Question about Aperture (Aperture Priority Mode)

[Wizzard005]

Aloha all,

I am still learning here. I hope this doesnt come accross as a dumb question.

Anways, When shooting in Aperture Priority Mode, how do i know how much Aperture?

I assume

Bright Sunny Hawaii Day ISO 200 Should be ok?

I took like 5 pictures with different Aperture F stops and they just about look the same to me. I think the higher the number the more other things come into focus?

Anyone know of a good video that explains these settings? I want to take more pictures off of auto mode and get using the custom modes....

Anyways, thank you all for your time...!

 

[Steph]

In aperture priority mode, you choose the aperture and the camera will determine the shutter speed for correct exposure. If you change the aperture to take a picture of the same scene, the camera will change the shutter speed accordingly to keep the same exposure. So in terms of 'brightness' you won't see any difference. The only difference you are likely to see is in depth of field (the area that appears in focus in your picture). The smaller the aperture (the higher the F number) the larger the depth of field. Also if you shoot hand-held be careful when choosing your aperture. Depending on lighting coniditions, if you choose too small an aperture, the camera will choose a long shutter speed during which you won't be able to keep the camera steady and will therefore obtain a blurry picture.

 

[Overread17 5]

It depends very much what you shoot as well as what the conditions are and also what effect you want the shot to have. You are right that the greater the f number (smaller the aperture) the more depth of field you have, but this is also affected by the distance between you and the subject (as well as subject and background as well). Try looking for a depth of field calculator which should give you some idea as to how apertures work.
Past that I would say got and find a good book on a subject area of your interest (such as sports or studio) which lists settings alongside its photos - looking at how others shoot the same subjects and also as what effects they get from such settings will start to teach you the general settings for your areas of interest.
Beyond that its a case of experimentation - start making notes or writing a blog/diary where you not only look at your photos, but look at and write down the settigns *aperture, shutter speed, ISO* that you used - then critique the photo (and forum post it as well if you like) and work out where you went (if you did ) wrong.
Say you were shooting a surfer and he was all blurry - checking your settings you might find you shutter speed and assume that it is too slow for such a shot - speeding it up and trying again might give you a better, sharper shot.

 

[TamiyaGuy]

As to a tutorial video, there are probably tons, but none I know of . But I could give you an idea of which apertures to use.

A larger F-number (e.g. f/16, f/22 etc) means a smaller aperture diameter. This means less light getting onto the image sensor, which in turn means that you need a longer shutter speed to create a "correct" exposure. Likewise, a smaller f-number (e.g. f/2.8, f/4, f/5.6 etc), brings more light onto the image sensor, and can be used when you need a fast shutter speed. Be careful when using very small apertures, as you may experience camera shake at slow shutter speeds.

Aperture can also regulate depth of field (DOF), which is how much of the scene is in sharp focus. The larger the aperture (smaller f-number), the LESS depth of field, and the smaller the aperture, the larger the DOF. A smaller aperture is useful when there are subjects in the foreground & the background which you want to keep in focus, and a larger aperture is good for when you want to blur the background (or the foreground in some cases). Depth of field is not an exact science, as it changes depending on focal length, aperture, focus distance, and even photographic media. There are plenty of Depth of Field calculators out there, a quick Google search should get you something.

Just one more thing: A lens performs at its best at mid-range apertures, never at the extremes. It's only a slight difference, but if you don't are about DOF, shutter speed, and you just want to get the best quality your lens can give you, try an aperture between f/8 and f/11.


Edit: Ah, nuts. Why does someone always beat me to it???

 

[Wizzard005]

from what it sounds like, if using this mode, i should really use a tri-pod? Just wondering, if i wanted to take a picture sof a valley or something, and I wanted it to be very clear and crisp, is this mode for me? I assume yes, just at a higher number?

 

[Overread17 5]

Landscapes need a small aperture (f16+) and thus need a longer (slower) shutterspeed to get light in. Most landscape shots are also taken in the "golden hours" that is one hour before and after sunset/sunrise when light is softer - of course its also when light is weaker - hence needing longer shutter speeds still.
Now you could compensate with boosting ISO -- but then you are going to get noise into the shot - which is something you don't want. The result is that most landscape photographers shoot with a tripod - to steady the camera - they also use either a remote release or the timer function in the camera to reduce shake even more for those tack-sharp shots