Experimenting today, I noticed a few things relating to exposure, shutter speed, ISO

snapsnap1973 · Apr 13, 2013

Hi.

I was inside today under incandescent lights and was fooling around with my Sony Cybershot DSC-H20 (not the best camera, but I'll be getting a better one soon). I'm new to photography and really know very little.

Anyways, I noticed a few things while "fooling around".

1. I noticed that my lcd screen gets lighter and darker depending on what I set my shutter speed or f-stop to. Depending on my camera's zoom, I only can choose between two f-stops anyway. For example at full wide I can only choose either F8 or F3.5 I think.

2. I noticed that as I set the ISO number higher (3200 is max for my camera) that my screen gets lighter and I can select a higher shutter speed.

3. Why can't I set a shutter speed like "2000" indoors without getting a black screen?

4. Is the screen getting lighter or darker a "direct" result of the sensor or is it merely a "graphical" representation of what the picture would look like if I were to shoot as those particular settings?

As an example I did:

I set ISO to 400 indoors under incandescent lighting.
I selected F3.5 fstop
I had to put shutter speed at "20" to get 0EV.

I've got a couple questions:

1. What would be the advantage of selecting "F8" instead of F3.5 in the above case?

2. I'm assuming that "20" means 1/20th of a second. If I were to want to film "fast action" and wanted to say set my camera to "2000" shutter speed, would I consequently have to bring up the ISO to get enough light indoors?

SCraig · Apr 13, 2013

You need to learn the basics of exposure and how aperture, shutter speed, and ISO relate to each other. All your questions will then be answered. Try These Tutorials.

Generally speaking, every situation has exactly one proper exposure. No more, no less. That exposure is achieved with a proper balance of aperture, shutter speed, and ISO and they MUST be balanced. You cannot change one without a corresponding change on one of the others. If you increase the shutter speed then it will stay open for a shorter amount of time so you must open the aperture to allow more light in or increase the ISO to make the sensor more sensitive to compensate. ANYTHING you change has pros and cons, and that is what has to be learned.

Designer · Apr 13, 2013

I presume that the manufacturer assumes that if you need to set the ISO higher, you will be taking a picture of a "darker" scene, so it boosts brightness in the LCD. Along with the higher ISO, the shutter speed can be (or should be) increased. It all balances out in the "exposure triangle".

The reason you can't set a really high shutter speed indoors is because there isn't enough light (usually).

By selecting a smaller aperture (f8) (and a correspondingly higher ISO) the shutter will now go to a reasonably fast speed so you can hand-hold the camera. 1/20th of a second is too long of a shutter opening to hold by hand (usually).

To capture fast action shots indoors you will have to set the ISO higher, open the aperture more, or a combination of both, depending the light and the action. Without knowing what "fast action" you are trying to capture, I think you could try a longer shutter opening say 1/1000 or 1/500 and still be fine.

So let's say you're trying to capture someone jumping. In this case, you might want to begin with the shutter speed set at 1/1000 of a second. Set the aperture next, depending on how much of the ambient light you wish to capture, or the depth of field (how deep is in focus). Let's just say you wish to set the aperture at f8. Now you can adjust the ISO and take a test shot to see how close your adjustment is to the proper exposure. Adjust the ISO again if needed, and try again until you are satisfied with the results.

table1349 · Apr 13, 2013

Start here. It will explain it all. Digital Photography Tutorials

Then go here and practice. Canon Explains Exposure

snapsnap1973 · Apr 13, 2013

Thanks all!! So I think I'm understanding a few things already!!

1. Increasing ISO is a tradeoff because it makes the image more "grainy"? Is this because you're decreasing or increasing the sensor's sensitivity?

2. So ISO basically has to do with sensor sensitivity?

off to read some tutorials!! lol

SCraig · Apr 13, 2013

snapsnap1973 said:
Thanks all!! So I think I'm understanding a few things already!!

1. Increasing ISO is a tradeoff because it makes the image more "grainy"? Is this because you're decreasing or increasing the sensor's sensitivity?

2. So ISO basically has to do with sensor sensitivity?

off to read some tutorials!! lol

It isn't "Grain" it's "Noise". Grain is in film, noise is in digital camera sensors.

Electrical "Noise" is present in all electronic circuits, but normally at a very, very low amplitude. Imagine turning a stereo on but playing no music. With the volume low you hear nothing but if you turn the volume to maximum you start to hear a hum from the amplifier circuits. Digital camera circuits are the same. As you turn the volume up (increase the ISO) the noise that is in the circuits starts to become noticeable, only instead of hearing it with your ears you see it as colored specs and loss of resolution in your images.

KmH · Apr 13, 2013

For several reasons the rear LCD screen cannot effectively be used to evaluate exposure, unless you are looking at the histogram and not the image itself.
The rear LCD can only be used to check framing, and for checking focus by zooming onto the image.
Understanding Digital Camera Histograms: Tones and Contrast
Understanding Digital Camera Histograms: Luminosity and Color

Light Guru · Apr 13, 2013

snapsnap1973 said:
Hi.

I was inside today under incandescent lights and was fooling around with my Sony Cybershot DSC-H20 (not the best camera, but I'll be getting a better one soon). I'm new to photography and really know very little.

Anyways, I noticed a few things while "fooling around".

1. I noticed that my lcd screen gets lighter and darker depending on what I set my shutter speed or f-stop to. Depending on my camera's zoom, I only can choose between two f-stops anyway. For example at full wide I can only choose either F8 or F3.5 I think.

2. I noticed that as I set the ISO number higher (3200 is max for my camera) that my screen gets lighter and I can select a higher shutter speed.

3. Why can't I set a shutter speed like "2000" indoors without getting a black screen?

4. Is the screen getting lighter or darker a "direct" result of the sensor or is it merely a "graphical" representation of what the picture would look like if I were to shoot as those particular settings?

As an example I did:

I set ISO to 400 indoors under incandescent lighting.
I selected F3.5 fstop
I had to put shutter speed at "20" to get 0EV.

I've got a couple questions:

1. What would be the advantage of selecting "F8" instead of F3.5 in the above case?

2. I'm assuming that "20" means 1/20th of a second. If I were to want to film "fast action" and wanted to say set my camera to "2000" shutter speed, would I consequently have to bring up the ISO to get enough light indoors?