BRB


Back on 7th January.

Serving humanity with dimensional analysis

Yesterday, The Godsister asked about the aperture values on a camera. The result was “OHHHHHHHHHHHHHHHHHHHH [excess H's truncated]. That explains a lot.”

I would like to think I have imparted the concept of dimensional analysis upon a 16 year-old. I would like to think that I have made a difference.



Edited chat transcript below:


Hi!
Hello Cute One.
Hello Pink Man! Can I ask something? Going to ask anyways
What is the unit of the aperture number? Does it have a unit?
Let me get you a proper reference
Ok, wikipedia's aperture articles says the following:
area = (f / 2N)squared x pi
N is the aperture number, and f is the focal length of the lens
If you want units I will need to take you down the road of dimensional analysis. It’s not hard; bear with me...
The area of a circle is:
Area = pi x r squared
Area is measured in square metres, r is measured in metres. square the r and the units match.
The same principle must also apply for the equation for aperture area
area = pi x (f/2N)squared
The unit of (f/2N) should then be length
f is the focal length of the lens
I don’t get the f/2N part
f/2N is just how the aperture number is made
Ok.
Someone decided that using this correlation would give a convenient system
Ok, so area = pi x (f/2N) squared
Why is it 2N then? Why not just N?
Again, it falls to definition issues.
If the equation for aperture had be made using N instead of 2N, the aperture values would come out differently
Ok.
So, it is a manufactured value that people have decided is convenient. For example, the metre was initially defined as the length from the equator to the North Pole, divided by 10 million
If aperture is the area of the thingy... then why is the focal length involved?
Anyway, back to (f/2N)
I’ll finish the units of aperture first...
(f/2N) should have a length unit, then when the length is squared it gives the area
We know that f is the focal length, which is a length unit
This length is divided by 2N.
Since focal length divided by something still gives length, the aperture number has no unit
Jumping a few steps ahead, the aperture is actually the ratio between the focal length and the hole diameter
And ratios between things of the same units have no dimentions
OHHHHHHHHHHHHHHHHHHHHHHHHH [excess H's truncated]
That explains a lot.
I thought the aperture number was just the area of the opening

The collective equipment rack / BRB

A collaborative piece between my brother and I.




Reverse Swing

Click here for large size image


His Canon 17-40mm f/4L USM lens
My variable power Nikon SB-25 flash
His Gorrilapod, to hang the flash from a sprinkler pipe
My wireless trigger to control the light remotely
His black Canon 300D, because my silver model does not look prissy enough
My reverse/back swing technique
His mastery of human photography
My Photoshop interpretation of the scene
His Photoshop interpretation of the scene here


Attaching the flash to a sprinkler pipe was not easy. Without a chair or similar platform, the lightest one among us was summoned to scramble on the tallest one’s shoulders to do the deed. And Joo Lee ended up on my shoulders-





***

I will be flying back to Malaysia on Wednesday night; touring Singapore with Diana, Jean and May from Friday to Sunday; visiting Hong Kong, Macau and Shenzhen with the family and cousins between Christmas and New Year; and will arrive in Melbourne on the 7th of January.

This blog will not be properly updated till after 7th January 2008.

Attempting to exercise my long-neglected linguistic abilities

While all my photographic equipment (10 lenses and 2 SLR bodies *hides face*) are with my brother


I had just cleared passport control. Fancy backlit shelves filled with tax-free alcohol, cigarettes, perfume and power-plug adapters clamoured for attention. Modern, groovy music leaked from the neon-lit doorway of a record store while across the mall, an employee in the Starbucks stood with a bored look.

Most travellers hustled on, ignoring the merchandise, their trolley bags’ wheels rattling and rumbling, the ladies’ high heels ticking on the tiled floor. Which was uncharacteristic in an airport; most areas in the airside of aerodromes are layered with carpet so thick and dense you could feel the gooey silence after the carpet soaks up all superfluous noises.

I had an hour before the flight was scheduled to depart. Deeming it wise to take a Brownian/Markovian random-walk instead of starting on my books, I wandered around looking at the pre-tax price of hard liqueur and staring absently at turbojet engines wind-milling lazily on idle.

I walked down a passageway between two overpriced retail outlets, turned a corner and was greeted by an empty boarding lounge. This was Gate 1, conveniently tucked away from the contrasting lights, chattering travellers and endless footfalls. In the lounge were rows and rows of seats, enough to hold the hundreds waiting to board a Boeing 747-400, all of them empty.

Making my way to the furthest end of the lounge where it was the quietest and where I could watch the door, I opened my book. In many ways, it was a classic text- The Classical Theory of Fields, by the noted physicist Lev Landau. As a photocopied classic text, it was also a copyright infringement.



***

Emirates Airlines was a completely different experience from the likes of Malaysian Airlines. For one, the food was actually enjoyable, not borderline edible. Well only the appetisers, side dishes and desserts; the main course, as in most in-flight meals, has the consistency of an over-steamed bowl of leftovers.

The entertainment system has a touch-screen system- passengers can jab at the monitor to command it to start showing Ratatoulle or play the 1988 UK chart toppers. Amazingly, the music albums had UK top singles listed in chronological order from 1952 to 2007. I, of course, was well and truly stuck in the late 80s to early 90s.


***

The 8-hour flight did not seem as dreadful as feared. I read a bit more of Landau, got distracted by dinner and started on a novel. After being deprived of novels for a year, it was a pleasure to read something that does not demand strenuous mental activity. (See this statement. Now it naturally follows that this is also true. And then if we allow the egg to rot, the Thunder Lizard will get angry. Follow? Good. Then when we use gravitational lensing to observe the passing of an n-brane, we will find the result. Correct?)

And when the brain got addled by this light reading, I turned on the video and watched The Matrix.

Trinity (Carrie-Ann Moss) is beautiful. Stop sniggering, it’s not the leather.

Tan Yee Wei will be in Singapore from tonight till Sunday night; this blog will not be undated in the meantime.

The One

The Auditor mentioned that an acquaintance of hers had found The One and would be getting married early next month. This proclamation was not unaccompanied by a small measure of wistfulness.

So what might it be like finding The One? While I cannot comment with the benefit of first-hand knowledge, exaggerated remarks can be made from various observations.



The observable universe contracts. From all directions, the horizon rushes forward as distant mountains and clouds sequentially wink out of sight. Eta-Carina no longer becomes a concern, while the Riemann Hypothesis, global warming, the Middle East conflict, corruption and a host of other nitty-gritty everyday issues disappear with a condescending flick of the hand.

Two entities merge in a strange superposition of emotional states. A witty t-shirt summarises this phenomenon in a flippantly simple statement, “when you are single, you are exactly as happy as you are; when you are in a relationship, you are as happy as the least happy person in the relationship.”

In parallel to these changes, the psyche reallocates its priorities. Where attention was distributed over a multitude of issues, the emotional resources are now concentrated on The One, and the relationship with The One.

The result- an emotional state that is almost apathetic to everything, and heavily dependent on The One. The opinion of others, the state of the economy, the weather and the Darfur crisis will not affect the emotional state of the individual. However, anything to do with The One will cause substantial swings in the happiness of the individual.




This concentration of emotional resources in one item (in this case, The One) is nothing short of putting all of one’s proverbial eggs in one carrying vessel. Economists advice investors to diversify their portfolios; doesn’t that principle of volatility minimisation apply here?

It could well be that The One is deemed best to carry our emotional and reproductive eggs, thus compelling us to put all our eggs in one basket. It also gives the illusion of having a good chance at managing one’s happiness. After all, if the relationship with The One is going favourably, then the individual would be happy. Instead of trying to solve the Riemann hypothesis and bring peace to the Middle East, one merely needs to ensure the relationship is a delightful one, and the pair will be happy.

The answer is, no, the principle of volatility minimisation does not apply here. The individual is willing to allow additional happiness volatility, in exchange for what is hoped to be a higher level of overall happiness.