balancing aperture and shutter

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  • maiMelissa
    I spent the past two days going over some topics in David Busch's book and it has been helpful (thanks to the guys in this forum that recommended it). Can you please give me any tips about how you get to balance the aperture and shutter speed to get a picture that comes out professional and nice. I have been reading about the two and I think I understand what they do but I'm still unclear how you get them to balance and produce the best picture. Is it just a trial and error thing that you get with experience?
  • Auston
    @maiMelissa - Hi Melissa, I first want to welcome you to the forum. I hope you get a lot of helpful advice. I know it has helped refresh a lot of things in my mind. Now for your question.

    I have not read the book you spoke of, but if it only covered aperture and shutter speed it left out another very important piece of the pie, ISO. To get a understanding of what I mean think of a tripod. If you don't have all three legs it isn't going to stand! So, I will try to fill in the gap I think your getting.

    A bunch of things go into getting the professional and nice photograph you are looking for. As I am sure you read in the book, aperture refers to the size of the opening in the camera lens. The larger the number the smaller the opening, which requires more light to push through to the sensor.

    Again, as you read in the book shutter speed is the amount of time the camera/lens lets in the light to set the image. So, a slow shutter speed lets in more light (when light is low) and a faster speed lets in less light (bright light).

    Now for ISO. This refers to the sensitivity of the image sensor. In old film cameras remember the ISO100, 200, 400, ect. Well the higher the number the more the sensitivity (i.e. shooting a birthday party indoors with poor lighting you would get better images with ISO100 film. Outdoors at a track/field event with bright sun light, you could use ISO400 or 800. This would help you freeze the action. More on that later).
  • Auston
    @maiMelissa - Now, let's tie it all together. If you have an aperture of f/2.8 this means the opening in your lens is fairly large. Then if you have your shutter speed set slow like 1/100 your camera/lens is going to let in a ton of light to the image sensor and can result in a really bright image or washed out picture. But, if you are in a low light situation and the same settings as above the camera/lens could let in enough light to give everything an even cast of light that can give a good image.

    Ok, lets change something. F/2.8 with 1/1600, in bright light this will give you a sharp subject and the blured back ground that you see in alot of the pro images. Change to a setting of f/8 with 1/1600 in the same light. This will still give you a clear subject but it will also bring things in the back ground clear.

    You need to look at the lighting and think about your ISO also. By changing your ISO it will let you get more fluctuation in your aperture and shutter speeds.

    With all that said, I would like to suggest that you take your camera, put it on full auto mode (the green square) and take pictures in all kinds of lighting situations. Then, after you download them, go to your info screen and look at the settings the camera used. Take note of the lighting, what aperture, shutter speed and ISO the camera used. This will start giving you ideas on what setting to input when you make the move to shooting in the more creative setting modes. It was recommended to me and it helped me big time.

    I hope this helped some.
    Auston
  • maiMelissa
    Thank you so much for the advice. It is very very helpful.
  • PBked
    Hi Melissa,
    As always, great advice from Auston. Here is a little something you can also try. On a bright day set your camera to progam P mode. Fix your ISO at 200. Now focus on your subject. By looking in the viewfinder, or on the display screen when using live view, you will see the aperture and shutter speed the camera has chosen. Keep focused on the same subject and rotate the thumbwheel; you will see that the camera has chosen new settings and each time you rotate the thumbwheel the camera will choose newer settings. This is called program shift. What the camera is attempting to do is provide a correct exposure for the given ISO. Theoretically, each setting should give you a correct exposure, but if you had been taking pictures at each setting you would see big differences. For example, if your camera had chosen a wide aperture like f/2.8 to maintain exposure, then your background would be blurred (shallow depth of field). Equally if it chose a small aperture like f/8 or 11 then your picture would have greater depth of field.
    Knowing and having control over aperture, shutter speed and ISO is what photography is all about. As Auston said, the more you experiment, the better you will become.
    Regards,
    PBked
  • lamson
    All good info from above comments. I also found the following site excellent to get a feel for shutter speed, aperture and ISO by playing with it: http://improvephotography.com/49/photography-beginner-shutter-speed-iso-aperture/
  • woodswill
    @ Iamson, excellent information you have mentioned here.
  • carolals
    Hi, I am also starting to experiment with full manual mode, but I don't understand why when I set my aperture and shutter speed I also have to check my exposure. When I move the wheel to get it to the correct balance (middle) then my shutter speed changes, so I end up with a different shutter speed. I have a Canon EOS 60D. Thank you!
  • Auston
    @ carolals - I am starting to shoot full manual as well and have noticed the same thing. I am researching it and will post my findings.
  • PBked
    Hi carolals and Auston,
    You should always start with exposure compensation zeroed in the middle. The camera's computer can only distinguish between black and white (dark or light) and the exposure compensation is the camera's way of letting you adjust on the fly. So you set aperture and shutter speed and then decide to use +1 exposure compensaion. The onboard computer says a little more light is needed so let's open the aperture by 1 stop. The size of the aperture does not actually increase but the shutter speed has to change to match the new setting. This is where ISO plays its part because it can help you get your shutter speed back to your original setting. Hope this makes sense. Isn't photography fun?
    Regards,
    PBked

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