My Top Ten Photo Fallacies
This is my top ten list of photo fallacies. Any comments - especially learned technical ones - are welcome.
- "Fisheye lenses distort the picture." - Showing straight lines as curves must be distortion? When people talk about a long lens they say it "compresses the perspective". A fisheye being a very short lens does the opposite and expands the perspective. Dig out a fisheye picture of a building & look at it. That wall near the edge of the picture curves right over - "it must be distortion?" Now get a ruler & balance it on your cheek-bone to one side of your eye. You can see it out of the side of your eye, albeit fuzzily, and it curves. Those of us who are short-sighted can view fisheye photos from a few inches away and they do look reasonably normal from that distance. OK there is some distortion but the basic curvy straight lines are just a perspective effect.
- "Polarising filters make the sky a nice dark blue." - They do sometimes but other times they make it a dull dark grey colour. I haven't figured out a way of telling in advance, but I suspect it's something to do with different wavelengths being polarised different amounts. Take a second photo without the filter just in case.
- "Always use a skylight filter." - Used to be number one but now slipping down the charts. It's supposed to protect the lens and it does but the chance of damage is so low you are better off saving the cost of the filters (expensive at one per lens; & a decent skylight filter costs more than some lenses) against the odd repair. Meanwhile your pics will be sharper & more contrasty and you can use your single skylight filter like any other - when it will make the picture better.
- "Viewing the Sun through a telephoto lens may damage your eyes." - A newcomer to the charts but spreading through photo mags like a computer virus. The Sun doesn't know whether you're looking at it through a telephoto lens or not. It puts out the same amount of energy all the time. Your eyes can be damaged if the energy hitting them is higher than normal and there are two ways of doing this with a lens. First a large aperture which collects lots of light - but telephotos tend to have small apertures. Second and more important is concentrating the sun's energy in a smaller image area (like a magnifying glass does) - a telephoto lens does the opposite & spreads it out across the frame. By now you've figured out that the wideangle lens is the dangerous one as it makes the Sun appear as a small spot. Your eye has no nerves & so can't warn you that you're burning a hole in it. Fortunately in an SLR you're actually viewing an image on a screen; this is why "20mm blindness" isn't in the medical textbooks. But there is a risk if you have a clear prism spot in the viewfinder.
- "Use the depth of field scale to determine what will be in focus." - Things don't jump from in-focus to out-of-focus; it's a gradual change and there's only one distance in focus at a time. But there is a point where you've reached the limit of the resolution of the film, the lens, diffraction or whatever. Thus there is a range over which everything appears in focus and there is a term associated with this aptly called the "circle of confusion". Unfortunately the people who calculate the scale on your lens live in a bleary world where all is hazy, prints are postage stamp size and "sharp" is the taste of neat stop-bath. Always focus directly on your subject and this especially applies to people's eyes. If you're desperate to include things at different distances from the camera then use the lens d-o-f scale as a last resort.
- "Films have a degree of exposure latitude." - In the vast majority of situations the contrast ratio of the subject is far greater than that of the film and there is only one optimum exposure. You might get "acceptable results" (whatever that is) when you're a stop out but why not get it right in the first place?
- "Nude photography is an art form." - Oh come on. Men like looking at women with no clothes on (or whatever other combination takes your fancy). It's that simple.
- "Use an orange filter for a dramatic sunset shot." - Save your money and instead take your picture with a shorter exposure. You will get the orange effect for free, and without blodging things which are genuinely white either.
- "Brand A lens is better than brand B lens." - I have yet to see a magazine test more than one sample of each lens. So any apparent variation between brands is just as likely to be a variation between samples; there's no way of telling.
- "How to make money with your camera." - If you have to read an article about it then you just haven't got the nous to do it yourself. Sorry. Your best chance of raising cash with your camera is to sell it.