Exposure question!!!!!

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DGN1984

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Hi,

Last night in the photography evening class I have just started we spent a fair bit of time discussing exposure. We did the whole photograph the white black and grey cards and they all come out the same colour thing.

What has confused me is my tutor was explaining that sometimes you may need to compensate for what the camera will do. For example if you were photographing a very dark skinned man with dark hair the camera automatically picks up that this subject is very dark and compensates for that by overexposing, sometimes too much. Therefore in these circumstances it is sometimes best to underexpose to get a correct exposure.

Similarly if you were photographing trees covered in very white snow the camera picks up that this is very bright and therefore underexposes so you may choose to overexpose slightly to get a correct exposure.

My question is

A) is this correct?
B) I'm now panicing that I need to slightly underexpose everything really dark and overexpose everything really light. Is this just in extreme circumstances? if the meter looks right can I go with this most of the time and adjust in Photoshop or do I need to always take the above into consideration?

I'm interested in your thoughts in this,

Thanks in advance

Dan
 
Thanks Dave,

I am planning to start photographing a lot of bands so bracketing is probably out as there is too much movement. How do I evaluate each exposure?

Cheers
 
^^^^^^^
Yup

Except, the histogram is a graphic representation of what the meter says, so may not be right even so. Look, and decide whether its right and go with what you feel. Metering won't be learned in a day.
 
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You can still bracket. It's not like your going to create HDR images of the bands.

The first thing to learn about photography is that you will NOT like a lot of your images. I don't like a lot of my images.

I would say if you take 50 photos and really nail 1 on the head, then I think you doing ok. My local pub has Live bands (mainly rock and metal) every friday night. On some nights I've come home with 250+ photos and failed to nail a single shot. You can't expect every photo from every session to be usuable.

You've just got to experiment. Just remember to take tons of shots.

P.s. Do as Dave suggested and bracket.
 
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Turn on the "blinkies" to show blow highlights on your LCD. It will then be up to you to decide if you need to compensate based on what is blown out.
 
Thanks mate,

Just before I dart out the office, would you bracket a whole stop either side or just a 3rd of a stop or what?
 
There is another method of course, which is a fall back, and that is to shot in RAW and not jpeg. This allows you to adjust the exposure, amongst other things, at the PP stage. I suspect the majority of TP members shoot in RAW format.
 
DGN1984 said:
What has confused me is my tutor was explaining that sometimes you may need to compensate for what the camera will do. For example if you were photographing a very dark skinned man with dark hair the camera automatically picks up that this subject is very dark and compensates for that by overexposing, sometimes too much. Therefore in these circumstances it is sometimes best to underexpose to get a correct exposure.

Similarly if you were photographing trees covered in very white snow the camera picks up that this is very bright and therefore underexposes so you may choose to overexpose slightly to get a correct exposure.

My question is

A) is this correct?
B) I'm now panicing (...)
Click to expand...

Yes it is correct.
No you don't need to panic!

I'd recommend getting hold of a copy of either Perfect Exposure or Understanding Exposure both of which address and clearly explain the issues (in different styles) - for a tenner you can't go wrong, and both are often in your local library as well.


As for gig photography - there's been plenty of topics with detailed advice about this on the forum recently. I've never had major problems shooting shows in Av mode & RAW, but tend to go for wider shots instead of closeups of artists. Oh, modern LED lights can really throw your white balance out though with all their saturated blue, which is another reason to shoot RAW. If I have time, I use a seperate (spot) light meter on the important areas and shoot manual though, but you aren't normally going to be able to do this...
 
Mark Christopher said:
You can still bracket. It's not like your going to create HDR images of the bands.

The first thing to learn about photography is that you will NOT like a lot of your images. I don't like a lot of my images.

I would say if you take 50 photos and really nail 1 on the head, then I think you doing ok. My local pub has Live bands (mainly rock and metal) every friday night. On some nights I've come home with 250+ photos and failed to nail a single shot. You can't expect every photo from every session to be usuable.

You've just got to experiment. Just remember to take tons of shots.

P.s. Do as Dave suggested and bracket.
Click to expand...

Aint ya glad it's digital and not film :naughty:
 
phil8139 said:
Aint ya glad it's digital and not film :naughty:
Click to expand...

Exactly.

and the other great thing with digital is that you can quickly check your images (albeit on a small screen) to see if the exposure looks OK, you can then work around the best images for the rest of your exposures, assuming the lighting doesn't change during the show too much. Mind you I've found that the image on the screen isn't really a great one to place all your trust in.

When I was using film on the paper I worked on the basis that to get the shot I needed I'd take between 7-15 frames. Of course you didn't know for certain then what the final result would be like until you pulled the negatives out of the developing tank. By which time it was too late to re-shoot and it was either (y) or :shake:.
 
johnnypanic said:
Turn on the "blinkies" to show blow highlights on your LCD. It will then be up to you to decide if you need to compensate based on what is blown out.
Click to expand...
Use the 'Blinkies'.I forgot about that one. Thanks for reminding me.
 
You can use automatic exposure bracketing (AEB) and on a DSLR you can determine how greater or lesser the amount of exposure change is (1 stop, 1/2 stop etc).

On some compacts you can set exposure compensation and do it manually. Set it to the - side for dark subjects, to the + side for bright subjects. The camera is set to exposure for a mid-tone gray. If it doesn't detect that gray, it will shift what it sees to be mid-tone gray. That's why you get grey snow sometimes. The histogram and the lcd playback is invaluable.

That's a bit complex for a beginning photography class, I usually leave it to week 5 of a 5 week course ...
 
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What your tutor was trying to demonstrate by getting you to photograph black and white objects is that under some circumstances your camera meter can be fooled in to giving the wrong exposure.

As a generalisation, the meter is programmed to assess the entire scene, assume that that the light across that scene will average to what would be reflected from an 18% grey card, and expose accordingly.

In a lot of cases this works fine, but it's not foolproof. As you have seen, pointing the camera at a black card, the camera assumes 18% grey and subsequently overexposes, because the scene is actually darker than the camera is assuming. The opposite is true when you point the camera at a white card.

If you look at a lot of the photographs that people posted during the last snowy spell, you will see that they didn't take the overall brightness of the scene in to account, left their cameras to fend for itself in assessing the correct exposure, and ended up with grey looking snow as a result.

As long as you are aware that the camera can be caught out in extremely bright/dark situations, you are on the right road to recognising when you need to give the camera a helping hand to get the exposure right.
 
DGN1984 said:
Hi,

Last night in the photography evening class I have just started we spent a fair bit of time discussing exposure. We did the whole photograph the white black and grey cards and they all come out the same colour thing.

What has confused me is my tutor was explaining that sometimes you may need to compensate for what the camera will do. For example if you were photographing a very dark skinned man with dark hair the camera automatically picks up that this subject is very dark and compensates for that by overexposing, sometimes too much. Therefore in these circumstances it is sometimes best to underexpose to get a correct exposure.

Similarly if you were photographing trees covered in very white snow the camera picks up that this is very bright and therefore underexposes so you may choose to overexpose slightly to get a correct exposure.

My question is

A) is this correct?
B) I'm now panicing that I need to slightly underexpose everything really dark and overexpose everything really light. Is this just in extreme circumstances? if the meter looks right can I go with this most of the time and adjust in Photoshop or do I need to always take the above into consideration?

I'm interested in your thoughts in this,

Thanks in advance

Dan
Click to expand...

That's basically right, but your terminology is wrong. You are not under or over exposing when you make adjustments. It's the meter that is doing that, because it's confused by a subject that has predominently light or dark tones which it tries to make grey, and you are correcting it.

String said:
^^^^^^^
Yup

Except, the histogram is a graphic representation of what the meter says, so may not be right even so. Look, and decide whether its right and go with what you feel. Metering won't be learned in a day.
Click to expand...

The histogram is nothing to do with what the meter says. It is a graphic representation of the actual exposure, and as such it is the most accurate measure of exposure you can get.

The LCD image, the histogram and blinkies are all derived from a JPEG of the Raw, with all the camera pre-sets applied - exposure, white balance, picture styles, noise reduction, the lot.

johnnypanic said:
Turn on the "blinkies" to show blow highlights on your LCD. It will then be up to you to decide if you need to compensate based on what is blown out.
Click to expand...

Blinkies are excellent, and give you a peg to hang the important highlights on. Get that right, and everything else will fall into line below.

Using the LCD, the histogram and blinkies together is the ultimate guide to optimum exposure.

DGN1984 said:
Thanks mate,

Just before I dart out the office, would you bracket a whole stop either side or just a 3rd of a stop or what?
Click to expand...

Shooting gigs is difficult. The subject is very testing for a start, then it all changes by the second.

Get a fix on the general light level as best you can using spot metering and then the LCD/histogram/blinkies, and then bracket using the auto-bracket feature. If you rattle off a sequence of three each time at 0, +1 and -1 you should increase your hit rate a lot.

So long as the blinkies are not going mad on the subject itself, you won't over-expose. The more exposure you can give without that happening, within reason, the better contrast and less noise you'll have. If there are lights in the picture, they will probably blow. Let them, you'll never hold them without the rest of the image going too dark.

Aim to get the blinkies just flashing on skin highlights, like cheeks and noses etc, then knock it back 1/3rd of a stop. If you shoot Raw, that will give you a little bit more headroom in post processing (but it's not a get out of jail free card).
 
HoppyUK said:
That's basically right, but your terminology is wrong. You are not under or over exposing when you make adjustments. It's the meter that is doing that, because it's confused by a subject that has predominently light or dark tones which it tries to make grey, and you are correcting it.

The histogram is nothing to do with what the meter says. It is a graphic representation of the actual exposure, and as such it is the most accurate measure of exposure you can get.

The LCD image, the histogram and blinkies are all derived from a JPEG of the Raw, with all the camera pre-sets applied - exposure, white balance, picture styles, noise reduction, the lot.

Blinkies are excellent, and give you a peg to hang the important highlights on. Get that right, and everything else will fall into line below.

Using the LCD, the histogram and blinkies together is the ultimate guide to optimum exposure.

Shooting gigs is difficult. The subject is very testing for a start, then it all changes by the second.

Get a fix on the general light level as best you can using spot metering and then the LCD/histogram/blinkies, and then bracket using the auto-bracket feature. If you rattle off a sequence of three each time at 0, +1 and -1 you should increase your hit rate a lot.

So long as the blinkies are not going mad on the subject itself, you won't over-expose. The more exposure you can give without that happening, within reason, the better contrast and less noise you'll have. If there are lights in the picture, they will probably blow. Let them, you'll never hold them without the rest of the image going too dark.

Aim to get the blinkies just flashing on skin highlights, like cheeks and noses etc, then knock it back 1/3rd of a stop. If you shoot Raw, that will give you a little bit more headroom in post processing (but it's not a get out of jail free card).
Click to expand...



This advice for blinkies is spot on. I often hear people saying disparaging things if you say you use blinkies to judge exposure, but for the life if me I don't understand why people would ignore such a useful tool. They show you WHICH areas of the images are blown which is really important and far more useful than a histogram IMO. As hoppy says you have a bit of latitude with RAW so if your brightest important tones in your picture are almost blinking everything else falls into place.
 
lensflair said:
This advice for blinkies is spot on. I often hear people saying disparaging things if you say you use blinkies to judge exposure, but for the life if me I don't understand why people would ignore such a useful tool. They show you WHICH areas of the images are blown which is really important and far more useful than a histogram IMO. As hoppy says you have a bit of latitude with RAW so if your brightest important tones in your picture are almost blinking everything else falls into place.
Click to expand...


:plus1: :agree:

I don't even use the histogram... takes too long to analyse and in a complicated scene isn't anywhere near as helpful as the blinkies, as the histogram doesn't tell you what the exposure on the subject is like, just the overall exposure across the entire scene!
 
Hi Everyone,

Thanks for all the posts, tips and advice, it is really appreciated so thanks a lot.

I shot at a gig last night for the first time ever (I have put details of how I got on on another thread I started and will post some pictures over the weekend) Mark, you are on the money, 115 pictures taken last night and I've probably got two or three that I'm relatively happy with for a first time shoot but even still they are a million miles away from the stuff I look at and think, wow, that's good!

Richard, I will take your advice and pick up one of the books you recommended so thanks for that.

I think for now I will use the LCD screen to try to determine if the exposure is around about correct as the histogram looks too complex at this stage. Is it just a case of taking a few test shots and having a look on the LCD with the display showing the picture details to decide when your exposure is where you want it??

Now the big question! last night when looking back through the pictures on the LCD with all deatils displayed, parts of the image were displaying blinking symbols. I've never seen this before and had no idea what this was. I intended to post today to ask and can see that over night there are already a few posts on this. Ultimately as I understand it when viewing the picture details once I've taken the picturethe areas that are overexposed will blink. last night the lights on stage were blinking but there's not much I could've done about it. What are the main advantages of this feature and how/when should I use it. I will also do some research myself.

For your information I am using a Canon 450D

Thanks again for all the replies

Cheers

Dan
 
Anyone who says the histogram and blinkies are not the best guide to accurate exposure doesn't appreciate how digital works. And I'd inlcude Bryan Peterson in that (author of that inexplicably popular book, Understanding Exposure) who dismisses the whole thing in one sentence!

The point is, the LCD/histogram/blinkies show an actual image - there's no guesswork, which there is a lot of with any meter reading. If you know what you're looking at, they cannot be wrong - it's only if you misinterpret them. The facts are there.

The main danger is just looking at the image/picture and thinking it looks fine, so everything's good. But this is highly dependent on the viewing conditions and the brightness setting of the LCD. For example, we often turn that up so it can be seen better in sunlight, which is dangerous. Likewise, in very dim light, like the OP's gig perhaps, even an underexposed image can look okay on the screen.

The blinkies give you an absolute guide to the exposure ceiling on the sensor, though they actually begin to flash fractionally before the subject blows, as a warning, and they will also flash at slightly different levels according to the contrast setting in picture styles. They'll never be far off, but there's maybe a stop of difference available by testing your own camera/settings and post processing regime to see exactly where you are.

Shooting a gig is a good example of using both the histogram and blinkies together, because it's quite likely that you'll have very bright lights directly in the picture which you're never going to hold, and the histogram will be a good guide to how far you can push things. Looking at the histogram for that, there will be a very bright area on the right, blinkies flashing, then probably a gap to a lump around the middle which is the main subject, and then a large area of dark tones on the left which is the background.

In that situation, I would forget the bright lights and let them blow to heck, but increase the exposure to pull the mid-tones up a bit. Make sure they're just to the right of the middle with a decent amount of light in there. On the whole though, I agree that trying to read too much into a histogram on the hoof is difficult. They vary a lot even with the same subject, but just look at the general shapes on the right and middle particularly. Get that sorted, and let the left shadow end look after itself unless it's particularly important.

Edit: the point about pushing things to the right of the histogram, is that there is far more data recorded there - like many times more than the left. That's what gives much better tone separation, cleaner colours and much less noise. Under exposure is death to image quality - dark, muddy colours, lots of noise - but over exposure (blinkies flashing) means you've blitzed it and got nothing! With subjects like a gig, that's a tricky balance to strike :D
 
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DGN1984 said:
... What are the main advantages of this feature and how/when should I use it.
Click to expand...

Once you have taken the photo, the 'blinkies' and histogram are aids to let you know if it has exposed correctly.

The blinkies will show you over (and possibly under) exposed parts of the image.
The histogram will show a graph of exposure for the image.

An 'ideal' histogram of an nice even image is a nice symmetrical shape, starting just in from one end, rising smoothly, flat along the top, then falling smoothly to finish just in from the other end. IE using the full extend of your cameras exposure range but not exceeding it.

In practice, histograms are often quite uneven, but you shoudl still aim to have them 'fit' in the display, rather than shifted to one end (and clipped).
If they are shifted to one end, you should use exposure compensation to shift it back towards the centre and re-shoot.

At other times, there is simply too much range for the camera to capture it all - the histogram is clipped at both ends.

In this case the 'blinkies' will show you which areas on the shot were over exposed (clipped on the right of the histogram), allowing you to decide if you are happy you have done the best you can, or want to over or under expose to try and get more shadow detail or reduce blown highlights.

In your example, you would expect the lights to be blown, but would probably not want anything else to be blinking.
 
Faldrax said:
Once you have taken the photo, the 'blinkies' and histogram are aids to let you know if it has exposed correctly.

The blinkies will show you over (and possibly under) exposed parts of the image.
The histogram will show a graph of exposure for the image.

An 'ideal' histogram of an nice even image is a nice symmetrical shape, starting just in from one end, rising smoothly, flat along the top, then falling smoothly to finish just in from the other end. IE using the full extend of your cameras exposure range but not exceeding it.

In practice, histograms are often quite uneven, but you shoudl still aim to have them 'fit' in the display, rather than shifted to one end (and clipped).
If they are shifted to one end, you should use exposure compensation to shift it back towards the centre and re-shoot.

At other times, there is simply too much range for the camera to capture it all - the histogram is clipped at both ends.

In this case the 'blinkies' will show you which areas on the shot were over exposed (clipped on the right of the histogram), allowing you to decide if you are happy you have done the best you can, or want to over or under expose to try and get more shadow detail or reduce blown highlights.

In your example, you would expect the lights to be blown, but would probably not want anything else to be blinking.
Click to expand...

No. There is no such thing as an ideal shape to the histogram, which depends entirely on the range of tones in the subject. If you are shooting an elephant on a grey background then you would get a lump in the middle as described, but otherwise, hardly ever.

The only thing I'd agree with is that, ideally, the whole scene should be contained between the two ends but in reality that's not often the case. And bearing in mind that there is so much more data recorded on the right than the left (round numbers, like 100x times more) then there is great merit in pushing the important tones further to the right (Expose To The Right technique). So long as nothing important is blown (blinkies flashing) you will max out the sensor and get optimum image quality that way.

The rider there is that if you push things a long way to the right, then you need to shoot Raw and darken things down a bit in post processing to restore the tonal values to their rightful position, but the reward for that is much better shadow tone separation and less noise.

A simple guide to reading the histogram is to check to see if there's a gap on the right. If there is, then you're wasting potential quality. Push the lump to the right, make sure blinkies aren't flashing on anything important and you're there.
 
Peter10d said:
There is another method of course, which is a fall back, and that is to shot in RAW and not jpeg. This allows you to adjust the exposure, amongst other things, at the PP stage. I suspect the majority of TP members shoot in RAW format.
Click to expand...

Shooting RAW will not compensate for incorrect exposure! All that happens in raw format is that the image is native to what was captured by the camera. Normally with jpegs the camera will apply an algorithm designed to give the best balance between image size, quality etc. Using RAW and over or under exposing will still give an over or under exposed picture!
 
khitomer said:
Shooting RAW will not compensate for incorrect exposure! All that happens in raw format is that the image is native to what was captured by the camera. Normally with jpegs the camera will apply an algorithm designed to give the best balance between image size, quality etc. Using RAW and over or under exposing will still give an over or under exposed picture!
Click to expand...

But an over/under exposed RAW that can be corrected (unless the exposure is completely FUBAR'd) without any noticable degradation in quality and is generally more forgiving in terms of PP than a JPEG.
 
This is probably getting too complex for this thread but I think the reason some don't like using the histogram etc is that a lot of cameras (the cheaper ones) only display a brightness histogram rather than an RGB histogram.
The problem being that, with a brightness histogram you could having clipping of the red channel (for example) which is not seen on the histogram. I've seen this quite often with my D50, something like a red flower can look perfectly exposed but when you try to recover so detail from the flower (even using raw) you find it isn't there. That used to be my main complaint about the D50 IQ until I realised what was happening.

There is some quite useful info about it here...
http://www.primeimages.co.uk/Photography%20tips/photo%20tips3.htm

Toby
 
Russ77 said:
But an over/under exposed RAW that can be corrected (unless the exposure is completely FUBAR'd) without any noticable degradation in quality and is generally more forgiving in terms of PP than a JPEG.
Click to expand...

I think the point is that the way it was orignially expressed (now qualified) suggested that shooting Raw somehow gave immunity to exposure errors, which it absolutely does not.

The JPEG is generated from the same Raw file whichever way you do it, but the difference is that if you work on the Raw file you can re-access the original data, including the stuff that the JPEGing process has discarded, and process it differently/better.

And you can get more out of most images that way, but the reality is that if you are more than a stop out with the Raw you've either not got optimum data to work with, or it's blown off the top of the scale anyway and unrecoeverable. You still have to be careful.
 
khitomer said:
Shooting RAW will not compensate for incorrect exposure! All that happens in raw format is that the image is native to what was captured by the camera. Normally with jpegs the camera will apply an algorithm designed to give the best balance between image size, quality etc. Using RAW and over or under exposing will still give an over or under exposed picture!
Click to expand...

I agree with your point, however assuming the shot is not way out in terms of exposure, RAW gives you the option to adjust it, usually to good effect within a couple of stops either way.
 
I got off my bum and went down the pub on Thursday night with my camera. Got a few shots that I think I can use. Sadly I forgot my speedlite and I don't like the in camera flash. Just Shot in RAW at ISO 800 all night compensating for exposure on the fly. Used a Canon 400d with 50mm f/1.8

GigShot06.jpg


GigShot02.jpg


GigShot04.jpg


I even got some shots on the way home!

WorkMen01.jpg


All photos as shot with a little quick sharpening. Now for the bit I don't like! Post Production!
 
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