Canon 550d, Shutter speed and aperture help!

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11josh112

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Hi, i Just got my first dslr the other day(Canon 550d with 18-55mm lens).
and i know that you have to lower the shutter speed for the object to be more blurry but when i do that it takes all the light out and i end up with a dark picture. could someone tell me why this is? and how to get that effect to work.

Also with aperture i beleive you have to have it higher for the background to blur and focus on that one object. well then when i put it higher it doesnt seem to blur the background and the image just gets darker...help?

Would much appreciate it, thanks!:)
 
hi josh,

aperture workd the opposite, the higher the number the smaller the gap in the aperture meaning less light but more in focus.

shutter speed also allows in less light the quicker you set it, the higher the speed the morr blur youll get from handheld or panning.

make sure you have a decent iso (sensitivity to light) set too.
 
I posted this the other day for a similar question, sounds like it may help you also:

"Look up information on the exposure triangle and start with the basics. That is Aperture, Shutter Speed and ISO.

Learn what each of them does and how it affects your images, and the link between them. I would start off playing with either Tv (shutter priority) and Av (aperture priority) as you only have to worry about 1 at a time and the camera will handle the others.

Experiment with faster shutter speeds to freeze the action in your images and slower speeds to blur it. Wide apertures (lower f number) to blur the background in your photos (can be nice on portraits) and narrow apertures (higher f number) to have more in focus (better for multiple people or landscapes for example).

ISO adjusts how sensitive to light your camera sensor is, the higher the ISO the more sensitive. The higher the ISO the more noisy (lower image quality) your picture will be so generally it is best to use the lowest ISO you can.

These 3 settings in combination control how much light enters your camera and how sensitive your camera is to that light. It is a balancing act between exposing your image correctly and getting the creative effect you want in your image.

If you have any specific questions post them up :thumbs:"
 
Assuming you bought a new camera Josh :shrug: you should have a little book in there which they call a manual :thumbs: I suggest you sit down with said book and camera and go through a few of the pages ;) For isolating your subjects and obtaining a bit of Bokeh there will be examples printed in there.
 
I would assume you are using manual mode i you are getting underexposed images, so take it out of that for now and use either shutter priority (Tv) if you want to control the freezing or bluring of motion, or aperture priority (Av) for controling the depth of field.
The camera will make sure the exposure is correct, so you will get the effect you want.
Once you get to grips with the exposure triangle and how everything interacts, you can then go back into manual mode if you feel like it.
 
Thanks guys, very useful infomation:)
 
I would add to the above that taking lots of photos using different settings will help you come to terms with your camera. Start by setting to either av or tv and adjusting one setting only (aperture in av, shutter speed in tv) and remember that the lower the "f" number the more light the camera can capture
 
It might be an idea to select Manual mode and to keep an eye on the cursor above the exposure scale in the view finder. If the cursor is smack in the middle you'll get what the camera thinks is a correct exposure. You can then alter in turn the ISO, aperture and shutter speed and see the effect that each have both on the position of the cursor and the final image. You'll see what makes the picture too bright or too dark and the effect each of the magic three things have... shutter, aperture, ISO.

Once you've got the hang of that you should be able to alter your aperture to get more or less depth of field and be able to compensate by altering the shutter speed and / or ISO to get a good exposure.

Or, if depth of field is what you want to play with, just select Aperture Priority, set your aperture and ISO and let the camera set the shutter speed.
 
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Hey Josh, first off good call on your camera, it's a really good mid-level slr. I have the same one.

All the advice above is excelent. I'll just add it's usually a fight between shutter, aperture and ISO to get the right exposure. They all have their ups and downs so it ends up being a mix depending on what you are trying to shoot.

After you have the basics just experiment, alter the settings and see what you get each time. You will soon pick it up.

If you want motion blue on a subject look for about 1/30th shutter speed.

Remember, the faster the shutter speed is, the less time light has to reach the sensor. To counter this, you need to increase the aperture size (lower f number) or increase the ISO. Usually ISO is increased last, as it adds noise to the image the higher it goes.

Best of luck.
 
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