Hi Folks: I am taking a close up of a deep yellow flower under uniform light. Spot metering the yellow petals of the flower indicated a shutter speed 350 for a certain F stop.
I metered a grey card next to the flower under the same light and took a reading - shutter speed: 500 ( same F stop )
What settings should I use to get a better exposure of the yellow flower ? 350 ( reading from the flower ) or 500 ( reading from the grey card )
Thanks Allen
Place you camera settings on the gray card reading. Pat P.S. If you want to learn the difference do one at each setting.
Allen: Pat is right on. If you meter for the yellow petals, the meter tries to turn the flower to medium grey. That is how meters operate. They measure the amount of light needed to produce medium grey. Incidentally, an incident light meter works a lot better in a situation like this.
Regards,
Do as Pat suggested. Don't forget to calculate for bellows extension. Your 6" lens probably became a 12" to get that frame filled with flower. J
Doug: Just to check my own understanding of things: I think that metering a gray card in the subject position utilizing a relfected light meter IS taking an incident reading. No? -jb
Jeff -
How so?
Jeff,
Reflected light and incident light are two different things. Incident light is the light around you that allows you to see an object. Reflected light is the light that is reflected off an object, which may or may not be the same as incident light. For example, take two objects that are the same color, but one with a glossy or metallic finish and one with a dull or matte finish. If you did a reflected light reading on the two objects you would get two different results because the shiny object would reflect more light. The incident light reading would likely be between the two (depending on how much light was absorbed by the dull object).
Sir Ansel talks about this in The Negative in nauseating detail starting on page 10.
If you have a proper grey card, positioned in light from the same direction and of the same intensity as you measure with your meter in the incident mode, and if your meter is calibrated for that same grey (not all of them are, and even if they were, they may have drifted with time and travel) then the reflected and incident readings should agree. If you look back at the original post we're talking about a difference of about 1/3 stop here....and we don't even know if this is a color photograph.
Let's see, a third of a stop would be about right to make that flower a DEEP yellow which is what we're after. Place those petals about Zone 4 2/3 to get them deeeeeep. J
Allen: The two types are different, although both should render a medium grey card as grey. The incident meter measures the amount of light falling on the subject. In theory, a properly calibrated incident light meter (I ain't never seen one), would render the subject properly, with light tones light and dark tones dark in the prper shades dependant upon surface reflections. A reflected light meter measures the light reflected from the subject. It then meters that light to give the exposure 18%grey, or medium grey. If you meter a white wall, it will give an exposure that results in medium grey. If you meter a black wall, it will give an exposure that raises the value to a medium grey. That is the advantage of using Adam's Zone System with a reflected light meter. You can place the exposure zones where you want them and tailor the neg with more or less development, within a range of several stops. It's really less complicated than it sounds. The incident light meter is very fast to use as long as the meter is in the same light as the subject. Coupled with a bit of experience to change exposure a bit when need, it can render good results. Most movies are shot using incident light meters for color films. I didn't intend to ramble on so much.
Regards,
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