New to photography - using Aperture priority

[drest]

Am working my way through the Learning Plan and thought I would try out the CC part of this website. I am currently using the Aperture priority mode on my camera. Please feel free to make any comments/how to improve etc etc. Am new to posting photos so am hoping this works...

Thank you

http://i1081.photobucket.com/albums/j360/drest/NTPAa.jpg

http://i1081.photobucket.com/albums/j360/drest/NTPA1a.jpg[/CENTER][/LEFT]

[ricktas]

rather than us CC your efforts, as you are the one learning. Tell us what you discovered about using Aperture Priority mode, not just what setting the aperture did, but also what does it do to your shutter speed as well

It would be interesting to hear what you learned, rather than have us tell you the why and how, first. Then we can respond to what you think you have learned and add to your knowledge

[drest]

Please excuse my use of novice language :) I was using a low f number on both these shots as I was experimenting with the DOF. Given the low f number my shutter speed was not particularly fast - 1/20 and 1/30 respectively. There wasn't a lot of light as I was mostly under trees late in the afternoon, in lighter conditions I think I would have expected my shutter speed to be faster. I assume the slower shutter speed was ok for these shots due to the larger aperture? I believe the shot of the snake skin illustrates how a large aperture will create a smaller DOF - there is only a fairly small portion of the snake skin in focus and that is in the centre. I wonder if this shot would look better if the foreground was also in focus?

[iberg]

If you're letting more light in via a larger aperture setting (confusingly, a lower f-number), then you'd expect the camera to dial in a higher shutter speed while you are using Aperture priority.

In the first shot, it looks like your shutter speed may have been a little slow - it could be sharper, and that may be due to camera shake (more probable with slower shutter speeds).

There's a rule of thumb for that - 'one' over your lens focal length. Thus, using a 50 mm fl lens for eg, use a shutter speed with a minimum of 1/50th. a 100 mm fl will give you a minimum of 1/100 sec shutter speed and so on. You end up using a support (eg a tripod or even a beanbag) very quickly, once you get into longer lenses - especially without effective 'shake reduction' or whatever your own camera maker calls it.

As to foreground focus (or not) - they are some of your artistic choices. Does it work for you? Have fun and experiment! :)

[TonySlattery]

Just to confuse things a little more. The depth of field is also influenced by the focal length of the lens.

A wide angle lens has a deeper focal length than a telephoto lens, which tends to "compress" things because it brings distant objects closer.

Also the macro settings on the camera has a pronounced effect on the depth of field and the focal length and aperture setting does not seem to have much influence on the dof. Don't know why, just know that's what happens.

my 5 cents worth.

[ameerat42]

And to debunk an increasingly popular generalisation - sorry, Tony, but not you directly - focal length does NOT ALWAYS have a very direct influence on depth of field. Rather, the actual, ie physical size of the lens aperture does, and (heck!) coupled with distance to subject.

Although there are lots of (and quite abstruse) references on this, the one from Wikipedia is "fairly" digestible, although you've got to be partial to liberal servings of algebra, seasoned with some semantics. This long treatise is found here. (http://en.wikipedia.org/wiki/Depth_of_field#DOF_vs._focal_length)
Am.

[colinbm]

Thanks Am
I knew all that :o
Col

[richardb]

Check this table out (DOF calculator selectable in left column) http://www.dofmaster.com/doftable.html :D

My worry is the free roaming around snake....wooow.:eek:
:gday: