Just for the fun of it - ISO percentage

[Robert Watcher]

In another discussion, a few photographers were using the data provided by Lightroom to figure out the percentage of images that they shoot at each ISO. The actual number of images is easy enough to come by (Lightroom provides these for each ISO), but the percentage of images shot at each ISO setting required a little knowledge of Algebra and a few struggled with figuring that out.

Well I decided to use my little bit of Algebra knowledge necessary to computer programming, and threw together a USELESS little Online APP to calculate the percentages at each ISO, based on the numbers provided by Lightroom (or any other database for that matter. Even if you don't care, it can still be fun just entering numbers and clicking buttons and see what you get .

ON-LINE PERCENTAGE CALCULATOR FOR YOU TO FIGURE OUT YOUR ISO's WITH:


www.finchandchimps.com/calculate_percentage



If you have the numbers from Lightroom or any other database, just enter them in the ISO boxes and press Calculate Now. The percentage values are on the right side. I built it to "Round" the percentage value to decimal points. Hope you enjoy.

--

[Robert Watcher]

if anyone likes fiddling with php and wants to make something of their own, here is the simple processing engine part of the script that I made - to give a head start:

if($_POST['calc']){
    $iso = $_POST['iso'];
    $isottl = array_sum($iso);
    $cnt = 0;
    foreach ($iso as $val) {
        if($val>0){
            $calc = round(($val*100)/$isottl, 2);
            $per[$cnt] = "$calc%";
        }else{
            $per[$cnt] = "0%";
        }
        $cnt++;
    }
    $perttl = array_sum($per);
}

with "name=iso[]" being the form input Post value, and "$per[]" being the returned array containing percentage values

[Robert Watcher]

In Lightroom, I have around 130,000 files that are all from paid jobs over the last few years (wedding, portrait, commercial) from Olympus and Nikon DSLRs. There are no personal files or art and stock files (they would account for even more high ISO files).

These are the percentages from these files (pretty well exactly what I expected with the mid range 400 to 800 predominant)

100 ISO - 7.25%
200 ISO - 15.21%
400 ISO - 40.49%
800 ISO - 23.68%
1600 ISO - 11.92%
3200 ISO - 1.45%

---

[felix.reichardt]

How do people survive without being able to calculate such numbers w/o excel or online page

[blumesan]

Originally Posted by Robert Watcher

but the percentage of images shot at each ISO setting required a little knowledge of Algebra and a few struggled with figuring that out.
--

Algebra When I went to school (admittedly a long time ago) it was called long division and taught in about the 3rd grade. The fact that a few struggle with figuring that out is, unfortunately, all too believable and depressing.

[Stercus Vultus]

Amen

[Robert Watcher]

Originally Posted by blumesan

Algebra When I went to school (admittedly a long time ago) it was called long division and taught in about the 3rd grade. The fact that a few struggle with figuring that out is, unfortunately, all too believable and depressing.

You must be "quite old" if they didn't have algebra when you went to school . By the time I went to school in the 1960's what I learned along with geometry, trig, logarithms (calculus), etc - was called Algebra and it was in high school for us Canadians. Pretty intense stuff for Grade 3'ers. A different ball of wax than long division (which I did learn in early grades) as far as what I perceive long division to be - http://en.wikipedia.org/wiki/Long_division. Algebra is commonly working with unknowns for example by using variables - http://en.wikipedia.org/wiki/Algebra.

Unfortunately while schools commonly teach algebra - they seldom implement it in a practical application - - - so it is east to ignore the value of it and forget about it. Fortunately I remembered enough of what I learned in school to find its value when I became self taught in computer programming in the 1980's.

Anyway - these fun little apps aren't too complicated as far as the math - - - they are just simple tools to get results easily.

[TimBlodgett]

ISO
100 0% (Im not even sure my camera has a 100 ISO :P )
200 1.42%
400 28.34%
800 20.29%
1600 47.83%
3200 2.13%
6400 0%

This just goes to show I love my D90's high ISO capabilities.

[Robert Watcher]

This just goes to show I love my D90's high ISO capabilities.

Good stuff.

[blumesan]

Originally Posted by Robert Watcher

You must be "quite old" if they didn't have algebra when you went to school . By the time I went to school in the 1960's what I learned along with geometry, trig, logarithms (calculus), etc - was called Algebra and it was in high school for us Canadians. Pretty intense stuff for Grade 3'ers. A different ball of wax than long division (which I did learn in early grades) as far as what I perceive long division to be - Long division - Wikipedia, the free encyclopedia. Algebra is commonly working with unknowns for example by using variables - Algebra - Wikipedia, the free encyclopedia.

Well, if you call pushing 78 is "quite old", you are right. However they did indeed have algebra, trigonometry, solid geometry and calculus which I studied in high school. Simple division is another matter, as you have said, and is taught in grade school. Or at least it was in my day. Today I imagine most grade schoolers use a hand held calculator.

In any case, if one wishes to know what percent of a known total (divisor) is represented by a known number (dividend), there are no unknowns (except for the answer). You simply divide the sum into the number (and move the decimal point 2 places to get percent). No algebra required.

By the way, I have absolutely nothing against using calculators or short computer programs to generate these answers. I am, however, depressed and alarmed by the fact that too many high school graduates today are completely lost without such crutches.

[Carusoswi]

Not to belittle the OP, and I'm not pushing 78 although I was in grade school in the '60's so I'm no spring chicken, either, but, as I was reading that post, I thought to myself that it would be so much simpler to simply take the total number of photos shot at a given ISO, divide by the total number of photos, and, there you have it, the percentage of the total that were shot at that particular ISO.

I envy those of you who were exposed to trig and calc in school. My little country district didn't offer such advanced studies.

Caruso

Originally Posted by blumesan

Well, if you call pushing 78 is "quite old", you are right. However they did indeed have algebra, trigonometry, solid geometry and calculus which I studied in high school. Simple division is another matter, as you have said, and is taught in grade school. Or at least it was in my day. Today I imagine most grade schoolers use a hand held calculator.

In any case, if one wishes to know what percent of a known total (divisor) is represented by a known number (dividend), there are no unknowns (except for the answer). You simply divide the sum into the number (and move the decimal point 2 places to get percent). No algebra required.

By the way, I have absolutely nothing against using calculators or short computer programs to generate these answers. I am, however, depressed and alarmed by the fact that too many high school graduates today are completely lost without such crutches.

[blumesan]

Originally Posted by Carusoswi

... but, as I was reading that post, I thought to myself that it would be so much simpler to simply take the total number of photos shot at a given ISO, divide by the total number of photos, and, there you have it, the percentage of the total that were shot at that particular ISO.
Caruso

That was my thought as well. But that does require long division. Absent that ancient skill, a calculator, or a program such as the one Rob has provided.

[machmode]

so thats why my algerbra teacher ment when he said algerbra will come in handy........o brother.i could have predicted that off the top of my head.math let the brainiacs work with it.im doing well without it.i can count past the number of my pay check .thats as much math as i need