ISO sensitivity VS. exposure time VS aperture

bump iso for more light, bump exposure for less light

Higher iso = more noise, but brighter picture at same exposure time and aperture.
Learn how far you can go with shutter speed without getting images blurry. I recommend beginners to not go below 1/60th with their kit lens and use smallest possible iso.

>>2893790

You need to get your terms straight. Exposure refers to the overall brightness of an image, so there's no way it can be a factor of itself.

Instead, your three variables are: aperture, shutter speed and ISO. Coincidentally, these are listed in order of the magnitude of the effect they have on the image as well.

Since aperture has the biggest effect on how a photo looks, it should usually be the first one you set. You should have an idea of how much depth of field you want in your photo and select the appropriate aperture. Do you want the background in focus with lots of detail in the image? f/16. Do you want an extremely shallow depth of field with the background out of focus? f/2. Do you want a little depth of field and super-sharp lens performance? f/8.

Once you have your aperture selected, you'll need to choose your shutter speed. Typically, you don't have a lot of options once your aperture is set. You'll have one speed for a classic, technically perfect exposure, and everything else will result in underexposure or overexposure (darker and brighter).

Shutter speeds have very little effect on the photo until you start getting down into the 1/125s and slower range. Motion blur starts to show up at these shutter speeds. There are two types of motion blur that you can expect: your subject moving, and your own hands moving the camera. If your subject has motion blur, that's okay. It can be a really interesting artistic effect in an image, and it can be something you're looking for. However, motion blur from your hands (known from here on as camera shake) is not desirable, as it means the entire photo will be blurry, instead of one single part. Reliably, regardless of what lens you're using, camera shake is uncontrollable at 1/15, 1/8, 1/4, and on. When you start to get down into these speeds, you should open your aperture to its biggest setting (remember, it's a fraction, so smaller numbers = bigger aperture).

If your aperture is wide open (cont'd)

>>2893790

ISO:
Sensitivity to light
Defines how light of a picture a finite amount of light produces. Higher iso produces a brighter picture with the same amount of light.
Aside of the High iso side effect of grain/noise that is all ISO does (unlike time and aperture).

Exposure time:
Quantity of light captured,
defined by the length of time you let light in the camera.
You can think of a water hose analogy, the longer the hose is on (exposure time) the more water (light) is accumulated.
So far the final effect is just like with iso except for the very relevant following:
More time = more motion blur, motion being anything from object motion, your trembling hands motion, rotation of the earth motion and so on, stuff appears smeared in the direction of the motion.
Less time = less motion blur, can taken to the extremes where even the fastest motion appears blur free/frozen in motion.

Aperture:
Quantity of light captured,
defined by the size of the aperture hole light is let thru.
Again hose analogy, you adjust the water valve more closed and less water is accumulated.
So far the final effect is just like with iso except for the very relevant following:.... that you already figured out depth of field due to optics principles


Basically you have to juggle with these three, or more like primarily with time and aperture to achieve or avoid a certain effect they produce.
(ISO being more of a parameter selected according to available light)

>>2893800

and you still can't get a well-exposed image with a fast-enough shutter speed, you need to bump up your ISO. You should try to shoot at or near base ISO as much as you can. Lower ISO has much better image quality than high ISO, since not only is the image less noisy, but it's also got more dynamic range, more color depth, and finer tonality. However, noisy but sharp is always better than blurry but clean, and you should prioritize ISO over shutter speed and aperture when shooting in low light.

So what do you do if you want a large depth of field AND a very short shutter speed (for instance, in street photography)? At f/16, you might only be able to shoot at 1/125 or 1/250. If you want a truly time-stopping shutter speed (say, 1/1000 or above), you'll need to adjust your ISO.

Keep in mind that stops are equivalent no matter what you're adjusting. Opening up from f/8 to f/5.6 has the same effect as increasing your shutter speed from 1/1000 to 1/500, which as the same effect as boosting your iso from 800 to 1600. This means two things: When you adjust one, you have to adjust something else in the opposite direction to maintain the same exposure. It also means that there are many, many settings you can use to get the same exposure.

Let's say you're using f/8, 1/500s, ISO 200. If you open up to f/5.6, your image will be overexposed unless you increase the shutter speed to 1/1000s OR decrease the ISO to ISO 100. Similarly, if you drop your shutter speed to 1/250s, you'll have to stop down to f/11 or (again) drop your ISO to 100 to adjust for the overexposure. If you drop your shutter speed to 1/125 from 1/250, you'll have to stop down to f/16. In fact, the following combinations will all give the same exposure as our example:

>f/8, 1/500s, ISO 100
>f/8,1/1000s, ISO 200
>f/8, 1/2000s, ISO 400
>f/8, 1/4000s, ISO 800
>f/8, 1/8000s, ISO 1600
>f/5.6, 1/1000s, ISO 200
>f/5.6, 1/2000s, ISO 400
>f/4, 1/2000s, ISO 200
>f/16, 1/125s, ISO 200
>f/2, 1/8000s, ISO 200

>>2893818

So it's really easy to see how confusing this can get if you aren't sticking to one variable at a time. Figure out what look you need in your photo and go from there.

>>2893790
>I kinda understand that smaller aperture = lower depth of field
wrong -- google is your friend, OP.

>>2893792
what are you