Grey Card as a substitute for light meter

Is there any occasion where grey card can't substitute for light meter?

ummmm.....when you mistakenly forgot your grey card at home or left it at a buddies house?

disneydork06 wrote in post #5934052
ummmm.....when you mistakenly forgot your grey card at home or left it at a buddies house?

Hmm, forgotten to bring a lighter gadget but did bring a heavier light meter

Guys, serious in any lighting situation whereby lightmeter work better than grey card ?

A gray card, by itself, cannot measure light levels. You need a meter to measure the light reflecting off a gray card.

If your question is really whether or not a handheld meter is better than your camera's meter plus a gray card, the answer is that the handheld meter (assuming it has the ability to measure light in an incident mode - typically using a white hemisphere) is far simpler and faster to use but probably no more "accurate". Technique, of course, is an important factor.

It depends on your gray card and how mid-tone it really is, etc.

I use one of these...

http://www.photovision​video.com …_Code=P&Categor​y_Code=DCT

Which gives me shadow, midtone and highlight. I shoot it, look at the histogram, and adjust exposure if needed to get the three peaks biased to their proper expected alignment..... and as an added bonus i can use it for custom white balance as well.

That Photovision dark/medium/light card is interesting
because of the three spikes it puts into the histogram
to give clear markers of important luminosity values.
Don't know if its worth $60, but thought provoking.
Thanks for the tip.

Grey card cannot substitute for a light meter because grey card is used to correctly color balance the picture and a light meter is used to correctly balance the exposure.

Those two used together will assure great results as far as color and exposure balance.

tmcman wrote in post #5935844
That Photovision dark/medium/light card is interesting
because of the three spikes it puts into the histogram
to give clear markers of important luminosity values.
Don't know if its worth $60, but thought provoking.
Thanks for the tip.

It's paid for itself many times over with what it's done to help with my exposure and with my white balance... and it's easy to use and one less device that requires batteries

Discov3ry wrote in post #5936073
Grey card cannot substitute for a light meter because grey card is used to correctly color balance the picture and a light meter is used to correctly balance the exposure.

Those two used together will assure great results as far as color and exposure balance.

If you shoot a true mid-tone gray card as most of the frame you should be able to see in the histogram a 'spike' that represents the mass gray area and this spike should be centered in the histogram. This is how you can use it as a 'meter'. So the Photovision target simply adds the white and black to the equation so now you get three spikes to align which makes it that much easier.

How do you use a grey card?? and where can you get one?

Kimberwhip wrote in post #6111507
How do you use a grey card?? and where can you get one?

Gray card can be used to properly set both the exposure and the white balance..

Place the gray card in some place that has the same light as the subject.
Try to avoid any reflections; placing the gray card at an angle usually solves that problem.
Make sure to fill at least the central part of the viewfinder and take a shot.

Use that shot to set custom white balance in your camera (consult your camera instruction manual if you don’t know how to do that).
Use the same aperture/shutter speed/ISO that was used for the gray card shot to set the correct exposure.

You can find some kind of gray cards in every decent camera store.
I have the smallest WhiBal gray card and I like it..

http://www.rawworkflow​.com/products/whibal/i​ndex.html

wrap a bit of white paper on the end of your grey card...

shoot at the grey card and the white part...

you should have two spikes in the histogram... the mid tone and the highlight...

adjust shutter, aperture or ISO to get the further right spike to shift as close to the right end as possible.

It's not perfect but it's saved me on numerous occasions.

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Thanks!