Originally posted by flyer You should forget all that crap about "crop factor" and just get use to what you get with a given lens on your camera. It's a lot easier to work that way. On an APS-C sensor, the normal lens is more or less 30 mm. Anything shorter is wide, and anything longer is tele. Case solved.
Absolutely!
As a long-time 35mm film user, I spent about five minutes thinking about crop factors, when I got my K10D. Then I realized that it didn't matter. As you say, you just need to learn a couple of reference points: 30-35 is "normal", less than 30 is wide, longer than 35 is tele, greater than 200 is long tele.
The same thing happened back in the seventies, when there was a push to switch to the metric system (which has been the official standard in the US since 1870, BTW). Insurance agents and everyone else were giving away english-metric converters, instead of calendars. This led people to believe that they needed to know how to convert from miles to kilometers, or from gallons to liters. You don't. You just need to learn that the speed limit is 100kph, instead of 65mph. You need to learn that your morning commute is 32 kilometers, rather than 20 miles. Comfortable room temperature is 20C, rather than 70F. This perceived math requirement may be one reason that it never caught on.
The only time that crop factor might be an issue is if you regularly switch between 35mm film (or FF dslr) and an aps-c dslr. Even then, only the reference points change. On FF, 50mm is "normal", less than that is wide, more than that is tele.