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Light Metering - what do you use


Karl Janisse

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Just looking to see what tools each of you use in your metering the exposure of a scene. I currently use a combination of a Minolta MK.IV incandescent light meter and the waveform/histogram from the camera itself (in this digital age). I am looking to use a spot meter more for more accurate readings but I am wondering if I should throw some money down on a Minolta or Sekonic. Or just use the spot metering of my Canon 60d SLR instead.

 

What do you find works the best in metering a scene effectively?

 

Cheers!

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I use two light meters. One is a spot meter, Minolta Spot (no longer made...), and I predominantly use it to check contrast between objects in the scene.

 

I use a Sekonic L-308DC, an incident/reflectant meter, for general 'how much light is falling on the scene'.

 

Since I don't have a camera or monitor that has a waveform display, I have calibrated my Sekonic with an effective ISO value for a given camera ISO setting, to yield a 50% IRE level. This may be 'higher' than some people, and one may see 35-45% mentioned in other articles/threads on the subject. It is dependent on the camera and the available 'curves' or responses that the camera has.

 

In any case, matching up the meter ISO and resulting levels is required, as the 'specs' for camera manufacturers relative to ISO ratings, has some variability.

Edited by jeclark2006
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I don't know that there is a 'preference', each mode of measurement has its benefits and detractions.

 

The popluar Sekonic L-758-cine, is incident/reflectance and spot... so for one meter you have all three when needed.

 

Since I have had spot meters for years, I bought the Sekonic L-308DC for the incident and Footcandle/Lux readout. This is helpful in that most pro lights are listed in terms of footcandles/lux output at various distances, and many articles about 'how a shot was done', in magazines, journals and blogs, list things in fc/lx as well.

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I use the Sekonic L-758 Cine, and whilst it's great to have the spot and incidence meters in one, it's WAY too complex and difficult to actually use any of the million special features it has - and consequently, if you accidentally nudge it into the wrong mode, it can be a nightmare to find your way back to your basic metering mode.

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Karl,

 

One thing to watch out for when using a light meter with a DSLR for video is that the metering device (I own a Sekonic L-758) assumes that your lens has 100% optical efficiency. No lenses I know of have 100% optical efficiency. There's always some loss due to coatings and whatever... So the meter is useful for measuring T-stops, as on cinema lenses, since this takes the optical efficiency into account. F-stops are not an accurate measurement of light through the lens since it only takes mechanical dimensions of the optical system into account. What you'll find on sites like the excellent DXO Mark is that some lenses that are rated at f/2 are actually T/2.2 or T/2.3. Usually the cheaper the lens the more difference there will be between the f-stop and T-stop rating. I've run into this problem before on shoots where people showed up with a DSLR and a cheapie SLR lens. After I metered the key light the exposure was visibly off between the two same camera bodies with different lenses.

 

So if you meter a scene also know the optical efficiency (via the DXO Mark data) of the lens or use a lens that has marks in T-stops. Then you'll be better off at accurately metering light, if that's what you're really trying to achieve.

 

The article on "F-number" on Wikipedia is an excellent tutorial. Hope this helps.

 

Stuart

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illuma.blogspot.com

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