I recently bought a film camera (Minolta X-700) and I wasted a whole roll because I inverted the aperture (i.e, 2 = sharp, 32 = blur)...

I'm interested to see how the roll turns out - gave it for development the other day, had a good laugh with the employees though.

I now have a mnemonic for it: Blor - a (somewhat) portmanteau of Blur and low. So low aperture = blur.

Edit for clarification: I mean low number (2 vs 32) = blur

tiagod 6 hours ago | parent | next [-]

High aperture = Blur

Unfortunately the lower number actually means bigger aperture.

And that's what exactly confused me :)

With my mnemonic, I say low *number = blur

I should have been more specific

The aperture size is usually described as e.g. f/32, where f is a camera-specific constant.

Denominator, not numerator. That's why larger number = smaller aperture.

	▲	armadsen 3 hours ago \| parent \| next [-]
		To be a little more precise, f is not a camera-specific constant. It's the focal length of the lens. It's a formula that tells you the diameter of the entrance pupil. So at a focal length of 50mm, an aperture value of f/2 means an entrance pupil diameter of 25mm. But photographers generally just say "f2", meaning an aperture value of two set on the dial of the camera/lens. It's one stop faster (twice as much light) as f/2.8. It'll give you a relatively shallow depth of field, but not as shallow as e.g. f/1.4.
	▲	2 hours ago \| parent \| prev [-]
		[deleted]

The larger the entrance pupil is, the narrower the depth of field is.

The smaller, i.e. the closest to an ideal pinhole camera, the wider the depth of field is. A an ideal pinhole camera has infinite depth of field.

Unfortunately the aperture f numbers are the wrong way round; larger numbers correspond to smaller diameters.