dining rooms or pubs -- nice and flat on top, and you can balance th. camera on top to eliminate your hand shake - just press the shutter very carefully.
Bracing or using a tripod/gorilla po won't eliminate blur from the motion of your subjects, of course. But motion blur contrasted against the crystal clear still elements is part of the beauty of low-light photography.
posted by jb at 5:57 PM on June 23, 2010
So really I'm just commenting to second emilyw's excellent suggestions for sucessful low-light photography without a tripod. I love an empty wine or pint glass, myself, for photos of dim dining rooms or pubs -- nice and flat on top, and you can balance th. camera on top to eliminate your hand shake - just press the shutter very carefully.
Bracing or using a tripod/gorilla po won't eliminate blur from the motion of your subjects, of course. But motion blur contrasted against the crystal clear still elements is part of the beauty of low-light photography.
posted by jb at 5:57 PM on June 23, 2010
If your camera has a manual mode where it allows you to set the ISO setting to a high value or auto, try using that when not using flash. The picture might be noisy, but this will reduce the shutter exposure time and may decrease blur. But what the others said too, practice bracing.
It also helps to figure out how much your arms/body move generally with your breathing/standing and taking advantage of a relatively low motion period to press the shutter.
Also, what I have found helps is to try to press the shutter in a fluid motion, rather than abruptly.
posted by ssri at 10:57 PM on June 23, 2010
It also helps to figure out how much your arms/body move generally with your breathing/standing and taking advantage of a relatively low motion period to press the shutter.
Also, what I have found helps is to try to press the shutter in a fluid motion, rather than abruptly.
posted by ssri at 10:57 PM on June 23, 2010
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Slightly-less-than-noob reply: I believe it's because the flash (and auto-flash) setting is timed to a very quick "exposure," meaning you'd have to move very fast to get a blurry image. Disable flash, and the camera will capture the view for a slightly longer period, to increase the amount of light received.
posted by filthy light thief at 1:16 PM on June 23, 2010