So many wayward photographers, so little time. Seriously, those of us who think we can get by without a separate meter are kidding themselves. Just ask Kirk Tuck. His recent column in ProPhotoResource.com very methodically, thoroughly and understandably explains why the “no meter” concept is a myth. He goes on and tells you how to profile your camera’s light transmission and dynamic range. Want to lift your quality up to a new level? Read on.
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Full article (reprinted with permission) after the jump
by Kirk Tuck
Let’s start by admitting that not every project in the world needs the accuracy and precision of a separate light meter. And let’s go on record understanding that, while meters may be objectively accurate many times cameras and lenses, as closed loop systems, may not be quite so objectively accurate. Wouldn’t it be nice if you could take a highly accurate and ﬂexible meter and program it to “understand” the inconsistencies of your particular camera and lens system?
Let me put this in real terms. I have a Nikon D700 and I love to shoot it with my 60mm AFS lens. But, when I shoot in a way that makes stuff look good on the rear LCD it ends up being way too dark on my carefully calibrated computer system back at the studio. Bummer. That means I’ll need to use levels and curves to “pull up” the exposure to get the distribution of tones I was originally looking for when I took the shot.
Photoshop geeks may think, “no big deal.” But every time I pull those peaks and valleys in the histogram over to the right hand side of the graph I introduce the potential for banding in the lower tones and I end up shadows that lack real detail. Being a bit compulsive I’d like to start out with the right exposure. And believe me, relying on the histogram as it appears on the camera LCD is not the way to get there.
Here’s a novel assertion: The camera histogram sometimes lies! Really. Honestly. Camera manufacturers set the histogram “panic points” (blinking highlights, etc.) to trigger well before the ﬁle overloads. And there may be different set points for different ﬁle types. Finally, small bits of bright light may throw off the accuracy of the histogram at the top end of the graph. The camera’s metering and evaluation system may obsess about not allowing a specular highlight to go to 255 and, as a consequence, may underexpose a scene radically in order to preserve those bright points of useless information.
Most pros who cut their teeth on short latitude color transparency ﬁlms still carry and use incident light meters to combat the less gifted, in camera, reﬂected light metering system. But in the last few years I’ve found that there is an bizarre relationship between accurate metering and the overall “transmission value” of digital cameras and their lenses.
(Transmission value is a metric introduced by ﬁlmmakers who are obsessed by getting it right in the camera the ﬁrst time because they don’t really have the option to “ﬁx” each frame in PhotoShop(tm). Each ﬁlm camera and its attached lens is tested to determine how much light actually gets to the ﬁlm plane at each aperture. The directors of photography know that lens coatings, mechanical tolerances and more can affect the actual transmission capability of all lenses. The “t-stop” is the true value as it relates to a sensor or ﬁlm gate).
Most photographers take the f-stop information provided by the camera manufacturer at face value. Studies from the ﬁlm industry (where much more expensive and hand calibrated lenses are the norm) indicate that there can be anywhere from 1/3 of a stop to a stop and a half of leeway in most optical systems when comparing f-stops to t-stops. And the camera’s set point for white point warnings is non uniform as well.
So, rather than curse the darkness, or spend countless hours doing triage in post processing, what is the dedicated perfectionist to do? That’s precisely what Sekonic asked. And they’ve provided a viable (if time consuming) way of working all of this out. The technology comes packed into their new L-758DR Digitalmaster light meter.
This is the ﬁrst affordable light meter that can accept camera/lens proﬁles and have them available to the photographer during the actual metering process. You’ll have to read the manuals and load the software, but here, in a nutshell, is the basic process:
1. Acquire calibrated, printed chart from Sekonic (additional $169).
2. Evenly light chart with constant lights.
3. Set up shooting camera and lens.
4. Take incident meter reading from subject position and transfer the reading to the taking camera.
5. Take test photograph.
6. Download test photograph into supplied exposure processing software and process.
7. Take the proﬁle and transfer to the meter while it is attached to your computer via USB.
8. Select that proﬁle while metering for that speciﬁc camera and lens combination.
9. Enjoy highly accurate exposures calibrated for your particular capture system.
10. Eliminate several painful and destructive steps in post processing.
Could you do the same thing by shooting a subject with the meter reading and then evaluating it on your monitor? Pretty much so. But can you really keep a number of camera and lens combinations in your head and refer to them in real time? Some of you can. I can’t.
None of this would matter if the L-758DR wasn’t already a meter worth owning. But it is. I’ve owned a number of Sekonic meters and they just keep getting better and better. The L-758DR is my “go-to” ﬂash meter in the studio and my reference ambient incident light meter on all locations and I would venture to say that in the two months I’ve owned it I’ve shaved hours off the usual post production chores.
For those of you who are unfamiliar with the meter it is one of the “Swiss Army Knife” meters that provides both ambient and ﬂash readings, incident and reﬂective readings, average and spot metering. And it does all of these things with a high degree of elegance. It also comes with a built-in PocketWizard trigger. You can “test ﬂash” your lighting set up without a sync cord or a push on the ﬂash test button.
The ISO and exposure (EV) range are more expansive than even the latest cameras and the whole thing is class four splash proof. It has all the bells and whistles you would expect from a top meter and then some.
Why do I still like to take incident light meter readings on all my shoots? Here’s my favorite meter story. …… Back in the early 1990’s I spent a lot of time “street shooting” in Europe. I used two different camera systems, a Leica M4 with a 35mm Summicron and a Nikon F5 with a short zoom. The Nikon had a state of the art evaluative exposure system which even took subject color into consideration. The Leica had no built in meter so I carried a small incident light meter with me.
I shot Kodachrome 64 in both cameras. I began to notice that the exposures from the Nikon F5 were all over the place. Generally within a stop of the optimum exposure but nearly always 2/3’s of a stop over or under. That made the images harder to print and harder to sell to photo editors. The Leica was a different story. I would take an incident light meter reading and keep shooting at the same settings until the light changes. (I took readings about every ﬁfteen minutes or every time I moved into a new lighting situation). The Kodachromes from the Leica were amazingly consistent (why wouldn’t they be????) and very accurate. And here’s why: The light falling on a subject rarely changes during a shoot but reﬂective light measures much differently depending on the shade, the color and the absorbency of the subject’s surface. Just shifting a reﬂective meter by ﬁve percent was enough to change the reading. A subject with a black shirt or a white shirt was enough to throw off objective exposure accuracy by an unacceptable percentage.
My take away lesson from all of the above is: When money and time are involved in a shoot, bring along an incident light meter. Does it have to be the top of the line? Of course not. The important thing is to know the relationship between your meter and your camera system. The Sekonic L-758DR is like the icing on a cake. It’s another level of precision beyond your competitors and it will save you time.
And, it looks cool to whip out a fabulous meter and take the magic readings. That’s what photographers do in movies and that’s what clients love to see.…
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