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Author Topic: Camera or lightmeter?  (Read 1959 times)

FunPhotons

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Camera or lightmeter?
« on: January 18, 2013, 10:05:38 AM »
Which is better for managing exposure? It seems to me that the camera is because it measures the actual light received. For example, using a light meter on a black backdrop won't tell you how to expose properly, it seems, but I'm not knowledgable on the subject.


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Camera or lightmeter?
« on: January 18, 2013, 10:05:38 AM »

STEMI_RN

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Re: Camera or lightmeter?
« Reply #1 on: January 18, 2013, 10:36:11 AM »
There's actually a great little article in the Feb 2013 Popular Photography (Pg 26, titled "Tone Dome") that talks about the benefits of using a light meter vs in camera metering.  I'll give you the gist of it.

Camera metering measures the light reflecting off of your subject.

A light meter measures the light HITTING your subject.

Therefore, the camera metering is subject to errors due to things like background, backlighting, or high contrast scenes.  So for the best exposure possible (even given in 1/10 of a stop) Use a light meter.  But for most photos, the camera metering is fine. 

It's a good 2 page article, grab it if you can.
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Re: Camera or lightmeter?
« Reply #2 on: January 18, 2013, 11:02:34 AM »
Histogram + Chimping > Lightmeter

It allows you to not only view the amount of light but how light shapes around a subject. I only used lightmeters with film and even then, I used Polaroids more. In the end, the light has to enter the lens to make a photo, why bother?

That's just me, I can't speak for others.

awinphoto

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Re: Camera or lightmeter?
« Reply #3 on: January 18, 2013, 11:54:02 AM »
Your thought of the camera and light received is slightly flawed...  Here is why... The meters, no mater which mode you have it on, is a reflective light meter...  It see's what hits an object, gets absorbed, and then bounces back to the camera... That's kinda why if you shoot a dark object in a dark environment, the camera may over expose or if your shooting someone skiing or a wolf in the snow, the camera may under expose...  This is why exposure compensation becomes relevant... the camera (and the reflective meter) gets tricked and you need to, at times, overcompensate or out-think the situation. 

A good light meter, should have what's called an incident light meter setting.  That's basically recording the actual light falling on your subject.  It's not as convenient... you have to meter your subject at your subject pointed in the direction of your camera, but you can almost pretty much treat that reading as gold.  Also on some meters you can retract the dome (incident light meter) to pinpoint light sources if you want to section off what light is and how that will affect your photo.  If you have strobes you can pinpoint the light from each strobe, determine to a 1/10th of a stop what ratio you want, and what the overall exposure is...  Yes, you may have to slow down to think through what your doing, why your doing it, and become a smarter photographer, but it is what it is. 
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Re: Camera or lightmeter?
« Reply #4 on: January 18, 2013, 12:03:04 PM »
I understand how a light meter works, I had an old minolta meter that was ok when I shot my TLR. I understand meters go for 18% grey and compensate.

It's a waste of time for me shooting digital, and so-so when I'd use polariod backs on my 501CM.

awinphoto

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Re: Camera or lightmeter?
« Reply #5 on: January 18, 2013, 12:24:11 PM »
Your thought of the camera and light received is slightly flawed...  Here is why... The meters, no mater which mode you have it on, is a reflective light meter...  It see's what hits an object, gets absorbed, and then bounces back to the camera... That's kinda why if you shoot a dark object in a dark environment, the camera may over expose or if your shooting someone skiing or a wolf in the snow, the camera may under expose...  This is why exposure compensation becomes relevant... the camera (and the reflective meter) gets tricked and you need to, at times, overcompensate or out-think the situation. 

A good light meter, should have what's called an incident light meter setting.  That's basically recording the actual light falling on your subject.  It's not as convenient... you have to meter your subject at your subject pointed in the direction of your camera, but you can almost pretty much treat that reading as gold.  Also on some meters you can retract the dome (incident light meter) to pinpoint light sources if you want to section off what light is and how that will affect your photo.  If you have strobes you can pinpoint the light from each strobe, determine to a 1/10th of a stop what ratio you want, and what the overall exposure is...  Yes, you may have to slow down to think through what your doing, why your doing it, and become a smarter photographer, but it is what it is.

The reflected light meter might not know it is shooting a black cat in a coalmine or a white cat in a snowstorm, but the assumption has to be that the photographer does. Incidence meters have such limited real world value because if you can't get to where the subject is, think sports, wildlife, landscape etc etc, then it doesn't work. Whereas looking at the histogram and playback image, and an understanding of what you are actually taking a picture of, do.

On the other hand studio shooters really still can benefit from a good flash meter to get ratios dialed in.

True enough... that's where I mentioned exposure compensation and such... When I went to school, we shot film, so every project we shot we had to turn in the negative (ISO 400), polaroid positive (ISO 125) and a Color Slide (ISO 50)... that way the teacher knew we truely did nail the shot and didn't compensate in the darkroom.  We learned to have that freaking contraption glued to our hip.  To a point, I know where my strobes are and distances and power settings so I can guesstimate pretty close what my ratios are without metering..  If i'm sitting with a commercial client, damn right, i'm taking my meter out, especially for formalities.  Also back in the film days, camera meters were crap... they were awful.  Some film cameras didn't even have meters...  Now we got 63 zone meters with the 5d3 and 7d and the rgb sensor with the 1dx... on a base point they may be more sophisticated than sekonic meters...  But, for someone new... I always recommend someone to shoot tripod and light meter... slows you down... slows your though process and allows you to properly look at a scene... anaylize the scene...  learn from the scene...  learn about composition...  and in this situation, really learn about light. 
Canon 5d III, Canon 24-105L, Canon 17-40L, Canon 70-200 F4L, Canon 100L 2.8, 430EX 2's and a lot of bumps along the road to get to where I am.

FunPhotons

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Re: Camera or lightmeter?
« Reply #6 on: January 18, 2013, 01:15:01 PM »
I'm not so sure ... one comment people make is that the camera can make bad exposure decisions due to foreground/background. That is true, but that is a mistake of the camera algorithms and hardware, not the exposure information. If the camera had enough exposure sensors and was smart enough it can make the optimal decision.

I'm still thinking the camera - ideally - has the most information. Who cares about incident? If you're photographing a black body in daylight you don't want to expose for daylight, you want to expose for black body. The camera has the advantage that it knows everything there is to know about what the sensor is going to see. In reality it doesn't use all that information (not enough exposure point) but that's beside the point.


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Re: Camera or lightmeter?
« Reply #6 on: January 18, 2013, 01:15:01 PM »

jhpeterson

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Re: Camera or lightmeter?
« Reply #7 on: January 18, 2013, 01:26:03 PM »
Interestingly, I've come back to using a hand-held meter a good bit more in the past couple years.
Since the in-camera ones have vastly improved in the last three decades or so, about when I started my career, I'd almost given up on using them for all but studio situations.
However, I've found them very helpful outdoors in checking ambient light on overcast days. Even the best cameras and metering techniques can be fooled by the relatively bright sky. My histograms have become much more consistent, which yields me quicker work flow.
I highly recommend that anytime you question the reading your camera gives you, pull out that hand-held meter. It may not work all the time, like when you and the subject are in different light, but in most cases it will give you more confidence in your settings.
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awinphoto

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Re: Camera or lightmeter?
« Reply #8 on: January 18, 2013, 01:28:54 PM »
I'm not so sure ... one comment people make is that the camera can make bad exposure decisions due to foreground/background. That is true, but that is a mistake of the camera algorithms and hardware, not the exposure information. If the camera had enough exposure sensors and was smart enough it can make the optimal decision.

I'm still thinking the camera - ideally - has the most information. Who cares about incident? If you're photographing a black body in daylight you don't want to expose for daylight, you want to expose for black body. The camera has the advantage that it knows everything there is to know about what the sensor is going to see. In reality it doesn't use all that information (not enough exposure point) but that's beside the point.

Yes and no... remember... the meters, reflective and incident, all they are looking for is 18% gray... The cameras have spot reflective, evaluative reflective, etc...  but dark on dark, light on light... the meter is still looking to make it 18% gray, no matter how you slice it... incident... the rule of thought is, if you get the correct overall exposure (incident), unless your light changes, your exposure doesn't change... You shoot something black, you want it to be black, not gray...  That's why you would want incident, not reflective, or outthink reflective and compensate...  no reflective meter is going to outthink a photographers brain so that's where the meter's incidence saves your butt.  You can trust a meter from frame to frame and hope it's getting it right, or you can get the correct overall exposure and set it and forget it, until the light changes that is.  Now-a-days, cameras are getting better, but I wouldn't say they are better than a meter or a photographers mind   
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FunPhotons

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Re: Camera or lightmeter?
« Reply #9 on: January 18, 2013, 02:16:33 PM »
I'm not so sure ... one comment people make is that the camera can make bad exposure decisions due to foreground/background. That is true, but that is a mistake of the camera algorithms and hardware, not the exposure information. If the camera had enough exposure sensors and was smart enough it can make the optimal decision.

I'm still thinking the camera - ideally - has the most information. Who cares about incident? If you're photographing a black body in daylight you don't want to expose for daylight, you want to expose for black body. The camera has the advantage that it knows everything there is to know about what the sensor is going to see. In reality it doesn't use all that information (not enough exposure point) but that's beside the point.

Yes and no... remember... the meters, reflective and incident, all they are looking for is 18% gray... The cameras have spot reflective, evaluative reflective, etc...  but dark on dark, light on light... the meter is still looking to make it 18% gray, no matter how you slice it... incident... the rule of thought is, if you get the correct overall exposure (incident), unless your light changes, your exposure doesn't change... You shoot something black, you want it to be black, not gray...  That's why you would want incident, not reflective, or outthink reflective and compensate...  no reflective meter is going to outthink a photographers brain so that's where the meter's incidence saves your butt.  You can trust a meter from frame to frame and hope it's getting it right, or you can get the correct overall exposure and set it and forget it, until the light changes that is.  Now-a-days, cameras are getting better, but I wouldn't say they are better than a meter or a photographers mind

I agree on many of your points, but we have to separate out where the best spectral information is (reflected or incident) and who makes the best decision. Ignore the latter, obviously the photographer makes the best final decision, and ignore that a light meter can check all over a scene to a higher precision than a camera. Focus on the first question, where is the best information for exposure.

My point is that a camera isn't an incident light measuring device, it's a reflected light measuring device. Therefore, the best conditions for exposure measurement are reflected, i.e. at the camera. In the real world the vagaries of your camera and exposure system may mean that a incident light meter does a better job.

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Re: Camera or lightmeter?
« Reply #9 on: January 18, 2013, 02:16:33 PM »