Light meters...

[gravity0]

I'm obviously new at photography so I'm learning that the more I get into it the more I realize there's a lot that I don't know. So my question is would I benifit from a light meter even though the camera has one built in?

thanks for your time

 

[Big Mike]

A light meter is a great tool...and you can get more accurate readings when you measure the 'indecent light' rather than the 'reflected light'. That just means that you measure the light falling on the subject, rather than the light reflecting off of it. A camera's meter is a reflected meter, so you may have to adjust the settings it gives you, depending on the reflectivity of your subject. Also, a light meter can be great for understanding lighting ratio and exposure latitude.

So would you benefit from a light meter? sure. Do you really need one? Maybe not. If you have a digital camera, you can instantly check your exposure and adjust if required. Check out THIS link.

Now, if you are shooting with manually set flashes or studio strobes...then a flash meter is a very valuable tool.

 

[tsaraleksi]

Sure you can benefit from a light meter, but you'd be much better off learning the internal meter and a lot of other things before you can benefit from an external meter. Using the histogram can get you a lot that a handheld meter used to provide when shooting film.

 

[gravity0]

A light meter is a great tool...and you can get more accurate readings when you measure the 'indecent light' rather than the 'reflected light'. That just means that you measure the light falling on the subject, rather than the light reflecting off of it. A camera's meter is a reflected meter, so you may have to adjust the settings it gives you, depending on the reflectivity of your subject. Also, a light meter can be great for understanding lighting ratio and exposure latitude.

So would you benefit from a light meter? sure. Do you really need one? Maybe not. If you have a digital camera, you can instantly check your exposure and adjust if required. Check out THIS link.

Now, if you are shooting with manually set flashes or studio strobes...then a flash meter is a very valuable tool.

Good read thanks. Now it's starting to come together a little. I'm a little confused now though. What does the histogram have to do with F-stop. I told you I was a noob.

One more thing. Does this light meter tell you what to put the camera settings on to get the best exposure? Isn't that taking the fun out of it? I find it sort of fun trying to find the exact setting for a given picture.

 

[Big Mike]

Good read thanks. Now it's starting to come together a little. I'm a little confused now though. What does the histogram have to do with F-stop. I told you I was a noob.

F-stops are the scale or measure that we use to describe the lens aperture. Most light meters will also give you readings in F-stops. The lens aperture has a direct bearing on the exposure...and the histogram is a graphical representation of your image exposure. Most digital cameras have a range of about 5 stops...so the histogram might have 5 sections. But usually when you talk about the histogram and F stops...you might say something like 'The histogram shows that you should increase the exposure, so open the aperture one F stop'.

One more thing. Does this light meter tell you what to put the camera settings on to get the best exposure? Isn't that taking the fun out of it? I find it sort of fun trying to find the exact setting for a given picture.

That's the idea . Of course, 'best exposure' is a subjective term. You are free to set the exposure to whatever you want. Where a light meter can help you here, is letting you know the difference between different areas in your scene. For example, you might have some light areas and some dark areas. If you meter them and see that they are 3 stops different...then you can assume that you might still get some detail in the shadow areas if you expose for the brighter areas. But if they are 5 stops different...then you will probably loose detail in the area that you don't expose for.

 

[gravity0]

F-stops are the scale or measure that we use to describe the lens aperture. Most light meters will also give you readings in F-stops. The lens aperture has a direct bearing on the exposure...and the histogram is a graphical representation of your image exposure. Most digital cameras have a range of about 5 stops...so the histogram might have 5 sections. But usually when you talk about the histogram and F stops...you might say something like 'The histogram shows that you should increase the exposure, so open the aperture one F stop'.


That's the idea . Of course, 'best exposure' is a subjective term. You are free to set the exposure to whatever you want. Where a light meter can help you here, is letting you know the difference between different areas in your scene. For example, you might have some light areas and some dark areas. If you meter them and see that they are 3 stops different...then you can assume that you might still get some detail in the shadow areas if you expose for the brighter areas. But if they are 5 stops different...then you will probably loose detail in the area that you don't expose for.

So, a histogramed image is showing more toward the right (over-exposure). I should highten my F-stop, bigger number. But if my histogram is showing more toward the left, that's under-exposure and should then decrease my F-stop.

Is this right??

That second part just opened my eye up a bit more about this hobby. I had no idea you would even consider the showy details. Wow, thanks again.

 

[Big Mike]

So, a histogramed image is showing more toward the right (over-exposure). I should highten my F-stop, bigger number. But if my histogram is showing more toward the left, that's under-exposure and should then decrease my F-stop.

That's the basic idea yes...if you are shooting in manual mode. If you are in any of the auto modes (aperture priority mode, for example) then changing the aperture won't change the exposure because the camera's meter will change the shutter speed to suit.

So when your histogram is showing over or under exposure, you will want to adjust your exposure...which could mean changing the aperture, the shutter speed or the ISO...or a combination of them. In the auto modes, you could adjust the EC (exposure compensation).

HERE is a good technique for using your histogram.

 

[gravity0]

That's the basic idea yes...if you are shooting in manual mode. If you are in any of the auto modes (aperture priority mode, for example) then changing the aperture won't change the exposure because the camera's meter will change the shutter speed to suit.

So when your histogram is showing over or under exposure, you will want to adjust your exposure...which could mean changing the aperture, the shutter speed or the ISO...or a combination of them. In the auto modes, you could adjust the EC (exposure compensation).

HERE is a good technique for using your histogram.

Well crap, I normally shoot in Ap priority so how would I change my exposure if needed shooting in this mode? I have a Canon 40D

I've been reading up on F-stop and the numbers are making sense now. 2*1.414=2.8 This is half an F stop and each stop is half the area of the one before it.

 

[Big Mike]

I've been reading up on F-stop and the numbers are making sense now. 2*1.414=2.8 This is half an F stop and each stop is half the area of the one before it.

Close. It's a full stop from F2 to F2.8...but yes, it's half as much light. Each time you double or half the amount of light...it's a full stop.

Well crap, I normally shoot in Ap priority so how would I change my exposure if needed shooting in this mode? I have a Canon 40D

Use EC. I think the default control for adjusting this, is just turning the thumb wheel...provided you have the on switch turned all the way on.