a1 Photo Tips

Today, I feel like musing a bit about how you can control the appearance of your subjects by how you choose some basic camera settings.

See the picture here, of the young woman? Notice how large her head appears to be, relative to the rest of her body! This is what happens when you use a wide-angle setting on your digicam. In this case, the effect was used very effectively to convey a sense of “being close”.

This is the advantage of using a wide-angle setting when taking pictures: to fill the frame with the subject of interest, you have to take the camera really close! Which is also obvious when you see the result - you feel it when looking at a picture like this one.

Here are some pictures I made today of candles and the banister of a staircase, to show the different effects of wide-angle (short focal length) compared to telephoto (long focal length). First, I put my digicam on a wide-angle setting. Now notice how large the distance appears to be, between the two candles! Also note what a large area of the back wall is visible in the images.

I also tried to show the difference in depth of field between a large aperture (f=2.5) and a rather small one (f=8.0). In both cases, I focused the camera on the nearest candle. Well, you can see that the background is sharper at the smaller aperture, but the difference doesn’t appear that great here.

That is partly because f=8.0 isn’t a really small aperture - but it’s the smallest I have on my Canon Powershot digicam. More advanced cameras come with aperture settings down to maybe f=22.

How come smaller apertures have higher numbers? It is because the numbers are actually fractions, like: 1/2.8 … 1/4.0 … 1/5.6 … and so on; so they really DO get smaller! But for convenience, they are always shown in the simplified form like: 2.8 … 4.0 … 5.6 … and so forth, omitting the “1/” part. More advanced cameras have these f-numbers engraved on the lens barrel, and imagine having to include all those “1/”:s… It would get kind of redundant.

Same thing with shutter speed settings, by the way - and for the same reason. They are usually shown as, for instance, “250″ rather than “1/250″ - to mean “1/250 of a second”.

OK, now the telephoto version of the candles on the banister:

Here I needed to take the camera further away from the subject than in the wide-angle shots above, to make the nearest candle fill the frame just right. As a result, the perspective is changed, plus the distance between the candles appears shorter now. And note how you now see a much smaller area of the wall in the back - because the moderate telephoto setting enlarged it.

This compressed perspective - which is partially caused by the greater distance to the subject - makes the image look more flat. You actually feel that the camera wasn’t as close to the subject (the nearest candle) as in the wide-angle shots. On the other hand, the background is now more manageable - there is less of it showing up, which is often an advantage.

And now what about the depth of field again? Well, there seems to be a really noticeable difference now; the picture shot at f=2.8 shows a much more blurry background than the other - proving that “telephoto lenses give a shorter depth of field than wide-angle lenses”, which you are told on the first page of every book about Photography.

(I could complicate things by taking that statement apart, but I won’t do that here.)

So what did we learn in School today? Well, for instance we learned about the Aperture scale, that it is actually a scale of fractions:

Also, we learned that wide-angle and telephoto settings give huge differences in how a subject is rendered. Wide-angle is useful to show we are CLOSE to a subject, while telephoto settings make it easier to isolate a subject by cropping a distracting background.