As the name implies, a “crop factor” is just that and only that. Nothing special – it doesn’t change what the lens is doing nor does it change the perspective or image characteristics.

On point-and-shoot cameras, the focal ranges are all over the place. My wife’s Sony Cybershot has a zoom range of 6.7mm to 20.1mm. Does that mean it only shoot ultra-wide angle shots? Absolutely not - but it would if I stuck a full frame 24mm x 36mm imaging sensor in there. It would be a simple calculation to figure out the equivalent crop factor but what good will that do? It would only tell me the exact size of the imaging sensor.

It is what it is. Mental conversion is not necessary – just understand what look you are after and what your equipment will give you. If I had a 5D, 1DmkIII, and a 40D (corresponding to 1.0x, 1.3x, and 1.6x crop factors) slung over my neck at the same time, I wouldn’t carry a chart of focal length conversions – I would just use what camera with what lens to get the image width that I was looking for. You can see that cropping the full frame 5D image down would have the same effect as using the 1.3x or 1.6x cameras. Whether the image resolution would hold up is a different matter though.


Use the metric system analogy: The US is, I believe, the last country on this planet to still not use the metric system. Why? Because I always hear people saying “How many MPH’s is that?” or “How many feet is that?”, or “How many gallons is that?”. As long as one tries to compare one convention to another, undue effort and confusion will occur.

Just adopt and use would be my philosophy :thumbsup: