I actually like to use P mode for quick candid shots (where I can pick a subject and shoot… ie point and shoot). And there is plenty of good reason to be in P mode. That’s the mode of choice when you cannot control either the subject or the background.
If using a film camera the above doesn’t apply well since there will be plenty of photographs that require tweaking in Photoshop. However if using a digital camera, which most of us are using now, shooting in P mode allows for plenty of photographs to come out terriffic with just a little bit of post-processing work with Photoshop.
Since no one has posted why they don’t shoot with P so here goes a quick rundown of why to use other modes than just P. Please feel free to criticise my quick rundown as I just may end up learning something.
Tv – Controls the shutter speed only. The camera will try to choose the proper aperture for the correct exposure. I will try to explain below the word “try” as this will help explain why other like to take full control of their camera.
Av – Controls the aperture only. The camera will try to choose the proper shutter speed.
M – Allows you to control both the shutter speed and the aperture
A-Dep – (Auto Depth of Field) is a weird mode but kinda useful for those that are newer to their cameras. The camera is in Aperture Priority mode sorta but the camera selects the depth-of-field. All the blinking focus point thingies, blink to let you know what part of the picutre will be in focus.
*ISO also plays an important role, which I will explain
Why be in Tv mode? It controls the blurriness of the subject.
This allows you to set the shutter speed to capture fast-moving (sports) objects. And it allows you to perfrom the “drag the shutter” technique where you take a picture using your flash. If you don’t drag the shutter you will get an image of a person that looks like they’re in a cave and you can only see the person and not the surroundings. By dragging the shutter you allow the flash to flash and you allow a bit of extra time for the ambient (background) light to brighten up the surroundings. If you were in P mode, you’ll most likely have to settle for cavelike pictures for the rest of your photographic life.
Why be in Av mode? It controls the blurriness of the background
I believe that almost all photographers love to see a blurry background in normal lighting while the subject is in perfect focus. To get this effect you need to open your aperture wide. The wider it’s open the blurrier the background, but if you open it too wide you may be the undesired effect of having the person’s face half in-focus and half out-of-focus. Perfecting the Av mode is one of the bigger accomplishments you’ll be proud of learning as a photographer.
Why be in M mode? Well that’s just crazy talk! Controlling both the blurriness of both the background and the subject all at the same time! I use it for any posed shots where I can control both the subject and the background.
Why be in A-Dep mode? It’s a nice mode to look at, but I don’t really use it. If anyone has some situations where this mode is handy. Let me know so that I can learn something.
ISO Speed – This is the base. When you snap a picture the ISO determines the amount of light is needed to create the correct exposure. A picture is “captured light” and the ISO is the sensitivity to light. So when you set the ISO low (ie 100) it requires more light to hit the sensor for the correct exposure. When your ISO is set high (ie 800) plenty less light is needed for the correct exposure. The tradeoff is that the higher you set your ISO speed the grainier the picture.
The way that you capture the amount of light needed is either by letting in light by opening your aperture wider and keeping your shutter open longer. When you let in too much light then your pictures get “blown out” and when you don’t let in enough light you get an underexposed picture. The tricky part is getting the entire picture properly exposed (ie taking a picture of a person standing in front of a window). This is where techniques such as the “shutter drag” come in handy and/or messing with your flash output settings.
Explaining the “try” thing.
When you choose either Tv or Av you’re allowing your camera to make its own best guess as to what the other setting should be. When you take a picture the camera adjusts for the correct exposure by finding out what will make the white objects white. When there are more than one white objects, the desired white object might be underexposed because the camera exposed properly for the other white object. This results in pictures that may not have the desired blurry background or desired proper exposure of the subject if they are standing in front of a bright background. The best way to expose the whole picture properly is by using the Manual mode and having a bit of experience with what the desired aperture and shutter speed are vs. what the proper settings are. So the best explanation I can think of is that the camera is only capable of finding the proper settings and unable to find what the desired settings are.
Edited by Brian Rice on Jun 25, 2008 at 12:38 PM GMT