cannon 400d

[ghillies 209]

look up the sunny f/16 rule..

 

apature is the depth of veiw in focus.. the smaller the hole (the higher the number) the less light gets in, so f/10 @ 1/200 of a sec, f/11 makes the apature smaller so the shutter speed goes down (slower) by one, sort of in oposites, each time the apature gets smaller by one 'step' the shutter speed has to slow by one step to get the same exsposure.

 

so ... slower the shutter speed the more blur, the higher the xzoom/magnification, the darker it is so the shutter speed has to slow to allow 'more light in'..

 

if your working in TV mode (shutter speed priority) then say your on 1/500'th of a second on a hi zoom (200mm for arguements sake) on f/ 8, if its too dark you'd have to turn the apature number down one stop (make the iris wider) to let more light in.. if it was too light tuen the f/ number up to close the whole and 'darken the picture'.

 

the iso makes the 'film' or sencer image devolope quicker.. so you could keep your faster shutter speed and the f/ number at where you want it and turn the iso up to lighten, or turn the iso down to darken, but... the image quolity suffers noise the higher the iso... the more dosh on a camera the higher the iso you can 'get away with'.. ish...

 

so, you have a shutter speed, thats the legth of time the sencers 'exsposing for' slower it is the more blur but the darker you can shoot a shot (3 minutes in pitch black sort of thing to 1/4000'th of a second or more in strong bright light).

 

the apature, the wider open (the lower the number, yes it goes the opoite way) the less is in clear focus, so f/1.8 youd have a head only in focus (for exsample) and everything else blurred out, but on f/32 the head the horozon and all the forground in focus..

but, the zoom range, and the distance change it a bit.. so at 10 feet away f/1.8 is about 3 or 4 inch in focus, at 100 feet 20 or 30 feet in focus...1000 feet three qaurters the image (or all depending on the lens) behind to the horizon and about a quarter infront of the subject in focus.... zoom in it gets a little less than zoomed out.(again depending on the lens)

 

so, besides apature and shutter speed, theres the ISO, you'll get one 'exsposure setting' say iso 100 f/8 1/200'th of a second gives a good image but its blurred.. change the iso up and it'll be something like iso 400 f/8 1/500'th.. but theres more noise on the image.(or leave it at iso 100 and turn up the shutter speed(less of a second so faster) for a slightly darker image for one stop....to a blacked out image at several stops faster........or open up the iris(apature) to let more light in, in turn the shutter speed can go a little faster, but then you lose a bit of in focus distance).

 

so three parts, you chose what you want in focus(f/) and where by focusing some where, then select a shuter speed primarily to allow the picture to look light enough (but also so its fast enough to not blur...)

the iso i chose for image quolity and suffer the loss of shutter speed, or out of desperation i turn the iso up lol.. but at the end of the day if you want a particular shot in low light and moving..iso goes up, the apature gets set wide as posable so that the shutter speed can be quicker if it's moving...........

 

three parts to jugle.. one goes up the other goes down, (iso makes everything 'faster' or slower depending on what you want) to get a happy snap shot medium lol.

 

unfortunatly the lighting type makes a difference, so you have to put the time in and see what happens so you know... unless yu just want a snap shoot then auto away and suffer it lol or pay more...

 

 

edited a couple times..oops sorry lol, dun now though.

Edited August 22, 2009 by ghillies