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09-07-2008, 06:17 PM   #16
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Newbie questions like this can best be solved if by read through the camera manual thoroughly and pick up a few basic books on photography to get a basic grounding on camera operation and exposure...

09-07-2008, 06:42 PM   #17
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QuoteOriginally posted by FHPhotographer Quote
You're right about the exposure... but I thought exposure was set to the AF point, and maybe that's the problem? Is there anybody out there using a K100 who can help me out with this? Thanks,
FHPhotog
Somebody correct me if I'm wrong here, but my understanding about setting the exposure to the AF point will only work with matrix metering and not with center or spot metering.
09-07-2008, 07:38 PM   #18
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QuoteOriginally posted by alohadave Quote
It doesn't even stop down the lens since the lightmeter knows what the aperture is set to and can calculate the correct exposure (assuming that it's not a manual lens). What pressing the AE-L/Green button does is calculates what the camera would choose as the optimal aperture/shutter combination based on the pre-programmed exposure curve.

The camera has a set of aperture/shutter speed combinations that it selects based on the available light, this is called the program line. Pressing the AE-L/Green button activates this program and overrides your manual settings. It's like switching into P mode for a second without moving any dials.
You are so correct! I use M mode for metering my non-A lenses and seldom use it with my A-mount glass. As a result I tend to think of it in the stop-down sense because that is how it works for those lenses. Thank you for the more correct description as it applies to A-mount lenses.

Steve
09-07-2008, 09:53 PM   #19
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OP response #4

QuoteOriginally posted by creampuff Quote
Newbie questions like this can best be solved if by read through the camera manual thoroughly and pick up a few basic books on photography to get a basic grounding on camera operation and exposure...
Well, you have managed to get my hackles up. It's a bit presumptuous to suggest that I haven't read the manual; I've read it, and as I think you can see from the responses, others have read it as well and have different interpretations of not only what it says, but what it "means" and how that information can be emperically applied.

So I hope you're not suggesting that "newbie questions" shouldn't be brought to the forum? If not here, where? This is how a lot of us learn, "newbie" and experienced alike. I can assure you from my experience as a teacher that there as many ways to learn as there are individuals to learn: some watch and listen, some need to hear the lecture and others do best by reading and verbal communication means little to them, others work best with computer-mediated interaction (the internet and forums like this) etc, etc.
End of the rant...

FHPhotog

09-07-2008, 10:01 PM   #20
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OP response on EC

QuoteOriginally posted by Marc Sabatella Quote
If you had looked at the display to the right side of the viewfinder, you'd have noticed it telling you whether it thought the exposure was too bright (positive numbers), too dark (negative numbers), or right on (0.0). At least, for lens that support auto-exposure. With manual exposure lenses (ones with an aperture ring not set to the "A" position), you only see that display while holding the DOF preview button.
Marc, why do you assume I didn't look to the right of the viewfinder? In fact I did, and if you had read the original post you would have seen that I did and both shots read as 0.0 for exposure compensation. However, believe it or not, your post helped me to finally "get" how to use of the AE-L button in Manual...and for that, thanksFHPhotog

Last edited by FHPhotographer; 09-07-2008 at 10:13 PM. Reason: added comments in bold
09-08-2008, 02:20 AM   #21
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QuoteOriginally posted by Marc Sabatella Quote
BTW, despite our preconceived notion that the avocado is dark and the banana light, in the grand scheme of things, they are not actually all that different - both are considerably darker than the background, and the lightest areas on the avocado are actually no darker than the darkest areas on the banana. So depending on *exactly* where your spot meter is pointed, it is not actually unreasonable that the meter would suggest the same exposure in both cases.

Actually I see the two photos as having slightly different exposure - the second one is lighter.

With meters the most pertinent thing to remember is this: it sees everything as a neutral grey card. Despite the color differences which our eyes bias yellow as 'brighter', in the greyscale as Marc suggests the differences are not that great.

There are a couple of ways around this: one, use an incident meter. Two use a form of zone exposure: essentially on this level what this means is adjust exposure up or down based on how much lighter or darker you wish the metered area to be, relative to a neutral grey.
09-08-2008, 04:17 AM   #22
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QuoteOriginally posted by Marc Sabatella Quote
BTW, despite our preconceived notion that the avocado is dark and the banana light, in the grand scheme of things, they are not actually all that different - both are considerably darker than the background, and the lightest areas on the avocado are actually no darker than the darkest areas on the banana. So depending on *exactly* where your spot meter is pointed, it is not actually unreasonable that the meter would suggest the same exposure in both cases.
QuoteOriginally posted by Nesster Quote
Actually I see the two photos as having slightly different exposure - the second one is lighter.

With meters the most pertinent thing to remember is this: it sees everything as a neutral grey card. Despite the color differences which our eyes bias yellow as 'brighter', in the greyscale as Marc suggests the differences are not that great.

There are a couple of ways around this: one, use an incident meter. Two use a form of zone exposure: essentially on this level what this means is adjust exposure up or down based on how much lighter or darker you wish the metered area to be, relative to a neutral grey.
Both you and Marc are incorrect.

I checked the exposure using the histogram in PSP X2 the dark avacado has a grey scale value of 65 and the banana about 165, this is 2 1/2 stops different, and the camera will meter based upon this value.

Also the two items are within a greyscale of 2 in the successive photos, hence are the same exposure. I will not argue about different exposures on what amounts to 1/20 of a stop difference between them

The bottom line is this was an operator error, which he accepted he made. Lets move forward and not make additional mis conceptions seem real
09-08-2008, 05:23 AM   #23
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LOL I stand corrected

09-08-2008, 05:27 AM   #24
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QuoteOriginally posted by RollsUp Quote
Somebody correct me if I'm wrong here, but my understanding about setting the exposure to the AF point will only work with matrix metering and not with center or spot metering.
You're right. The spot meter is *always* in the center of the frame.
09-08-2008, 05:55 AM   #25
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This and many other exposure related subjects can be daunting with SLR's. Particularly those moving from auto cameras and P&S systems. To anyone reading this and even possibly the OP, Byran Peterson's "Understanding Exposure" is an excellent book that makes all this and much more about photography much easier and clearer.
09-08-2008, 09:26 AM   #26
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QuoteOriginally posted by Lowell Goudge Quote
I checked the exposure using the histogram in PSP X2 the dark avacado has a grey scale value of 65 and the banana about 165, this is 2 1/2 stops different, and the camera will meter based upon this value.
Not a good comparison because in taking the picture, an exposure curve has already been applied that may have altered the relationship. Also, the conversion to gray scale uses it's own algorithm to determine value based on the RGB values, but the meter is responging to the overall light level according to its own physical characteristics. Bottom line - a spot meter on the actual fruit in real life might have told a different story.

But in any case, I also pointed out that there are light areas on the avocado and dark area on the banana, and these are not so dissimilar. Obviously, the darkest area of the avocado is considerable darker than the lightest area of the banana.

QuoteQuote:
Lets move forward and not make additional mis conceptions seem real
Well, there may still be some confusion here, because the OP is indicating that the meter read 0.0 in both cases. I am offering a possible explanation of that.
09-08-2008, 09:33 AM   #27
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QuoteOriginally posted by FHPhotographer Quote
Marc, why do you assume I didn't look to the right of the viewfinder? In fact I did, and if you had read the original post you would have seen that I did and both shots read as 0.0 for exposure compensation.
I assumed when you wrote "0.0" you meant that you had dialed in 0.0 exposure compensation (presumably while in one of the auto exposure modes), and didn't realize that this number was ignored when using M mode. I certainly wasn't meaning to "scold" you for not looking, although I realize now that it might have sounded that way.

So as far as I can, there are probably three thing at play here in explaining why the meter reading was the same:

1) If you were expecting the meter spot to follow the focus spot, you were mistaken - spot metering is always the center. But given that the picture shows you trying to center on the different fruit, I'd say that's probably *not* the issue.

2) If you were centering on the different objects and *still* got the same reading, then I'd guess maybe you underestimating the size of the spot, and your reading was actually being influenced by the background as well.

3) If you were pointing at a relatively light area of the avocado and a relatively dark area of the banana, I'm still not conivnced they *aren't* about the same value.
09-08-2008, 10:12 AM   #28
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Understanding Exposure just may be the best $16 I spent on Amazon.

Now the thing with these 2 photos though is that your focus point has no bearing on the exposure at all. Both shots were taken in full manual: 200 ISO, 50mm, 1/3s @ f/2.8. Aside from focus point they are identical. You could have de-focused a 3rd shot completely so both the avacado and banana were blurred and you'd still get the same "exposure".

The only thing that could change the metering between these 2 shots is if the light changed. Turn on or off a light, open/close a blind and the light reflecting off the subjects and through the lens changes. Or, for example if you were outside in direct sunlight for shot 1 and then a cloud covered the sun in shot 2 then you'd have different exposures if you changed nothing else.
09-08-2008, 10:42 AM   #29
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No variations between images...

QuoteOriginally posted by Venturi Quote
Understanding Exposure just may be the best $16 I spent on Amazon.

Now the thing with these 2 photos though is that your focus point has no bearing on the exposure at all. Both shots were taken in full manual: 200 ISO, 50mm, 1/3s @ f/2.8. Aside from focus point they are identical. You could have de-focused a 3rd shot completely so both the avacado and banana were blurred and you'd still get the same "exposure".

The only thing that could change the metering between these 2 shots is if the light changed. Turn on or off a light, open/close a blind and the light reflecting off the subjects and through the lens changes. Or, for example if you were outside in direct sunlight for shot 1 and then a cloud covered the sun in shot 2 then you'd have different exposures if you changed nothing else.
Wish this were true, but both were shot under artifical indoor light, no changes in light or shadow, no variations, the only "difference" from one to two is that the camera was shifted from spot-on the avacado to the banana,
FHPhotog
09-08-2008, 10:46 AM   #30
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A logical explanation

QuoteOriginally posted by Marc Sabatella Quote
I assumed when you wrote "0.0" you meant that you had dialed in 0.0 exposure compensation (presumably while in one of the auto exposure modes), and didn't realize that this number was ignored when using M mode. I certainly wasn't meaning to "scold" you for not looking, although I realize now that it might have sounded that way.

So as far as I can, there are probably three thing at play here in explaining why the meter reading was the same:

1) If you were expecting the meter spot to follow the focus spot, you were mistaken - spot metering is always the center. But given that the picture shows you trying to center on the different fruit, I'd say that's probably *not* the issue.

2) If you were centering on the different objects and *still* got the same reading, then I'd guess maybe you underestimating the size of the spot, and your reading was actually being influenced by the background as well.

3) If you were pointing at a relatively light area of the avocado and a relatively dark area of the banana, I'm still not conivnced they *aren't* about the same value.
1. According to the camera/manual the AF and AE spots are linked, but I could be reading that wrong
2. This seems the logical explanation
3. That I don't know, except they were on the same horizontal plane (the kitchen counter, not to be too technical)
Thanks for the responses and I didn't mean to go off on you... just honest disagreement without, I hope, being disagreeable,
FHPhotog
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