Canon Rebel T3i better lens for focusing entire shot?

[TheColorBug]

I have the lens that came with my T3i and while I can take some pretty nice pictures with it, I'm looking to purchase a lens where I can focus the shot in its entirety instead of just a single part of it with the background blurred. Obviously the more affordable the better, but I take excellent care of my property so if it's a bit higher-priced but well worth it, I'm all ears.

My aplogies if there are particular terms for this issue, I'm a newbie with photography!

[ScottyP]

What you seem to be describing is a desire for a large depth of field in focus. Luckily, this is something even cheap lenses can give you.

Depth of field in focus (DOF) is controlled by the size of the opening in the lens (the aperture). Lenses have an adjustable size opening, controlled by aperture blades. A lens that can open up very wide is expensive, and the wide opening gives you a shallow DOF, so your subject will be in focus but the background and foreground will be a blur.  

Any lens, though, even cheap ones, can pinch the opening down to a pinhole size (a small aperture). A small aperture gives you lots of DOF. If you want the most possible stuff in focus in your shot, from the close things all the way to the farthest thing, you want to just set a small aperture.  Oddly a small aperture is a large f/number. Put the camera in AV mode on the top dial. Set the aperture to a high f/number, like f/16 or f/22. Different lenses have different limits on the f/number. 

This, however, runs you into another issue. A tiny opening in the lens gives a lot of DOF but lets very little light in.

You would either need lots of light, or a slow shutter speed, but too slow a shutter and you get blurry images. You could raise the ISO to make the camera need less light, but that creates ugly grainy noise in the image. Basically, you will only be able to get decent photos with a tiny aperture if you have lots of light, like bright sunlight. 

Of of course you could get a tripod and then you can set as long a shutter time as you need because the camera won't shake, but you can only shoot still things (rocks, buildings, still life).  It won't work on moving things, like people, animals or even flowers blowing in the wind. 

In the end it is a compromise. You may only be able to get as narrow an aperture as, say, f/8 with the given light.  Maybe even less narrow, like f/4 or f/5.6, etc., without jacking the ISO up beyond the level at which your camera can deliver decent image quality. That is really about ISO 800, maybe a little more, max for your camera. 

[TheColorBug]

So it's more appropriate to configure my settings properly than a different lens entirely? Huh, I had no idea that was even an option. Thank you so much for your help!

[ScottyP]

There are many free short 3 minute videos on YouTube, Google Videos, etc., on the "EXPOSURE TRIANGLE"..  Watch 3 or 4 or them and this is actually very easy to get your head around. 

[Waddizzle]

Here is a useful on line tool that calculates depth of field.

http://www.dofmaster.com/doftable.html

[ScottyP]

There is also a thing called the "hyperfocal distance". This is the distance which, if you focus there, gives you the maximum possible DOF in focus.   The distance varies with the length of lens and the type of camera and (I think) the aperture. There are free hyperfocal distance calculators you can consult, but the rule of thumb is to focus on something which is 1/3 of the distance into the scene you want in focus, so the other 2/3 is behind your focus point. This is really more frequently used for landscapes than for people I think. 

[ebiggs1]

" I'm a newbie with photography!"

We all were once.  

Just remember two things low focal length numbers plus high aperture numbers equal a large depth of field. (DOF)

Example, 18mm at f8 will have more of the shot in focus than 250mm at f2.  Another factor to consider is how close or far from the main subject you are as DOF will change as distance changes.

[TTMartin]

Digital Photography 1 on 1: Episode 55: Calculating Hyperfocal Distance