Use of a Light meter

Why Use A Light Meter

For general, standard photography such as quick snaps of the kids, a day at the beach, and even sports photography, a light meter would be difficult to use because of the high speed pace, there wouldn’t be much time to meter before taking a shot. You’ll end up missing more shots than it’s worth.

So where do light meters shine? Portraits, mainly. We at Bui Photography shoot a lot of our portraits outdoors and with flash strobes off-camera. Because of that, it’s far easier to photograph in the Manual mode exposure because we know exactly the look and feel of what we want to achieve whereas our camera doesn’t. In case I’ve lost you, unless your camera is broken in Manual mode, there is no auto exposure metering because you have to set the shutter and aperture yourself.

So how do figure out what shutter and aperture to use in relation to the power of flash and ambient lighting? What if you want more flash power than ambient? What if you want to balance ambient and flash? Unless you can meter the scene with your eyes and translate it to a f-stop and shutter speed values, you’ll have to do what many people do: guess and chimp. By guessing, you would set your shutter speed to your max sync speed (1/250 on a  HYPERLINK "http://www.bhphotovideo.com/c/product/518204-REG/Canon_2011B002_EOS_1Ds_Mark_III_SLR.html/BI/2448/KBID/3281" Canon EOS 1Ds Mark III, 1/200 on a  HYPERLINK "http://www.bhphotovideo.com/c/product/583987-REG/Canon_2764B004_EOS_5D_Mark_II.html/BI/2448/KBID/3281" Canon EOS 5D Mark II) and set your flash power to half or quarter power for faster recycle times and guess an aperture of f/5.6 or something and take a shot. Then you review on your LCD to see if it looks good or not. Repeat and make the changes as necessary. Terribly inefficient wouldn’t you agree? And even if you think you nailed the exposure, wait until you extract those images on your computer, you’ll find you were still off. Look how much time you are wasting on the technical aspect in setup and post processing! I don’t know about you, but I rather be spending time being creative. Also keep in mind, unless you are using one the new fancy cameras with their high resolution (920,000 pixels) LCD screens, the LCD screens on your camera are not good tools to judge color or exposure because it’s not accurate! You can use the brightness histogram which will be a bit more accurate, but in certain lighting conditions, it won’t help you much.

This is where the light meter comes in to ensure that you don’t just have good exposure or close to perfect exposure, but perfect exposure. After you’ve properly calibrated and learned to use a light meter, you’ll find that you’ll trust the values from your light meter more than what you see on your camera’s LCD. When I use the light meter, I put my model where I want her to be, put a strobe based on how I want to light her, pull out my meter and set it to my max sync speed and ISO  and do a test pop and it tells me the exact aperture and how much flash power versus ambient. I can either bring my light source closer to the subject or dial up the flash power to get less ambient lighting or lower my flash power for more ambient lighting. Set those values in camera and start the creative process!

By getting perfect exposure and  HYPERLINK "http://blog.buiphotography.com/2009/05/white-balance-woes-in-the-workflow/" setting custom white balance, everything is properly exposed and the colors just pop. Not only that, when I extract the images, instead of wasting time correcting color and white balance issues, I’m spending time selecting keepers and cropping.

You’re probably wondering why a light meter is more accurate than the camera’s built-in exposure meter, the answer is simple. The camera’s built-in meter works off reflective metering which functions with the camera metering light reflecting off the subject. This works well for the most part, but in situations where lighting is all over the place, the camera can be tricked and meters off the brightest part and under-exposes the entire scene. In a case of a forest with some light beams coming through, the camera might be confused with the light beams and try to expose for it which would make the entire scene under-exposed. With a light meter, usually used as an incident meter (you can get light meters that are incident meters with reflective meters built in) which measures light directly as it would fall on the subject and gives you a very accurate metering of the scene. In addition, you can move the light meter to meter multiple sources an average all the readings for a proper exposure. An example would be a portrait shot where you have your key light, hair light, and fill light. Each of the light sources are pointing in various directions and with a light meter you can read the output of each light.

Light meters also work extremely well for ambient metering for the very same reason. Even if you’re not using strobes and shooting only with ambient lighting, you can meter your subject and dial in a precise aperture/shutter values to get perfect exposure.

Which Light Meter Should I Buy?

For the most part, any light meter will work plenty fine. I personally use a  HYPERLINK "http://www.bhphotovideo.com/c/product/221078-REG/Sekonic_401_358_L_358_Flash_Master_Meter.html/BI/2448/KBID/3281" Sekonic L-358 with  HYPERLINK "http://www.bhphotovideo.com/c/product/221079-REG/Sekonic_401_621_Digital_Radio_Transmitter_Module.html/BI/2448/KBID/3281" RT-32 remote trigger module because we are heavily invested in the PocketWizard system and the L-358 lets us remotely trigger the strobes when we press the measure button. If you don’t use PocketWizard, but some other wireless trigger technology, you could still use the L-358 and just not buy the optional remote trigger module and trigger the strobes manually. The second biggest reason I like the L-358 is because it tells you how much flash power is being used versus ambient. This is a real plus because you don’t have to guess at values if you want more ambient than flash or more flash than ambient; a very powerful tool that I use very often.

One of our other staff photographers uses a  HYPERLINK "http://www.bhphotovideo.com/c/product/361574-REG/Gossen_GO_4033_Digipro_F_Flash.html/BI/2448/KBID/3281" Gossen DigiPro F and likes it for it’s slim profile and no-nonsense use. You can’t really go wrong with either Sekonic or Gossen. It really comes down to what your needs are and which light meter offers what you need.

Conclusion

Getting perfect exposure doesn’t have to be difficult or pain-staking. It doesn’t have to even be done in Photoshop or Lightroom. It’s much faster and less destructive to get the exposure at the time you take the image as opposed to fixing it later. One of the best investments in this area is a light meter, whether it is a Sekonic or Gossen, you don’t need a $600 light meter. The entry level Sekonic or Gossen do more than plenty for many people and saves you time and saves your sanity, it more than pays for itself. Be on a look out for how to use a light meter 

Lesson learnt

After using the light meter for the studio shots, I have taken these readings as a starting point to achieve the effects that I want to create. After listening to Mr Steve's advice and watching how the reading s are used and interpreted, there should be no excuse for not getting the image that I wish to project.