My personal 400D's underexposure FAQ

Started Nov 13, 2006 | Discussions
oriomenoni Contributing Member • Posts: 556
My personal 400D's underexposure FAQ

I hope that this can help to stop the irrational rumours that keep going on.
I am really tired of reading unaccurate things about this subject.
I put here what I learned from my personal experience.

Q.: So, does the 400D actually underexpose or not?

A: It seems to underexpose more or less constantly for most people using Evaluative mode. A minority of people only report some occasional underexposure, always with Evaluative mode.

Q.: Is this underexposure real, or does it come from the comparison with 300D and 350D (which are known to overexpose)?

A.: This is debated. Some people (the majority) claim that the underexposure is real and that it shows also from comparison with non-Canon SLRs. Some other people claim that the 400D meters correctly and that it's the 300D and 350D that meter wrong.

Q.: Does 400D only feature the Evaluative metering mode?

A.: No, it features three metering modes: Evaluative, Partial, and Centre-weighted.

Q.: Does the camera underexpose with the other metering modes?

A.: No. With the Partial and Centre-weighted modes, the 400D does not underexpose, on the contrary it shows the same results as the predecessors (300D and 350D), that is, some overexposure, ranging from +1/3 to +2/3, although in some cases I even got a +1 stop (compared with external Gossen MultiPro meter).

Q.: Is this Evaluative mode underexposure a hardware's fault? Is the sensor of 400D less sensitive to light? Are there other hardware components of 400D that are faulty and cause this underexposure?

A.: No, the use with Partial and Centre-weighted modes show that the sensor is not less sensitive than those of 300D or 350D. And neither are there problems with other hardware components of 400D. The underexposure with Evaluative mode is merely the result of a software calibration.

Q.: So where is this problem located?

A.: It is merely a matter of how much importance or "weight" the algorhythm of the Evaluative mode gives to the different measurement points. The Evaluative mode measurement seems to be somehow related to the location of the AF points. Let's not forget that the 400D has a different AF system than the 300D's and 350D's. Let's say you shoot a landscape with horizon in the middle, if the algorhythm "says" that the sky is more important than the land, you'll end up with a correctly exposed sky and a slightly underexposed land. Of course it is more complicated than this (and the 9 points location is not rectangular), but it can serve as an example.

Q.: Can a competent use of camera prevent that?

A.: YES! Too many people now expect to just point and shoot with a reflex. Then I say they have gotten the wrong type of camera. Reflex photography does not work like that. You have an assistance from the automation, but ultimately, it's about you the photographer knowing your camera and how to use it. GET TO KNOW YOUR CAMERA. Learn how to meter it. There is a useful button in your 400D, it's the Exposure Lock button. LEARN IT AND USE IT. Meter your scene by centering the view on the most sensible part of the scene, then press the AE button, recompose and shoot. Professionals do always meter accurately their scenes. You are not so much better than a professional, that you can skip that part and pretend to always get good pictures. Either shoot like professionals shoot, or sell your SLR and get a point-and-shoot camera.

Q.: So, if it's not a hardware problem, should I keep my 400D?

A.: Yes you should!! The 400D is an excellent camera that rewards you with quasi-professional images at a fraction of the price of a professional camera. To return it (or even worse, to send it to servicing) because of this supposed underexposure "problem" would be the most stupid thing that you could do.

Q.: Can I expect that a firmware update fixes the problem?

A.: In theory, yes: since this is obviously a software "problem", a firmware update may definitely fix it. But I doubt that such "fixing" firmware will ever be released.

Q.: Why?

A.: Because in my opinion, this "problem" or "fault" is not a problem or fault in Canon's engineer eyes, but an actual improvement on the metering performance of 400D compared to 300D and 350D. And I agree with them. If you use your 400D long enough to learn how it meters and works, it will turn out to be an advantage and not a feature. I personally rarely rely on the Evaluative mode, but when I do, I get significantly LESS thrash shots that I used to get with my 300D (by trash shots I mean shots that are unrecoverable even with RAW).

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Sony a7R II
Glenn W. Veteran Member • Posts: 6,428
Re: My personal 400D's underexposure FAQ

That's all fine... but I think maybe you left off a question or two...

Like... How come when I take a shot with my 350D at some specific ISO, shutter, and aperture setting the histogram shows 2/3 EV greater then if/when I take the same shot with the same settings on a 400D?

(and by the way that's a hypothetical question since I don't own a 350D or a 400D) I did however try a 400D and compared it to my 300D... and in some lighting situations with the exact same ISO, shutter, and aperture settings, the 400D did seem to have a histogram that showed 1/3 to 2/3rds lower then the 300D's did. Ths mostly seem to happen in artifical light, in sun light the histogram was nearly identical.

oriomenoni wrote:

I hope that this can help to stop the irrational rumours that keep
going on.
I am really tired of reading unaccurate things about this subject.
I put here what I learned from my personal experience.

Q.: So, does the 400D actually underexpose or not?
A: It seems to underexpose more or less constantly for most people
using Evaluative mode. A minority of people only report some
occasional underexposure, always with Evaluative mode.

Q.: Is this underexposure real, or does it come from the comparison
with 300D and 350D (which are known to overexpose)?
A.: This is debated. Some people (the majority) claim that the
underexposure is real and that it shows also from comparison with
non-Canon SLRs. Some other people claim that the 400D meters
correctly and that it's the 300D and 350D that meter wrong.

Q.: Does 400D only feature the Evaluative metering mode?
A.: No, it features three metering modes: Evaluative, Partial, and
Centre-weighted.

Q.: Does the camera underexpose with the other metering modes?
A.: No. With the Partial and Centre-weighted modes, the 400D does
not underexpose, on the contrary it shows the same results as the
predecessors (300D and 350D), that is, some overexposure, ranging
from +1/3 to +2/3, although in some cases I even got a +1 stop
(compared with external Gossen MultiPro meter).

Q.: Is this Evaluative mode underexposure a hardware's fault? Is
the sensor of 400D less sensitive to light? Are there other
hardware components of 400D that are faulty and cause this
underexposure?
A.: No, the use with Partial and Centre-weighted modes show that
the sensor is not less sensitive than those of 300D or 350D. And
neither are there problems with other hardware components of 400D.
The underexposure with Evaluative mode is merely the result of a
software calibration.

Q.: So where is this problem located?
A.: It is merely a matter of how much importance or "weight" the
algorhythm of the Evaluative mode gives to the different
measurement points. The Evaluative mode measurement seems to be
somehow related to the location of the AF points. Let's not forget
that the 400D has a different AF system than the 300D's and 350D's.
Let's say you shoot a landscape with horizon in the middle, if the
algorhythm "says" that the sky is more important than the land,
you'll end up with a correctly exposed sky and a slightly
underexposed land. Of course it is more complicated than this (and
the 9 points location is not rectangular), but it can serve as an
example.

Q.: Can a competent use of camera prevent that?
A.: YES! Too many people now expect to just point and shoot with a
reflex. Then I say they have gotten the wrong type of camera.
Reflex photography does not work like that. You have an assistance
from the automation, but ultimately, it's about you the
photographer knowing your camera and how to use it. GET TO KNOW
YOUR CAMERA. Learn how to meter it. There is a useful button in
your 400D, it's the Exposure Lock button. LEARN IT AND USE IT.
Meter your scene by centering the view on the most sensible part of
the scene, then press the AE button, recompose and shoot.
Professionals do always meter accurately their scenes. You are not
so much better than a professional, that you can skip that part and
pretend to always get good pictures. Either shoot like
professionals shoot, or sell your SLR and get a point-and-shoot
camera.

Q.: So, if it's not a hardware problem, should I keep my 400D?
A.: Yes you should!! The 400D is an excellent camera that rewards
you with quasi-professional images at a fraction of the price of a
professional camera. To return it (or even worse, to send it to
servicing) because of this supposed underexposure "problem" would
be the most stupid thing that you could do.

Q.: Can I expect that a firmware update fixes the problem?
A.: In theory, yes: since this is obviously a software "problem", a
firmware update may definitely fix it. But I doubt that such
"fixing" firmware will ever be released.

Q.: Why?
A.: Because in my opinion, this "problem" or "fault" is not a
problem or fault in Canon's engineer eyes, but an actual
improvement on the metering performance of 400D compared to 300D
and 350D. And I agree with them. If you use your 400D long enough
to learn how it meters and works, it will turn out to be an
advantage and not a feature. I personally rarely rely on the
Evaluative mode, but when I do, I get significantly LESS thrash
shots that I used to get with my 300D (by trash shots I mean shots
that are unrecoverable even with RAW).

OP oriomenoni Contributing Member • Posts: 556
Re: My personal 400D's underexposure FAQ

Glenn W. wrote:

That's all fine... but I think maybe you left off a question or two...
Like... How come when I take a shot with my 350D at some specific
ISO, shutter, and aperture setting the histogram shows 2/3 EV
greater then if/when I take the same shot with the same settings on
a 400D?

I will make this test as soon as my 300D comes back from servicing.

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Sony a7R II
SebbyNC Regular Member • Posts: 149
Re: My personal 400D's underexposure FAQ

I found my 300D to generally underexpose shots, so I usually dial in some positive EC.

magicmikey Regular Member • Posts: 256
Re: My personal 400D's underexposure FAQ

oriomenoni wrote:

Q.: Does the camera underexpose with the other metering modes?
A.: No. With the Partial and Centre-weighted modes, the 400D does
not underexpose, on the contrary it shows the same results as the
predecessors (300D and 350D), that is, some overexposure, ranging
from +1/3 to +2/3, although in some cases I even got a +1 stop
(compared with external Gossen MultiPro meter).

Glad to see that's the way yours works. Mine underexposes in all metering modes. I shot photos just last Thursday to test this. It metered nearly the same indoors with all three modes and all needed +1/3 to get a proper exposure. This was done in a room that has dark beige walls that and no white highlights to throw the meter off.

Michael

dwpmazer Junior Member • Posts: 39
Re: My personal 400D's underexposure FAQ

I am a newbie, so excuse me if this question doesn't pertain to the situation.

When you do you exposure test, will you be doing it with all three exposure modes or just evaluative?

I am on the verge of buying an xti... very interested in your results.
--
dwpmazer

MiguelF Regular Member • Posts: 442
Re: Congartulations!

oriomenoni:

That was a good sumarizing of the "ïssue". I am not even near of a good amateur, (I am a medical doctor), but I have noticed exactly what you clearly and precisely explained. It is a question of metering. Fifteen days after I got the 400D I decided to shoot just center weighed and in some cases evaluative with +2/3 EV, and voila! I have posted in these days some Santo Domingo colonial shots. They are not terrific, but I am just learning to handle this beauty to which I regret not to have enough time to spend with it.

Thanks again!

-- hide signature --

Miguel

magicmikey Regular Member • Posts: 256
Re: My personal 400D's underexposure FAQ

Here's an example where someone posted their results. If you notice, he used center-weighted averaging metering and still had to add +2/3 EC.

http://forums.dpreview.com/forums/read.asp?forum=1031&message=20847113

I have no doubt that center-weighted and partial metering both seem to work better than the evaluative metering but using them doesn't "fix" the sensitivity issue.

Michael

secheese Regular Member • Posts: 454
Re: My personal 400D's underexposure FAQ

oriomenoni wrote:

Q.: Can a competent use of camera prevent that?
A.: YES! Too many people now expect to just point and shoot with a
reflex. Then I say they have gotten the wrong type of camera.
Reflex photography does not work like that. You have an assistance
from the automation, but ultimately, it's about you the
photographer knowing your camera and how to use it. GET TO KNOW
YOUR CAMERA. Learn how to meter it. There is a useful button in
your 400D, it's the Exposure Lock button. LEARN IT AND USE IT.
Meter your scene by centering the view on the most sensible part of
the scene, then press the AE button, recompose and shoot.
Professionals do always meter accurately their scenes. You are not
so much better than a professional, that you can skip that part and
pretend to always get good pictures. Either shoot like
professionals shoot, or sell your SLR and get a point-and-shoot
camera.

Sorry, although your info is great for you and I with experience, I should be able to hand my 400D to my wife (who knows diddly about cameras), set it on Full Automatic (green) for her, have her shoot all day long, return home and dump straight to printer with PicBridge and as get good of results as she did with my G6 and A85 P&S cameras. And... as we all know... she will get primarily dark pictures. Even Canon make this claim in the 400D manual (page 40)... they use the verbiage "point-and-shoot" and "prevent botched pictures".

m1ks Senior Member • Posts: 1,803
Re: Thorough comparison tests between three models
Paul Stricklin Senior Member • Posts: 1,074
Re: My personal 400D's underexposure FAQ

I have 3 different printers here that produce 3 diff print values from the same direct print image. My little HP photosamrt 375 does its own thing and prints almost everything brightly while the Epson R300/1280s propduce light/dark prints from same source file.

MY C8080 does produce nicely saturated contrasty images just like the drug store snaps shots people take home to show thier frineds. 300D needs lots of pumping up to get anywhere near the same results regaurdless exposure.

Took me quite some time to adjust.
--
Club, Event Photographer to pay for the equipment
Nature, Landscape for the joy of life

LPS

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Canon EOS 80D
tmr Senior Member • Posts: 1,520
These FAQ don't cover all the situations being discussed ...

Seems to be a few slightly different issues going on here that aren't all covered by your FAQ. As others have mentioned, some XTi's, including mine, exhibit this issue in all meter modes.

Here is another test I did on a color checker chart (because as some have mentioned a standard gray card should be slightly shifted left). This is in center weighted mode. This took about +1 EC to correct.

http://forums.dpreview.com/forums/read.asp?forum=1031&message=20866005

Note that I did some flash tests tonight that mostly came out well (though several still had the same left shift). This seems strange, but perhaps someone can figure something out where the flash shots would do better than no flash.

 tmr's gear list:tmr's gear list
Canon EOS 400D Canon EOS 5D Mark III Canon EF 50mm f/1.2L USM Canon EF 85mm f/1.8 USM Canon EF 135mm F2L USM +4 more
Andy Watkins Regular Member • Posts: 476
Re: My personal 400D's underexposure FAQ

I think there is far more variation in individual cameras than you suspect.

I own a 300D and in automatic modes which I never use, it always significantly UNDER exposes. So much so I suspected the camera was defective when I bought it. TO be honest I still do, but I have learnt to compensate.

When I borrowed a friends 400d and tried it on every mode I could find, I found no problems with it at all. It consistently did an excellent job of exposing in any reasonable situation. it was much BRIGHTER than my 300D in same circumstances.

My conclusion....

My 300D is not a very good example
My friend has a good example of a 400D

I shall buy a 400D next year and hope it is as good as his, but it does seem to be pot luck.....

Andy

Chippy99 Senior Member • Posts: 2,111
Re: My personal 400D's underexposure FAQ

Andy Watkins wrote:

I think there is far more variation in individual cameras than you
suspect.

I own a 300D and in automatic modes which I never use, it always
significantly UNDER exposes. So much so I suspected the camera was
defective when I bought it. TO be honest I still do, but I have
learnt to compensate.

When I borrowed a friends 400d and tried it on every mode I could
find, I found no problems with it at all. It consistently did an
excellent job of exposing in any reasonable situation. it was much
BRIGHTER than my 300D in same circumstances.

My conclusion....

My 300D is not a very good example
My friend has a good example of a 400D

I shall buy a 400D next year and hope it is as good as his, but it
does seem to be pot luck.....

My second 400D is about half a stop brighter than the first one.

Chip

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tmr Senior Member • Posts: 1,520
Re: My personal 400D's underexposure FAQ

I tried XTi's at two different stores today and got the same left shifted histogram (between +1/3 to 2/3 to correct) as mine. I'm concluding that this is probably how it is intended to be, though there does seem to be some variation among various users.

 tmr's gear list:tmr's gear list
Canon EOS 400D Canon EOS 5D Mark III Canon EF 50mm f/1.2L USM Canon EF 85mm f/1.8 USM Canon EF 135mm F2L USM +4 more
vari001 Contributing Member • Posts: 815
Re: My personal 400D's underexposure FAQ

I wonder - what a sef-confidence writing that! The best is at the end

"this "problem" or "fault" is not a
problem or fault in Canon's engineer eyes, but an actual
improvement

Wow! Permanent darkness is not the problem but the improvement! Certainly there can be even more space for improvements as it is not completely dark yet... inspite of metering mode.

oriomenoni wrote:

I hope that this can help to stop the irrational rumours that keep
going on.
I am really tired of reading unaccurate things about this subject.
I put here what I learned from my personal experience.

Q.: So, does the 400D actually underexpose or not?
A: It seems to underexpose more or less constantly for most people
using Evaluative mode. A minority of people only report some
occasional underexposure, always with Evaluative mode.

Q.: Is this underexposure real, or does it come from the comparison
with 300D and 350D (which are known to overexpose)?
A.: This is debated. Some people (the majority) claim that the
underexposure is real and that it shows also from comparison with
non-Canon SLRs. Some other people claim that the 400D meters
correctly and that it's the 300D and 350D that meter wrong.

Q.: Does 400D only feature the Evaluative metering mode?
A.: No, it features three metering modes: Evaluative, Partial, and
Centre-weighted.

Q.: Does the camera underexpose with the other metering modes?
A.: No. With the Partial and Centre-weighted modes, the 400D does
not underexpose, on the contrary it shows the same results as the
predecessors (300D and 350D), that is, some overexposure, ranging
from +1/3 to +2/3, although in some cases I even got a +1 stop
(compared with external Gossen MultiPro meter).

Q.: Is this Evaluative mode underexposure a hardware's fault? Is
the sensor of 400D less sensitive to light? Are there other
hardware components of 400D that are faulty and cause this
underexposure?
A.: No, the use with Partial and Centre-weighted modes show that
the sensor is not less sensitive than those of 300D or 350D. And
neither are there problems with other hardware components of 400D.
The underexposure with Evaluative mode is merely the result of a
software calibration.

Q.: So where is this problem located?
A.: It is merely a matter of how much importance or "weight" the
algorhythm of the Evaluative mode gives to the different
measurement points. The Evaluative mode measurement seems to be
somehow related to the location of the AF points. Let's not forget
that the 400D has a different AF system than the 300D's and 350D's.
Let's say you shoot a landscape with horizon in the middle, if the
algorhythm "says" that the sky is more important than the land,
you'll end up with a correctly exposed sky and a slightly
underexposed land. Of course it is more complicated than this (and
the 9 points location is not rectangular), but it can serve as an
example.

Q.: Can a competent use of camera prevent that?
A.: YES! Too many people now expect to just point and shoot with a
reflex. Then I say they have gotten the wrong type of camera.
Reflex photography does not work like that. You have an assistance
from the automation, but ultimately, it's about you the
photographer knowing your camera and how to use it. GET TO KNOW
YOUR CAMERA. Learn how to meter it. There is a useful button in
your 400D, it's the Exposure Lock button. LEARN IT AND USE IT.
Meter your scene by centering the view on the most sensible part of
the scene, then press the AE button, recompose and shoot.
Professionals do always meter accurately their scenes. You are not
so much better than a professional, that you can skip that part and
pretend to always get good pictures. Either shoot like
professionals shoot, or sell your SLR and get a point-and-shoot
camera.

Q.: So, if it's not a hardware problem, should I keep my 400D?
A.: Yes you should!! The 400D is an excellent camera that rewards
you with quasi-professional images at a fraction of the price of a
professional camera. To return it (or even worse, to send it to
servicing) because of this supposed underexposure "problem" would
be the most stupid thing that you could do.

Q.: Can I expect that a firmware update fixes the problem?
A.: In theory, yes: since this is obviously a software "problem", a
firmware update may definitely fix it. But I doubt that such
"fixing" firmware will ever be released.

Q.: Why?
A.: Because in my opinion, this "problem" or "fault" is not a
problem or fault in Canon's engineer eyes, but an actual
improvement on the metering performance of 400D compared to 300D
and 350D. And I agree with them. If you use your 400D long enough
to learn how it meters and works, it will turn out to be an
advantage and not a feature. I personally rarely rely on the
Evaluative mode, but when I do, I get significantly LESS thrash
shots that I used to get with my 300D (by trash shots I mean shots
that are unrecoverable even with RAW).

busterjet Regular Member • Posts: 134
Re: My personal 400D's underexposure FAQ

Useful information for sure,

But instead of shooting grey cards, walls and other tests, why not just get out there and take real world photos and ENJOY yourself? If you look for problems, you will find them, and make yourself unhappy.

I am new to DSLR and the 400D (XTi) is my first one, so I have nothing else to compare it with. But I'm simply delighted with the results. Sure, I've had to do some EC adjust on some photos, but that's what I expected, that's why they have the dial.

Just wanted to put a DSLR newbie's point across, because I feel the 400D is a fantastic introduction to the world of "proper" photography.

-- hide signature --

My photos are featured on http://www.freedigitalphotos.net

vari001 Contributing Member • Posts: 815
Re: My personal 400D's underexposure FAQ

Lucky you! Enjoy!

However not all 400D users are happy as you. I feel cheated as i have to use a permanent shift +2/3 which seems to be far too much. Inside, outside, everywhere.

busterjet wrote:

Useful information for sure,

But instead of shooting grey cards, walls and other tests, why not
just get out there and take real world photos and ENJOY yourself?
If you look for problems, you will find them, and make yourself
unhappy.

I am new to DSLR and the 400D (XTi) is my first one, so I have
nothing else to compare it with. But I'm simply delighted with the
results. Sure, I've had to do some EC adjust on some photos, but
that's what I expected, that's why they have the dial.

Just wanted to put a DSLR newbie's point across, because I feel the
400D is a fantastic introduction to the world of "proper"
photography.

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