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Author Topic: Optimal exposure  (Read 3290 times)

digitaldog

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Re: Optimal exposure
« Reply #20 on: November 24, 2020, 01:47:47 pm »

If someone else can answer my question without forcing me to read nine treatises on Raw measurements and RAW digger, I'd appreciate it.
Translation: Would someone please step up and hold Alans hand so he doesn't have to do the work/study we have. 🥵
We do now know the answer to my question to him: no, he didn't. 😰
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bjanes

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Re: Optimal exposure
« Reply #21 on: November 25, 2020, 11:33:59 am »

If someone else can answer my question without forcing me to read nine treatises on Raw measurements and RAW digger, I'd appreciate it.

Alan,

Yes, most digital cameras have spot metering. Steve Perry has a good introduction here.

A handheld spot meter has a well defined metering area, usually 1 degree, while the angular camera spot metering varies with the focal length and is not that well defined. Most cameras meter from the selected focus point, but the size varies considerably. According to Steve, Nikon's metering area is about 4 mm with a 24 x 36 mm sensor area. In the article he tells how you can check your own camera. I have calculated the angular metering area in degrees for various focal lengths and the results are shown in the attachment. For comparison, the moon subtends approximately 0.5 of a degree.

Bill
« Last Edit: November 25, 2020, 11:42:44 am by bjanes »
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Alan Klein

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Re: Optimal exposure
« Reply #22 on: November 25, 2020, 11:46:07 am »

Alan,

Yes, most digital cameras have spot metering. Steve Perry has a good introduction here.

A handheld spot meter has a well defined metering area, usually 1 degree, while the angular camera spot metering varies with the focal length and is not that well defined. Most cameras meter from the selected focus point, but the size varies considerably. According to Steve, Nikon's metering area is about 4 mm with a 24 x 36 mm sensor area. In the article he tells how you can check your own camera. I have calculated the angular metering area in degrees for various focal lengths and the results are shown in the attachment. For comparison, the moon subtends approximately 0.5 of a degree.

Bill
Thanks, Bill.  I haven't calculated the degrees of my spot.  But zooming in gets it pretty small.  My question though was whether a spot reading on a digital camera is different than one in a regular spot meter?  Are the readings the same other than the degrees.  Could someone use the zone system for example or do you have to offset values for the digital camera's readings? 

digitaldog

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Re: Optimal exposure
« Reply #23 on: November 25, 2020, 11:54:14 am »

Alan,

Yes, most digital cameras have spot metering.
Indeed they do. Users need to understand what they report and understand the effects of using such settings for optimal exposure. Does Alan know/understand what a spot meter does when pointed at a black cat or white dog and then obtaining optimal exposure???
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bjanes

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Re: Optimal exposure
« Reply #24 on: November 25, 2020, 11:55:52 am »

Thanks, Bill.  I haven't calculated the degrees of my spot.  But zooming in gets it pretty small.  My question though was whether a spot reading on a digital camera is different than one in a regular spot meter?  Are the readings the same other than the degrees.  Could someone use the zone system for example or do you have to offset values for the digital camera's readings?

As far as I know, zone concepts should apply to the camera spot metering. If you are metering off a white subject you would have to add 2.3 EV of exposure. For a mid-tone subject, no compensation would be necessary, and for a dark target you would need to decrease exposure from the metered value. I would advise reading your manual and doing some experimentation. Andrew's reply was characteristically nasty, but he has a point.  >:(

Bill
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digitaldog

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Re: Optimal exposure
« Reply #26 on: November 25, 2020, 11:57:56 am »

As far as I know, zone concepts should apply to the camera spot metering. If you are metering off a white subject you would have to add 2.3 EV of exposure.
So JPEG and raw would be treated the same by adding 2.3?
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Andrew's reply was characteristically nasty, but he has a point.  >:(
Indeed I do.
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Alan Klein

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Re: Optimal exposure
« Reply #27 on: November 25, 2020, 12:06:58 pm »

Indeed they do. Users need to understand what they report and understand the effects of using such settings for optimal exposure. Does Alan know/understand what a spot meter does when pointed at a black cat or white dog and then obtaining optimal exposure???

Andrew, I've been shooting for 60+ years.  You can see my results on Flickr link below or Youtube https://www.youtube.com/channel/UCDzogShfhgCHh2rVvEsFOJQ.  I'll match my results with yours or anyone else here.  In any case, I don't shoot black cats or white dogs.  I did own a gray poodle that I shot a lot.  Easy to meter.    :)

digitaldog

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Re: Optimal exposure
« Reply #28 on: November 25, 2020, 12:20:02 pm »

Andrew, I've been shooting for 60+ years. 
Oh I've only been doing it 50. A good decade doing so as a profession.
So you've been producing optimal exposures for 60+ years? If so, why all the cries for help here?
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I'll match my results with yours or anyone else here.
You've already provided a snapshot in the other forum where you blew out highlights. I've seen your results.
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In any case, I don't shoot black cats or white dogs.
But could you and expose optimally using any kind of spot meter? You can of course remove the words cat or dogs and find all kinds of objects that fool meters and those that use them.
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I did own a gray poodle that I shot a lot.  Easy to meter. 
What makes you believe mettering anything isn't? Misunderstandings of the process it would appear.
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bjanes

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Re: Optimal exposure
« Reply #29 on: November 25, 2020, 12:23:25 pm »

My point again is, in retrospect, no Histogram is needed to optimally expose an image. As was done by at least two of us for decades with transparency film.
A raw Histogram IS useful to get to the understanding towards learning how to optimally expose for that kind of data, and to see what, if anything, a converter develops from that in terms of brightness in highlights that may appear to clip (but are not) or those that do clip but shouldn't and can be minimally recovered. After that, no need for any Histogram. 
If Photographers would spend a fraction of their time ignoring JPEG Histograms for exposure and LEARN to use Spot reflective and incident meters, LEARN how they can be fooled, they would spend a lot less time doing stuff other than making images.

Yes, you can expose without using a histogram or blinkies but these tools are helpful in many situations. If you are doing static subjects such as landscapes you can use your spot meter and Ansel's techniques. If you are doing action photography such as sports or wildlife, spot metering the subject can be problematic. A glance at the histogram or the blinkies may be more productive. Incident metering would not be advisable if you are photographing a lion or distant scene where the lighting may be different than that at the camera.

Bill
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Alan Klein

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Re: Optimal exposure
« Reply #30 on: November 25, 2020, 12:28:18 pm »

Oh I've only been doing it 50. A good decade doing so as a profession.
So you've been producing optimal exposures for 60+ years? If so, why all the cries for help here? You've already provided a snapshot in the other forum where you blew out highlights. I've seen your results. But could you and expose optimally using any kind of spot meter? You can of course remove the words cat or dogs and find all kinds of objects that fool meters and those that use them. What makes you believe metering anything isn't? Misunderstandings of the process it would appear.
I'm not an expert like you.  I make mistakes, unlike you. I'm trying to match your perfection.  :)

In any case, having just taken up 4x5 film photography, I have to up my game regarding exposure.  I'm trying new methods.  Asking questions is what a forum is supposed to be about.  If we all looked things up and could figure it out from reading 6 journals, why bother with the forums?  If all you're going to do is criticize and make snide comments all the time, why are you here?  To bother people? It would be nice if you were a little more accommodating.  No one's competing with you when they ask you a question.  Show a little patience.

digitaldog

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Re: Optimal exposure
« Reply #31 on: November 25, 2020, 12:38:05 pm »

I'm not an expert like you.
We are now in violent agreement. No one is born an expert in anything. Experts are made by study and work. And by implementing critical thinking, listening to others who are experts themselves and peer reviewed. Testing and work. This is something some cannot do; easier to struggle and ask then do.
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I make mistakes, unlike you
Rubbish. A really stupid statement without a lick of proof or knowledge or critical thinking either. It's why I and others don't take you seriously and even thoughtful and helpful people like Bill may sour on your rubbish.
 "Men are more apt to be mistaken in their generalizations than in their particular observations". -Niccolo Machiavelli
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I'm trying to match your perfection
Rubbish. A really stupid statement without a lick of proof or knowledge or critical thinking either. It's why I and others don't take you seriously and even thoughtful and helpful people like Bill may sour on your rubbish.
"Have no fear of perfection-you'll never reach it."  -Salvador Dali
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In any case, having just taken up 4x5 film photography, I have to up my game regarding exposure.
Yes, you believe without schooling, that 4 x5 (chrome, neg; major difference) has to be treated differently than digital in terms of LEARNING to expose optimally. Yet all the URL's that show how this is done were ignored. This is your idea ignoring how to learn:
If someone else can answer my question without forcing me to read nine treatises on Raw measurements and RAW digger, I'd appreciate it.
And now you say:
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It would be nice if you were a little more accommodating
Read, learn, study what has been provided. THEN ask questions based on the materials.
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Show a little patience.
My patience with your inability to learn and study the material provided disappeared awhile ago. If some of us can take the time to learn this stuff, then take the time to write articles and make video's for free, you can at least make an effort to VIEW them and attempt to LEARN from them. But alas, that's not been your history here. And so, I have no more patience with your inability to study the materials provided.
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Alan Klein

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Re: Optimal exposure
« Reply #32 on: November 25, 2020, 12:51:04 pm »

Have a nice day, Andrew.

digitaldog

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Re: Optimal exposure
« Reply #33 on: November 25, 2020, 12:56:30 pm »

Have a nice day, Andrew.
Every day I learn something new is a nice day Alan. Give it a try.  ;)
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Doug Gray

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Re: Optimal exposure
« Reply #34 on: November 28, 2020, 05:53:02 pm »

Every day I learn something new is a nice day Alan. Give it a try.  ;)

Agree. Every day I learn something new is a good day.
Every day I learn something that changed what I thought I knew is a great day.

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