DIY Grey Cards

[clams]

So I'm finally making the jump from Av to manual and i was wondering if there were any DIY grey cards to make my transition a little easier. I know that there are a ton available at my local photo shot but I'd like to try to make one myself first.

[arkphotos]

I don't think Av-> manual will affect your white balance.
(sorry - i have no actual advise on a diy gray card)

[Tixeon]

Personally I'd invest in a good Incident hand held meter or use the Sunny 16 rule if on a tight budget. You were referring to achieving correct exposures & not white balance - right?

check out my post http://photography-on-the.net/forum/showthread.php?t=671277 for results of using the Sunny 16 rule - no meter or grey card involved............tw

[PhotosGuy]

White balance not ...balanced? What am I doing wrong? (http://photography-on-the.net/forum/showpost.php?p=6692103&postcount=14)

[number six]

Ummm, looks to me like clams is asking about exposure, not white balance. Which, of course, is the same in Av or M.

[clams]

Yeah i was referring to using the grey card to measure exposure. The exposure changes a lot in Av giving me weirdly exposed pictures when ppl with dark or light clothing pop up. I'd just like to set the exposure once for the light condition I am in and not have to worry about constantly compensating like in Av mode. The grey card I believe will help me with that. I mean, if I get really cheap, I could just meter off my hand... Personally I'd invest in a good Incident hand held meter or use the Sunny 16 rule if on a tight budget. You were referring to achieving correct exposures & not white balance - right?



That sunny sixteen rule looks interesting though. I'll try it out. My sigma 30 has f/16 as its highest aperature so I got lucky right there. But I think I'll need to just use a plain old meter if I want some shallow DOF.

[SOK]

Hi,

I was interested by your post. It's not uncommon to hear people refer to 'making the jump from AV to Manual', but they often don't relate the jump to metering rather than exposure.

I hope you don't take this the wrong way, but I've found that those who don't understand shooting in Manual mode don't actually understand shooting in AV mode either.

I'm not suggesting you don't understand exposure...but judging by your post, it sounds like you've only really starting to give some thought to metering now that you're contemplating switching to Manual mode. (Forgive me if this is not the case, just my interpretation of your OP).

The thing is, metering works exactly the same regardless of whether you shoot M, Av, Tv, P, or G (Green Box).

I'm going to go out on a limb here and suggest that you would be better served by learning about, and experimenting with your camera's internal meter than mucking around with grey cards, incident meters and Sunny16 at this stage. (I'm not saying they don't have their purpose, but personally I prefer being able to shoot without relying on any of them to get consistent exposures).

First, if you don't 'get' the concept of in-camera metering, Cambridge In Color (http://www.cambridgeincolour.com/tutorials/camera-metering.htm) has a good intro article on it, but I suggest searching Google and POTN for additional resources.

Second, experiment. Put your camera in M mode, and choose spot metering (it helps to understand what spot metering refers to...consult your manual if you don't). Start with a middle-ish grey subject (it doesn't have to be exact...just close). Centre the needle, and make an exposure. Keep the lighting and camera settings constant, and then watch how the meter responds to different subjects. Choose a variety of things (black suits, white walls, green grass, blue sky) and eventually you'll learn how to 'see' the way your camera is seeing the world. Whilst it's undoubtedly rooted in science, there is a certain art in mastering in-camera metering that can only come from experimentation.

[PhotosGuy]

Ummm, looks to me like clams is asking about exposure, not white balance. That will be the next question? ;)

OK, so, this is what I use: Need an exposure crutch? (http://photography-on-the.net/forum/showthread.php?t=89123)

Why? Post #47 (http://photography-on-the.net/forum/showpost.php?p=5191658&postcount=47)

[clams]

Hi,
The thing is, metering works exactly the same regardless of whether you shoot M, Av, Tv, P, or G (Green Box).


I think I understand that aspect of metering pretty well. Matrix metering meters the whole scene with some funky averaging formula, spot meters that 3ish percent indicated by the circle in the viewfinder, partial meters off a bigger area than spot, and center does the whole frame with emphasis on the center of the frame. It's just the fact that the meter reads the changes in the scene constantly in Av mode and Tv, therefore changing exposure values constantly due to the semi-automatic nature of those modes. I think this is mostly right? Correct me if I'm wrong.

The main reason I'm trying to switch to manual. So that regardless if ten people with white shirts pop in, the exposure value will stay constant to how the light is hitting the subject. I thought that the grey card would help me out with metering the light that hits the subjects.

That link to the exposure crutch pretty much seems like what I'm looking for though. A question about that link to the exposure crutch though. It says that I should expose to the right. I'm pretty sure that that's a technique to retain highlight (or shadow?) detail but requires post processing in ACR. True? Untrue? Sorry for all the beginner questions.

[toxic]

The main reason I'm trying to switch to manual. So that regardless if ten people with white shirts pop in, the exposure value will stay constant to how the light is hitting the subject. I thought that the grey card would help me out with metering the light that hits the subjects.

If you know the "correct" exposure settings already, there's no need for a gray card. It just lets you do it with having to take a bunch of test shots.

A question about that link to the exposure crutch though. It says that I should expose to the right. I'm pretty sure that that's a technique to retain highlight (or shadow?) detail but requires post processing in ACR. True? Untrue? Sorry for all the beginner questions.

Exposing to the right is to minimize noise and maximize the detail recorded in a scene. It can result in an overexposed-looking image.

On the Sunny-16 rule: All this means is outdoors in daylight, the "correct" exposure is about 1/ISO at f/16. If you are familiar with exposure, you should know this does not mean you must be at f/16.

[Jon Foster]

Clams, have read this book?

http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003

It's actually a pretty good read and may help you out a bit.

Jon.

[number six]

I think I understand that aspect of metering pretty well. Matrix metering meters the whole scene with some funky averaging formula, spot meters that 3ish percent indicated by the circle in the viewfinder, partial meters off a bigger area than spot, and center does the whole frame with emphasis on the center of the frame. It's just the fact that the meter reads the changes in the scene constantly in Av mode and Tv, therefore changing exposure values constantly due to the semi-automatic nature of those modes. I think this is mostly right? Correct me if I'm wrong.

The main reason I'm trying to switch to manual. So that regardless if ten people with white shirts pop in, the exposure value will stay constant to how the light is hitting the subject. I thought that the grey card would help me out with metering the light that hits the subjects.

You're exactly right. The classic case is shooting a basketball game in an evenly-lighted gym. If you use Av or Tv you'll get different exposures on the guys with the white jerseys and they guys with the dark ones.

Very strange.

In this case, once you've got a good exposure (never mind the gray card, just take some test shots), use the settings of that good exposure in M and you'll be fine.

-js

[SOK]

It's just the fact that the meter reads the changes in the scene constantly in Av mode and Tv, therefore changing exposure values constantly due to the semi-automatic nature of those modes. I think this is mostly right? Correct me if I'm wrong.

No, no - you're spot on. Apologies if my first post sounded condescending, but it was hard to gauge your understanding of metering specifically.

What I was trying to get at was; where a grey card provides a reference for you to center the metering needle on, there are usually plenty of items within real-world scene that you can use instead of a grey card.

The key difference is that in most cases, you won't want to center the needle....but you do need to know where the needle should sit.

In your example of 10 people wearing white shirts, you could meter off the shirts and expose at just under +2 stops as a starting point. Or you could use Frank's venerable hand metering trick and expose for 1+ stop as a starting point. There are 'constants' for green grass, black suits, grey pavements and blue skies....it's just a matter of learning them!

Hope this clarifies my earlier ramblings!

[tzalman]

clams >> It says that I should expose to the right. I'm pretty sure that that's a technique to retain highlight (or shadow?) detail but requires post processing in ACR. True? Untrue? Sorry for all the beginner questions.
Yes, post processing is 50% of ETTR.

[PhotosGuy]

A question about that link to the exposure crutch though. It says that I should expose to the right. I'm pretty sure that that's a technique to retain highlight (or shadow?) detail but requires post processing in ACR. True? Untrue? Sorry for all the beginner questions. I chimp flat white to the far right. Somewhere in that thread I point out the difference between that & ETTR.
Different strokes for different subjects/applications.

[clams]

No, no - you're spot on. Apologies if my first post sounded condescending, but it was hard to gauge your understanding of metering specifically.

What I was trying to get at was; where a grey card provides a reference for you to center the metering needle on, there are usually plenty of items within real-world scene that you can use instead of a grey card.

The key difference is that in most cases, you won't want to center the needle....but you do need to know where the needle should sit.

In your example of 10 people wearing white shirts, you could meter off the shirts and expose at just under +2 stops as a starting point. Or you could use Frank's venerable hand metering trick and expose for 1+ stop as a starting point. There are 'constants' for green grass, black suits, grey pavements and blue skies....it's just a matter of learning them!

Hope this clarifies my earlier ramblings!

Hmmm do you think that you could point me to some reference page with these constants? Much appreciated.

[SOK]

I hope I haven't led you astray here....

The reason I put the word constants in inverted commas is because the word is helpful - but not altogether perfect - for describing how to meter off real-world examples. It's not perfect because in the real world (particularly in nature) there are no constants when it comes to reflectivity for the purpose of metering. But there are certainly guidelines that can give us a starting point. I can't think of any sites that have a comprehensive list of such guidelines, but I think that would be slightly counterproductive anyway.

It brings me back to my original post where I suggested you experiment with your meter in your surroundings. All in-camera meters don't behave to the same tolerances, just as all 'green grass' isn't exactly the same.

Just get out, experiment, and see what the results are! Jot your findings down if you wish...it'll be better than reading someone else's!

To be sure, the technique involves a lot of experimentation and chimping, and a quite few dodgy exposures before it becomes second nature...but I still reckon it's quicker/easier than mucking around with a grey card.