35mm exposure help

[keith7]

i use a 300v mainly in manual. if i use a grey card in the same light as my subject does this guarantee a correct exposure. i've been told to use hand +1 or greenery -1 if no grey card. if these are correct are there exceptions to the rule in certain lighting conditions? cheers.

[Jon]

If it's in the exact same light as your subject, it assures you of a "technically correct" exposure. But it doesn't allow for high-key or low-key subjects or for mood shots. And hand+1 or grass are commonly-used substitutes. Where there's an extremely brightly-lit light subject (snow scene or beach & water for instance), you'd need to underexpose a grey card reading some to keep from blowing out the highlights. Conversely, if there's deep shade you may need to open up to get detail in the shadows.That's why the histogram's often recommended for adjusting your exposures.

[scottbergerphoto]

Your camera meter is set up to make whatever it sees, black, white and all shades in between, 18% Grey. That is called a "Normal Exposure". Test it out for yourself. Put your camera on P and fill the viewfinder with a black, then white then grey objects. They will all look grey. You need to get to a "Correct Exposure" or what the image should actually look like.
In a simplified Zone System, you use your camera on partial or spot metering to fill the partial/spot metering circle with a major tone(your reference tone) in the subject. A tone that is the most prominent or most important in the image. Take a reading in Manual Mode. Be sure to fill the partial/spot metering circle with that tone. Then adjust your Normal Reading based on the difference between the reference tone you selected and 18% Grey
Black(4.5%)- Dark Grey(9%)- 18%Grey- Light Grey(36%)- White(72%)

From the above, select the tone your reference tone is closest to. Adjust your "Normal Exposure" based on where the reference tone you selected is in relation to 18% Grey. For Black, reduce the exposure by 2 stops, Dark Grey, reduce by 1 stop, etc. In a simplified Zone System, white is two stops from 18% Grey. To get a Correct Exposure for white, you need to open up your aperture or slow your shutter speed by two stops. Each tone listed represents one stop.
The principle is that if one of the major tones in a subject is correctly exposed, the rest will all fall into line. So to get back to your original question, if you use an 18% Grey card and it is in the same light as your subject, when you meter off of it, the Normal Exposure and the Correct Exposure are the same. So as long as the Grey Card is metered correctly(fills the viewfinder or partial metering circle), the rest of your image should be correctly exposed.
For more info on metering:
http://www.kodak.com/global/en/consumer/products/techInfo/af9/

Regards,
Scott

[Sam North]

This might help with general exposure difficulties:

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EXPOSURE AND LIGHT

Camera Light Metering Systems

Modern SLRs use segment metering and the more expensive cameras use all of the metering methods listed below:

Segment: the camera calculates the best exposure based on light readings from different areas (for example, the EOS 33 and 300D each have 35 "zones".)

Partial: the meter takes a reading from about 10% of the overall image. This can be very helpful.

Spot: similar to partial, but reading taken from only a central 2 or 3% of the image area. Accurate if used properly.

Centre-weighted average: the meter takes a reading from the whole scene, but gives much more importance to the central area.

Light Metering Problems

To put it crudely, the camera's light meter mixes the subject's different light levels together to come up with an average tone. Occasionally the best of camera light meters can be 'fooled' when your overall subject is too bright or too dark. You might end up with grey coal (too much exposure) or grey snow (too little).

To overcome this problem you will need to increase or decrease exposure. This is known as exposure compensation. If your camera does not have an exposure compensation facility, you can manually change exposure by altering the shutter speed or aperture value (or changing ISO speed).

If depth of field is important, compensate by altering shutter speed. You may need a tripod if the shutter speed becomes too slow.

Note: Colour print film is not sensitive to minor exposure changes and some believe it is best to actually overexpose just about everything by 1 stop. Black and White film is best shot at the recommended reading.

Here's what you should look out for:

Dark background, mid-tone subject: underexpose, on average 1 stop (colour print film benefits very little from underexposure).

Dark background, very bright subject, (such as a swan on a dark lake): will cause underexposure if subject is prominent in frame or overexposure if scene is dominated by dark background.

Bright background, dark subject; predominantly white subject (for example, snow): overexpose 1-2 stops (perhaps even more with print film).

Accurate results are more likely in certain situations if spot or partial metering is used to meter a mid-tone or to isolate the subject from its background. Consider using a hand-held light meter or an 18% grey card.

Bracketing for Correct Exposure on Slide Film

For awkward subjects it's best to bracket your shots, especially when using slide film. (Some digital exposures may also benefit from bracketing and referring to the histogram.) Bracketing is taking a series of photographs at different aperture or shutter values, for example: -0.5, camera's suggested reading, then +0.5. Although this uses more film, you are more likely to get one slide that pleases you. Note: Bracketing is rarely necessary with print film. In difficult situations try: -1, meter reading, +1.5 or even +2.0.

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Try this too:

http://photography-on-the.net/forum/showthread.php?t=27342&highlight=


Sam

[keith7]

cheers for the replies can you just confirm what i think i know please.
(i use film so do not have a histogram just to let you know)

with centre weight in manual to gain a "technically correct exposure" you either use grey card, hand+1 green-1 or use the zone system to predict a midtone then dial in correction depending on the tone of your main subject.

if you use a grey card to obtain a reading then recompose to a subject that is black or white the exposure will be correct.(in these situations my exposure bar will typically show +2 for white after recomposing for white or -2 for black.)

i hope this is clear.
cheers

[scottbergerphoto]

cheers for the replies can you just confirm what i think i know please.
(i use film so do not have a histogram just to let you know)

with centre weight in manual to gain a "technically correct exposure" you either use grey card, hand+1 green-1 or use the zone system to predict a midtone then dial in correction depending on the tone of your main subject.

if you use a grey card to obtain a reading then recompose to a subject that is black or white the exposure will be correct.(in these situations my exposure bar will typically show +2 for white after recomposing for white or -2 for black.)

i hope this is clear.
cheers
You need to either use your meter's spotmeter function if you have one or make sure that your grey card or image tone completely fills the viewfinder or partial metering circle in Partial Metering. The rest of your statement is correct except that Kodak recommends that when using an 18% Grey Card:
1. Subjects of Normal Reflectance: Increase exposure by 1/2 stop
2. For light subjects use the Grey Card Reading, Very light subjects decrease by 1/2 stop.
3. For dark to very dark subjects increase the indicated exposure by 1-1 1/2 stops.
I believe the reason for the needed corrections when using a grey card is because todays meters are looking for closer to 12% Grey, which is less reflective then an 18% Grey card. It gets a little confusing, but 1/2 stop is easily fixed in conversion.
Regards,
Scott