Why is auto exposure so useless?

[Justinr]

Raw files, plus auto exposure and exposure compensation. I'm happy!

Cheers,

Excellent news!

[Justinr]

I've been very impressed as well, their engineers even managed to make smooth exposure adjustments in real time which you often can't spot in a video.

By the way, someone can explain to me why shooting tractors is so much harder than shooting sports?

Good question, sports shots never seemed to pose the same problems, but I haven't done any with the D3 so it wouldn't really  be fair to comment beyond that, other than to remind ourselves that the camera can carry 30,000 reference shots to compare your frame with and so set the exposure, perhaps sports feature more strongly in that collection than machinery?

Here's one that made it as a two page spread for a major vintage magazine over here, all manual exposure, I guess you'll have something shot with AE that's featured somewhere you'd like to show us.
 

Edit: Correct image now attached.

[razrblck]

I guess you'll have something shot with AE that's featured somewhere you'd like to show us.

Actually yes. Program mode, matrix metering, -1EV to preserve highlights. It was used as a book cover.

[Justinr]

Actually yes. Program mode, matrix metering, -1EV to preserve highlights. It was used as a book cover.

Excellent news! Sunsets will no doubt feature in the cameras bank of reference images as well.

[pegelli]

Here's one that made it as a two page spread for a major vintage magazine over here, all manual exposure, I guess you'll have something shot with AE that's featured somewhere you'd like to show us.

Showing more shots with Manual exposure doesn't prove AE is useless. It can only prove Manual exposure is good as well.
I actually have nothing against Manual exposure and use it sometimes myself, but 95% of my shots is with AE.

Cover of the Dutch Magazine "Prikkels"
Shot in Aperture Priority AE mode.

[Justinr]

Showing more shots with Manual exposure doesn't prove AE is useless. It can only prove Manual exposure is good as well.
I actually have nothing against Manual exposure and use it sometimes myself, but 95% of my shots is with AE.

Cover of the Dutch Magazine "Prikkels"
Shot in Aperture Priority AE mode.

Of course it doesn't, but it does indicate that I do have some idea of what this photography lark may be all about. There are a few on here who are under the impression that I only started yesterday and base their contempt upon that proposition. If it works for you then fine, but kindly accept it doesn't work for everybody or in all situations.

[pegelli]

Of course it doesn't, but it does indicate that I do have some idea of what this photography lark may be all about. There are a few on here who are under the impression that I only started yesterday and base their contempt upon that proposition. If it works for you then fine, but kindly accept it doesn't work for everybody or in all situations.

But if it works for others pls. kindly accept it's not useless. It might be useless for you, but that doesn't mean it's true as a general statement.

Btw, did you notice that in the tractor picture you posted the clouds are blown out as well as some of the red channels on the top of the tractor?

[Justinr]

But if it works for others pls. kindly accept it's not useless. It might be useless for you, but that doesn't mean it's true as a general statement.

Btw, did you notice that in the tractor picture you posted the clouds are blown out as well as some of the red channels on the top of the tractor?

But I have done in a previous post, indeed in the OP I noted the circumstances in which it had no use.

They are not totally blown, there still some texture in the sky, certainly on my screen and the magazine.  But the engine and mechanical's are clearly shown and that's what's important. You may have seen a post of mine in the '2 stops under landscape' thread where I clearly state that sometimes you just have accept a white blanket for the sky as much as you would wish for an alternative. This is Ireland after all.

[Petrus]

This is Ireland after all.

Ireland or not, shooting RAW and exposing for the sky not to blow out, still gives you about 5 stops worth of shadow detail to dig out in the conversion. Even the engine might be there.

OT: used to drive one of those at my godfather's farm in the early sixties, starting when heavy enough to press the clutch down standing on it...

[Justinr]

Ireland or not, shooting RAW and exposing for the sky not to blow out, still gives you about 5 stops worth of shadow detail to dig out in the conversion. Even the engine might be there.

OT: used to drive one of those at my godfather's farm in the early sixties, starting when heavy enough to press the clutch down standing on it...

If the photograph was about the sky then I would have exposed for the sky, or used a filter, but in this case I didn't want any drama to detract from the machine, not that there was much there on the day, the sky would just have been a darker mix of greys. I used a graduated filter on the one attached in a similar situation but I'm not sure that it does the tractor any favours TBH.

MF have actually reintroduced the 35 into their range for the African market, they'll tell you that it is exactly the same as the older model but dig a little deeper and you'll find that it has a new direct injection head and one or two other updates. But still, it's good to see that simplicity still has its place!

[pegelli]

I agree the readers of that magazine are probably more interested to check that the right fuel pump is installed and not so much in a blown out (or dramatic) sky.

In your second picture indeed the dark clouds add nothing to the tractor and might even be distracting. Also the grad filter didn't help prevent all blow-outs, the bit of white sky between the exhaust and the cabin still shows a solid 255, 255, 255. Shooting raw and pulling the highlights gently would probably have brought out a bit of white/bright cloud texture.

[Justinr]

I agree the readers of that magazine are probably more interested to check that the right fuel pump is installed and not so much in a blown out (or dramatic) sky.

In your second picture indeed the dark clouds add nothing to the tractor and might even be distracting. Also the grad filter didn't help prevent all blow-outs, the bit of white sky between the exhaust and the cabin still shows a solid 255, 255, 255. Shooting raw and pulling the highlights gently would probably have brought out a bit of white/bright cloud texture.

The grad filter was there to darken the sky, not the tractor, there are bound to be small areas which escape unless the cab was the same height as the bonnet.

That photo was used by the importers on some of their advertising material and it all looked a bit glum anyway. Throw in  violations caused by the printing process and it all becomes rather academic. Does there need to be a reading in every last pixel? If anything the shot is underexposed rather than over exposed, a compromise was reached although no doubt I am the only one that has ever done such a wicked thing in photography.

[pegelli]

Does there need to be a reading in every last pixel? If anything the shot is underexposed rather than over exposed, a compromise was reached although no doubt I am the only one that has ever done such a wicked thing in photography.

I think that depends on the use. In this picture it's not a problem in my mind, just an observation. However in a landscape shot I usually like it better when I don't have larger areas at 255/255/255 and get as much texture in the clouds as possible. Still some smaller strands of 255/255/255 don't hurt and you certainly need to watch that whole sky/clouds doesn't become too grey since that's even worse compared to a few areas of pure white.

[Justinr]

I think that depends on the use. In this picture it's not a problem in my mind, just an observation. However in a landscape shot I usually like it better when I don't have larger areas at 255/255/255 and get as much texture in the clouds as possible. Still some smaller strands of 255/255/255 don't hurt and you certainly need to watch that whole sky/clouds doesn't become too grey since that's even worse compared to a few areas of pure white.

Well that's pretty much my position as well, again if you refer to the '2 stops under landscape' thread I think that is what I suggest. Commercial photography is creating an image suitable for its intended use, which might not be the same as one that meets the critical demands of Lula posters, as strange as that may seem.

[Justinr]

So why are you pushing people to look at your website when that has no relevance to "Why is auto exposure so useless?"


 Bogus - what you have not done is provide any example photographs showing there were "circumstances in which it had no use".

Because I'm a scheming oligarch bent on world domination.

It's the eating of babies that does it y'know.

[Rory]

Why is auto exposure so useless?

Because I'm a scheming oligarch bent on world domination.

It's the eating of babies that does it y'know.

This about sums it up for this thread.

[Slobodan Blagojevic]

Pardon me for reviving this old and contentious thread, but one thing has come to my attention recently that might additionally explain matrix/evaluative metering inconsistencies.

Although it was indeed briefly mentioned in the initial Wikipedia article I referenced to on page 4 (where the main "culprit," was a bank of "30,000 scenes"), I've come across a diagram that explains visually how focusing points might contribute to differences in exposure of the same scene. In other words, matrix/evaluative metering shifts exposure emphasis based on the selected focusing point. The illustration comes from this Canon link.

While I was aware of such a function (one of my Canons had a menu option to link AE point to AF point) and I was using it actively, it only recently dawned on me that it might have contributed to the issues Justin was facing. As much as this function is predicated on the assumption that where you focus is where your main point of interest is, thus the overall exposure should be based on that too, there are situations where this may not be necessarily so. In other words, although the whole scene is the same, two (or more) subsequent exposures may not be, depending on where you focus.

[torger]

Another note about auto exposure is that it's designed like for a film camera. This may be changing now (I'm not following the latest so well), but it has been so for a long time.

When the raw image is converted to a jpeg there's a fixed contrast curve applied and auto exposure is trying to put midtones in the middle of that contrast curve so you get a good looking jpeg. This means that in terms of optimal raw exposure it will under-expose in certain conditions, certainly in low contrast conditions.

[razrblck]

Nikon Matrix metering takes into consideration color hue and saturation as well. If you have the same subject under the same light, but one is red and the other is blue, you will get different results.

[stamper]

There is supposedly 30,000 images in the camera that is referenced when you press the shutter and the camera chooses one of them. What I don't understand is if you have a setting of +1 EV or a setting of -1 EV are there any images that correspond to any of the two settings?