Canon 7D and 1D MarkIV Metering?

[Julian Mole]

Hi,

After having initially learnt the very basics of exposure theory, which enabled me to go out take lots of photos and then wing it using the histogram to adjust! I am now trying to get a real grip on the whole exposure thing.

So my question is, how does the metering of these two camera models compare to the advice given by Arthur Morris for exposure compensation in Av Mode using Evaluative metering (which I have read stands true for my current camera the 40D)?

For example, the 1D MarkIII is said to need 1/3 stop more light adding than is suggested in these guidelines.

The reason I ask is that I have been trying to guess at the EC used in images on this website and in Arthur's bulletins and then reference that with what was actually used, however I have noticed that although I'm improving I am still out with some guesses and thought this could be something I need to account for.


Looking forward to your answers,

Julian.

[Mark Young]

Julian, I was almost going to post the exact same question last night.
I've just purchased a new 7D as an upgrade from my 400D, which I pick up later today. And after looking at information here, on Canon's site and other places, it seems the 7D is a huge learning curve when it comes to getting the correct exposure. The main area I was interested in was the metering modes and when to use them. I noticed that not a lot of people actually post what metering mode they use when posting images, but I thought that this information would be just as critical as what aperture and SS was used. I was reading Birds as Art II last night which is a great source of info, it might be worth you getting your hands on a copy. I find it very 'meaty', but I'ld rather have that than not enough info.

I think the key here is to practice, experiment and work out what works best in any given situation.

[Julian Mole]

Hi Mark,

Thank you for your reply, interesting that you should be considering the same question.

I perhaps ought to have mentioned in my original post that I have been learning by carefully reading the relevant chapters of ABP I and II (as well as Digital Basics and this article: http://www.birdphotographers.net/ezine/mar08_01.aspx ) and making sure I fully understand what they say.
I grasped the basics from quickly reading some of this material when I first got them but didn't take the time to gain a complete understanding, now I want to learn it properly.

Good luck with your new 7D, from what I read it seems an excellent camera.

Julian.

[Desmond Chan]

Try this link:

http://www.dummies.com/how-to/conten...on-eos-7d.html

The basics of getting the proper exposure are the same no metter which cameras you use, all-manual field camera from decades ago or 1D Mk IV. Just remember even the in-camera exposure meter of the same model of cameras from the same brand could give you slightly different results.

[Flavio Rose]

Don't agree with Desmond at all. If you have an external photometer (e.g., clipped onto your hotshoe), then you can use the same exposure algorithm for all cameras. Reading the external photometer will however slow you down ever so slightly, so I don't think bird photographers do that. If instead you rely on the internal "evaluative" exposure meter/firmware plus some EC, the exposure you get is the result of a complicated computation done by the camera firmware and your results can vary from one model to another. Canon will even warn you that that their exposure hardware and firmware on the new model are new and improved, meaning you need to relearn how to use it when you get the camera.

Maybe Nikons are different and more consistent. Maybe use of spot metering on Canons would be more consistent.

[Desmond Chan]

Don't agree with Desmond at all. If you have an external photometer (e.g., clipped onto your hotshoe), then you can use the same exposure algorithm for all cameras. Reading the external photometer will however slow you down ever so slightly, so I don't think bird photographers do that. If instead you rely on the internal "evaluative" exposure meter/firmware plus some EC, the exposure you get is the result of a complicated computation done by the camera firmware and your results can vary from one model to another.

Maybe Nikons are different and more consistent. Maybe use of spot metering on Canons would be more consistent.

Well, recently on the ETL board, they had a sunny 16 rule "contest". Go take a look at what they say about the sunny 16 rules. Do a research on it if you want to. Then think about why it still works regardless of the camera you use. It has nothing to do with the latest technologies or any complicated formula you have today since the sunny 16 rule has been in existence pretty much since day one.

With all due respect, using an external meter does not necessarily mean slowing you down in photographing birds.

Canon will even warn you that that their exposure hardware and firmware on the new model are new and improved, meaning you need to relearn how to use it when you get the camera.

And you believe that? Ok :D

Just so you know, I rarely use auto exposure mode.

[Don Lacy]

HI Julian, Here is one of the best books I have ever read on exposure http://www.amazon.com/Understanding-...4769082&sr=1-2 it helped me finally get a grasp on what I needed to do to get the images i wanted.

[Flavio Rose]

Just so you know, I rarely use auto exposure mode.

Arthur Morris in ABP says use evaluative plus EC, and so I have doggedly tried to learn that. Evaluative on my new 7D definitely works differently from my prior Canon; I notice it in shots of darker birds like brown pelicans against sky, which for some reason require more +EC on the 7D.

[Desmond Chan]

Arthur Morris in ABP says use evaluative plus EC, and so I have doggedly tried to learn that. Evaluative on my new 7D definitely works differently from my prior Canon; I notice it in shots of darker birds like brown pelicans against sky, which for some reason require more +EC on the 7D.

Allow me to quote what I said in 3 above:

Just remember even the in-camera exposure meter of the same model of cameras from the same brand could give you slightly different results.

And I think Don Lacy's suggestion to Julian could help you tremendously.

[Julian Mole]

Hi Desmond, Flavio and Don,

Thank you for furthering this discussion.

HI Julian, Here is one of the best books I have ever read on exposure http://www.amazon.com/Understanding-...4769082&sr=1-2 it helped me finally get a grasp on what I needed to do to get the images i wanted.

I think my slightly vague use of the phrase "basic understanding" might have been slightly misleading. (I also have a tendency for understatement!)
But your suggestion Don is an excellent one, for I have already learnt a lot from the book you recommended and have in fact just received the new edition of it - I must say the revisions have made an already excellent book into a truly outstanding one!

But what I am keen to do now is to get a truly comprehensive understand of exposure and fill in some of the gaps in my knowledge as well as reinforce what I have already learnt. eg. how to meter in each mode (spot, centre weighted and evaluative), where to meter the scene in each mode, what compensation needs to be added, why that compensation differs between the modes, which metering mode is best suited to which type of photography, etc, etc.

Hence when it comes to guessing the compensation Arthur Morris used in his images (usually in Av or Tv modes) I want to know whether he added an extra 1/3 of a stop of light to the recommendations he gives because he was using a 7D or 1D Mark IV.

To illustrate this Arthur mentions this in the thread "Think Fast: Exposure Quiz" (in the Tutorial and Educational Resource forum) when refering to the Exposure Compensation he used to create each image, he says it would have been different if he had been using his 1D MarkIII rather than his 40D, see quote below from this post http://www.birdphotographers.net/for...ll=1#post87979

"So my answers would be: 40D, -1, and -1/3. Had I had a MIII in my hand, they would have been: MIII, -2/3, zero."


I think this is what Flavio is getting at in the quote below, but Desmond may be right in that it could even vary between samples of the same model of camera (something I hadn't considered).

Evaluative on my new 7D definitely works differently from my prior Canon; I notice it in shots of darker birds like brown pelicans against sky, which for some reason require more +EC on the 7D.

May be I should have emailed Arthur directly, but I try not to bother him as I know he is busy man.

Julian.

[Flavio Rose]

And I think Don Lacy's suggestion to Julian could help you tremendously.

I am not sure why someone who "rarely" uses auto exposure mode is giving people advice on how to use auto exposure mode. Or perhaps the advice is not to use it? If so, I think I will stick instead with Arthur Morris's advice for now.

I read the Peterson book -- an older edition with photos of the author's wife on grainy ISO 400 color film -- quite a while ago. It's a good book but I don't recall that it answered the question of the degree of variation of "evaluative" metering from one camera to another. To repeat my basic point, I think "evaluative" metering is a complicated and totally undocumented algorithm carried out by the camera in firmware and each camera's "evaluative" metering takes some getting used to.

[Desmond Chan]

I am not sure why someone who "rarely" uses auto exposure mode is giving people advice on how to use auto exposure mode....

Somehow I have a feeling I can use your 7D or whatever better than you do, even in the auto-exposure modes :)


Flavio, just call Canon and let them tell you what button to push :D


Have a nice day !!

[Arthur Morris]

Let's play nice boys and girls :)

[Arthur Morris]

OK,, my turn.

1- First, study the principles in the section on exposure in ABP. If there is anything out there better, I would like to see it.

2-I could understand using an incident meter with film (even though 99% of the folks who used had no clue how to use it properly).

3-Using an incident meter with digital makes zero sense to me in part because (as above) few folks know to use it properly, but mainly because of the following:

4-Folks make getting the right exposure with digital much too complicated. All that you need to do is add or subtract light so that you have data halfway into the highlights box on the histogram--the fifth box with Canon, the 4th with Nikon, while making sure that you have only a few at most flashing pixels. This approach only works perfectly 100% of the time with front lit subjects.

5-If you have more than a few seconds with a subject with digital, you should be able to come up with a decent exposure 100% of the time.

6-A really good photographer will be competent working in both Manual mode and Av mode (or any other automatic mode). And regardless of what some very fine photographers will tell you, there are times when an automatic mode is best, and other times when it can save the day where folks in Manual mode are dead in the water.

7-For situations that require you to make split second adjustments in order to come up with a use-able exposure, see #1 above and the section on EXP in ABP II and study hard. Such situations often feature unusual and spectacular lighting; if you can only guess, you may fail.

8-Different digital camera bodies from the same or from different manufacturers will almost always require different amounts of EXP Compensation (and these differences can be much larger than what most folks realize). Anyone moving say from a 40D or a 50D to a 7D or a MIII or MIV will need to learn to add a lot more light than they used to especially when working with low light and scenes that average to brighter or well brighter than a middle tone. In the same situations, Nikon users will need less plus compensation. Before you go thinking that Nikon is better you had best know that if you have a white subject in bright light and a blue water background with Nikon you will likely be subtracting at least one full stop of light (more if the subject is small in the frame) while Canon users are making images with good histograms in the same situation at zero or even +1/3 stop. You need to pay at one end or the other.

9-There is no need to come up with a "perfect exposure" with digital. You would need a microscope to see any possible difference between a good exposure and a perfect exposure. Not so with film :)

That's about it. Want to know more? Ask here after you read the two books :) BTW, order both and take $10 off the package.

[Arthur Morris]

PS; to get directly back on target, metering with the MIV and the 7D is quite similar. And, both of those cameras need more light than a 40D.

[Julian Mole]

Thank you Arthur for taking the time to clear up any confusion and also to answer my initial question - I really appreciate it.

As for your chapter on Exposure Theory in ABP reading it carefully has really helped me get a better understanding, especially the part about Spot metering with compensation. However I still have quite a bit to learn, some of which will come through practice, but I hope that can get to the point where I no longer look through the viewfinder and think "...Now, how the **** do I workout the correct exposure!?". :-)

Thanks again,

Julian.

[Arthur Morris]

YAW. Best advice of all: study the stuff in Exposure Simplified in ABP II; it makes things relatively simple and covers about 95% of the various situations.

[Julian Mole]

...Anyone moving say from a 40D or a 50D to a 7D or a MIII or MIV will need to learn to add a lot more light than they used to especially when working with low light and scenes that average to brighter or well brighter than a middle tone.

Just wanted to add that Arthur's comment above, about the 1D MIV needing lots more positive compensation in low light conditions, answers why a +1 2/3 EC still produced an underexposed image of the Pectoral Sandpiper in BAA Bulletin337: http://www.birdsasart.com/bn337.html
Because when I first read that (having studied the image and guessed at the EC) it really had me scratching my head, and was a major reason why I started this thread in the first place!

[Arthur Morris]

Just wanted to add that Arthur's comment above, about the 1D MIV needing lots more positive compensation in low light conditions, answers why a +1 2/3 EC still produced an underexposed image of the Pectoral Sandpiper in BAA Bulletin337: http://www.birdsasart.com/bn337.html Because when I first read that (having studied the image and guessed at the EC) it really had me scratching my head, and was a major reason why I started this thread in the first place!

In that case I was fighting for shutter speed and did not want to increase the ISO :) The noise was easily controlled.

[Julian Mole]

So did I misunderstand the situation there Arthur? Are you saying that you deliberately underexposed the image, knowing that you could recover it in post processing and still have less noise than if you had used ISO1600 in the initial capture?

[Arthur Morris]

Yes, but possibly not true. Or possibly true. That was my decision at the time. Do see BAA Bulletin 338 for more thoughts on using the higher ISOs when needed ....

[Don Lacy]

Hi Julian, Sorry for the late reply here is another book you might find helpful http://www.amazon.com/Perfect-Exposu...ref=pd_sim_b_1 in it Jim explains his thought process in determining the exposure needed to capture images show cased in the book.

[Julian Mole]

Thanks Arthur, I have now read that and taken note, but I guess my original point about the Exposure Compensation was correct. Because if you had been using a 40D to create the Pectoral Sandpiper image +1 2/3 EC would have produced close to a correct exposure but you mention that with the 1D MIV you should have actually used +3 EC to get the correct exposure in those low light conditions!

[Arthur Morris]

Julian, You are on the right track :)

[Julian Mole]

Hey Don,

Thank you for the recommendation, I shall definitely check it out in due course - it is available to buy here in the UK (I just checked).

Incidentally I was out yesterday practicing using Av mode with Evaluative metering, on the local ducks, swans, coots and pigeons! The light was pretty poor but I was just interested in dialling in my EC, taking the photo and then seeing how I did! It went pretty well, I even continued to use it when I ought to have changed to manual because of a changing background (a swimming duck) but I just wanted to see if I could keep getting my adjustments right! :-)

[Charles Glatzer]

Meter patterns are used to determine exposure, meter modes are used to adjust/change variables. Big difference!
No one method is the end all. If you want to use Av I suggest you learn to do so in conjunction with AE lock, least you will be constantly changing the comp values to adjust for tonal variation every time you move the camera viewpoint.

Best,

Chas