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Forum: Pentax DSLR Discussion
01-03-2012, 05:38 PM
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I believe it's already explained and how to deal with it.
But here goes.
- why is the duck blown out.
Well here comes the 12.3% that we were discussing.
Light meter are pretty dumb, the don't know what is black or white, they simply average everything out to a value the standard says 12.3% reflective grey.
That means if you photograph white snow it turns grey for example because the meter doesn't know any better, so you need to over expose to compensate in that case.
Alright next step. You had set the metering to center average, that means it looks the most at the centre, so what is there will influence the meter the most and the further away you get from the centre the less important the meter finds.
You're lucky you have a white duck in the center or else it would blownout the highlights even more.
The meter would also have seen the duck with the blown highlights but since that's only a small part of the whole frame and you've quite a darker background where it also looks at it simply average things without thinking further.
- Tips to prevent burned out highlights are already given by others.
- If you question about meter modes.
Spot metering would have make little difference unless you metered the blown out duck, if you for example meter the darker background the duck in the middle would also have been blown out.
So don't use spot metering with any auto mode!
Spot metering is useful if you use M-mode and use the green button to take a "one-time" metering.
For automode either chose Matrix-metering or if you want more insight and predictability use centre weighted.
That works also, forgot about that one.
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Forum: Pentax DSLR Discussion
01-03-2012, 05:18 PM
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It's still about light metering though.
You did got your answer i hope. =]
The question mark is there because i didn't understand what you mean and so i asked you, that's what question marks are for right?
You can believe what you want but the standard is 12.3%, i'm very sorry but you nor i can change that, you've to live with.
The good news is it's like this already for years so just keep doing what you always do.
Nothing to do with the duck but everything to do with lightmetering though and i believe we were blaming the lightmetering right so we aren't that far off from track ;)
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Forum: Pentax DSLR Discussion
01-03-2012, 04:22 PM
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What do you mean correct 18%?
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Forum: Pentax DSLR Discussion
01-03-2012, 02:57 PM
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Ah yes but those meters meter correctly it's when you use a grey card when you need to compensate.
If you've a light meter and a grey card you can try it out, use the camera to meter from the grey card and use the light meter, wanna bet the exposure of the geycard is slightly darker.
Ansel Adams has always been promoting 18% grey, that's propably why we hear it so much and read it in books.
incidental, shooting whit a grey card and not compensating will help you for not clipping the highlights :)
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Forum: Pentax DSLR Discussion
01-03-2012, 02:52 PM
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I've read that Nikon engineer has stated that they are confirm with the ANSI standard, so that is 12% or at least around that number.
I've read that for example the sekonic light meters are around the 14% give or take.
How are you checking this btw?
Just take a photo of a white paper and make sure it fills the whole frame and set the metering to zero.
Then in photoshop or something like that take a RGB reading and translate that to a grey value, that way you see where it metered for.
or use the histogram in the camera or liveview, you see that the white paper will peak slightly to the left and not in the center of the histogram.
The camera meters for 12% so it wants to make something that kind of grey so it turns your white paper into 12% grey, if it was 18% it would be in ther center.
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Forum: Pentax DSLR Discussion
01-03-2012, 01:09 PM
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Try live view, it should roughly give the same metering although it works differently.
Multi segment???
Any way.
- matirx metering looks at the whole frame and takes into account the focus point, camera orientation, light distribution and probably also things like focal length and maybe a lot more.
It has these "presets" so to say, so it knows how a landscape photo looks like and it tries to get a correct exposure for that to explain it in a simple way.
- centre weighted meters in the centre the most and the value goes down to further you get to the edge.
- spot metering meters one spot, you can set it to follow the focus point if you want.
Centre weighted is probably the best mode if you want to know what the camera is doing since the spot metering point is quite small so the value can jump up and down quite a bit.
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Forum: Pentax DSLR Discussion
01-03-2012, 11:37 AM
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Ever read the instruction Kodak put with those grey cards?
It says you need to open up with 1/2 stop when using the greycard for exposure :p
 Quote: "Meter readings of the gray card cshould be adjusted as follows-
1) For subjects of normal reflectance increase the indicated exposure by 1/2 stop.
2) For light subjects use the indicated exposure; for very light subjects decrease exposure by 1/2 stop
3) If the subject is dark to very dark increase the indicated exposure by 1 to 1.5 stops" Anyway the ANSI PH3.49-1971 "American National Standard for General-Purpose Photographic Exposure Meters (Photoelectric Type)" stated 30 +/- 5 footcandles which work out about 12.3% reflective.
Either your meters aren't confirm with the standard or you have read it wrong.
http://david.spielman.com/Gray_Card/ANSI_PH3_49_1971.PDF |
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Forum: Pentax DSLR Discussion
01-03-2012, 09:30 AM
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You just need to learn when problems arrive.
This btw the reason why i shoot in M mode instead of letting the camera do the metering for me
If you do that you're underexposing with 1/2 stop ;) Light meters are calibrated to approx 12% grey, 30 +/- 5 footcandle to be more precise.
18% grey comes from printing industry.
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