Tuesday, April 30, 2013

Is is

One rarely writes two identical words together in a sentence   But one hears this particular twinning all the time, often form the smartest people in the world:

The question is, "Is this OK?"

This bugs me.

If I had to write this sentence, I would say something like this:

We fundamentally need to know if this is OK.

Saturday, April 27, 2013

Scoring an exercise session

I joined Fitocracy some time ago.  It is a nice social site for posting your workouts and getting points.  But of course, the points don't matter, except to motivate you.

Having said that, the Fitocracy algorithm strongly favors weight lifting: Lifting 100 pounds five times is "equivalent" to running a mile.  Yeah, right!

Therefore, I decided to create my OWN point system (again, the points don't matter), which rewards the sort of exercise *I* do (jogging).

Here is the way I figure it (qualitatively).  You get more points for:

  1. Running farther,
  2. Running faster,
  3. Running with extra weight (including your own weight).
The last item is based on the reality that heavier runners expend more energy.  For example, let's say you are a svelte 130 pound marathon runner, who averages around 5:30/mile for short runs.  What would she be able to do with, say, 60 pounds of extra weight?  Could she halve her pace (11:00/mile) for a 5K with that extra weight?  Hmm?  HMMMMM?

Long story short (and I think this will need tweaking), I'll take this form for the algorithm:

Points = (scaling1)*(C1 + miles) + (scaling2)*(C2- pace) 

I'll arbitrarily say that a 1-mile run at a moderate pace for me is worth 5 points.  I'll also set scaling2=C1=1.0 (yeah, I know, the units don't match; ignore it).  A moderate pace for me is 13:00/mile (C2).  Do the arithmetic to see that scaling1=2.5:

points = 2.5*(1 + miles) + 13 - pace.

Now, we add a factor for the weight.  Since BMI is a better measurement of your overweight-ness, I have settled on this formula:

Points = 2.5*(1 + miles) + 0.4*BMI - pace.

There is only one more factor that I have to add in: you can only get points if you go at least 1/2 mile.

Using this scoring system, here are some examples of an 11-point 5K run for different BMI values:
  • 25:00, BMI=22
  • 30:00, BMI=26
  • 32:30, BMI=28
  • 35:00, BMI=30
  • 37:30, BMI=32
The world record 5K is 12:37 by Kenenisa Bekele of Ethiopia.  Let's say this particular human specimen has a BMI of 18.  Kenenisa would have received 13.4 points for this run.  Patrick Mahu's world's best marathon of 2:03:35 would have earned him (assuming a BMI of 16) 64 points!

My point system favors more frequent, shorter exercises, which is what I need right now.  That is, it is better for me to do five 2-mile runs in a week than three 5K's (about 40 points versus 33 points).

My sort-term goal is 25 points per week.  I hope to increase this to 40 points per week over the coming weeks.

Friday, April 26, 2013

Zoom versus Prime lenses

I know how I stand on the whole "Zooms versus Primes" debate: I prefer primes.

A "zoom" lens has the ability to change its focal length; a "prime" lens does not.  Here is a link to my son's incredible Canon EF 24-70mm f/2.8L zoom lens.  Here is a link to my incredible Canon EF 50mm f/1.4 lens.  In terms of image quality, it is arguable that these two lenses, at 50mm, are quite similar.

  • Variable focal length
  • You can often get a decent zoom lenses with image stabilization for a reasonable price.  For example, this new kit lens from Canon.
  • Heavier lens is sometimes easier to hold steady.
  • It seems that the newest technologies appear on zoom lenses first (like the kit lens linked to, above).
  • Great IQ for not much money
  • Small and light (in most cases)
  • Usually, primes are faster (have a larger maximum aperture) than zooms
  • Many artistic photographers like the constraint of a single focal length (and I am one of them).  It forces you to look at the scene carefully and find the interesting perspectives.
  • Only one moving part (focus)
  • Some primes are incredibly small (e.g., this Canon 40mm pancake lens).
  • To get comparable image quality to a prime, you have to spend a lot of money
  • Large and heavy
  • Usually, zooms are slower (have a smaller maximum aperture) than primes
  • Lots of moving parts (focus, zoom and (often) image stabilization)
  • Cannot change the focal length
  • Image stabilization is not common.  When you can get it, it is quite expensive (at this time).

So, I prefer primes for the reasons I state here.

The bottom line for me is stated as Image Quality/Price--you can't beat that ratio in primes.


Friday, April 19, 2013

Leica, continued.

Actually, I think I need (someday) to buy a Leica body.  This one would work for me:


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