A confused noob

[nadineb]

From what I have read about photography, a slow shutter speed lets more light in and thus having a photo with more light or exposure.
But sometimes while using my camera (EOS 400D), when I slow down the shutter speed as much as I can, I get a normal photo with normal lighting (sometimes even darker than usual).

Am I missing something? Is there something I just don't understand?
..or am I just a total noob?

 

[divided]

Well the amount of light is determined in part by shutter, but ALSO by aperture size.

 

[photelle]

And also by ISO. It's a 3-way relationship.

Need more light? Raise ISO, open up (wider aperture, i.e. smaller f-stop number), or lower shutter speed. You want the little ruler thing in your viewfinder to have the arrow pointing around the middle for a proper exposure (also depends on how you're metering and the lighting, but.. start with the middle). You move the arrow around by changing the ISO, aperture, and shutter speed. Don't let your shutter go to low if you're hand holding! You'll end up with blurry pictures.

 

[Sideburns]

you were probably in program mode. If you shoot manual, you'll see the difference. slow shtuter means blur though

 

[Johnboy2978]

Think of it like a water hose with the aperture being the circumference or the girth of the hose. A larger aperture, bigger water hose, (smaller number like f/1.4) allows more light in while a smaller aperture, like a straw, (larger number f/16) lets in a smaller amount. A larger aperture allows the exposure to be made in a shorter amount of time (a faster shutter speed like 1/180) while a smaller aperture takes longer amount of time to get the same exposure (a slower shutter speed like 1/60).
If you take a meter reading of a scene and the light meter tells you that a proper exposure could be made with an aperture setting of f/8 and a shutter speed of 1/180, you can achieve that same picture by increasing your shutter speed 1 stop and decreasing the aperture 1 stop and still have the same exposure value of 0 (or 2 or 3 or x stops as long as it is proportional or vice versa). This knowledge allows you to change the depth of field (DoF) for a portrait (having a larger aperture like 2.8) and blur the background while keeping the subject in focus. It will also allow you to create images like freezing action (with faster shutter speed) or slowing action like making a water fall smooth and 'wispy' with a slower shutter speed.

The third variable is the ISO which changes the sensitivity of film (or sensor) to light. A lower ISO like 100 will decrease the amount of noise or grain but makes it less sensitive to light and therefore forces you to use slower shutter speeds in low light (sometimes making it vulnerable to camera shake and motion blur). Higher ISO like 800 is more sensitive to light (allowing for higher shutter speeds when you can't lower the aperture any more due to lens limitations) but introduces more grain/noise.

So, the ISO, aperture, and shutter speed all are inter-connected.

 

[sirsteezo]

Think of it like a water hose with the aperture being the circumference or the girth of the hose. A larger aperture, bigger water hose, (smaller number like f/1.4) allows more light in while a smaller aperture, like a straw, (larger number f/16) lets in a smaller amount. A larger aperture allows the exposure to be made in a shorter amount of time (a faster shutter speed like 1/180) while a smaller aperture takes longer amount of time to get the same exposure (a slower shutter speed like 1/60).
If you take a meter reading of a scene and the light meter tells you that a proper exposure could be made with an aperture setting of f/8 and a shutter speed of 1/180, you can achieve that same picture by increasing your shutter speed 1 stop and decreasing the aperture 1 stop and still have the same exposure value of 0 (or 2 or 3 or x stops as long as it is proportional or vice versa). This knowledge allows you to change the depth of field (DoF) for a portrait (having a larger aperture like 2.8) and blur the background while keeping the subject in focus. It will also allow you to create images like freezing action (with faster shutter speed) or slowing action like making a water fall smooth and 'wispy' with a slower shutter speed.

The third variable is the ISO which changes the sensitivity of film (or sensor) to light. A lower ISO like 100 will decrease the amount of noise or grain but makes it less sensitive to light and therefore forces you to use slower shutter speeds in low light (sometimes making it vulnerable to camera shake and motion blur). Higher ISO like 800 is more sensitive to light (allowing for higher shutter speeds when you can't lower the aperture any more due to lens limitations) but introduces more grain/noise.

So, the ISO, aperture, and shutter speed all are inter-connected.

good explanation. I'll keep that in mind when I start taking my photos.

 

[Viperjet]

You were most likely shooting on "P" mode. Switch to "M" (manual) mode and you will be able to adjust all three elements of allowing light onto the photograph (aperture, ISO, shutter speed). Have any more questions? PM me, I know that camera pretty well...

 

[nadineb]

Wow guys you're the best. Thank you everyone I will keep all that in mind :thumbup:

 

[nadineb]

You were most likely shooting on "P" mode. Switch to "M" (manual) mode and you will be able to adjust all three elements of allowing light onto the photograph (aperture, ISO, shutter speed). Have any more questions? PM me, I know that camera pretty well...

Yeah, I really need someone that's really good at this camera, I will PM you if I need anything!

 

[dostagamom]

What a GREAT explanation johnboy2978. You really helped to clear up some confusion. I am really trying to get better at this.
Thanks again