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Author Topic: Why is auto exposure so useless?  (Read 108492 times)

Petrus

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Re: Why is auto exposure so useless?
« Reply #140 on: August 27, 2015, 11:21:57 am »

My recollection of the old Zenits I kicked off with was that the meter wasn't entirely unreliable and certainly good enough to produce some well exposed prints. But film was a lot more forgiving.

What?

Good old slide gave maybe 7 stops from shadows to blown highlights, now newest Nikons and Sonys deliver over 14 stops. Where have you been the last 10 years?

I had to get the exposure within -0.5 to 0 from perfect slide. Now I can go -4 to + 1 and still get as good or better frame from my Nikons. More latitude?
« Last Edit: August 27, 2015, 11:43:24 am by Petrus »
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Justinr

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Re: Why is auto exposure so useless?
« Reply #141 on: August 27, 2015, 11:41:00 am »

What?

Good old slide gave maybe 7 stops from shadows to blown highlights, now newest Nikons and Sonys deliver over 14 stops. Where have you been the last 10 years?

Transparencies always had a much lower range than negative so lets compare like with like. Digital has spent the last 10 years trying to catch up with negative. And that's colour, pushing at B&W could yield all sorts of details at either end.

Now here's a fellow who has a few thoughts on the subject.

http://www.120studio.com/dynamic-range.htm
« Last Edit: August 27, 2015, 11:42:34 am by Justinr »
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Petrus

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Re: Why is auto exposure so useless?
« Reply #142 on: August 27, 2015, 11:50:25 am »

Now here's a fellow who has a few thoughts on the subject.

http://www.120studio.com/dynamic-range.htm

If you cite that article as something reliable, well, actually I can not really think anything nice to say, so I say nothing.
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pegelli

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Re: Why is auto exposure so useless?
« Reply #143 on: August 27, 2015, 11:51:39 am »

Now here's a fellow who has a few thoughts on the subject.
and is shooting jpg. Do you think what he presents is a valid and relevant conclusion?
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pieter, aka pegelli

Justinr

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Re: Why is auto exposure so useless?
« Reply #144 on: August 27, 2015, 12:03:48 pm »

Lads lads, why the hate? Where's the bitterness coming from? What's the problem?
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pegelli

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Re: Why is auto exposure so useless?
« Reply #145 on: August 27, 2015, 12:08:07 pm »

Lads lads, why the hate? Where's the bitterness coming from? What's the problem?
There is no bitterness and hate from my side, I think we're having a technical discussion and are trying to understand some of the points you're making.
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pieter, aka pegelli

Petrus

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Re: Why is auto exposure so useless?
« Reply #146 on: August 27, 2015, 12:14:34 pm »

I think this is bordering on funny actually.
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Justinr

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Re: Why is auto exposure so useless?
« Reply #147 on: August 27, 2015, 12:16:20 pm »

I think this is bordering on funny actually.

 Indeed, I gave up taking you and Pegelli seriously about lunchtime today,
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Rob C

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Re: Why is auto exposure so useless?
« Reply #148 on: August 27, 2015, 12:37:05 pm »

Okay, I picked up on this thread during my bar lunch today, and not having digested either the 'meal' or the thread too well, I feel I might be able to contribute a simple solution to all of this crap that seems to be going down.

1. The words infer and imply do not mean the same thing.

2. Old cameras never did well with exposure if using their own built-in abilities, other than those with spot, which was also usually far too wide to be much use.

3. For olde filme days, you learned to use a Weston with or without Invercone. For black/white you directly measured the darkest shadow (by reflected light reading of it) that was important to you, exposed for that and developed for the highlights i.e. you tended to differ somewhat from the recommended processing times the makers suggested, and, as with camera makers, they suggested, assuming that you were bright enough to know what your intended result was all about.

For transparencies, you used the same meter, with an Invercone fitted, and simply pointed from the subject to where the camera was; if the subject was more side-lit than directly, you pointed between camera and light - usually sun in my case - and set the machine to that. If you couldn't get close enough to the subject with the Invercone, you could use a real spot meter and measure a highlight, such as a white person's face, open a stop and a bit, and click.

My Nikon F had no metering prism; the F2 came with a Photomic head which after the first attempt, I refused to consult ever again; the F3 had a meter of sorts, and the F4s I kept for such a short time that I can't truthfully remember much about it, other than it never loaded properly first time, causing much embarrassement, and a rapid selling off of it. The various FM bodies were only bought to enable a faster flash synch, and rarely used: they sounded and felt like old sardine tins. With rust. The tins, not the cameras.
Once I'd bought myself a Minolta Flash Meter 111, the various Westons went to permanent sleep.

4. Happy digital days. I only ever bought two Nikon digital bodies, the D200 and the D700. On both, Matrix works bloody well enough to make life reasonably free from tears. But, as with everything that's supposed to 'help' you into foolproof mode, it can be a mixed blessing because it takes away the will to think beyond pretty pretty image: you slide into the bad habit of only seeing what's in the viewfinder and not thinking much beyond that, quite a different approach to film, as detailed above.

But there's a perfectly good solution which removes the need to depend on anything but the ASA ISO setting: use an incident light meter and trust it. I've run tests recently on that very thing, and if I set the camera to what the incident light reading is, ignoring the silent screams of protest of the built-in meters, I don't blow highlights where they exist (and not all shots have them) and the other tones fall into place just like with transparencies.

This may read as heresy to some - I neither know nor care - but it works for me on those tests and that's all that matters to me. Try it for yourselves if you still have hand-held meters.

Rob C

Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #149 on: August 27, 2015, 12:40:05 pm »

Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #150 on: August 27, 2015, 12:46:14 pm »

... Matrix works bloody well enough to make life reasonably free from tears...

And this short sentence, ladies and gentlemen, succinct and eloquent, embodies everything some of us so dearly missed during Rob's absence.

Justinr

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Re: Why is auto exposure so useless?
« Reply #151 on: August 27, 2015, 12:50:47 pm »

Okay, I picked up on this thread during my bar lunch today, and not having digested either the 'meal' or the thread too well, I feel I might be able to contribute a simple solution to all of this crap that seems to be going down.

1. The words infer and imply do not mean the same thing.

2. Old cameras never did well with exposure if using their own built-in abilities, other than those with spot, which was also usually far too wide to be much use.

3. For olde filme days, you learned to use a Weston with or without Invercone. For black/white you directly measured the darkest shadow (by reflected light reading of it) that was important to you, exposed for that and developed for the highlights i.e. you tended to differ somewhat from the recommended processing times the makers suggested, and, as with camera makers, they suggested, assuming that you were bright enough to know what your intended result was all about.

For transparencies, you used the same meter, with an Invercone fitted, and simply pointed from the subject to where the camera was; if the subject was more side-lit than directly, you pointed between camera and light - usually sun in my case - and set the machine to that. If you couldn't get close enough to the subject with the Invercone, you could use a real spot meter and measure a highlight, such as a white person's face, open a stop and a bit, and click.

My Nikon F had no metering prism; the F2 came with a Photomic head which after the first attempt, I refused to consult ever again; the F3 had a meter of sorts, and the F4s I kept for such a short time that I can't truthfully remember much about it, other than it never loaded properly first time, causing much embarrassement, and a rapid selling off of it. The various FM bodies were only bought to enable a faster flash synch, and rarely used: they sounded and felt like old sardine tins. With rust. The tins, not the cameras.
Once I'd bought myself a Minolta Flash Meter 111, the various Westons went to permanent sleep.

4. Happy digital days. I only ever bought two Nikon digital bodies, the D200 and the D700. On both, Matrix works bloody well enough to make life reasonably free from tears. But, as with everything that's supposed to 'help' you into foolproof mode, it can be a mixed blessing because it takes away the will to think beyond pretty pretty image: you slide into the bad habit of only seeing what's in the viewfinder and not thinking much beyond that, quite a different approach to film, as detailed above.

But there's a perfectly good solution which removes the need to depend on anything but the ASA ISO setting: use an incident light meter and trust it. I've run tests recently on that very thing, and if I set the camera to what the incident light reading is, ignoring the silent screams of protest of the built-in meters, I don't blow highlights where they exist (and not all shots have them) and the other tones fall into place just like with transparencies.

This may read as heresy to some - I neither know nor care - but it works for me on those tests and that's all that matters to me. Try it for yourselves if you still have hand-held meters.

Rob C



Hand held meters!

Good lord, didn't they go down with the ark? OK, not all of them did, I still have mine (I think) both digital and analogue. I remember an item in BJP in which we were informed that one particular purveyor of meters had developed an instrument specifically for digital capture and went to some length to explain why it was different from the film version. Alas, I can't remember the details but it all sounded very convincing at the time. I do wonder what happened to them though, swept away by the tide of histogram analysis no doubt.
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Justinr

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Re: Why is auto exposure so useless?
« Reply #152 on: August 27, 2015, 01:15:18 pm »

Show what you mean by "poor exposure".

Side-by-side show AE "poor exposure" versus "manual exposure" of the same scene.

Isaac, did you not say the following -

Much of the thread is indigestible. I hope you have more luck with the meal.

You obviously failed to even attempt masticating parts of it because we have been through this before. Anyway, could I refer you to an earlier post of mine -

Quite so, it has its uses but I look at the situation like this.

A camera is very much a tool as far as I am concerned, it is one I enjoy using but even so it has to prove effective at its purpose.

When I cover a story/feature/event I need that that to tool to work at it's optimal capacity, or as near as for 100% is hardly likely to be achieved.

The major reasons for deletion of shots is incorrect exposure, therefore I need to maximise the percentage of shots that are either correctly exposed or near enough for them to be easily and satisfactorily adjusted back on the computer.  

At a guess, but after some consideration, I would say that the yield of acceptable shots using AE alone was never more than 50%. By using manual that yield is greatly increased, probably nearer to 80 or 90% (excluding test shots which are never intended to be kept).

Is it really acceptable that a tool costing thousands of dollars can only achieve such a success rate when left to its own devices?  Others on here have expressed their satisfaction with AE, which is fair enough, it seems that their work might conform more to what is generally regarded as press photography and the camera's firmware can more happily deal with it.  I have found myself specialising in machinery (not just tractors) and here it seems that cameras struggle to perform as they would in other situations.

This is a genuine problem encountered not just by me but by others working in the same area using the other big name in cameras. Trying to apply the reasoning of hobby photographers (nothing against them, I was one myself) to a commercial situation is not helping to define, clarify or answer the difficulties encountered.  


There, that should explain it again.
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Isaac

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Re: Why is auto exposure so useless?
« Reply #153 on: August 27, 2015, 01:34:46 pm »

There, that should explain it again.

What you have again demonstrated is that you are unwilling to show any examples of AE "poor exposure". It must be really really difficult to take a photo with "poor exposure" using AE ;-)


Here's a DPreview of the Nikon D3
http://www.dpreview.com/reviews/NIKOND3/22
Could you point out where the AE is assessed or even mentioned?

There are a couple of mentions:
-- "Arguably the best metering of the bunch (1005 pixel RGB sensor)*"
-- "Metering struggles to keep up if you shoot at the very fastest continuous rate (i.e. in manual focus mode at 9fps or 11fps in DX mode)."


I'm not so sure TBH. I do find that colours and saturation levels, or perhaps the relationships between colours, start to deteriorate the greater the depths or heights from which you try and recover the image. Maybe on much more recent equipment it is different but the D3 I have  (age  4 or 5) isn't particularly generous in this quarter and anything more than about two stops isn't worth bothering with, but that's subjective.

*"…the D3 an usually wide exposure latitude, able to pull back both shadow and highlight detail if your exposure goes awry in the press scrum or when trying to follow the action at 9 frames per second. As the example below shows the ability to pull back color information is impressive, and though you can't expect miracles these are some of the most pliable RAW files we've yet seen."*
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pegelli

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Re: Why is auto exposure so useless?
« Reply #154 on: August 27, 2015, 01:38:06 pm »

Indeed, I gave up taking you and Pegelli seriously about lunchtime today,
Haha, that's really funny. I think you gave up talking seriously a lot earlier, or do you blame that on your key board?
Well, I guess I'll stop here. Let's call it a win-win if we don't exchange any more ideas from now on  ;)
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pieter, aka pegelli

Justinr

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Re: Why is auto exposure so useless?
« Reply #155 on: August 27, 2015, 01:39:45 pm »

What you have again demonstrated is that you are unwilling to show any examples of AE "poor exposure". It must be really really difficult to take a photo with "poor exposure" using AE ;-)


There are a couple of mentions:
-- "Arguably the best metering of the bunch (1005 pixel RGB sensor)*"
-- "Metering struggles to keep up if you shoot at the very fastest continuous rate (i.e. in manual focus mode at 9fps or 11fps in DX mode)."


*"…the D3 an usually wide exposure latitude, able to pull back both shadow and highlight detail if your exposure goes awry in the press scrum or when trying to follow the action at 9 frames per second. As the example below shows the ability to pull back color information is impressive, and though you can't expect miracles these are some of the most pliable RAW files we've yet seen."*


Isaac, I don't give a flying feck whether you believe me or not, my name is here as is a link to my website so everybody knows who I am and I stand by my word.
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Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #156 on: August 27, 2015, 01:50:07 pm »

... Make some ... exposures and show them here -- that might be interesting.

Look who is talking! ;)

Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #157 on: August 27, 2015, 01:59:37 pm »

My bad, Isaac, my bad :)

Justinr

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Re: Why is auto exposure so useless?
« Reply #158 on: August 27, 2015, 02:00:30 pm »

I expect the other posters also "stand by [their] word" !

Make some AE "poor exposures" and show them here -- that might be interesting.

I wonder if you would care to indulge me while I explain a somewhat awkward flaw in this scheme.

If I were to post some badly exposed images would you believe they were genuine problem files or would you suspect that I had just made them up to prove a point?

If you consider that I made them up then there is nothing that can be done to persuade you of my concerns.

If you were to take my word that they were genuine then why do you seem so reluctant to believe what I said in the OP?
« Last Edit: August 27, 2015, 02:02:13 pm by Justinr »
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Petrus

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Re: Why is auto exposure so useless?
« Reply #159 on: August 27, 2015, 02:24:21 pm »


If I were to post some badly exposed images would you believe they were genuine problem files or would you suspect that I had just made them up to prove a point?

As far as I know there is no way to manipulate RAW files. Give us some RAW files and we can even see what the exposure system was and if exposure compensation was used.

If you are not shooting RAW and using the manipulation possibilities it offers (like several stops of exposure correction), this discussion is quite useless.
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