does the D30 metering system su......

Gary41969 · Aug 15, 2001

thanks for the post

DavidP said:
If the D-30 would actually decode the color information first,
before taking the picture, it could then determine (or at least
make a good guess) at the overall reflectivity of the scene, and
better determine how much exposure compensation is required.

That's how camcorders work, and I think is the principle behind
Nikon's RGB-metering system. (Someone will correct me if I'm wrong
about that, I'm sure).

At any rate, the D-30 doesn't do that. Color information is only
determined AFTER the exposure has been made.

The "evaluative" mode can solve many common exposure problems, like
a back-lit subject, for example. It does this through some fairly
sophisticated algorithms, comparing the light levels from the
current scene to those stored in memory, for proper exposure
compensation.

I would like to believe this, but I have never seen any difference between eval & partial. I specifically did a strong backlit test and eval & partial were almost identical, only the ctr wtd ave setting showed a significant difference (improvement). Can anyone post an example of an image where evaluative really makes a difference. I would really like to understand what it does so I can use it better. I'm beginning to agree with another poster that the D30 Eval mode is not very sophisticated.

DavidP #28649 said:
But, when a scene is overall very light (like snow, for example),
or very dark, there's just no way for the camera to "know" that the
scene is like this. The photographer has to make the compensation.

Now, with negative film, it may SEEM like the camera is metering
better . . but that's only because negative film is more forgiving
of exposure mistakes (especially over-exposure). The D-30 is more
like slide film -- very unforgiving of exposure mistakes, and NO
forgiveness if you've overexposed.f

as I said in another post, I spent 10yrs shooting slides with an EOS 10S and never saw the kind of exposure hassles I have with the D30

DavidP #28649 said:
Another misconception you mentioned in another post. A "good
exposure" is NOT necessarily centered. That's only true for a very
neturally balanced picture.

If the overall scene is very light, then a proper exposure will
have a histogram that's shifted to the right. A dark scene will
have a histogram that's shifted to the left.

thanks for that info

Gary

kurt · Aug 15, 2001

Gary, great discussion, and you've added some more detail and context to it..

Gary41969 said:
I have thought about this, but I spent 10 yrs shooting 35mm slides
in a Canon EOS 10S without seeing these kinds of exposure problems.
I thought that slides (unlike prints) were not subjerct to exposure
comp by the lab. Am I wrong?

I'm not the best person to answer this... as I only shot print film during my brief (2 year) step into photography before switching to the D-30... so I was more tuned to the adjustments done by the labs on prints...

Gary41969 said:
I certainly agree with a (slight) bias to underexposure since blown
out highlights are the absolute worst result. But in my experience,
it is often miles away from that, the upper half of the histogram
is often empty. And despite how good the D30 is on noise, you still
pick up significant noise when adjusting this far in PS. In fact,
in some of my tests, after compensating in PS, the noise level can
easily get to be about where it was with my Oly C2020.

Ah... this is the point where you need to find a balance between a few factors...

1. Is your D-30 seriously underexposing an 18% grey card? There's lots of references, both here and on Rob's forum, to test this...

2. If not, then use exposure compensation when taking the shot to get the exposure close for the critical elements in the composition - as discussed by others... white or dark "objects of interest" (as are often the case in your example shots) will be exposed toward neutral... compensation will take them back towards where you would like to be

this is an intersting part of digital photography that I've had to learn.. finding the best way to expose, with highlights being so critical... yet retaining shadow detail, and the ability to pull it out without noise...

3. Does the whole shot fit within the EV range, and can be manually compensated to where final adjustment doesn't result in excessive noise...

I guess by experience and trial and error (lots of error), I now have a good feel for where to place exposure... such that I don't have noise problems when doing the final adjustment in photoshop...

Gary41969 said:
I believe that exposure comp and sharpening are 2 very different
animals. Exposure comp is applied BEFORE the data is captured while
sharpening is applied AFTER. This means that there is no real loss
to applying sharpening outside the camera while exposure comp. can
never be applied outside the camera without suffering noise
consequences.

My comment was on the logic that goes into P&S cameras... that they bias both exposure, and post processing (sharpening, contrast, color saturation) towards non-manipulated output directly to a printer, or on the screen... vs. the logic that went into the D-30's

While I'm no expert compared to most here, I and would say that if your exposure was close, you can pull it up to final levels without much/if any addition of noise.... I wouldn't necessarily agree with the statement that "exposure comp can never be applied post shot without suffering noise consequences" especially with some of the tools for processing (including EV comp) RAW that are available

It's the way-off underexposures, and the EV ranges that go beyond the capabilities of the sensor that cause the most noise grief...

Gary41969 said:
as I said above, doing it in PS results in a lower quality image
(noisier) than if the exposure was correct before capturing the
pixels.

But what is correct exposure??? In some of your examples.. the entire data range for the image was contained in the histogram, it just moved higher or lower (making the whites whiter with proper exposure) Making this adjustment in PS, with this data available, shouldn't result in noise... sometimes auto-level does butcher stuff, since it changes the endpoints ... so just a levels adjustment is better... it's all experimentation/experience...

OK... so someone else gets to expand/confirm my knowledge about histograms/exposure and PS...

Generic blanket statements:

If you just adjust the levels slider in PS... it's similar to EV comp in the camera (as long as you don't shift off one side or the other)

Auto-levels does more... it adjusts the endpoints for each color to try and gain as much dynamic range as possible (which may be where some of your noise in introduced)

Comments for all out there who know far more that me?

Gary41969 said:
As above, due to noise concerns in the current state of the digital
art, a poorly exposed digital negative is fundamentally of lower
quality. It is much the same situation as with zoom scale, a
digital image must be captured much closer to the magnification you
want it, since digital negatives cannot withstand enlargement
anywhere near as well as color film (at least for now).

I guess I haven't had experience with the noise that you've seen... My reponse was based on the common P&S perceptions...

I'll make the blanket statement that if you're having serious noise problems with most images doing a simple auto-level in PS... you may just need more time to settle in to familiarity with the D-30...

this is not meant as a cut or jab at you at all... It honestly it took me 1-2 months to get really comfortable with feeling that I could get the shot I wanted, to come out at the quality level that I wanted, most of the time... and yes, a key has been to try and get exposure as close as possible, so as little post-manipulation has to be done...

At the same time.. I felt like I learned 10x faster with the D-30 than with film to get to that level, with the instant feedback of the histogram and image review... but it was still a process before it came naturally... I can just imagine the effort and patience it took to learn with only film... I feel like I've cheated a bit (ok, a lot) learning with the D-30...

Kurt

Gary41969 · Aug 15, 2001

thanks for the reply,

I agree with your basic assumption (digital gives the freedom to take and discard far more pictures than ever before) but completely disagree with the conclusion. Since I now can get instant feedback and delete any bad shots, I now should be able to come home with a far far HIGHER percentage of good shots. When I shot slide film I did not spend much time worrying about exposure, I spent a lot of time worrying about composition. Before the instant feedback of digital I did not really understand exposure controls well so I almost always shot in fully automatic mode, so if my film camera had the AE problems, I should see a great deal of them in my boxes of slides. And I certainly didn't see a consistent trend, I had a roughly even split of over/under exposed.

And to your point, when I am shooting creatively (landscapes, scenery, etc) where I can examine the results and reshoot, I get good results. The problem is when I am shooting indoors and I cannot reshoot since the candid opportunity passes, this is when I am frustrated by all of the underexposed shots.

Serra said:
Gary said:

I have thought about this, but I spent 10 yrs shooting 35mm slides
in a Canon EOS 10S without seeing these kinds of exposure problems.
I thought that slides (unlike prints) were not subjerct to exposure
comp by the lab. Am I wrong?

Click to expand...

Ok, fine. Now let me point out something that you said before:

MagicAngel said:

Now I admit that I am a rank AMATEUR , so I want to get some
opinions from people who understand the exposure
system better than I...

Click to expand...

Ok, now am I to understand that you are an amateur who was in the
past shooting slide? I see the problem! On the average outing how
many rolls of slide film did you shoot? 10? 15? 20? No, I doubt
that. The cost would have been too high. So the average amature
might shoot two rolls of film at one event, if that many. Like the
zoo or at the lake. Now you might be one of those amatures who
blows film like a pro, but I doubt it.

So, here is the problem that I see. Last time you took your D30
out shooting, how many frames did you shoot? 200? 300? Yes, that
is very likely. What the heck they are free right? Shoot till
your finger falls off. Lets say you shot 200 frames or the
equilivent 10 rolls of 20 exposure film. Now, here is the problem.
When you were shooting slides, you shot 20 exposures and now you
are shooting 200 exposures. I'm willing to bet that the 20
exposure you shot as an amature at some event were mostly good
shots with good exposure. When I was shooting film for myself,
like on vacation, when I was a pro, I would average about 15 good
shots per role. My exposure and focus were right on, 15 out of 20
shots. Now that I'm shooting on the D30, for myself, I average
about one or two good shots out of every 20. Heck, I was shooting
clouds the other day and I burned off 100 shots before I got the
one I wanted. Are you starting to see the problem? I'm willing
to bet that you don't put the same cost on your images with digital
as you did with film. Digital is free and film is expensive to buy
and expensive to print. Therefore you don't spend as much time
trying to get every shot perfect. When you download you get a lot
of bad shots, out of focus, bad exposure, poor in general because
you don't value each shot the same as you did when you were
shooting film.

In other words, you can't compare your shots, shot-by-shot between
digital and film. It is different and in YOUR mind and in MINE, we
know that the digital shots don't cost a penny so we are willing to
shoot more because we know we can, they are free. You and I both
likely come home with the same number of 'keepers' as we did when
we were shooting film, but I doubt that the number of 'tossed'
images is even in the same power as it was with film.

What is boils down to is that you are an AMATEUR . In other
words, when you were shooting slide film, every time you pressed
the button, you felt it in your wallet. Now that your wallet is
empty (i.e. you got a D30). You don't feel that same constraint to
limit the number of exposures, so you are willing to take riskier
shots, that often don't work out. Not that any of this is bad, it
doesn't mean you aren't just as good of a photographer as some pros.

So back to what you said:

MagicAngel said:

I have thought about this, but I spent 10 yrs shooting 35mm slides
in a Canon EOS 10S without seeing these kinds of exposure problems.
I thought that slides (unlike prints) were not subjerct to exposure
comp by the lab. Am I wrong?

Click to expand...

Are you wrong? I think you are correct, but I think you aren't
asking the right question. Will you see as many exposure problems
on slide film as you do on the D30? No, you will take much more
time setting up the slide shots, so many more will be good.

Of course, I might be totally wrong, but that is my opinion on this.

Gary41969 · Aug 15, 2001

Kurt,

this is a great discussion, thanks for taking the time to get into it. And don't worry about cuts or jabs, I am very hard to offend and there is a tremendous amount I would like to understand better. And strong challenges to my thinking always helps.

Kurt said:
Member said:

I have thought about this, but I spent 10 yrs shooting 35mm slides
in a Canon EOS 10S without seeing these kinds of exposure problems.
I thought that slides (unlike prints) were not subjerct to exposure
comp by the lab. Am I wrong?

Click to expand...

I'm not the best person to answer this... as I only shot print film
during my brief (2 year) step into photography before switching to
the D-30... so I was more tuned to the adjustments done by the labs
on prints...

Member said:

I certainly agree with a (slight) bias to underexposure since blown
out highlights are the absolute worst result. But in my experience,
it is often miles away from that, the upper half of the histogram
is often empty. And despite how good the D30 is on noise, you still
pick up significant noise when adjusting this far in PS. In fact,
in some of my tests, after compensating in PS, the noise level can
easily get to be about where it was with my Oly C2020.

Click to expand...

Ah... this is the point where you need to find a balance between a
few factors...

1. Is your D-30 seriously underexposing an 18% grey card?
There's lots of references, both here and on Rob's forum, to test
this...

I need to tes this

Member said:
2. If not, then use exposure compensation when taking the shot to
get the exposure close for the critical elements in the composition

as discussed by others... white or dark "objects of interest" (as

are often the case in your example shots) will be exposed toward
neutral... compensation will take them back towards where you would
like to be

this is an intersting part of digital photography that I've had to
learn.. finding the best way to expose, with highlights being so
critical... yet retaining shadow detail, and the ability to pull it
out without noise...

I agree

Member said:
3. Does the whole shot fit within the EV range, and can be
manually compensated to where final adjustment doesn't result in
excessive noise...

I guess by experience and trial and error (lots of error), I now
have a good feel for where to place exposure... such that I don't
have noise problems when doing the final adjustment in photoshop...

Member said:

I believe that exposure comp and sharpening are 2 very different
animals. Exposure comp is applied BEFORE the data is captured while
sharpening is applied AFTER. This means that there is no real loss
to applying sharpening outside the camera while exposure comp. can
never be applied outside the camera without suffering noise
consequences.

Click to expand...

My comment was on the logic that goes into P&S cameras... that they
bias both exposure, and post processing (sharpening, contrast,
color saturation) towards non-manipulated output directly to a
printer, or on the screen... vs. the logic that went into the
D-30's

While I'm no expert compared to most here, I and would say that if
your exposure was close, you can pull it up to final levels without
much/if any addition of noise.... I wouldn't necessarily agree
with the statement that "exposure comp can never be applied post
shot without suffering noise consequences" especially with some of
the tools for processing (including EV comp) RAW that are available

My point is that adding exposure comp after the fact will always add some noise, it may well be undetectable or completely acceptable, but if you are amplifying the pixel brightness, it stands to reason that you will also be amplifying the undesired (noise) differences between them. Which is of course why I agree that using levels in PS is very acceptable if the exposure is not too far off.

Member said:
It's the way-off underexposures, and the EV ranges that go beyond
the capabilities of the sensor that cause the most noise grief...

Member said:

as I said above, doing it in PS results in a lower quality image
(noisier) than if the exposure was correct before capturing the
pixels.

Click to expand...

But what is correct exposure??? In some of your examples.. the
entire data range for the image was contained in the histogram, it
just moved higher or lower (making the whites whiter with proper
exposure) Making this adjustment in PS, with this data available,
shouldn't result in noise... sometimes auto-level does butcher
stuff, since it changes the endpoints ... so just a levels
adjustment is better... it's all experimentation/experience...

In this statement I am defining "correct" exposure as what the photographer wanted. My point is that you have a better quality digital negative if the exposure is very close to what you want it to be, since like magnification (zoom scale) and unlike sharpening, you can (theoretically) not do exposure comp. after the fact as well as before (in terms of noise).

Member said:
OK... so someone else gets to expand/confirm my knowledge about
histograms/exposure and PS...

Generic blanket statements:

If you just adjust the levels slider in PS... it's similar to EV
comp in the camera (as long as you don't shift off one side or the
other)

It is similar in the effect it has on the histogram, but it is very different on how it is accomplished, and therefore in what kind of side effects it has. EV comp in the camera affects what shutter speed/aperature is used, so it determines how much light hits the sensor, it does not do any manipulation on the pixel data. When done well it allows the sensor to work in the optimal part of its dynamic range. EV comp outside of the camera not only has to have some effect on noise, it also is likely to be working on data captured in a non-optimal part of the sensor dynamic range. Again, I think there is a good analogy to optical vs. digital zooming (admittedly not as dire consequences as digital zoom). With optical zooming, you get the image right before it hits the sensor, with digital zoom you pick up negative artifacts in direct proportion to how much you need to adjust the image.

Member said:
Auto-levels does more... it adjusts the endpoints for each color to
try and gain as much dynamic range as possible (which may be where
some of your noise in introduced)

good point, although I thought it was trying to remove color casts. Is that the same thing?

Member said:
Comments for all out there who know far more that me?

Member said:

As above, due to noise concerns in the current state of the digital
art, a poorly exposed digital negative is fundamentally of lower
quality. It is much the same situation as with zoom scale, a
digital image must be captured much closer to the magnification you
want it, since digital negatives cannot withstand enlargement
anywhere near as well as color film (at least for now).

Click to expand...

I guess I haven't had experience with the noise that you've seen...
My reponse was based on the common P&S perceptions...

I'll make the blanket statement that if you're having serious noise
problems with most images doing a simple auto-level in PS... you
may just need more time to settle in to familiarity with the D-30...
this is not meant as a cut or jab at you at all... It honestly it
took me 1-2 months to get really comfortable with feeling that I
could get the shot I wanted, to come out at the quality level that
I wanted, most of the time... and yes, a key has been to try and
get exposure as close as possible, so as little post-manipulation
has to be done...

no offense taken, but I will say my problems are not in PS, they are in getting the image close enough before it gets there. When I get an image from the camera that I would call reasonably exposed, I feel very confident that I can effectively do the final tweaks in PS.

Member said:
At the same time.. I felt like I learned 10x faster with the D-30
than with film to get to that level, with the instant feedback of
the histogram and image review... but it was still a process before
it came naturally... I can just imagine the effort and patience
it took to learn with only film... I feel like I've cheated a bit
(ok, a lot) learning with the D-30...

I agree again, I have learned 10x what I did in 10yrs of film shooting just using the D30 for the last few months.

Gary

Member said:
Kurt

Michael Eckstein · Aug 15, 2001

Just to post an interesting point. Outdoor Photographer magazine (England) just had a review of the D30 and the author said that the D30 has the most accurate metering system of any Canon camera todate.

DonCohen · Aug 15, 2001

Gary41969 said:
It has been back to Canon twice, once for auto-off fix where I
asked for calibration but they didn't do it. And it just got back
from a service trip where I included a lengthy explaination and
many samples. They seem to feel that it is right. I haven't tried a
grey card, how should I perform that test, what should I look for?

Go to:

http://www.dlcphotography.net/D30Tips.htm#anchor7648

This is a quote from Chuck Westfall who used to post at Rob Galbraith's D30 Forum. It gives the specifics on how to check your meter's calibration yourself. I have this included on a page of "D30 Tips" on my website. Feel free to browse around and see if anything else there is useful to you.

Gary41969 said:
good point, I have just started to shoot raw

I have a page devoted to issues/tools/workflow relative to working with the D30's Raw Format files:

http://www.dlcphotography.net/RawFormatWorkflow/RawFormatWorkflow.htm

Regards,

Don
http://www.dlcphotography.net

MagicAngel · Aug 15, 2001

Gary said:
And to your point, when I am shooting creatively (landscapes,
scenery, etc) where I can examine the results and reshoot, I get
good results. The problem is when I am shooting indoors and I
cannot reshoot since the candid opportunity passes, this is when I
am frustrated by all of the underexposed shots.

Perhaps my conclusion was incorrect, I will admit that the D30 is harder to use than my 35mm camera, but can give me the same results once it is mastered. I still remember not being able to get my 35mm camera to give me good exposures constantly. Of course I was 15 and didn't really understand the whole f-stop thing yet....

I also have to admit that I did have a digital P&S camera before the D30. I very much wanted to get into digital and P&S was the only thing that was available. I did feel strange going from a totally decked out 35mm camera to a little P&S digital, but I made it.

Using my P&S camera I never really had a problem with indoor candid picture exposures. The first time I shot indoors with my D30 was a total disaster. It took me about an hour of playing to come up with a way to shoot that resulted in correct exposures, mostly becuase of the flash. Under normal indoor ambient light, I never really had a problem, the same rules that I used for film seem to be working on digital, but flash was impossible. One shot would be so dark you couldn't see it, followed by a bunch of shots that were white. I went down the EV route to solve the problem, but I realized later that was a novist mistake, it wasn't about compensation, it was about telling the camera what I expected and getting it to produce what I needed. I now feel confident that I can shoot indoors and get good exposures with the flash, but there was a learning curve.

Good luck.

Gary37301 · Aug 15, 2001

your experience sounds very similar to mine. I just need to get farther up on the "learning to tell it what I want" curve. I still suspect the D30 is not quite as good as it could be at helping on that one. But I certainly agree that the results are well worth the effort.

thanks

Gary

Serra said:
Gary said:

And to your point, when I am shooting creatively (landscapes,
scenery, etc) where I can examine the results and reshoot, I get
good results. The problem is when I am shooting indoors and I
cannot reshoot since the candid opportunity passes, this is when I
am frustrated by all of the underexposed shots.

Click to expand...

Perhaps my conclusion was incorrect, I will admit that the D30 is
harder to use than my 35mm camera, but can give me the same results
once it is mastered. I still remember not being able to get my
35mm camera to give me good exposures constantly. Of course I was
15 and didn't really understand the whole f-stop thing yet....

I also have to admit that I did have a digital P&S camera before
the D30. I very much wanted to get into digital and P&S was the
only thing that was available. I did feel strange going from a
totally decked out 35mm camera to a little P&S digital, but I made
it.

Using my P&S camera I never really had a problem with indoor candid
picture exposures. The first time I shot indoors with my D30 was a
total disaster. It took me about an hour of playing to come up
with a way to shoot that resulted in correct exposures, mostly
becuase of the flash. Under normal indoor ambient light, I never
really had a problem, the same rules that I used for film seem to
be working on digital, but flash was impossible. One shot would be
so dark you couldn't see it, followed by a bunch of shots that were
white. I went down the EV route to solve the problem, but I
realized later that was a novist mistake, it wasn't about
compensation, it was about telling the camera what I expected and
getting it to produce what I needed. I now feel confident that I
can shoot indoors and get good exposures with the flash, but there
was a learning curve.

Good luck.

Andrew Grant27981 · Aug 15, 2001

Gary said:
please check out:

Gary41969 said:
these have a nearly half empty histogram. Is this what you would
expect from your D30 in these situations?

thanks,

Gary

If the carpet in the first image is very light in color then I could end up with a similar exposure. I notice some detail in the right side of the histogram though not very much.

The second image looks a little less unexposed. I see some white in the image and the histogram does appear to have some detail at the end of the right hand side.

Having said the above, I find my D30 overeposes at least as much as it underexposes.

Gary37301 · Aug 15, 2001

Don,

DonCohen said:
Member said:

It has been back to Canon twice, once for auto-off fix where I
asked for calibration but they didn't do it. And it just got back
from a service trip where I included a lengthy explaination and
many samples. They seem to feel that it is right. I haven't tried a
grey card, how should I perform that test, what should I look for?

Click to expand...

Go to:

http://www.dlcphotography.net/D30Tips.htm#anchor7648

This is a quote from Chuck Westfall who used to post at Rob
Galbraith's D30 Forum. It gives the specifics on how to check your
meter's calibration yourself. I have this included on a page of
"D30 Tips" on my website. Feel free to browse around and see if
anything else there is useful to you.

thanks a lot for this, it is a great help, I am going out now to buy a grey card. Is there anything I need to know to buy the correct one?

This is a good test of the basic metering capability, but it specifically avoids one thing I would like to know. I could believe that partial metering is working correctly, but evaluative seems like it should be offering what I am looking for, ie. some extra intelligence to provide a pleasing exposure when the subject is very different from the rest of the frame. Again I am surprised that I never see any significant differenct between partial and evaluative. Could it be that evaluative is not working correctly on my camera? Or maybe as someone else has posted it is just not very sophisticated.

thanks,

Gary

Member said:
Member said:

good point, I have just started to shoot raw

Click to expand...

I have a page devoted to issues/tools/workflow relative to working
with the D30's Raw Format files:

http://www.dlcphotography.net/RawFormatWorkflow/RawFormatWorkflow.htm

Regards,

Don
http://www.dlcphotography.net

Gary37301 · Aug 15, 2001

sorry to reply to my own post, but:

I greatly apreciate and enjoy the philosophical discussion generated here, but I would really like more answers to a single question:

after reviewing the pictures I posted (noting the exposure settings), do you think your own D30 would give similar results to mine in the same situation?

Whether I agree with the metering design/philosophy or not I would like to know if it is working as designed.

thanks again for all the great replies.

Gary

Gary said:
Sorry for the slightly obnoxious title and the long post, but I
wanted to get a lot of readers…

I have had my D30 since Feb, (I was one of the lucky ones to pay
full price) and like others I love it for the beautiful images it
can provide. However, I have become very frustrated with the
metering system. Like others that have posted, I find that it often
underexposes by ½ to 1 stop in situations where my old point and
shoot cameras would expose just fine. If it was consistent I could
just set the exposure comp and forget it, but I find that it is
extremely sensitive to the location of the focus rectangle that is
used for metering, a slight movement of the focus point can make a
huge difference in exposure.

I just got it back from its second trip to Canon Factory Service.
They sent me a nice form letter telling me that its flash metering
system is within factory specs and I just don’t understand
how it works (which may well be true). They must have a lot of
exposure complaints to have a 2-page form letter at the ready.

Now I admit that I am a rank amateur, so I want to get some
opinions from people who understand the exposure system better than
I.

I have read (in this forum) and it seems logical that a correctly
exposed image has a centered histogram. Is this not true? The
metering system in my camera seems to try and get the subject in
the center of the histogram at all costs, even if it means that
there is NO information in the histogram beyond the halfway point
(ie. the subject is the brightest thing). I would think that an
“evaluative” exposure mode would try and keep the
subject somewhere in the brighter half of the histogram, with its
actual location being dependant on how much information exists in
the image that is brighter than the subject, with a goal being a
reasonably centered histogram. Is this wrong?

I also think that it is odd that I have never seen any significant
difference between the different metering modes, especially between
evaluative and partial. Moving the focus point a very small amount
will usually make a far bigger difference. In fact my experience
would lead me to believe that the evaluative mode is doing spot
metering.

Below are a number of sample images I have taken to test the
metering; I would love to have feedback on them from those in the
know. Is my camera really working as a $3000 camera should? Is it
working correctly but just a poor metering design? Or do you think
that there is really something wrong with it?

All the pictures below have the histogram and a portion of the EXIF
data superimposed on them:

2 indoor natural light images, first with the default auto exposure
and the second using AELock to set the exposure from a darker area
of the image:

Similar subject, this time with 550EX flash, without and with +2/3
flash exp. comp:

Still another indoor natural light shot showing how it makes the
subject the center of the histogram in spite of the fact that it is
the brightest thing in the scene. This is intelligent metering?????
Am I missing something?

Here are 2 indoor flash shots where again the default exposure
seems too dark, and a flash exposure comp of +2/3 seems more
correct:

Finally, a set of images showing how the different metering modes
make virtually no difference in the exposure of the images:

My experience so far tells me that there are 2 ways to get good low
light exposures (my camera seems to have no trouble in bright
outdoor lighting):
- ignore the subject and always AELock on a portion of the scene
that is 50% bright
- set a +2/3 exposure and flash exposure compensation, and hope the
subject isn’t so dark relative to the rest of the scene that
it will blow out the highlights
Either one is quite a pain when trying to shoot quickly

What do you all think?

Finally, to add insult to injury, even though Canon did not do
anything to fix the exposure of my camera, they did something to
the viewfinder so that now when the shot is in focus it looks out
of focus in the viewfinder! I tried moving the diopter thru its
entire range with no luck. Anyone else have this problem and know
what is wrong?

Sorry again for the long post, I hope this is a valid use for this
forum. Thanks for any help.

Gary

Gary37301 · Aug 15, 2001

Haven't gotten to read the review, but if it is based on outdoor natural light, I would not be surprised. My D30 seems to be deadly accurate in those conditions. It is when I go indoors with/without a flash that I start to see problems.

Gary

Michael Eckstein said:
Just to post an interesting point. Outdoor Photographer magazine
(England) just had a review of the D30 and the author said that the
D30 has the most accurate metering system of any Canon camera
todate.

Radek Tezaur · Aug 15, 2001

I have a few of points to make:

1. So you have been shooting slide film for ten years and never had these problems? Did you shoot a lot indoors? Because the images you seem to be complaining about are taken indoors.
I believe slide film may give you similar fits indoors.

2. Canon's evaluative metering is weighted toward the selected focusing point. This may explain why partial and evaluative are often close. This can laso be modified on mosta Canon bodies by a custom function.

3. Take an obviously underexposed picture, like the sheet of paper on the carpet. Now how is the camera to know that this is a white sheet on gray carpet, or a gray sheet on black carpet? No histogram will help. No RGB metering can solve this either. Your brain knows that most sheets are white and compensates so you see it white... A camera does not know it is looking at a sheet of paper. Its best bet is 18% gray, and that is what you get.

benoit · Aug 15, 2001

Gary,
I own a D30 since last december and am very pleased with it.

I have taken many studio shots with that camera with Broncolor lighting system and can tell you I see right away the difference between each stop. Broncolor let me go by increments of 1/10th of a stop and it's calibrated at t 0.01 for a speed of true 1/300th of a second. Even color temperature does not vary by much from stop to stop. Same results with a borrowed Graphit pack that goes up to 1/7000th of a second. My personnal concern is more on a color level which can always be neutralised with the white sampler (that is if I have a true white on the picture). It seem that my D30 tend to shoot a little cyan. I get around it however with other software manually.

My build in flash seem to work properly and the exposures are acceptable. I also use a Metz flash unit, but I am not too pleased with it.

I don't like much this histogram because I can't alter it like I would with a software from a professional back to arrange the values the way I would like. Yes, the curve should be within the limits, but variations are going to be great according to the dominants and the size of an object compared to it's background. A histogram that look like it's lacking info on the right or left drastically can actually be appropriate for example. Take a small black item on pure white background and you'll see what I am talking about. However, while the histogram may look strange, if your black look good, you probably don't want to touch anything. Try with 50% black and 50% white background and compare the histogram with the one from your new grey card now. The histogram can be confusing if you have not yet worked much with one. Anyway, by viewing your images, you can easely determine if they are ok or not and remember that your film camera never had a histogram and you never worried about it before you got into digital.

I have also played with the auto bracketing that works real well. May be you could try it to determine if the exposure varies in the same proportions.

Other point, shoot Raw as much as you can. You've spend $3000 and if you want jpg, that's a luxury. Get a Microdrive if necessary. I can put around 300 Raw files at iso 100 in all type of light situations on mine (1GB).
Good luck

Gary said:
Sorry for the slightly obnoxious title and the long post, but I
wanted to get a lot of readers…

I have had my D30 since Feb, (I was one of the lucky ones to pay
full price) and like others I love it for the beautiful images it
can provide. However, I have become very frustrated with the
metering system. Like others that have posted, I find that it often
underexposes by ½ to 1 stop in situations where my old point and
shoot cameras would expose just fine. If it was consistent I could
just set the exposure comp and forget it, but I find that it is
extremely sensitive to the location of the focus rectangle that is
used for metering, a slight movement of the focus point can make a
huge difference in exposure.

I just got it back from its second trip to Canon Factory Service.
They sent me a nice form letter telling me that its flash metering
system is within factory specs and I just don’t understand
how it works (which may well be true). They must have a lot of
exposure complaints to have a 2-page form letter at the ready.

Now I admit that I am a rank amateur, so I want to get some
opinions from people who understand the exposure system better than
I.

I have read (in this forum) and it seems logical that a correctly
exposed image has a centered histogram. Is this not true? The
metering system in my camera seems to try and get the subject in
the center of the histogram at all costs, even if it means that
there is NO information in the histogram beyond the halfway point
(ie. the subject is the brightest thing). I would think that an
“evaluative” exposure mode would try and keep the
subject somewhere in the brighter half of the histogram, with its
actual location being dependant on how much information exists in
the image that is brighter than the subject, with a goal being a
reasonably centered histogram. Is this wrong?

I also think that it is odd that I have never seen any significant
difference between the different metering modes, especially between
evaluative and partial. Moving the focus point a very small amount
will usually make a far bigger difference. In fact my experience
would lead me to believe that the evaluative mode is doing spot
metering.

Below are a number of sample images I have taken to test the
metering; I would love to have feedback on them from those in the
know. Is my camera really working as a $3000 camera should? Is it
working correctly but just a poor metering design? Or do you think
that there is really something wrong with it?

All the pictures below have the histogram and a portion of the EXIF
data superimposed on them:

2 indoor natural light images, first with the default auto exposure
and the second using AELock to set the exposure from a darker area
of the image:

Similar subject, this time with 550EX flash, without and with +2/3
flash exp. comp:

Still another indoor natural light shot showing how it makes the
subject the center of the histogram in spite of the fact that it is
the brightest thing in the scene. This is intelligent metering?????
Am I missing something?

Here are 2 indoor flash shots where again the default exposure
seems too dark, and a flash exposure comp of +2/3 seems more
correct:

Finally, a set of images showing how the different metering modes
make virtually no difference in the exposure of the images:

My experience so far tells me that there are 2 ways to get good low
light exposures (my camera seems to have no trouble in bright
outdoor lighting):
- ignore the subject and always AELock on a portion of the scene
that is 50% bright
- set a +2/3 exposure and flash exposure compensation, and hope the
subject isn’t so dark relative to the rest of the scene that
it will blow out the highlights
Either one is quite a pain when trying to shoot quickly

What do you all think?

Finally, to add insult to injury, even though Canon did not do
anything to fix the exposure of my camera, they did something to
the viewfinder so that now when the shot is in focus it looks out
of focus in the viewfinder! I tried moving the diopter thru its
entire range with no luck. Anyone else have this problem and know
what is wrong?

Sorry again for the long post, I hope this is a valid use for this
forum. Thanks for any help.

Gary

benoit · Aug 15, 2001

To complete the negative versus slide descrition from DavidP, a slide will definitely start showing moves in at 1/4 of a stop. Some minilabs can print negatives that are 2 or more stop over and give great prints. Color accuracy changes however. As a simple example, most one time use camera are loaded with film speed of 800 today to help sales and reduce reject by customers! Pretty bad, but it works.

I think David has a great point. Digital certainly does not mean getting away from proper exposures and expect great pictures. It's more like having your own lab and take responsability for all actions

DavidP said:
If the D-30 would actually decode the color information first,
before taking the picture, it could then determine (or at least
make a good guess) at the overall reflectivity of the scene, and
better determine how much exposure compensation is required.

That's how camcorders work, and I think is the principle behind
Nikon's RGB-metering system. (Someone will correct me if I'm wrong
about that, I'm sure).

At any rate, the D-30 doesn't do that. Color information is only
determined AFTER the exposure has been made.

The "evaluative" mode can solve many common exposure problems, like
a back-lit subject, for example. It does this through some fairly
sophisticated algorithms, comparing the light levels from the
current scene to those stored in memory, for proper exposure
compensation.

But, when a scene is overall very light (like snow, for example),
or very dark, there's just no way for the camera to "know" that the
scene is like this. The photographer has to make the compensation.

Now, with negative film, it may SEEM like the camera is metering
better . . but that's only because negative film is more forgiving
of exposure mistakes (especially over-exposure). The D-30 is more
like slide film -- very unforgiving of exposure mistakes, and NO
forgiveness if you've overexposed.

Another misconception you mentioned in another post. A "good
exposure" is NOT necessarily centered. That's only true for a very
neturally balanced picture.

If the overall scene is very light, then a proper exposure will
have a histogram that's shifted to the right. A dark scene will
have a histogram that's shifted to the left.

Christopher Fritz · Aug 15, 2001

I tried this on several of my underexposed images and it works very well. I am trying to understand what it is doing.

I guess that the copied blured image is used as a mask to select certain regions in the main image, but exactly what is the Fill comand doing to lighten the image?

Thanks for any help.
Chris Fritz

Doug Walker said:
"I used this process to lighten the dark photo that I found better
than levels: (Try it!) I even did it in action / batch mode and
completed 400 hundred piuctures in about 30 minutes with minimal
effort.
CORRECTING UNDEREXPOSED PICTURES WITH PHOTOSHOP

Correcting underexposed shots:

Follow along open your picture.

Image/Duplicate/OK

Image/Mode/Grayscale/OK

Filter/Gaussian Blur ( give a factor 4.0) OK

Now select your original file leaving the copy open

Original selected:

Select/Load Selection (Channel Black) Check Invert OK

Edit Fill/ Use: 50% Gray / Opacity: 100% (experiment with it)

Mode: Color
Dodge (you can apply this more than once using different Opacity's)
That's it!!!
Try it you'll like it.

Doug Walker

Steve Mason · Aug 16, 2001

Excellent thread, and many great contributions by all!

If you haven't been there yet, in this months Vivid Light e-magazine (anyone who hasn't seen this magazine, do. It's very good) has an excellent article by Moose Peterson about light, and exposure. Really gets you thinking.
It's here:

http://www.vividlight.com/articles/604.htm

Gary said:
Sorry for the slightly obnoxious title and the long post, but I
wanted to get a lot of readers…

Al Goldis · Aug 16, 2001

Short answer, yes. I just tested my D30 in a similar situation. I don't know if it's "working as designed," but mine meters and exposes almost exactly the same as yours.

Want to hear something really frightening?... For a "standard" exposure compensation I use -2/3. In most situations that gives me the best exposures. Blown hilights are bad.

Often if I'm shooting people wearing dark suits I'll drop the compensation even lower. But of course, if I'm shooting subjects wearing light colored clothes, or other bright objects I up the compensation.

Actually, most of the time I use manual exposure anyway.

Before you say "but manual exposure doesn't work for run and gun or dynamic situations," or "but I'll miss the right moment or facial expression," I say wanna bet?

In the overwhelming majority of situations the light doesn't change. You can walk into the room (or outside), look around and have plenty of time to find a good exposure before you actually want to shoot anything. Take a test shot, check the LCD and the histogram, adjust, repeat until you get what you want. Flash or available, it works for both. Then you're ready to go when something happens. Maybe that won't work if you're outside on a partly cloudy day and the sun keeps going in and out of the clouds. Or if things are happening in two places that are lit differently. But like I said, even for the vast majority of dynamic situations, the lighting isn't dynamic and I think with manual exposure you're way ahead of the game.

And yes, I think the D30's metering system is largely to blame. But it is what it is, and it's not that hard to deal with.

Gary said:
sorry to reply to my own post, but:

I greatly apreciate and enjoy the philosophical discussion
generated here, but I would really like more answers to a single
question:

after reviewing the pictures I posted (noting the exposure
settings), do you think your own D30 would give similar results to
mine in the same situation?

Whether I agree with the metering design/philosophy or not I would
like to know if it is working as designed.

thanks again for all the great replies.

Gary

Brian S · Aug 16, 2001

Just thought I'd throw this one out there since we are talking about getting correct exposure consistantly. I am a pro and shoot daily with the Kodak DCS 560 (canon body) as well as the D30. My father has a G1 and had very very inconsistant exposrue problems. As an example, we tested the camera on a fixed subject, camera on tripod, and in 10 shots in a row, several would be 'correct' and several more were way way blown out (+1 to +4 or more stops overexposed) After much frustration and a calibration check by Canon, we concluded that the Canon off camera cord which was attached to the hot shoe but DID NOT have a flash attached was the cause of the problem. If you are using the off camera cord on a flash bracket and take the flash off to fit the camera in a case - be aware of this. As I said, I am a pro and didn't even think of this. To anyone using a flash setup, run some tests to see if you remove your flash from the off-camera cord but still leave it on the hot shoe - does it give inconsistant results.

Just curious if this is a 'well duh, and you call yourself a pro' or a mistake others may have made or a clue to inconsistant exposures.

Gary37301 · Aug 16, 2001

Al,

thanks a lot for doing a test.

Funny, I have just been thinking that going manual and leaving it set might be a good way to go. It does seem to me that lighting probably does not vary as much as the (finnicky) D30 metering system does. Unfortunately I have very little experience and knowledge with controling exposure (which I'm sure you have surmized already) so I have been hesitant to try it. Given your input I will definitely try it. It seems like it could be very liberating not to futz with AEL & FEL for every shot. One question, do you use this technique with indoor flash shooting? This is where I find the most hassle (especially since FEL annoys the subject with 2 flashes per shot).

thanks again,

Gary

Al Goldis said:
Want to hear something really frightening?... For a "standard"
exposure compensation I use -2/3. In most situations that gives me
the best exposures. Blown hilights are bad. Often if I'm
shooting people wearing dark suits I'll drop the compensation even
lower. But of course, if I'm shooting subjects wearing light
colored clothes, or other bright objects I up the compensation.

Actually, most of the time I use manual exposure anyway.

Before you say "but manual exposure doesn't work for run and gun or
dynamic situations," or "but I'll miss the right moment or facial
expression," I say wanna bet?

In the overwhelming majority of situations the light doesn't
change. You can walk into the room (or outside), look around and
have plenty of time to find a good exposure before you actually
want to shoot anything. Take a test shot, check the LCD and the
histogram, adjust, repeat until you get what you want. Flash or
available, it works for both. Then you're ready to go when
something happens. Maybe that won't work if you're outside on a
partly cloudy day and the sun keeps going in and out of the clouds.
Or if things are happening in two places that are lit differently.
But like I said, even for the vast majority of dynamic situations,
the lighting isn't dynamic and I think with manual exposure you're
way ahead of the game.

And yes, I think the D30's metering system is largely to blame.
But it is what it is, and it's not that hard to deal with.

Gary said:

sorry to reply to my own post, but:

I greatly apreciate and enjoy the philosophical discussion
generated here, but I would really like more answers to a single
question:

after reviewing the pictures I posted (noting the exposure
settings), do you think your own D30 would give similar results to
mine in the same situation?

Whether I agree with the metering design/philosophy or not I would
like to know if it is working as designed.

thanks again for all the great replies.

Gary

Click to expand...

does the D30 metering system su......

Member

kurt

Guest

Member

Member

Senior Member

DonCohen

Guest

Senior Member

Active member

Senior Member

Active member

Active member

Active member

Forum Enthusiast

Senior Member

Senior Member

Forum Enthusiast

Steve Mason

Guest

Senior Member

Brian S

Guest

Active member

Keyboard shortcuts