help me understand spot metering, please

[jasonkt]

I'm working with a photographer who shoots fashion and beauty mostly, and on set I will take readings for his assistant with a sekonic meter. I know how to operate it and I realize that the adjustments he makes to the camera and lights relate to the f-stop the meter is reading. If it's relevant, we are using strobes, packs, and pocket wizards.

Thing is, I'm still not feeling like I understand exactly why the photographer sets his camera to the setting he comes up with. We will meter all the lights individually and adjust them (I learned why from advice on this forum), and then we'll do a general reading. I want to be able to predict what to set his camera's f-stop to, and if it is artistic license, can you explain when people might be inclined to do what?

Would a photographer ever set his camera to 8.0 after getting a reading of 8.0? How about the other range, what kind of reading/setting combination would be "just absurd"? (I'm assuming its stuff like getting a reading of 1.8 and shooting 32)

Basically, I want to learn as much as I can outside of the experience in the studio, please post links if you have 'em!

Thanks for all your help so far and for any help here, you guys are great.

 

[JerryPH]

- Understanding Exposure by Bryon Peterson

- Master Lighting Guide for Portrait Photographers

- Light: Science and Magic: An Introduction to Photographic Lighting

These 3 books have answers to all the questions you could possibly want to ask.

 

[christopher walrath]

Hi, Jason. If you know the basics of exposure then applying light meter readings is the next step. Well actually the Zone System might be the next step. We'll try to make this quick and painless.

You can control where you want which light values to fall in your negative/file. Say you meter your subject, light caucasian skin. It reads, say, EV13 which would be any combination giving equal exposure to 1/60th second at f/11. Good rendition of white skin is on exposure zone VI (6). This is one step above the middle zone V (5). Exposure zones are easy as well.

The Zone System, created by Ansel Adams and Fred Archer in 1941 provides photographers with a way to control exposure, development and printing. Whether with an analog or digital workflow, the idea applies regardless. There are grades of light measured in shades of gray from pure black to pure white, 11 zones in all. Light meters read 18% gray which is Zone V (smack dab in the middle). The lower the zone number, the less exposure given that area of the negative/file/print. The higher, the more exposure.

Back to our model. White skin looks better portrayed just above middle gray/zone V/what you light meter reads. So you place this on zone VI. By doing so you have placed a light value WHERE YOU WANT IT, not where the dummy meter told you to put it. The meter assumes that you want an average exposure to be safe so it tells you what settings to employ to attain a safe and average exposure. But if you want an area to be brighter or darker than the setting your meter told you to use will allow, you change it.

The light meter is only a starting point. The rest is up to you. For more on the Zone System, I would suggest picking up a copy of Ansel Adams' 'The Negative'. Chapter four lays it all out and makes it all very clear. The book also covers every aspect of exposure and can be easily related to digital capture as well.

 

[jasonkt]

Thanks! It's funny, every time I think I'm about to figure something out, I end up realizing how much more I need to know! I am getting new books saturday so I will take a look at all of these.

 

[MarcusM]

The lower the zone number, the less exposure given that area of the negative/file/print. The higher, the more exposure.

What a great explanation of the Zone system. I just recently started reading about this. Thanks.

The only thing I didn't understand was that you said the lower the zone #, the less exposure and the higher the #, the more exposure?

From what you said, a lower zone # is a darker shade of gray, wouldn't you want more exposure to pull out detail, and less exposure for higher zone #s to avoid blowouts?

 

[christopher walrath]

I spoke hastily and a clarification is in order. I was referring to the amount of exposure received in that portion of the neg/file/print. The darker a portion of the subject is, the less light is reflecting from it and the less amount of exposure at that area of the negative (sorry, film user, neg is just more natural for me) will receive and thus resides on a lower exposure zone. Lower zone number, less exposure RECEIVED. But thanks for calling me on it, Marcus. Did not want to mislead anyone.

Oh, and Jason, I'm the same way. Trying to figure out bonafide reciprocity adjustments needed for use with my homemade medium format pinhole camera. Try saying that fast five times. No matter how much you know, there's always more to learn.

 

[tjphotography]

Studio lights have a range of about 7 f stops.

When adjusting the light output it is usually trial and error using the light meter the first couple attempts. Remember, the correct exposure is a combination between shutter speed, ISO, and aperature.

On the light meter, the shutter speed and ISO are pre-set and thus, the reading you get is for the F-stop that will give you the correct exposure. If you are wanting a certain F stop you will either need to increase the light output or decrease it based on your first trial firing the lights.

Travis
www.tjphotography.com