Use Super-Fine Large or RAW Quality

Always, always,  always! Its best to get a large CF card, and always shoot using the best quality setting your camera offers. You never know when you will take a photo that you really like, and you want enlarged.

If you start with high quality images, you can easily re-size them, and lower the quality on the computer with your image processing/image management software to create small files for emailing for to put on web sites. But if you start with a low quality image, and want an 8x10 enlargement.... its tough luck, you just can't do it.

For example - Recently my daughter, when taking snapshots, came back with a couple of images (out of about 100 she took!), that my wife really liked. She suggested we get 8x10 enlargements made and display them at our cottage. If my daughter had been using a low quality mode, we would not have been able to do this.

Distance Focusing: Using Manual Focus

(and Learning about Depth of Field)

The camera's auto-focus is good, but by no means perfect. If you know how far away your subject is, its better to use manual focus. Its simple and quick to manually focus, if you know the distance, and if you read the camera's manual and play with manually focusing for a few minutes.

But how can you possibly know the distance?! There is one obvious case... when you are shooting at "infinity". That is, when you subjects are far away.

But how far away is "infinity"? In photography, the question is not a philosophical one, but rather a matter of optics, some math and a concept called "depth of field".

Depth of Field:

In theory, when you focus a lens, then is one specific distance from the lens that is "in focus" (or perfectly sharp), and every other distance is "out of focus" (less sharp, or blurry). The greater the distance away from the "in focus" distance, the more blurry, or more out of focus objects will be.

Now imagine as we approach the perfect in-focus distance, an object will be less blurry. At some point, the amount of blurriness becomes so small as to be undetectable. (And there is a specific way that this point can be calculated).

So in practice there is a range of distances around the "in-focus" distance which appear to be perfectly focused. This is called the depth of field.

Near Focus:

The closest distance from the lens that will be in focus

Far Focus:

The farthest distance from the lens that will be in focus

Hyperfocal Distance:

Now this is cool. "The hyperfocal distance is the nearest point at which you can focus and still have objects at infinity be in focus."  Because of depth of field, there will be some distance for which the far focus point is infinity.

Aperture Affects Depth of Field:

The smaller the aperture (i.e. the larger the f-stop), the larger  will be the depth of field. "Depth of field increases as the f-stop increases".

Lens Focal Length Affects Depth of Field:

The longer the focal length (i.e. the greater the telephoto), the smaller will be the depth of field "Depth of field decreases as the lens focal length increases, for a given camera"

But what does all this mean really? I used an openly available depth of field calculator program, by Jonathan M. Sachs from Digital Light and Color to calculate the following table for the Canon PowerShot S45:

So based on the above, here are some example "rules of thumb":

• When shooting at  wide angle (a common situation when shooting landscapes), if I just set my lens to focus at 10 ft and forget about it, everything from 5 ft to infinity will always be in focus, not matter what the f-stop!
• Worst case, if I set my focus to 52 ft, everything from 23 ft to infinity will be in focus, no matter what my f-stop or focal length. (and things closer than 23 ft may be in focus, depending on the actual f-stop and focal length.)
• If I set my focus at infinity, everything from 51.7 ft out will be in focus. (and things closer than 51.7 ft may be in focus, depending on the actual f-stop and focal length.)

Bottom line... for the PowerShot S45, "infinity" is effectively around 52 ft.