We all had a discussion about a lot of things that related to Exposure. The three pillars - shutter speed, aperture and ISO were discussed. Ever thought how we could measure exposure and how can we quantify it.
Let us say if we have a scene to shoot. Now we chose a shutter speed to shoot the same. We keep an aperture that is in accordance to the shutter speed such that the scene we shoot is exposed properly. I suddenly realize that the shutter speed is to be increased for some reason and I increase it. Now we know that aperture will have to be widened here to accommodate the change in shutter speed. This is done to maintain the same luminosity of the scene.
From the above example we can say that Exposure value (EV) is a number that represents a combination of a camera's shutter speed and f-number, such that all combinations that yield the same exposure have the same EV value (for any fixed scene luminescence).
Also, we can say that to achieve the same exposure value of a scene, there can be many combinations of shutter speed and aperture. Exposure thus can be said as the combination of shutter speed and aperture. Different combinations can lead to the same EV.
EV 0 corresponds to an exposure time of 1 s and a relative aperture of f/1.0.
Exposure value also is used to indicate an interval on the photographic exposure scale, with 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a stop. There are a number of articles on the net that can give you the different combinations required for same EV.
See below the combinations.
Once we read the above chart, we know that if we want an exposure value of 14 and we select shutter speed as 1/1000 then our aperture should be f4. Nothing, difficult here, all that we have to know is what exposure value is to be chosen. Then, we can select our shutter speed and aperture based on the chart given above. There are countless articles on the net that can display this chart. Take a print and keep it in your pocket for reference.
The question that arises now is, how to choose an exposure value. Well, this is the difficult part here. You'll have to browse through a lot of tables on the internet. Follow sunny 16 rule, know about the light conditions and the subject you are shooting. There are tables for this as well on the net. Go through them and figure out what works best for you. This will surely need time, patience and skill for sure.
The table above will give you the details for selecting exposure value. There are certain conditions on which these are calculated. You'll find table like these on the net easily.
For the sake of simplicity, I'll explain that shooting a scene in heavy overcast will give you an exposure value of 12.
Referring to the table above we can deduce that if my shutter speed is 1/500 then my aperture should be f2.8.
We talked a lot about the exposure here. We devised a way for calculating the perfect exposure based on the scene we shoot. Always remember, this is a guideline and you should see if this is actually helping you to get your desired result. In most cases it should. But in cases use you knack to get the correct picture you want. We can learn a lot of stuff, but ultimately trust yourself with your instincts. There are many rules to photography which we'll eventually discuss. Learn them and follow them, but give your shot your treatment to create magic. There is a lot more to exposure than this but for know we'll close the discussion here and move ahead. We'll come back to this topic later on for sure.
Let us say if we have a scene to shoot. Now we chose a shutter speed to shoot the same. We keep an aperture that is in accordance to the shutter speed such that the scene we shoot is exposed properly. I suddenly realize that the shutter speed is to be increased for some reason and I increase it. Now we know that aperture will have to be widened here to accommodate the change in shutter speed. This is done to maintain the same luminosity of the scene.
From the above example we can say that Exposure value (EV) is a number that represents a combination of a camera's shutter speed and f-number, such that all combinations that yield the same exposure have the same EV value (for any fixed scene luminescence).
Also, we can say that to achieve the same exposure value of a scene, there can be many combinations of shutter speed and aperture. Exposure thus can be said as the combination of shutter speed and aperture. Different combinations can lead to the same EV.
EV 0 corresponds to an exposure time of 1 s and a relative aperture of f/1.0.
Exposure value also is used to indicate an interval on the photographic exposure scale, with 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a stop. There are a number of articles on the net that can give you the different combinations required for same EV.
See below the combinations.
 |
| Exposure Value Chart |
Once we read the above chart, we know that if we want an exposure value of 14 and we select shutter speed as 1/1000 then our aperture should be f4. Nothing, difficult here, all that we have to know is what exposure value is to be chosen. Then, we can select our shutter speed and aperture based on the chart given above. There are countless articles on the net that can display this chart. Take a print and keep it in your pocket for reference.
The question that arises now is, how to choose an exposure value. Well, this is the difficult part here. You'll have to browse through a lot of tables on the internet. Follow sunny 16 rule, know about the light conditions and the subject you are shooting. There are tables for this as well on the net. Go through them and figure out what works best for you. This will surely need time, patience and skill for sure.
 |
| Exposure based on conditions |
For the sake of simplicity, I'll explain that shooting a scene in heavy overcast will give you an exposure value of 12.
Referring to the table above we can deduce that if my shutter speed is 1/500 then my aperture should be f2.8.
We talked a lot about the exposure here. We devised a way for calculating the perfect exposure based on the scene we shoot. Always remember, this is a guideline and you should see if this is actually helping you to get your desired result. In most cases it should. But in cases use you knack to get the correct picture you want. We can learn a lot of stuff, but ultimately trust yourself with your instincts. There are many rules to photography which we'll eventually discuss. Learn them and follow them, but give your shot your treatment to create magic. There is a lot more to exposure than this but for know we'll close the discussion here and move ahead. We'll come back to this topic later on for sure.
No comments:
Post a Comment