Question:

I had a question about the 1st assignment. You have provided us with a table to set our cameras for the correct exposure in direct sunlight.

Exposure settings for direct sunlight
ISO	Shutter Speed	Aperture Setting
100	1/125	f16
200	1/250	f16

Does this mean that when we take a picture in TV, AV, or P mode, we have to alter the aperture, IOS, and shutter speeds, or do we just take the picture and record those values that the camera automatically sets for us?

And if we do not simply record the values (for aperture, shutter speed, and IOS the camera automatically sets for us in the automatic modes)…and I wanted to take pictures around 4-7 in the afternoon, would I have to calculate the correct aperture, IOS, and shutter speed to use and alter them on my camera? I read that in dark or shady circumstances, you would need to increase the values by 4-5 stops. Would I have to do that f I am shooting in mid-afternoon/ shady locations?

 

Answer:

Great questions.  Thanks for asking.

The exposure settings are meant to have your camera on Manual (M) mode.  This means you control the light coming into your camera with your shutter speed (how long the exposure is) and aperture settings (how big the hole is inside the lens during the exposure.)

When you shoot in Tv mode, you are controlling how long the shutter is open.  The camera will set everything else based on how much light is available

When you shoot in Av mode, you choose how wide  you want your aperture to be and the camera will set everything else.

P mode is program mode.  With Program mode, you can change the ISO and it will stay at that setting.  It will then adjust the aperture and shutter speed for you.  If you want to change one of these two two, you can and it will work to recalculate the exposure with the other.  For example: if you are using Program mode while taking pictures at an indoor birthday party you can set a high ISO so you don’t need to use the flash, and your camera will choose a combination of aperture and shutter speed to get a properly-exposed photo. You can then rotate the command dial (on some cameras it might be pressing a button) to change these values if you decide you want a wider aperture or slower shutter. Essentially your camera says “Here’s what I think will be good,” and then you take over and say “Thanks bro, I’ll take it from here” as you shift the values of your shutter and aperture using the dial on your camera.

Now, for the first assignment,  the selfie one,  you are welcome to shoot in any of the camera modes listed above.  If you want full control of your exposure though, the camera will need to be in Manual mode.  If you are shooting late afternoon or in the shade, you will need to either slow down your shutter and/or open your aperture and/or increase the ISO to compensate for the lack of lght.  Choose one and play around with it.  (I encourage experimentation.)  Then choose another an experiment with it too.  🙂

Hope this helps,

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Question:

If I have a 35mm lens with a 1.8-16 aperture and the camera has 42 megapixels, can I crop the picture in post to make it look like the 300 mm picture in the set below without “noise” so it’s in a high quality?

Thanks again,

 

Answer:

Noise is similar to static in a digital image.  It is where a pixel does not render the color correctly.  The grass is green, but the pixel will show it as gray or red or yellow…  Noise often shows when the camera’s ISO is set high to very high depending on the camera, the exposure is long (depending on the camera, think 30-seconds and longer), or the sensor is hot.

When you crop in from a 35mm shot to create one that has the same narrow viewing angle as a 300mm lens, what is happening is that you are actually ‘stretching” the pixels.  To make the math easy, let’s say you started out with a 30mm lens and cropped into the image to be 300mm.  This is ten times bigger.  If your sensor is a full 35mm sensor size, this means you have 6000 pixels across and 4000 down.  Using the example photos you provided, let’s say the barn is 300 pixels across.  This means those 300 pixels need to be displayed across 3000 pixels.  Finer details are not picked up.  As much detail as you have at 300 pixels will show up 3000, no more.

If an image is cropped too much, it starts to fall apart and looks more like Minecraft.  We call this pixelization.  Also keep in mind that if you image does have noise, the noise gets ten times bigger too.

Of course the best way to tell how far you are comfortable with cropping into a photograph is to try it.  With enough practice you will quickly learn what looks good on a standard laptop to a retina display to HD to print on glossy and matte paper.  Naturally, images that are tack-sharp and exposed well have a better chance of displaying well.  Also, keep in mind that you can manually “zoom” in most cases with your feet.  😉

Hope this is helpful,

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