Interesting Blog about Calculating Exposure

[Kevin Caulfield]

I just read the book by John Elder Robison, "Look Into My Eyes", a very interesting story. Wanting to know a bit more, I delved into his blog, and found that his most recent entry is about photographic exposure calculations, and the fact that we make things simpler throughout the years, and lose mathematicail skills -

http://jerobison.blogspot.com/2008/03/cameras-and-math-skills.html

 

[Christopher Walrath]

Just read it (my son has AS so near and dear) and it's unbelieveable. 'Pro autistic stance'? What the hell, he has Aspberger's Syndrome. No Shit! I'm glad I don't leave APUG often. THe world is full of crazies. Day skayeer me some.

 

[Dave Miller]

No surprise there, we use the same formula in the darkroom to calculate exposure changes when changing image sizes, however I must admit I now use an electronic calculator rather than log tables to do the maths.

 

[Kevin Caulfield]

Yeah, there's nothing overly scientific about the calculations. I just agree about the loss of mathematical knowledge in our newer generations. I've seen this first-hand through years of demonstrating chemistry practical sessions to undergraduates. And it's been a long, long time since I used log tables, but I do still understand what they mean and what they do.

 

[PVia]

Have you seen the thread this week on "rounding off" HC110 dilutions so you don't have to do the "hard" calculations? I mean no offense to that poster, but this is the kind of thing I was talking about...

People's eyes glaze over when confronted with math, but if they only took the short amount of time to understand a particular calculation, they would see how easy it really is...

 

[Kevin Caulfield]

Indeed. To square two numbers and then divide them is not rocket science. People are always trying to make things too simple and we will see the results in a couple of generations.

 

[Dave Miller]

Indeed. To square two numbers and then divide them is not rocket science. People are always trying to make things too simple and we will see the results in a couple of generations.

Here in England we are seeing it already, and have been for a couple of decades.

 

[Christopher Walrath]

Yeah, but I 'e-know' that poster you're referring to, P, and yes he is a nut. And off his rocker. And half on the loon. But don't guess him short. JBrunner is a photography nut and he has done so much with photography that it makes MY head spin. All photographers come up with short cuts and if those short cuts might help someone to dive in where they would stay on the edge otherwise then yay for short cuts. It's not always laziness, sometimes its just facilitation.

 

[Christopher Walrath]

Oh, and to find out just how knowledgable and loony Jason is, just go to youtube.com and do a search for 'j brunner' (Please note the space, there has to be a space, don't forget the space) and start watching.

 

[rwyoung]

Indeed. To square two numbers and then divide them is not rocket science. People are always trying to make things too simple and we will see the results in a couple of generations.

The original article makes it harder than necessary. At least in the sense that you have an extra step.

x^2 / y^2 = (x/y)^2

Save yourself the trouble of the extra "squaring" operation.

And if you want to use your log tables:
x^2 = antilog(2*log(x))

and

x/y = antilog(log(x) - log)

so

antilog(2*(log(x) - log))

Now, where did I put my slide rule...

p.s. and I forgot to add, you really only need to know a few "key" logs and antilogs to guestimate answers quickly. I say that with the regret that I have fallen prey to the siren song of cheap electronic calculators. So it would actually take me longer now to factor a number, shift decimal points, remember some logs, do basic arithmetic, then antilog back. Sigh.

 

[JBrunner]

Have you seen the thread this week on "rounding off" HC110 dilutions so you don't have to do the "hard" calculations? I mean no offense to that poster, but this is the kind of thing I was talking about...

People's eyes glaze over when confronted with math, but if they only took the short amount of time to understand a particular calculation, they would see how easy it really is...

Ok, I'm gonna stick up for that guy too. I talked to him this morning. It was so early he was still wearing his tinfoil helmet. He wasn't offended, but he did say that he didn't "round off" anything. He came up with a metric dilution and times for various films in the dilution, to give more useful development times, and provide a sensible alternative to the sixteen different possibilities confronting a novice processor who wants to use one of the greatest developers of all time. Since he needed a new dilution, a metric one made the most sense for the modern world.

He agrees that the dumbing down that seems prevalent in todays world is tragic and dangerous, but thinks in regard to photography that the digital revolution is more to blame than any developer regimen, and would like to see more people using cameras and processes that require active participation and thought. He said that alluding to his HC110 regimen was a poor example, but that he agrees with what you were trying to say.

He also said "innovation in photography always meets with some derision, because a few photographers are outright stiffs" (I don't understand exactly what he meant) and then went off to the coffee pot muttering something about making hamburgers with sacred cows (I didn't get that one either)...

Then he took off his tinfoil helmet and said that "rounding off would be something like H is 1:60 or TT=3" whatever that means.....

 

[sun of sand]

It isn't the students
It's the system in general
In fact, it's probably -mostly- you -the ones complaining- that are making the system what it is
either directly or indirectly knowing or unknowingly

 

[paxette]

The poor straw man is all bloody and bruised ...

He pulled two books off of some shelf, one old and one new then compared them and proclaimed, "all new books are indicative of this problem I think the world has!" But that "new" rule he is so harshly criticizing has been true since a diaphragm was inserted into a barrel lens eg: when folks like the Royal Photographic Society came up with a standard which said aperture ratios shall be 1:2.

but thinks in regard to photography that the digital revolution is more to blame than any developer regimen

That ran through my head as well as I read the rant.

 

[pentaxuser]

Here in England we are seeing it already, and have been for a couple of decades.

This is so true. 50% want everything about maths simplified and the other two thirds aren't even interested

pentaxuser