9th October 2009, 03:59 PM
i have searched on google about what is stop down 2 fstop. But too chim to understand.
for example, my 50mm lens f1.8.
2 stop down from f1.8, what is the fstop ? I seen the formula but very complicated.
anyone have a simple way to calculate ?
9th October 2009, 04:05 PM
U can try googling for it
1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22
Those are the typical 1 stop difference. Anything in between would be 1/3 or 1/2 stop difference, depending on ur camera.
1 stop difference means half the light of the previous stop. So basically, at f/1.4 you will get half the light of f/1. And at f/2, it will be half the light of f/1.4 and one quarter the light of f/1.
To ans ur qn, 2 stops below f/1.8 would be f/3.5
Last edited by yc2005; 9th October 2009 at 04:06 PM.
9th October 2009, 04:13 PM
so simply it means, if my camera is set to 1/2 stop. to get to 1 stop from the fstop, i dial 2 times, for 2 stop i just turn the dial 4 time.
1/2 + 1/2 = 1
1/2 + 1/2 + 1/2 + 1/2 = 2
am i right ?
9th October 2009, 04:20 PM
9th October 2009, 05:57 PM
9th October 2009, 06:06 PM
it is far easier to just keep working with f-stops
Originally Posted by iczboi
after a while you just get used to it, at least the part that matters to what you shoot.
for example, i am more familiar with small aperture side.. because i shoot landscapes.
9th October 2009, 07:11 PM
Actually it is very easy to remember the f numbers. Just remember 1 and 1.4. The rest are just x2 of these 2 numbers.
2, 2.8 (because 1x2=2, 1.4x2=2.8)
Each of the above is 1 stop from the next. So f/1 to f/1.4 is one stop, f/1.4 to f/2 is one stop, and so on. The bigger the number, the smaller the aperture (just take f as a constant, e.g. 1. So 1/8 is smaller then 1/11, for example). Stop down means to reduce the aperture. So stop down 2 stops means reducing 2 stops. You can easily find that out from the aperture numbers listed above.
9th October 2009, 07:18 PM
cool, this makes it clearer now...
Originally Posted by ziploc
9th October 2009, 07:23 PM