still confused by F-stops

ChroniC said:
I knew that would kill this thread.
Click to expand...

lol, pretty much :p

Or from a learner's pov, instead of using aperture as a light balance. Think of it as a way to break the amount of DOF you want, put it in Av mode and shoot, play with that and see how the shutter speed changes.
 
I just call it "cool star mode".

If I want nice stars in my images, I use a big F number.
If I want blurry blobs, I use a little F number.
:)
 
I would like to echo Tysonator's post.

Thank a lot for that explantation.

As I was reading that i kept thinking "ahh I see"

untill I got to the bit about the stars, lost me there i am afraid.

now if I am reading this correctly.

with a cheaper lens that has a higher f. number (for the example here one of our lense is 4 - 5.6 think) in low light, you can compensate bu openign th shutter up more, but that of of course means more chance of some slight moevement causing blur.

A good tripod and and perhaps one of those remote shutter things should help (I am mainly photographing still pics - pottery)
 
yep, basically if you can't open up the lens (lower F number) then you will have to leave the shutter open longer to get the same amount of light in or increase the ISO (make the 'film' more sensitive). If it's pottery then yes, a tripod and a remote would be ideal.

Look in to mirror lock-up as well at some point. :)
 
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Bolerus said:
I would like to echo Tysonator's post.

Thank a lot for that explantation.

As I was reading that i kept thinking "ahh I see"

untill I got to the bit about the stars, lost me there i am afraid.

now if I am reading this correctly.

with a cheaper lens that has a higher f. number (for the example here one of our lense is 4 - 5.6 think) in low light, you can compensate bu openign th shutter up more, but that of of course means more chance of some slight moevement causing blur.

A good tripod and and perhaps one of those remote shutter things should help (I am mainly photographing still pics - pottery)
Click to expand...

OK you have that almost right. I reitarate what you said.
The price of the lenses doesnt have much to do with it, although more expensive lens are normally capable of lower F-stop numbers i.e F2 or F1.4
If per say you had this lens or any other, in a low light situation, you would set either 2 things.
If the longest exposure at lets say F5.6 gives you an under exposed dark photo then
1- longer exposure
2- Drop the F-stop down to the next stop, and use the same length of exposure time. This should in theory, double the amount the photo is exposed, which would intern brighten it.
They both achieve the same thing, but have different effects on the photo.

Also when you say opening the shutter up makes blur, no!
Opening the shutter makes more light go in, i.e. F4(big hole) lets in double the light of F5.6 or F8(smaller) thus shortening the amount the camera lens aperture is open for, so thus would create less chance of blurring.
A downside to this is that i would get less depth of field, and something i wanted my not be in focus. Thuen i need a tripod to achieve that.
But if you dont want to lower the F-stop number

Longer exposure = possible blur, infact i was taught, anything under 1/60 of a second, you need a tripod. A camera will record the slightest breathing movement anything under 1/60, and sometimes 1/60

Here is an example.
Low light - I have camera set to F11 for 1/15 of a second, and i get a nicely exposed picture but it is blurry, and i have no tripod.
(anything under 1/60th of a second blurs without tripod)
Solve this by

Drop the F-stop down to F4, thus making the aperture bigger, and more than doubling the amount of light going in.
This then makes it easier for my film to expose, so i have to cut down the exposure timing. By looking at what i had previously posted, you would see it works out to 1/125 of a second, and i wouldnt get blurring.

Lower F-stop number = shorter exposures, less blurring, larger aperture(hole), lower depth of field

Higher F-stop numbers = longer exposures, more chance of blurring, small aperture (hole), high depth of field.

Dont confuse larger apertures (hole) as being a large number.
Is this making sense
 
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we do have a tripod, and alwasy us it, but dont have a remote (yet)


I was toying with the idea of seeing if the cam has a built in timer and maybe use that,

but yeah i think i have the genral principle
 
Bolerus said:
we do have a tripod, and alwasy us it, but dont have a remote (yet)


I was toying with the idea of seeing if the cam has a built in timer and maybe use that,

but yeah i think i have the genral principle
Click to expand...

All cameras have a timer.
 
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