EV compensation and ambient meters... Help!

[monkey]

Okay, this may seem like a really stupid question... Do I need to EV

compensate when using my Sekonic 308 in ambient mode? <p>Or should it

be spot-on regardless of the lighting conditions?

[monochrome11]

i think you mean incident metering...

 

from Sekonic's site...

 

Advantages Of Incident Meters

A better alternative to reading the light in many scenes is to use an ?incident? meter. Hand-held incident meters read the intensity of light falling on the subject and are usually taken from the subject position. Because they are not affected by variances in subject color or reflectance, incident meters accurately record the amount of light falling onto the subject. In the majority of situations, an incident reading is extremely accurate and records tones, colors and values correctly.

 

Hope that helps...

[ben z]

"In the majority of situations" isn't the same as "always". I use a 308B and have used other incident meters too. If you think about it, the exposure is determined by the amount of light reaching the film. That light is what is reflected off the subject. If the subject reflects 100% of the light incident upon it, then an incident reading is accurate. If however, some of that light is _absorbed_ by the subject, then the amount of light reaching the film will be less than what was incident upon the subject. That absorption occurs to a certain extent with any subject other than a shiny one, but significantly with dark, matte subjects like clothing, wood, brick, and fur to name a few. So the traditional wisdom has always been to open up a little (I find about 1 stop usually works) from an incident reading for extremely dark subjects. With print film unless you're at the end of the underexposure range (which is where you are in my experience with today's fast film rated at their posted speed) it might not show in the print, but the phenomenon is there and I see it even in print film for that reason.

[al_kaplan1]

With very contrasty lighting you should take an incident reading with the meter pointing at the camera position, then make a reading pointing more towards the light source and another reading of the light on the darker side. Decide what's important to you. Bias your exposure to give you detail where you want it.

[ronald_moravec1]

You need very little compensation for an incident reading. If the subject is very light or dark and you do not it rendered that way, perhaps because it takes a large portion of the picture, then compensate. But the result will not be normal tones for that particular subject. All assuming shutter and meter are accurate.

[ronald_moravec1]

One more cavat, the subject you are trying to render falls on the straight line portion of the curve. You may need to move a subject off the shoulder or toe. I rarely find the need.

[douglas k.]

If you have tested your equipment (camera shutters, meters, films, processing) then you need no compensation. Such compensation as, e.g., Ben recommends above is usually needed to overcome sloppy technique in those other areas. To put it differently, the whole point of incident metering is to eliminate the need to compensate for subject reflectance: used properly, an incident meter measures light hitting the film plane, and if your shutter is accurate and you have a properly-established film speed, then simply taking a reading and setting the camera will work fine. Those who recommend "opening up" for very dark subjects and/or "closing down" for very light subjects have simply not found their appropriate film speed and processing techniques (or they drop off film at Costco and hence are trying to compensate for slipshod processing).

[ben z]

I agree that poor processing and poorly adjusted shutters and film of unknown or unpredictable speed make any kind of metering inaccurate. However a simple test of shooting 2 shots of a frame-filling non-shiny, black subject using slide film in a camera with an accurate (perhaps electronic) shutter, processed by a reputable lab: one shot at the incident meter reading, and another opened up one stop, will quickly prove whether this technique is faulty or not.

[monkey]

Thank you.