living and loving the life of a photographer
17/May/2007
Photo Basics: The Messenger Pitch
So there's one photo that's been getting a lot more attention than I had anticipated. I've been getting calls about it. Some time ago, a collector wanted two prints from my Sri Lanka series to adorn his living room. After a LOT of pondering, he decided to buy two of the same prints and hang them side-by-side. Strange, but who's to argue!
This photo also sparked off an online chat with a friend recently. I thought it might be worthwhile sharing a quick lesson in the basics of photography.
pixiechix21:: how did you manage to get so much light in that bus pic in sri lanka?
msram:: it's the normal lighting from inside the bus, but shot late in the evening, so slightly longer exposure... and the light on the outside of the bus is from a street lamp
pixiechix21:: aperture and shutter speed... can you explain the difference between the two?
msram:: aperture is how wide the lens opens, shutter speed is how fast it opens (and closes)... together they control how much light enters the lens
pixiechix21:: so when do you decide that aperture has to open the most or least? meaning how do you decide?
msram:: if you want one particular exposure (amount of light), you can achieve it using various combinations of aperture and shutter speed. How do you pick a combination? Changing the aperture will vary the depth of field, i.e. how much the background will be in or out of focus. Changing the shutter speed will control motion (freeze a walking person or make him blur like a ghost)
pixiechix21:: so higher the shutter speed the more frozen the person is?
msram:: yes
pixiechix21:: and how does it work with the aperture?
msram:: the lower the aperture (i.e. f/2.8 instead of f/22), the more blurred is the background... but that's only in some cases... with a wide angle lens, if rarely matters... making the shutter faster and faster, you cut down the amount of light coming in. therefore you have to make the aperture wider and wider to get a good exposure.
pixiechix21:: so tell me, if its lower aperture it really means that the aperture has not opened wide enough, correct? or is it the other way around?
msram:: f/2.8 is a "wider" aperture than f/22 because we are talking inverse fractions here... 1/2.8 > 1/22
pixiechix21:: ok, thats what i was thinking, i knew smaller looking number was greateer than the bigger looking number... and how is shutter speed measured?
msram:: seconds... 1/200s, 1/60s, 1s, 1 minute even
pixiechix21:: ok! so tell me in the bus pic, what was the combination of the aperture and shutter?
msram:: I can't remember... you see, once we shoot the pic, we just forget about it
pixiechix21:: if you were to guess, i don't want numbers
msram:: I'd guess it was in the vicinity of 1/3s... rather slow
pixiechix21:: and thats shutter i believe?
msram:: yes, and the aperture must have been f/2.8, the widest I can get to allow maximum light at that shutter speed
pixiechix21:: cool! so how've you been otherwise?
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