I bought a new lens for my camera!
We all know that our eyes dilate in the dark to let in more light. If you've had an eye exam, you will know that a very dilated pupil can't focus on much beyond the end of your nose. If you are nearsighted, you may have discovered that you can "sharpen" distant objects by squinting. This has the effect of making your pupils smaller.
So it is with camera lenses. We call the range in which objects will be in focus depth of field. A shallow depth of field might be a few inches on either side of the focus point. A deep depth of field might be very large. If you want a photo to have only very specific objects in focus, you need a wide lens opening. In photography, the size of the aperture (represented by f) is measured by a number. The smaller the number, the larger the hole. Go figure.
If I've confused you, or you are interested in knowing more about the subject, take a look at this article.
My new Sony camera came with a lens with an incredible zoom range. That's really useful for a lot of the tourist-class photos that I take. But if I want to focus attention on a specific object by putting everything else out of focus, I need a lens that can open much wider than my zoom, which is limited to f3.5. So I bought a non-zoom lens (called a "prime" lens) that can open to f1.8. That's a big difference. Big enough to make shallow depth of field photography possible.
Getting good results takes practice, and where better to experiment than the Desert Botanical Garden on a golden late afternoon?
