Trying to get my head around Exposure!!

[km78]

I am really having a difficult time understanding the "Exposure Triangle". Is it just me, or is/did anyone else have trouble with this when they were starting out?

I picked up the book "Understanding Exposure" and have started to read it but it is not making a whole lot of sense to me yet. What my biggest problem is, is how to figure out which combinations of ISO/Aperture/Shutter Speed to use for each specific picture. Is there a rule as to which setting to set first or does it just all depend on the type of image you want to shoot?

I do understand how to get a basic correct exposure by adjusting my settings and looking at the light meter. And I think I pretty much know how to set my ISO accordingly. What I don't know how to do is automatically know which Aperture or Shutter Speed to use based on the scene. For instance...If I want to take a photo of my daughter outside and I want good DOF behind her, I know that my Aperture will give me the DOF but I don't automatically know which Aperture setting to use to give me that DOF and which Shutter Speed to use to go with it to give me a correct exposure.

If anyone knows of a super simple way to explain this, that would be great! TIA

 

[gw2424]

My best advice is to play with it. Seriously, screw up....ALOT. You will learn it and have fun in the process.

 

[Overread17 5]

Generally gw2424 has given the answer for most people - learn and get a "feel" for what different apertures in different situations give you. Most of the time you won't have much pre-planning time for photos so building up a "gut feeling" level of experience with things is invaluble. Also don't underestimate the value of taking shots over a series of settings (even the past masters with film did this - heck they did it even more to make sure they got that one working shot!)

After that you might also want to look up a depth of field calculator (there are many online even some aps for phones and tablets as well). This will let you calculate the actual depth of field as a value based upon the conditions and settings - its a great way to get a feel from the technical side of things.

 

[480sparky41 40]

You need to understand what each ISO does to an image, what each shutter speed will do to an image, and what each aperture will do to an image.

With all things, exposure is a compromise. Rarely do we have the luxury of having the PERFECT light, in the RIGHT amount, that will allow us to use the PERFECT aperture with the PERFECT shutter speed. You need to pick the one or two parameters of the Exposure Triangle that matches your image, and let the other parameter fall where it needs to.

 

[Light Guru]

This is probably the best article I have come across on the subject of exposure.

http://www.exposureguide.com/exposure.htm

 

[table1349]

Digital Photography Tutorials

Excellent resource for your questions now and probably in the future.

 

[KmH]

Use this online camera to play with the settings to see how they affect exposure, motion stopping, depth-of-field, and image noise - CameraSim simulates a digital SLR camera - SLR Photography Demystified

 

[sekhar]

See if your camera has a Depth of Field Preview button, that will give you a decent idea of how things will turn out. Not sure if you're only talking about manual mode, but do check out the aperture priority setting, where you can lock the f-stop and the camera will automatically set the shutter speed to get the right exposure. Also, be sure to shoot in RAW: these days you can recover a surprising amount of detail following exposure errors (e.g., in Adobe Camera Raw), especially at lower ISO.

 

[Light Guru]

See if your camera has a Depth of Field Preview button, that will give you a decent idea of how things will turn out. Not sure if you're only talking about manual mode, but do check out the aperture priority setting, where you can lock the f-stop and the camera will automatically set the shutter speed to get the right exposure. Also, be sure to shoot in RAW: these days you can recover a surprising amount of detail following exposure errors (e.g., in Adobe Camera Raw), especially at lower ISO.

Aperture is only one thing that effects exposure. You really need to understand the whole exposure triangle. Only learning what the aperture does is like learning to drive and only learning how to use the gas pedal.

 

[sekhar]

See if your camera has a Depth of Field Preview button, that will give you a decent idea of how things will turn out. Not sure if you're only talking about manual mode, but do check out the aperture priority setting, where you can lock the f-stop and the camera will automatically set the shutter speed to get the right exposure. Also, be sure to shoot in RAW: these days you can recover a surprising amount of detail following exposure errors (e.g., in Adobe Camera Raw), especially at lower ISO.

Aperture is only one thing that effects exposure. You really need to understand the whole exposure triangle. Only learning what the aperture does is like learning to drive and only learning how to use the gas pedal.

Sorry, what's your point? And I'm not being sarcastic, I really am curious. Was there something wrong in what I said? Or did you intend your response to the OP?

 

[pgriz]

In general, I recommend keeping the ISO at the base level (100 for Canon, 200 for Nikon), until you have a good reason to change it.

Next, for most shooting situations, you want to work with aperture first. There are three basic aperture ranges: wide open (f/1.2 to f/4, more or less), intermediate (f/5.6-f/11) and stopped down (f/16-f/64). The wide open gives you a "thin" depth of field, which can be great when you're trying to blur the background and keep your subject in focus. Intermediate apertures "generally" tend to be the sharpest and give you pretty good latitude with setting your focus - if you're off a bit, it won't show (much). Stopped down is usually used when you want extreme depth-of-field, OR you want a really slow shutter speed.

After setting the aperture, you see where your shutter speed ends up (say you're in apeture mode, Av in Canon, A in Nikon). If you're hand-holding, you have to be aware of the guidelines that your shutter speed should not be less than the reciprocal of the focal length (if you have a 50mm lens, then your minimum shutter speed should not be below 1/50 sec). You also have to think about what kind of effect you're going for - motion blur or freeze-action. Motion blur will be visible at 1/60 or less (depending on the speed of the subject moving across your plane of view), while 1/500sec and up will freeze most motion.

If you don't have enough light, you start opening up your aperture, then lowering your shutter speed. If that get's you into hand-held blur territory, then you start bumping up the ISO to get an acceptable exposure. If that fails, you need supplemental light (flash, reflected/redirected light, or a brilliant smile (j/k)).

What makes photography fun is the ability to choose the right combination of ISO, shutter speed, aperture, focal length to capture the feeling or detail in an effective manner. That comes with experience, as others have already noted.

 

[km78]

Thank you all for the suggestions. They really do help a lot!

 

[KmH]

Some Nikon DSLR's have a base ISO of 100, so use the base ISO of whichever Nikon DSLR you have.

 

[jwbryson1]

Watch this:

 

[Light Guru]

See if your camera has a Depth of Field Preview button, that will give you a decent idea of how things will turn out. Not sure if you're only talking about manual mode, but do check out the aperture priority setting, where you can lock the f-stop and the camera will automatically set the shutter speed to get the right exposure. Also, be sure to shoot in RAW: these days you can recover a surprising amount of detail following exposure errors (e.g., in Adobe Camera Raw), especially at lower ISO.

Aperture is only one thing that effects exposure. You really need to understand the whole exposure triangle. Only learning what the aperture does is like learning to drive and only learning how to use the gas pedal.

Sorry, what's your point? And I'm not being sarcastic, I really am curious. Was there something wrong in what I said? Or did you intend your response to the OP?

My point is that the original post wants to understand exposure. Setting a camera on aperture priority does not teach anyone about exposure. Yes the aperture effects the exposure but there is MUCH more to exposure then just aperture. Just like there is is more to driving then then gas pedal.