Camera modes
Camera modes are settings that allow you to set a setting which parameters you want to use
Program
It is an auto mode. Camera decides what should be the speed and aperture for the scene. It will allow you to change both by using a wheel and when you will close the aperture, the speed will lengthen and vice versa. Some cameras change aperture, some change speed and it depends on the brand.
Aperture Priority
It is a mode that controls aperture and shutter speed is adjusted accordingly. When exposure compensation is used, your camera will only modify shutter speed and aperture will stay at whatever you’ve chosen. This is the mode that is used by photographers the most.
Speed Priority
Speed priority lets you control the shutter speed of the camera and changes aperture for you. This mode is mostly used when you care about the speed the most. It is useful for sport of wildlife photography where you want to freeze the action. There’s only one downside and it is that the depth of field will not be consistent.
Manual
In this mode, you can control aperture and shutter speed by yourself. it is useful where you want to take your time while taking photo or you don’t trust the light meter. This probably is the least useful mode from all three
Highlights
- Program is a sort of “Auto” of exposure modes. The camera picks the aperture and speed it thinks are best suited to the scene, depending on a variety of parameters (for instance, it will usually try to use a safe handheld speed). You still have control, as you can change the picked couple with a turn of the control wheel. If you close the aperture, speed will lengthen, and vice versa. Whether the camera changes aperture or shutter speed when you use the exposure compensation button is up to internal algorithms. (View Highlight)
- Program is a pretty good mode that should be preferred to scene modes if you are still afraid to go into the more manual modes. You don’t have complete control, but at least you know exactly what is going on. It is also a good mode to use when you know you’ll only have a split second to take a shot and want to have sane parameters without having to touch anything. (View Highlight)
- Aperture priority is the default mode of most serious photographers (i.e. they use the other ones only when they have a good reason to). You control the aperture, and the camera takes care of the shutter speed. When you use exposure compensation, the camera will only modify shutter speed, leaving aperture to whatever you have chosen. (View Highlight)
- Speed priority is a bit more specialized. It is the exact opposite of Aperture priority: you choose the speed and the camera deals with the aperture. It is useful mostly when you need a specific speed to get the effect you are after. Sport and wildlife photographers in particular use S mode often, as they will need very high speeds (often 1/1000 or more) to properly freeze the action. The big downside of using S mode is that depth of field will potentially be all over the place. (View Highlight)
- Manual mode is possibly the least useful mode of all (though many consider it the purest). You get to fix both aperture and shutter speed yourself, with no help from the camera other than a mention of how off it thinks you are (usually via a set of bars in the viewfinder). This is useful mostly when you don’t trust the light meter for some reason. It is often possible to use exposure lock (the AE-L button) instead of going to manual. (View Highlight)