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Author Topic: Why is auto exposure so useless?  (Read 87616 times)

Justinr

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Why is auto exposure so useless?
« on: August 25, 2015, 11:58:06 am »

There I was standing in the middle of field covering a major classic tractor event for a couple of magazines. It was an overcast day that threatened rain although it was the middle of summer and yet, despite the multitude of settings I tried to obtain a reasonable exposure, nothing seemed to be working. I turned to a fellow writer who I know is also very fussy about his cameras and images, he too was struggling while a third colleague also confessed that only a fraction of his pictures were useable due to poor exposure. Thinking about it afterwards I decided to try manual and rely on the good old histogram and since that happy moment around 90% of my pictures are now 'keepers'  (how I hate that word!). Using flash is going to be a problem as I can't see anyway of selecting an intensity setting on my flash head and adjusting aperture or ISO to achieve the desired result, but for all other purposes taking a few test shots to get the right exposure seems to work just fine. Just for the record I was using a Nikon and the others Canon and to further rub salt into the wound many people were getting better exposures on their smart phones!

I've attached a few taken using manual exposure.
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Telecaster

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Re: Why is auto exposure so useless?
« Reply #1 on: August 25, 2015, 03:23:24 pm »

An EVF with a live histogram and/or zebras/blinkies is a lovely thing. Nowadays when I over- or underexpose it's entirely due to my own inattentiveness.

-Dave-
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Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #2 on: August 25, 2015, 03:48:47 pm »

Justin, this post would make more sense if you included "wrong" auto-exposure examples. Than we could tell you what you, not the camera, did wrong ;) Lovely pics, btw.

Justinr

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Re: Why is auto exposure so useless?
« Reply #3 on: August 25, 2015, 04:31:58 pm »

Justin, this post would make more sense if you included "wrong" auto-exposure examples. Than we could tell you what you, not the camera, did wrong ;) Lovely pics, btw.

Ah, but then I would need to include details of what the other experienced photographers were supposedly doing wrong!

Over the years I have been shooting digital there has always problems with exposure but it could never be allowed that digital cameras were in anyway flawed but all the fault lies with user. I never really bought into that and having been using digital for over ten years with all the various combinations of metering modes, ISO's  and settings with many thousands of images taken I still suffer problems of incorrect exposure, and I am not alone it seems.
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Slobodan Blagojevic

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Re: Why is auto exposure so useless?
« Reply #4 on: August 25, 2015, 04:40:37 pm »

... experienced photographers...

Vegetarian = an old Indian word for "bad hunter"

Experienced photographer = an old Indian word for those who never really bothered to learn the basics, yet survived years without it

 ;D

« Last Edit: August 25, 2015, 05:04:59 pm by Slobodan Blagojevic »
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jrsforums

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Re: Why is auto exposure so useless?
« Reply #5 on: August 25, 2015, 04:55:57 pm »

Assuming multicolored tractors with uniform overcast lighting, it seems similar to the case of shooting sports, particularly indoors.

In shooting basketball, with light and dark toned jerseys, you will drive yourself crazy trying to use autoexposure.  The light is not changing, but the camera sees different tones based on what you are focusing on and tries to compensate.

Your best choice with constant lighting is to take test shots to establish exposure, set on manual, and the click away.
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John

Justinr

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Re: Why is auto exposure so useless?
« Reply #6 on: August 25, 2015, 05:21:48 pm »

Assuming multicolored tractors with uniform overcast lighting, it seems similar to the case of shooting sports, particularly indoors.

In shooting basketball, with light and dark toned jerseys, you will drive yourself crazy trying to use autoexposure.  The light is not changing, but the camera sees different tones based on what you are focusing on and tries to compensate.

Your best choice with constant lighting is to take test shots to establish exposure, set on manual, and the click away.

Quite so, and to be honest I find the problem extends beyond the sort of circumstances you describe. Having found a reasonable exposure setting I then vary it with the changing light. On the day described a stop or two either way would be required from a base setting as cloud cover shifted and position in relation to the sun changed.

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Justinr

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Re: Why is auto exposure so useless?
« Reply #7 on: August 25, 2015, 05:24:12 pm »

Vegetarian = an old Indian word for "bad hunter"

Experienced photographer = an old Indian word for those who never really bothered to learn the basics, yet survived years without it

 ;D



One basic flaw of digital cameras is that each sensor is different. One company I worked for had to calibrate each and every body they bought to ensure consistency across their product even though the cameras were the same model and may have come off the production line one after the other.
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jrsforums

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Re: Why is auto exposure so useless?
« Reply #8 on: August 25, 2015, 06:13:05 pm »

One basic flaw of digital cameras is that each sensor is different. One company I worked for had to calibrate each and every body they bought to ensure consistency across their product even though the cameras were the same model and may have come off the production line one after the other.

I'm not sure how that would effect the situation you described.
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John

Justinr

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Re: Why is auto exposure so useless?
« Reply #9 on: August 25, 2015, 06:38:55 pm »

I'm not sure how that would effect the situation you described.

Nor am I. However, two thoughts.

1. It indicates that digital cameras are not the wonderfully precise instruments that we are led to believe they are.

2. If the camera firmware is set to respond to a certain exposure reading in a certain way then unless that response is calibrated to each individual sensor problems are going to occur.

I'm not knocking digital, only our our unquestioning belief that it is faultless and any deviation from perfection is automatically the fault of the user.
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jrsforums

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Re: Why is auto exposure so useless?
« Reply #10 on: August 25, 2015, 07:01:42 pm »

Nor am I. However, two thoughts.

1. It indicates that digital cameras are not the wonderfully precise instruments that we are led to believe they are.

2. If the camera firmware is set to respond to a certain exposure reading in a certain way then unless that response is calibrated to each individual sensor problems are going to occur.

I'm not knocking digital, only our our unquestioning belief that it is faultless and any deviation from perfection is automatically the fault of the user.

Who the heck is saying digital is flawless?  What point are you trying to make?
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John

BobShaw

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Re: Why is auto exposure so useless?
« Reply #11 on: August 25, 2015, 08:07:53 pm »

I decided to try manual and rely on the good old histogram and since that happy moment around 90% of my pictures are now 'keepers' 
Welcome to being a photographer.

Auto exposure will hardly ever be right because it relies on light reflected back from the subject (which depends on the subject itself) which has very little to do with incident light hitting the subject (which determines the correct exposure).
If you photograph a bride and groom separately standing next to each other in exactly the same light on auto (Av, Tv or anything except M) then the two exposures will be vastly different which is wrong. Set the exposure correctly on manual and never worry about "exposure compensation" which is to compensate for the getting it wrong. in the film days (or if you want to understand it better) you would use an incident light meter and measure the light at the subject.
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Tony Jay

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Re: Why is auto exposure so useless?
« Reply #12 on: August 25, 2015, 11:29:39 pm »

Nor am I. However, two thoughts.

1. It indicates that digital cameras are not the wonderfully precise instruments that we are led to believe they are.

2. If the camera firmware is set to respond to a certain exposure reading in a certain way then unless that response is calibrated to each individual sensor problems are going to occur.

I'm not knocking digital, only our our unquestioning belief that it is faultless and any deviation from perfection is automatically the fault of the user.
Sorry Justin this is absolutely and completely wrong.

Tony Jay
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Justinr

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Re: Why is auto exposure so useless?
« Reply #13 on: August 26, 2015, 02:55:48 am »

Sorry Justin this is absolutely and completely wrong.

Tony Jay

Would you kindly explain why?
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Petrus

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Re: Why is auto exposure so useless?
« Reply #14 on: August 26, 2015, 03:10:47 am »

I have been shooting away happily with auto exposure ever since I got my first DSLR Canon EOS-1d in 2002 (or so). If I know from previous experience that exposure compensation is needed I dial that in before I start shooting, or if the histogram says the same I make a correction. There are several metering patterns in my Nikons, but usually I just use the multi pattern, sometimes resort to center weighted or even spot, which is a bit dangerous if I forget to reset the camera back to default after the shot. I suspect OP had his camera on spot metering?

Generally the multi pattern metering combined by the huge exposure latitude of new Nikons can take care of practically every situation. There is always the old school possibility of locking the exposure and reframing also, if and when I know metering will be off.

In a desparate situation there is also the possibility of auto bracketing, which happens so fast that the tractor is not going to get away during the half second 3 frame burst…

Summa summarum: manual exposure is practically useless for me in 98% of shooting situations I encounter in daily press photography.
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Justinr

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Re: Why is auto exposure so useless?
« Reply #15 on: August 26, 2015, 03:12:54 am »

Who the heck is saying digital is flawless?  What point are you trying to make?

Most of those who's default reaction is to blame the user the moment they encounter any criticism of digital cameras. Look at the folk who stand aghast at the very thought of digital cameras being considered anything less than heaven sent miracles, even on this thread already.

The point I made in the OP is that auto exposure is a still pretty much a hit and miss affair as far as I am concerned and as one who does a reasonable amount of editorial work I think it fair to suggest that I am not a Sunday hobbyist who picked up a shiny new dSLR from a box shifter last week.
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Justinr

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Re: Why is auto exposure so useless?
« Reply #16 on: August 26, 2015, 03:18:06 am »

Welcome to being a photographer.

Auto exposure will hardly ever be right because it relies on light reflected back from the subject (which depends on the subject itself) which has very little to do with incident light hitting the subject (which determines the correct exposure).
If you photograph a bride and groom separately standing next to each other in exactly the same light on auto (Av, Tv or anything except M) then the two exposures will be vastly different which is wrong. Set the exposure correctly on manual and never worry about "exposure compensation" which is to compensate for the getting it wrong. in the film days (or if you want to understand it better) you would use an incident light meter and measure the light at the subject.

Been doing photography on a pro basis for around 12/13 years now, never full time admittedly, but I started off  doing weddings on a Bronica with said light meter for Wedding Services in the UK, a company owned by Kodak at the time.
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Justinr

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Re: Why is auto exposure so useless?
« Reply #17 on: August 26, 2015, 03:25:30 am »

I have been shooting away happily with auto exposure ever since I got my first DSLR Canon EOS-1d in 2002 (or so). If I know from previous experience that exposure compensation is needed I dial that in before I start shooting, or if the histogram says the same I make a correction. There are several metering patterns in my Nikons, but usually I just use the multi pattern, sometimes resort to center weighted or even spot, which is a bit dangerous if I forget to reset the camera back to default after the shot. I suspect OP had his camera on spot metering?

Generally the multi pattern metering combined by the huge exposure latitude of new Nikons can take care of practically every situation. There is always the old school possibility of locking the exposure and reframing also, if and when I know metering will be off.

In a desparate situation there is also the possibility of auto bracketing, which happens so fast that the tractor is not going to get away during the half second 3 frame burst…

Summa summarum: manual exposure is practically useless for me in 98% of shooting situations I encounter in daily press photography.

I'm not saying AE is always wrong, it's not, but only that I find more a more consistent exposure by doing it myself.

As for tractors then yes, they are moving darn quickly when you are trying to frame a particular shot. I'm not in the business of taking any old snaps of tractors but aim to achieve a particular or dramatic look which is why it is not unknown for my work to appear on magazine covers.
« Last Edit: August 26, 2015, 04:23:25 am by Justinr »
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Justinr

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Re: Why is auto exposure so useless?
« Reply #18 on: August 26, 2015, 04:06:28 am »

When "many people were getting better exposures on their smart phones" the answer to "Why is auto exposure so useless?" is simply that photographers mess it up.

When "many people were getting better exposures on their smart phones" the photographers would do better to set their cameras to auto everything like their smart phones ;-)


The correct exposure is the one that gives you the picture you want with least effort. The camera doesn't know what picture you want. The camera doesn't know how much effort you're willing to make.


So that's why cameras have AE modes :-)



Dumb luck and a very limited budget led me to buy a camera designed for full-time live view and I started using raw so WB could be adjusted. As-long-as the significant highlights are not-clipped the raw file provides tremendous latitude to adjust exposure in post-processing.

Full-time live view plus raw means that most-of-the-time all I need to do for my "correct" exposure is check the live view histogram -- so I use Manual.

I reject 90% but not because of "incorrect exposure", that just doesn't seem to be a problem anymore.

All well and good 99% of what I take clutters up the hard drive unused (I really ought to be more disciplined in clearing out the trash), but at the end of the day AE still requires a health warning that it is far from perfect.

One of the reasons I upgraded to a D3 was a belief that AE would be a great deal better than the Pentax's I left behind, this has proven not to be the case and although it has many virtues it's by no means perfect.

Good and consistent AE is quite possible as proven by my my Mamiya with a creaky old ZD back. It does tend to get it right but it's hardly a camera to go humping around fields so I reserve it for cover or static shots where there is the time for it to crank up and perform it's little wonders. See below.
« Last Edit: August 26, 2015, 04:14:17 am by Justinr »
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stamper

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Re: Why is auto exposure so useless?
« Reply #19 on: August 26, 2015, 04:12:41 am »

I'm not saying AE is always wrong, it's not, but only that I find more a more consistent exposure by doing it myself.

So what really is the problem? No camera is perfect and no photographer is perfect and you have learned a valuable lesson. I try to get the "best" exposure but as long as I don't over expose by 2 stops or underexpose by 2 stops then I know the exposure can be balanced out by processing. The problem is that some photographers are unwilling/unable to process their images and want a "perfect" exposure from their cameras. This won't happen for a long time to come. Hopefully you will be able to accept this and move on?
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