I'm reading Michael Freeman's book 'Perfect Exposure' hoping to improve my photography. I've seen comments in various magazines, etc. about the metering behaviour of various cameras, and wonder if anyone has any pointers, or tips, for the D90 (which I've been unable to find)?. Not sure if Magic D90 guides, or anything similar, contains the information I'm looking for?
D90 metering/exposure compenation
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Edbray a TP member on here has a post on exposure - that may help you out, before you go and spend your hard earned pennies... understaning exposure
Its not specifically aimed at the D90 thou - just thought that I would point that out..
Its not specifically aimed at the D90 thou - just thought that I would point that out..
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Not totally sure what kind of questions you have about metering :shrug:, kartracer, but as an opener I would say;
Nikon's "Matrix Metering" (that's the icon on your camera which looks like a dot with four squares around it
) is widely regarded as being one of the best all round metering systems ever designed for an SLR/DSLR camera. The D90 has a huge database of (300,000 IIRC 
) different types of scene and subject built in, which it uses to help compensate exposures with (rather than aiming for the standard '18% grey' light level).What this means is that you should get the most consistently acceptable results in a variety of different lighting conditions, if you leave your camera set to this setting. Besides which, we're talking about digital cameras here - it's not like the old days of film, when you had to get your exposure spot on the first time or bracket like hell :shrug:! Now, if your magic matrix metering results in a histogram where your peaks are bunched up at one end, you can can just dial in some exposure compensation and try again until it looks right.
As a side note, when I was learning about photography (only 18 months ago), I got really hung up on the whole subject of exposure and thought that there was some magic recipe for perfectly exposing any scene and that if I read enough books I would find it. When I tried pointing my camera at a tree (for instance) that was back-lit by sunlit clouds on blue sky, I was horrified that I could only get either a shot of a beautiful blue sky with a black tree in front of it, or else a beautiful green tree against a nuclear explosion of white clouds on whitish sky
. This exposure issue relates to something called 'dynamic range' and this is what a lot of newer photographers seem to be unaware of (not surprising, as a lot of the text books seem to skip around this subject ).My apologies if you know all of this already, but in short, some scenes are just 'un-photographable', at least in the sense that you can't just point a bare lens at them and expect all of the dark and light areas to magically squeeze themselves into a smaller range that your cameras sensor can deal with. Again, this is not about which exposure method you choose, it's simply physics. A lot of times, the best that you can do is to try and use a smaller size aperture (helps to decrease the dynamic range) and use your exposure compensation dial and the camera's LCD screen to decide how you want the final picture to look (i.e. with some black areas or with some blown highlights).
In my opinion, with a camera like the D90 (i.e. great auto metering system and very clear LCD display), it really is possible to just 'wing it' as I described above. I really don't know how much value there would be in a whole book devoted to metering systems, when the instruction manual pretty much covers what they do :shrug:. Still, I don't know what it is that you want to know about exposure, so I don't mean to put you off.
I hope that this post will help you in some way, although reading it back to myself, I'm not sure if it has the tone that I was aiming for (a bit patronizing, maybe :shake
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#2If you want high dynamic range in a single shot, I don't think there is a way around the Fuji Sx Pro or negative films.
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OK, let me try again.Think of light entering a lens and hitting the sensor like water going into a bucket (common analogy). With a wide aperture and the resultant quick exposure, the light (water) all goes in in one quick go and 'floods' onto the sensor, quickly filling up the sensor to it's light capacity but without the darker areas in the image having much time to make an impact and be recorded as dark browns, greens, or whatever colour they are.
Conversely, using a smaller aperture and longer exposure time restricts the very bright light (highlights) and slows down their flow to the sensor, whilst at the same time allowing the darker areas to make an impression on the sensor. The net result is that you get an image with less dynamic range, as the highs are darker and the lows lighter - you also get better contrast for similar reasons.
This may well be another reason why landscape photographers tend to prefer using the smaller apertures - it doesn't just benefit DOF
!Am I making sense yet :shrug:?
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If you want high dynamic range in a single shot, I don't think there is a way around the Fuji Sx Pro or negative films.
OK, my turn
...I don't understand this sentence at all :shrug:!?
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Think of light entering a lens and hitting the sensor like water going into a bucket (common analogy). With a wide aperture and the resultant quick exposure, the light (water) all goes in in one quick go and 'floods' onto the sensor, quickly filling up the sensor to it's light capacity but without the darker areas in the image having much time to make an impact and be recorded as dark browns, greens, or whatever colour they are.
Conversely, using a smaller aperture and longer exposure time restricts the very bright light (highlights) and slows down their flow to the sensor, whilst at the same time allowing the darker areas to make an impression on the sensor. The net result is that you get an image with less dynamic range, as the highs are darker and the lows lighter - you also get better contrast for similar reasons.
This may well be another reason why landscape photographers tend to prefer using the smaller apertures - it doesn't just benefit DOF
Am I making sense yet :shrug:?
not really - the amount of light it takes to exposue a pixel doesn't vary with time. You let the same amount of light in as you decrease app. size by also decreaseing shutter speed.
Thanks folks. This book covers in detail, and technically, things like dynamic range, etc.
And then there's HDR imaging - a multiple exposure teachnique.
I don't want to get sloppy, so I've revisiting the technical aspects, and want to move beyond snap-shooting to something more, er, artistic. So I figured that understanding exposure better might be a start.
My earlier reference to a magazine article was where someone said they recommended always shooting plus half a stop to compensate for the sensor. I thought the camera concerned was a Nikon D-something, but cannot recall. So that's why I was wondering about the D90.
I believe I've used Nikon matrix metering on my old F90X!
And then there's HDR imaging - a multiple exposure teachnique.
I don't want to get sloppy, so I've revisiting the technical aspects, and want to move beyond snap-shooting to something more, er, artistic. So I figured that understanding exposure better might be a start.
My earlier reference to a magazine article was where someone said they recommended always shooting plus half a stop to compensate for the sensor. I thought the camera concerned was a Nikon D-something, but cannot recall. So that's why I was wondering about the D90.
I believe I've used Nikon matrix metering on my old F90X!
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OK, my turn
I don't understand this sentence at all :shrug:!?
film has a far higher dynamic range then digital sensors - hence the suggestion its a good way of getting a higher range. The Fuji Sx'x are well know for the high dynamic range of the sensors
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Not to me, sorry. I don't think you can trick the laws of physics. If anything, the sensor might record a better image when meeting more photons in a shorter period of time, as the signal to noise ratio increases.
The Fuji Sx Pro Sensors have small and big sensor pixels adjacent to each other. The small one will obviously receive less photons than the big pixel and therefore might not oversaturate (blown highlights) when exposed to large quantities of light.OK, my turn
I don't understand this sentence at all :shrug:!?
With negative film, it is the non-linear progression of exposure in highlights.
Think of light entering a lens and hitting the sensor like water going into a bucket (common analogy). With a wide aperture and the resultant quick exposure, the light (water) all goes in in one quick go and 'floods' onto the sensor, quickly filling up the sensor to it's light capacity but without the darker areas in the image having much time to make an impact and be recorded as dark browns, greens, or whatever colour they are.
Conversely, using a smaller aperture and longer exposure time restricts the very bright light (highlights) and slows down their flow to the sensor, whilst at the same time allowing the darker areas to make an impression on the sensor. The net result is that you get an image with less dynamic range, as the highs are darker and the lows lighter - you also get better contrast for similar reasons.
This may well be another reason why landscape photographers tend to prefer using the smaller apertures - it doesn't just benefit DOF
Am I making sense yet :shrug:?
Yes, perfectly clear. See also HDR imaging techniques to extend the range.
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but not correct though
Freeman mentions that 'correct' exposure is what is commonly held/agreed.
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sorry - I should of been clearer, although Naboo32's train of thought makes sense - its not correct. Thats what I meant
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Not that this sentence of mine has anything to do with the OP - but I'm glad to read that I wasn't the only one who noticed what you mentioned there Nab's...
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OK, thanks Hugh. The reference to film and to the Fuji, make sense now. I think that it's the different way in which Cistron and I describe dynamic range, which confused me. I would have expressed it the opposite way around (i.e. if you don't want high DR in an image, use fil etc.). Semantics really, but it all makes sense to me now
.All I can really say in reply to this is that in my experience and in several books and articles that I've read, it is acknowledged that harsh highlights can be controlled by using smaller apertures. A logical extension of this is that when you get down to the very smallest aperture on any lens, you see a massive reduction in contrast.
I suppose that we could test this theory by taking two shots of any identical scene (with constant lighting) in which the histogram just exceeds both edges when using the largest aperture. Then, in the second shot we could use the min aperture. If what I believe to be correct is correct, then the histogram should show that the highs and lows are just within the limits of the range of the second image. In other words, the dynamic range of the overall image on the camera sensor has been reduced by virtue of the use of the smallest aperture.
Of course, it would be absolutely crucial to find a scene where the histogram is very close to it's limits, otherwise if it is already way over the DR that the camera can handle, we wouldn't see any significant difference between the two :shrug:.
I can't do this now from work, but I might have a go at the weekend and post some results.
So, sorry that I didn't really answer the question that you were asking KR, but at least you've found what you were looking for now
.
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Thanks Steve.
Yes, it was a complete surprise to me when I eventually discovered that the dynamic range of a digital camera is (currently) less than that of 35mm film and a long way short of what the human eye perceives.
It would be really nice if all beginners photography books would just come straight out and say this at the beginning. I'm sure that loads of newbies needlessly wander around asking themselves what they're doing wrong for the first few weeks/months, just as I did
.
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Thanks Steve.
Yes, it was a complete surprise to me when I eventually discovered that the dynamic range of a digital camera is (currently) less than that of 35mm film and a long way short of what the human eye perceives.
It would be really nice if all beginners photography books would just come straight out and say this at the beginning. I'm sure that loads of newbies needlessly wander around asking themselves what they're doing wrong for the first few weeks/months, just as I did
Totally agree
but unfortuneatly it wont ever happen thou which is a shame.I'll await for the day that an "absolute beginner" will write a book instead of the "pro's" writing one aimed at an absolute beginner.. will it ever be..:shrug:
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This might be a matter of flare. For example, blown out street lamps in night photography tend to produce more flare at smaller f-stops.
I'm happy to see your test results though.
Coming back to semantics, I define dynamic range as the maximum contrast that can be captured in an image. Usually for slide film that is roughly 10 stops (~1:1000), for negative film up to 14 stops (~1:16000), normal digital sensors will range from 8 to 10 stops, the Fuji S5 has been shown to capture 12 stops (~1:4000).
If the dynamic range of a scence is greater than your capturing capabilities, you will either lose detail in the bright or dark areas of your image. Bright sunshine and shadows can easily give you 1:100000, which cannot be banned onto an image without several exposures or the use of filters (yet).
It would be really nice if all beginners photography books would just come straight out and say this at the beginning. I'm sure that loads of newbies needlessly wander around asking themselves what they're doing wrong for the first few weeks/months, just as I did
Freeman makes this point clearly. The camera/sensor does not see the same as the human eye - the latter uses scanning and active vision to make up a persistent image. The sensor is adjusted to mid-tones, in an attempt to get a correct exposure of the image, or something like that...
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I think that we're moving closer to agreement here, Mike
.All that was causing confusion was that I was talking about the image on the sensor (i.e. what has been through the lens), whereas you were talking about the image in front of the camera/lens. If you keep that in mind you will see that each of us are actually talking about the same thing.
As for what you said about flare etc., I agree with that too
. All I said in my OP was that using a smaller aperture (than the largest possible) helps to decrease the dynamic range (on the camera's sensor). Stopping down does often help to reduce flare, which would in turn decrease the dynamic range of your final image, assuming that the flare present at the max aperture was the brightest thing in the original image .I should say, I'm really sorry that what I've said seems to be so 'wrong' in some people's view - I didn't set out to spread misinformation and will come back here and publicly apologise if what I have described is not backed up by any tests/expert opinions
.For the moment though, I know what I meant and I think it's correct
.
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Then it's a probably a very worthwhile read!Actually, I've just finished his "The Photographer's Eye: Composition" book, which was a bit 'dry', but I couldn't really fault his statements
.
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I should say, I'm really sorry that what I've said seems to be so 'wrong' in some people's view - I didn't set out to spread misinformation and will come back here and publicly apologise if what I have described is not backed up by any tests/expert opinions
For the moment though, I know what I meant and I think it's correct
Right or not
there is certainly nothing to apologise for contributing to an interesting (OK I'm a geek) discussion. That is the point of a discussion forum
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Right or not
Thanks for the comment, Hugh
.I must admit though, as I did state this thing more as a fact than as an opinion, I wouldn't feel right about not correcting that statement if it was proved to be factually incorrect.
I guess that I'm really the geek here
!
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...I've just finished his "The Photographer's Eye: Composition" book, which was a bit 'dry', but I couldn't really fault his statements
Would you recommend the book Nab's :shrug: as its handy to find out what people think/opinions on the these books...
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When I tried pointing my camera at a tree (for instance) that was back-lit by sunlit clouds on blue sky, I was horrified that I could only get either a shot of a beautiful blue sky with a black tree in front of it, or else a beautiful green tree against a nuclear explosion of white clouds on whitish sky
don't mean to add more confusion to the topic, but if I were in this situation, I would meter the sky and keep the detail there, although the tree will go dark, I would try fill flash first (or even a reflector to put some light on the tree), failing that then I would do a HDR image
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To be totally honest with you, Steve, my feeling after reading this book was that its message on composition was; "This is what a lot of people do regarding framing/focus/colour etc., but that makes it quite predictable and therefore not very exciting so try and do something different if you want your pics to stand out
". Kind of an 'anything goes' message and not much help, I thought.Quite honestly, I don't think that it told me anything that I didn't already know after a year of experimenting and reading stuff on this forum :shrug:. In some ways I felt cheated at buying it and not learning much from it, but on the other hand I felt quite relieved to know that there are no 'magic secrets' to composition
.Would I recommend it generally :|? Actually, no. I think that only beginners (or people who've just 'snapped' for years) would find the content educational, although I also believe that they would find it too intimidating, as it does get a bit overly technical in some parts (IMO).
I think that analysing your own, and other people's, photographs to see what you like and what you don't like about them is about the best (and cheapest) way to learn. That's just my opinion, which is what you asked for
.
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... That's just my opinion, which is what you asked for
That I did & I thank you for your opinion - also its saved me a couple of quid as well
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For those of who who've followed this thread, I have to report that I have made some test shots to support the statement put forward by me earlier, in which I stated that using a smaller aperture would produce an image on the sensor with less dynamic range than would one of similar exposure but at the max aperture, and the results don't support this as clearly as I would have expected :|.
I could be bothered to download them and try and find a way to show the histograms in this thread, but essentially I photographed the view from my window; once at f/2.8 and again a second later at f/32. Apart from the obvoius DOF differences, the images looked to be similarly exposed (actually the f/2.8 example looked brighter) and both of them showed a histogram which only just fitted into the range (i.e. no black and no pure white). It is true to say that in all of the test exposures that I made, the histograms for the f/32 exposures were all very slighltly narrower than those made at f/2.8, but this difference was so small as to make no major difference :shake:.
So, I accept that my earlier statement was, if not totally wrong, was certainly not as right as I made it sound. Please accept my apologies if I confused you and now try to forget what I posted.
Cheers!
Andy
I could be bothered to download them and try and find a way to show the histograms in this thread, but essentially I photographed the view from my window; once at f/2.8 and again a second later at f/32. Apart from the obvoius DOF differences, the images looked to be similarly exposed (actually the f/2.8 example looked brighter) and both of them showed a histogram which only just fitted into the range (i.e. no black and no pure white). It is true to say that in all of the test exposures that I made, the histograms for the f/32 exposures were all very slighltly narrower than those made at f/2.8, but this difference was so small as to make no major difference :shake:.
So, I accept that my earlier statement was, if not totally wrong, was certainly not as right as I made it sound. Please accept my apologies if I confused you and now try to forget what I posted
.Cheers!
Andy
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Think of light entering a lens and hitting the sensor like water going into a bucket (common analogy). With a wide aperture and the resultant quick exposure, the light (water) all goes in in one quick go and 'floods' onto the sensor, quickly filling up the sensor to it's light capacity but without the darker areas in the image having much time to make an impact and be recorded as dark browns, greens, or whatever colour they are.
Conversely, using a smaller aperture and longer exposure time restricts the very bright light (highlights) and slows down their flow to the sensor, whilst at the same time allowing the darker areas to make an impression on the sensor. The net result is that you get an image with less dynamic range, as the highs are darker and the lows lighter - you also get better contrast for similar reasons.
This may well be another reason why landscape photographers tend to prefer using the smaller apertures - it doesn't just benefit DOF
Am I making sense yet :shrug:?
Is any of that knowledge or did you just make it up as you went along?
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:nono: Hmm, trollishly worded ... but I'll bite
....Well, it's a mixture of fact (knowledge) and bad interpretation, of something which is quite complex.
The way that I described how light flows onto the sensor via different apertures is true (to the very best of my knowledge). What was less true was the way that I linked it to the dynamic range of the final image on the sensor (it really had more to do with contrast between the mid tones than the overall dynamic range of the captured image).
The effect which I was describing actually has more to do with what Cistron has already pointed out in an earlier post - a smaller aperture can reduce flare and compensate for some of the unwanted strong light that shooting at max aperture can produce, sometimes resulting in less blown highlights (which might ultimately give you a photo with a narrower dynamic range). It's more a function of the lens than the sensor.
My belief, up until yesterday, was that by using a smaller aperture the overall range from dark to light would be restricted - my tests proved that this is far less noticeable than I thought it was before, although there is some truth it to :|. Don't take my word for it though, try it yourself!
So, I've put the record straight. I've apologised for (unintentionally) posting misleading information, even though there is some truth in what I originally said and there's no a lot else to say :|.
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No worries, Andi. Let's put it down to a translation error
Gruess mir meine noerdlichen Nachbarn.
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No worries, Andi. Let's put it down to a translation error
Gruess mir meine noerdlichen Nachbarn.
Not "ver sprung d e r technik" then :bonk:(weird as they *** the "d e r" when not spaced)
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No worries, Andi. Let's put it down to a translation error
Gruess mir meine noerdlichen Nachbarn.
It was a translation error Mike, between my brain and the world around it
!
(weird as they *** the "d e r" when not spaced)
Not quite
.Actually it's "vorsprung durch Technik", which means (something like) 'progress through technology'. Durch is a German preposition meaning 'through' in the directional sense. Maybe TP has a built in grammar checker
!?[/UNREQUESTED_LANGUAGE_LESSON]
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:nono: Hmm, trollishly worded ... but I'll bite
Well, it's a mixture of fact (knowledge) and bad interpretation, of something which is quite complex.
The way that I described how light flows onto the sensor via different apertures is true (to the very best of my knowledge). What was less true was the way that I linked it to the dynamic range of the final image on the sensor (it really had more to do with contrast between the mid tones than the overall dynamic range of the captured image).
The effect which I was describing actually has more to do with what Cistron has already pointed out in an earlier post - a smaller aperture can reduce flare and compensate for some of the unwanted strong light that shooting at max aperture can produce, sometimes resulting in less blown highlights (which might ultimately give you a photo with a narrower dynamic range). It's more a function of the lens than the sensor.
My belief, up until yesterday, was that by using a smaller aperture the overall range from dark to light would be restricted - my tests proved that this is far less noticeable than I thought it was before, although there is some truth it to :|. Don't take my word for it though, try it yourself!
So, I've put the record straight. I've apologised for (unintentionally) posting misleading information, even though there is some truth in what I originally said and there's no a lot else to say :|.
So in other words, the answer to my question would be 'yes'.
The slight changes you saw in the histogram were probably due to the diffraction causing slight differences in the way the images were projected, and other such variables as slight camera movement, fractional changes in the light, etc.
Anything else is just a placebo.
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Actually it's "vorsprung durch Technik", which means (something like) 'progress through technology'. Durch is a German preposition meaning 'through' in the directional sense. Maybe TP has a built in grammar checker
I even googled it as well to get the correct saying/spelling & thats what it showed up as couldn't remember
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