Shutter, f Stop, ISO calculation.
- Thread starter Zilog
- Start date
- Messages
- 6,914
- Name
- Damien
- Edit My Images
- Yes
Hello.
I was shooting at f5.6 with a 1/200 shutter and ISO 3200. I would like to know if I was to use the same shutter speed but open the aperture up to f2.8 what could I drop the ISO down to?
Thanks
Try it and see!!
What are you shooting with those settings?
f5.6 to f 4 is one stop and to f2.8 is two stops.
So you can safely reduce the ISO by the same amount 3200 to 1600 is one stop and to ISO 800 is two.
As you increase the aperture by two stops you can reduce the ISO by two, hope that helps. Most of this photography lark is fairly simple mathematically, it has to be for me to get my head round it
So you can safely reduce the ISO by the same amount 3200 to 1600 is one stop and to ISO 800 is two.
As you increase the aperture by two stops you can reduce the ISO by two, hope that helps. Most of this photography lark is fairly simple mathematically, it has to be for me to get my head round it
- Messages
- 3,661
- Name
- Richard King
- Edit My Images
- No
in the dark or dim light/ I rarley get my cameras past 200 isoTry it and see!!
What are you shooting with those settings?
- Messages
- 4,613
- Name
- Paul
- Edit My Images
- Yes
That is a great help, thanks EJL2005 and AliB for explaining it to me
Slimbert, I am going to be photographing cyclist in low light. Last time I tried it I worked out the setting above worked fine apart from there was to much noise. This time I am taking my better lens with me and see if I can do any better.
Slimbert, I am going to be photographing cyclist in low light. Last time I tried it I worked out the setting above worked fine apart from there was to much noise. This time I am taking my better lens with me and see if I can do any better.
- Messages
- 23,200
- Name
- Richard
- Edit My Images
- No
The methematical relationship between exposure settings is mostly obvious, except when it comes to f/numbers.
Instead of the simple halving/doubling relationship that exists between shutter speeds and ISO, f/numbers run to the square root of 2, ie 1.4x approx. Therefore f/4 is double the light intensity of f/5.6 (4x1.4=5.6) and half the intensity of f/2.8 (4/1.4=2.8).
There is a logic to it, but it's obscure and not intuitive at all.
Instead of the simple halving/doubling relationship that exists between shutter speeds and ISO, f/numbers run to the square root of 2, ie 1.4x approx. Therefore f/4 is double the light intensity of f/5.6 (4x1.4=5.6) and half the intensity of f/2.8 (4/1.4=2.8).
There is a logic to it, but it's obscure and not intuitive at all.
- Messages
- 27,793
- Edit My Images
- Yes
