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ISO??
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How do you know you have the right ISO and F/number or is it just what each person likes them self..
Brendan,
FYI, if you’re looking for critique of the phots, you’re better off posting into the critique forums as you’ll get a better
response that way.As for ISO – well you should always try and use the lowest so that may be 100 or 200 depending on your camera.
Aperture or f-stop, well it depends on what you’re shooting and what depth of field (DOF) effect you want.
So if you’re shooting landscape you may the whole photo in focus from front to back, then you’d use say f16 or f22 for example
while focussing around a 3rd of the way into the scene.
If you’re shooting a portrait you might want to have the background out of focus and therefore would shoot more open ie a lower
aperture, say f1.8 on a 50mm lens.To add to Mark’s comment,
there is a book that many people recommend called Understanding Exposure by Bryan Peterson which explains ISO, shutter speed & F-numbers.
I think it’s a great book, but for sure all the information is out there on the web too.A bit of experimentation is always worth while, take a portrait photo of someone with very wide aperture, mid aperture and small aperture. Take photos of a stream with slow (1/15 sec), medium and fast (at least 1/200) shutter speeds and see what you get. Etc.
Martin
Im using exposure to mean a correctly recorded image film slide or digital
f stop or aperature, shutter speed and iso are all related, to give a correct exposure.
if a perfect exposure is f4 at 500 (1/500 s) and 200 iso to maintain the same ‘correct’ exposure you could use f 5.6 ( half the light reaches the film or sensor) at 250 (1/250s or twice the time) and use iso 200
now if you were to use iso 100 or iso 100 film, (‘slower’ ie less sensitive to light) to achieve the same ‘correct’ exposure you could use f4 at 500 or f5.6 at 250.
esentially increasing or decreasing a full f stop 4- 5.6 5.6-8 doubles or halves the amount of light, increasing or decreasing the shutter speed halves or doubles the amount of light, iso 100 is about half as sensitive to light as iso 200 and so on
This ignores the effect of the aperture or shutter speed on the type of picture you are taking, sports long exposure, portrait depth of field etc.
In general the lower the light the higher the iso and the bigger the aperture and slower the shutter speed you will need.
as always there are exceptions such as creative use of grain (which usually increases with iso) using lower iso settings to allow for longer ‘exposures’ in low light
ps dont take what i say as ‘gospel’ its how i undrestand the triangle
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