I dont get it--ISO vs. shutter spd.

[3p0rtlnd12]

So all I hear about is high ISO=noise. I think I know the diff. between ISO and shutter speed. I dont understand why people dont just shoot at like ISO 100 w/ a slower shutter speed? Help me!

sorry if its a silly question. :oops: :o

thanks

Amber

[nosquare2003]

If we want to freeze an action, we will need a higher shutter speed. So, we will need to have an high ISO sometimes.

[Tshoe]

Depending on the light available you need a higher ISO to be able to use a fast enough shudder speed to avoid blur. If it's during the day when there is plenty of light ISO 100 is fine but early morning or early evening your shudder speed could really be low to get the proper exposure if you are shooting anything moving.

[3p0rtlnd12]

ahhhhhhhhh, I see clearly now..

So next question, if you were just shooting like a city skyline (or anything w/o movement) would you THEN pick up on shutter and cut down on ISO..? tia

[xdjoynerx]

when your shooting at night time, you have 2 options with you want a clear picture.

use a tripod, and use a low iso, and a long shutter

but if you dont have a tripod, you cant use a long shutter or you will get tons of blur.. and the pic will just be a waste...

so you need to use a high iso (800) and a fast shutter speed. so the image is not blured, and its properly exposed.

any noise issues can be taken care of in post processing.

[robertwgross]

So all I hear about is high ISO=noise. I think I know the diff. between ISO and shutter speed. I dont understand why people dont just shoot at like ISO 100 w/ a slower shutter speed? Help me!


First of all, you have to get a reasonably correct exposure solution. As we all know, that is a mixture of shutter speed, aperture, and ISO setting.

If you have plenty of bright daylight, then you can get that correct exposure solution by all sorts of ways. All sorts of mixtures will do it.

If you don't have bright sunlight, maybe the light is very dim. You can get a correct exposure, but you have to start juggling things. You could consider to crank up the ISO to be very high, but then you may get lots of color noise. You could consider to drag the shutter speed out to be very slow, but then you might have a camera shake problem or a motion blur problem. You could consider to open the aperture up all the way. But many affordable lenses don't have super apertures like f/1.2. If you did have f/1.2, then you would have an incredibly thin depth of field, and that can make problems.

So, what do you want to do? You can start your mixture now, and there is no totally correct answer. That is where the photographer's mind starts operating. Which of my mixture values can I fudge around with and still get what I am trying to capture as an image?

---Bob Gross---

[CyberDyneSystems]

ahhhhhhhhh, I see clearly now..

So next question, if you were just shooting like a city skyline (or anything w/o movement) would you THEN pick up on shutter and cut down on ISO..? tia

Yes.. ANY still shot where you are not handholding can be handled at low ISO and longer shutter speeds.

[3p0rtlnd12]

Thanks guys,

Yeah, personally I usu. go for long shutter (because i never photograph moving objects at night) because I am shooting either: 1. cars or 2. the city. I def. dont go out at night w/o my three legged friend. Thank you for the clarification, SO MUCH TO FIDDLE AROUND W! definitely need to take a notepad out jot down some important do's and don'ts

Cheers,
Amber

[Persian-Rice]

To complete the argument, you can event adjust aperature to assist you in properly exposing an image.

The question is a good one, I dont think it has a defnitie answer. I think the solution lies in understanding the ffect each option has and also understanding what you want in your image.

ISO - Will add or reduce image noise..........
Shutter - Will blur the image or freeze it perfectly.
Aperature - Directly effects the DOF.

Each of these also directly have an effect on how the image is exposed.

Cheers.

[timmyquest]

I pretty much shoot

ISO 100 when there is plenty of light, not too much glass (50mm for example)

ISO 400 when i need shutter speed and light is decent

ISO 800 when there is not enough light

It's really that simple, you want to shoot at the lowest ISO possible...that applies to film and digital because the effects are the same.

[3p0rtlnd12]

To complete the argument, you can event adjust aperature to assist you in properly exposing an image.

The question is a good one, I dont think it has a defnitie answer. I think the solution lies in understanding the ffect each option has and also understanding what you want in your image.

ISO - Will add or reduce image noise..........
Shutter - Will blur the image or freeze it perfectly.
Aperature - Directly effects the DOF.

Each of these also directly have an effect on how the image is exposed.

Cheers.


This brings up another question :( lol,

Whats part does aperature play in this? isn't it similar to shutter? Sorry about my lack of photography jargon but isn't it basically like a hole that lets light in? and high ap=smaller hole?

OMG so confusing :cry:

Amber

[timmyquest]

Yes, the aperature simply put is an adjustable hole that adjusts the amount of light the lens lets into your camera.

But of course, that brings up another issue in DOF.

With a wide aperature you have a narrow depth of field, when it is small (lets less light in) you get a wider DOF.

[Olegis]

So all I hear about is high ISO=noise.

I must say that I'm extremely pleased with the noise levels produced by my 10D at aven the highest ISO settings. I did shoot at ISO 1600 in a few occasions, and if the images were properly exposed (not under-exposed that is), the noise was very acceptable.
IMO, if you don't plan to enlarge your prints beyond A4, you can safely shoot at ISO 1600, expose to the right and run the Noise Ninja (or some other noise removal software).

[3p0rtlnd12]

Yes, the aperature simply put is an adjustable hole that adjusts the amount of light the lens lets into your camera.

But of course, that brings up another issue in DOF.

With a wide aperature you have a narrow depth of field, when it is small (lets less light in) you get a wider DOF.

narrow depth of field is what in lay man terms? that the background will be blurred?

[Scottes]

narrow depth of field is what in lay man terms? that the background will be blurred?

Yes.

With a large aperture you let in more light so the shutter speed can be higher, but you get less Depth of Field so only certain things are in focus. With a smaller aperture you let in less light so you need a slower shutter speed, but you get more DoF.

This is more pronounced as the lens length or distance to subject increases. With a 50mm lens at f/8 focused on something 20 feet away gets you about 17 feet of DoF. Everything from 14 feet away from up to 31 feet away will be in focus. Aimed at something 50 feet away then everything from 30-144 feet will be in focus.

But a 400mm at f/8 focused on something 20 feet away gets you only 2 *inches* of DoF, and at 50 feet it's still only 1-1/2 feet of DoF.