Noob question, how to know what to change...


TPF Noob!
Aug 11, 2013
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So i got my self a 7100 about a week ago and i been reading a bit about all the settings here and there... So most of the settings have to do with lighting and im confused on when to change which..

I understand that aperture mode is better to use for portrait or still type pictures, and that shutter mode is for slow/fast moving picures... But Leets say i take a picture and its either to dark or to lights, i Can change my aperture, my shutter speed, my iso, my exposure compensation to help the picture get either brighter or darker, but which one do i use if i can get there in many ways?

For example if im a dark room i set my mode as aperture mode and set my aperture to full open lets say 1.8, let my shutter speed auto adjust, i take a picture and its dark, In this case i cant open my aperture no more, nor i can adjust my shutter speed, but i can change my ISO and my exposure compensation which one do i use? There are many cases like this, that i dont know whats the best way to go =) Maybe ill learn with time
You should understand that each variable has limitations and trade-offs.

For portraiture, your shutter speed (time it is open) should not be so long that you get movement in your model showing up in the photograph.

The aperture setting will affect the depth of field (depth of focus) so be aware that the more open it is, the less distance (fore and aft) will be in acceptable focus.

The ISO can go higher, but if too high, you will introduce electronic "noise" (seen as little specks) in your photograph.

So in reality, you can change all three to some degree or another and still get a good photograph, but just be aware that there are practical limits on each.
Start here, especially the "Concepts & terminology" portion. YouTube is also an excellent resource. Search terms such as "photographic exposure", "aperture priority", and "shutter priority".
Shutter speed

Those three variables are what make your exposure, nothing else. No matter the various bells and whistles and mode names those three settings are what defines and creates your exposure; no different from the film days. How you balance and weight each one depends on the mode you are using and on the effect you want as well as the lighting.

Exposure compensation has no effect on the exposure, what it does do is that in modes where the camera has a control over one or more settings (for example aperture priority where the camera has control over the shutter speed) it biases the cameras setting to over or under expose. This over or under expose is based off the meter reading that the camera gets and which it will normally attempt to zero on its meter scale. Sometimes you'll want to over or under expose and that is where exposure compensation comes in and tells the camera to over or under expose its setting based on the meter reading and the settings you've selected.

NOTE that this doesn't meant that your end photo will be under or over exposed as there are times when the cameras meter will be fooled and the cameras normal exposure will be under or over what you need. Two good examples are in strong snowy conditions where the camera meter will end up giving an underexposed photo if left to expose normally (thus you set exposure compensation to over expose); another is when shooting in strong sunlight and you might underexpose a little so that the highlights don't get blown out.

Also keep in mind that the mode won't affect the settings appearance - f8, ISO 100, 1/200sec will look the same in full auto - in manual and in all modes in-between.

The book Understanding Exposure by Bryan Peterson and the book series "The Digital Photography book by Scot Kelby" are two popular resources for beginners starting out right where you are; however nearly any good introductory book is going to cover the subject of exposure.
Adding flash is always an option if/when you're comfortable with it.
Learn the ways of shooting in manual mode my young Padawan. Use the light meter, Luke.
A few books will help give you a good grounding in this.

Pick up either Bryan Peterson's "Understanding Exposure" or the Scott Kelby "Digital Photography" series (which I think is up to four books now.)

These are intended for people just getting started.
Learn the ways of shooting in manual mode my young Padawan. Use the light meter, Luke.

Can you rely in that light meter?, like change aperture and ISO until u have it at 0? something like that?
In Manual Mode ("M"), move wheel and you will notice that the small bars will move either to the right or left of the zero point. When the bar is at zero that is the correct exposure for the aperture or the shutter speed that you have chosen. In Peterson's book that is what he continually refers to when he says he finds the "correct exposure".

In Manual Mode you can choose either a fixed number for the aperture or a fixed shutter speed. Push the +/_ button on top of the camera to switch back and forth between Ap and Shutter S to remain constant. For example, if you choose the Ap to be fixed, when you turn the dial to get the right exposure for that chosen aperture, it will be the shutter speed number that will change. The aperture remains the same that you chose.

In your situation, let's say you want the aperture set at f/4. If you are in Manual Mode and your resulting image is overexposed, you will notice that the bars on the line are to the plus side of the zero (In camera settings, you can choose to have the plus side be on the right side of the zero or the left side) When you turn the dial to get the bars to sit on the zero, notice what happens to the shutter speed. It will be changing, getting faster. If your image was underexposed, the bars would be on the negative side of zero, and the shutter speed will slow down as you turn the dial to get the lines to sit on zero.

Now, if your correct exposure is still not right for the look you want, then try changing the ISO, especially if you want a faster shutter speed for your set aperture. To see what I mean, set the camera to Manual Mode, set the aperture to f/4 with the ISO to 100. Find the "correct exposure" by getting the lines to zero and take note of the shutter speed. Now change just the ISO to say 400. Get the correct exposure again and look at what happened to the shutter speed. At ISO 400, the shutter speed that gives you the correct exposure for f/4 is faster than the shutter speed at f/4 when the ISO was 100. So, therefore, what is the correct exposure? It all depends on the look you want for you final image!

As Peterson points out in his book about understanding exposure, every image has at least 6 "correct" exposures! Speaking of Bryan Peterson, he has a book first published this year entitled, Exposure Solutions.

Books don't do it for you, then take a course for a month or two:
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On any programmed or automatic mode, changing any of the variables will have no effect. The camera will automatically adjust the exposure triangle to get the same exposure. The exposure that it will always get is the one that will render the scene a medium gray tone. It sometimes uses algorithms to appear to be more creative, but that is the principle.

The only way to influence the exposure is to apply exposure compensation or go to manual mode. OK technically there are more advanced ways but none you have to worry about now.

The D7100 is like an amateur magnet. Pretty much every amateur looking to get into photography or thinking he needs better equipment eventually sets his eyes on the D7100. If only they knew they could get better pictures for free with any camera if they understood photography. The D7100 probably does know more about photography than most of the people using it, but they don't realize that's the problem.
Can you rely in that light meter?, like change aperture and ISO until u have it at 0? something like that?
Yes, and at times you must be smarter than your camera, for example if your subject is to the far left of the frame and is standing in shade, your camera's meter wants to expose for the bright area that makes up most of the image area. The result will be an underexposed subject. In this case, meter on the subject to get the correct setting then recompose and click.

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