I am trying to set the aperture in my SLR, so that I get a blurry background and the foreground remains sharp (Low Aperture value)...But, the final image has a shake. Is a tripod required when manually setting the aperture value?
In general no, setting the aperture to a low value gives you more light on the sensor than a higher value. More light -> faster shutter speed-> less shake.
@primitiveprobe .. Is it "More light -> faster shutter speed"? If the shutter speed is fast, then it has to be less light, right? Correct me if I am wrong
I have found that I like to shoot in Manual more than in the Aperature setting because you can then change your shutter speed and ISO to get what you want, whereas with the Aperature setting, you're limited to manipulating the f-stop and nothing else (or, at least on my model, I think that is the case). I agree with what @primitiveprobe said, it sounds like you need a faster shutter speed if your final image has a shake -- BUT, I'm also going to be sort of surprised if your camera went to a slow shutter speed in Aperature mode (well, one that is slow enough to cause shake) when you had a low f-stop, too. Would be curious to see your photo and the exif info! :)
re-reading this, I realize you didn't say you were in aperature mode -- so maybe you were in manual all along? I have no idea what your lighting situation is, but try as low f-stop as you can go, a shutter speed at least as high as 1/200-1/300 and an ISO of 200-400 and then adjust from there?
@reks You're right, but missing my point. To obtain the correct exposure you need a certain amount of light to hit the sensor. There are two main parameteres you can control to obtain this, light opening (aperture) and time (shutter speed). When you use a large opening (small f-number) you can use a short shutter speed to obtain the same amount of light.
Similarily, when filling a glass of water, you can have the tap wide open for a short time, or fill the glass drop by drop over a long time, the amount of water in the glass is the same. The similarity end here, as in photography the way you fill your sensor impacts the resulting image.
Normally, a small f-number gives you lots of light and fast shutter speeds, hence no shake. If the shutter speed still is to slow to avoid shake you should increase the ISO to increase the sensitivity of your sensor.
The camera simulator is a great tool to play with these parameters.
@reks - Rekha, it would be interesting to see the photo and EXIF data associated with the photo.
However, Andreas' description of more light = faster shutter speed is correct.
The aperture is just an adjustable opening in the lens. The bigger the opening (smaller F #) the more light is available to the sensor. The smaller the opening (bigger F#), less light is available to the sensor.
The shutter is a curtain that regulates how long the light is exposed to the shutter. It is between the aperture and the sensor. So, if you have a lot of light entering the lens due to a large aperture, the shutter speed should be pretty fast in order to limit the amount of time that the light hits the sensor. For example, if you have aperture set to f2.8 (pretty large) and shutter speed set to 1 second, you likely would have an overexposed, and possibly blurry, image ( assuming a normal daylight picture). Now, if you speed up the shutter speed to 1/1200th of a second, you might end up with a nicely exposed image. These shutter speed examples are just examples and not meant to tell you what actual numbers to use for your shake problem. But, just know that a larger aperture generally will mean a faster shutter speed and less "shake".
But, as I mentioned in the beginning. If you can post the picture and provide EXIF data, that would be very helpful. Perhaps what you are seeing as shake, isn't really shake at all.
Touched on by others, but not answered is the primary question: what mode are you using?
If you are in Manual you will need to set Both the aperture and the shutter speed. Is this the case?
In Aperture mode, one need only set the aperture, the camera sets the shutter.
What I would suggest is first starting in aperture mode. Leave the ISO in auto. Take photos adjusting the aperture and, either while shooting or viewing the exif info later, note how the camera adjusts the shutter speed and ISO. As you get comfortable, start adding in variables like ISO and shutter speed.
A large aperture such as f/2 will give you a shallow depth of field. Depending on your lighting conditions you shouldn't have too much of a problem with shake, seeing as the aperture wide open. Are you shooting in aperture priority mode?
Other things to take into consideration are focal length and focal distance. You want to be closer to the subject you want to isolate. If you're shooting with a wide angle lens the foreground and background are both likely to remain in focus otherwise. Zoom in and use a longer focal length in order to get the desired blurry background.
the old school rule was don't ever have your shutter speed less than your focal length, else you get camera shake. So that's 50mm lens for instance, don't go less than /50.
Pretty easy to solve really, if you're indoors use a flash or raise your ISO.
It's also important to remember that using a smaller aperture (= larger f/number) for greater depth of field, will need a longer (slower) exposure which increases the risk of shake. One stop smaller doubles the lingth of exposure, 2 stops = 4 times, 3 stops = 8 times, etc. (The law of the inverse square)
Hello Everybody..
Thanks for all of your wonderful explanatory replies...I need to really go through all of them again to get better grasp of aperture settings...
Just to reply many of your questions...
-- I will try to get the photo out of my camera so that you can all see the Exif info.
-- Yes. I also need to try out increasing the ISO to check if the shake is avoided.
-- I am NOT using the complete manual ("M") mode...I am using "A" (Aperture mode) which means I can set only the aperture and the shutter speed is automatically set by the camera.
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I know it sounds obvious but it get confusing. If you still get shake then add more light or increase your ISO.
Similarily, when filling a glass of water, you can have the tap wide open for a short time, or fill the glass drop by drop over a long time, the amount of water in the glass is the same. The similarity end here, as in photography the way you fill your sensor impacts the resulting image.
Normally, a small f-number gives you lots of light and fast shutter speeds, hence no shake. If the shutter speed still is to slow to avoid shake you should increase the ISO to increase the sensitivity of your sensor.
The camera simulator is a great tool to play with these parameters.
However, Andreas' description of more light = faster shutter speed is correct.
The aperture is just an adjustable opening in the lens. The bigger the opening (smaller F #) the more light is available to the sensor. The smaller the opening (bigger F#), less light is available to the sensor.
The shutter is a curtain that regulates how long the light is exposed to the shutter. It is between the aperture and the sensor. So, if you have a lot of light entering the lens due to a large aperture, the shutter speed should be pretty fast in order to limit the amount of time that the light hits the sensor. For example, if you have aperture set to f2.8 (pretty large) and shutter speed set to 1 second, you likely would have an overexposed, and possibly blurry, image ( assuming a normal daylight picture). Now, if you speed up the shutter speed to 1/1200th of a second, you might end up with a nicely exposed image. These shutter speed examples are just examples and not meant to tell you what actual numbers to use for your shake problem. But, just know that a larger aperture generally will mean a faster shutter speed and less "shake".
But, as I mentioned in the beginning. If you can post the picture and provide EXIF data, that would be very helpful. Perhaps what you are seeing as shake, isn't really shake at all.
If you are in Manual you will need to set Both the aperture and the shutter speed. Is this the case?
In Aperture mode, one need only set the aperture, the camera sets the shutter.
What I would suggest is first starting in aperture mode. Leave the ISO in auto. Take photos adjusting the aperture and, either while shooting or viewing the exif info later, note how the camera adjusts the shutter speed and ISO. As you get comfortable, start adding in variables like ISO and shutter speed.
Other things to take into consideration are focal length and focal distance. You want to be closer to the subject you want to isolate. If you're shooting with a wide angle lens the foreground and background are both likely to remain in focus otherwise. Zoom in and use a longer focal length in order to get the desired blurry background.
the old school rule was don't ever have your shutter speed less than your focal length, else you get camera shake. So that's 50mm lens for instance, don't go less than /50.
Pretty easy to solve really, if you're indoors use a flash or raise your ISO.
Thanks for all of your wonderful explanatory replies...I need to really go through all of them again to get better grasp of aperture settings...
Just to reply many of your questions...
-- I will try to get the photo out of my camera so that you can all see the Exif info.
-- Yes. I also need to try out increasing the ISO to check if the shake is avoided.
-- I am NOT using the complete manual ("M") mode...I am using "A" (Aperture mode) which means I can set only the aperture and the shutter speed is automatically set by the camera.