Tuesday, February 25, 2020

Weight-Loss Data

For the last 2.5 years, I've been weighing nearly daily, trying to lose weight plus determine what behaviors helped or hurt. Take a look:

My weight for the last 2.5 years.

Look closely and some patterns appear:
  • I lose weight best between the New Year and the end of the spring semester.
  • Summers are flat or even a bit of gain.
  • Weight creeps up in fall, and I'm lucky if I don't put on much over the Thanksgiving to Christmas holidays.
What's going on? A clue comes by looking at a couple of years of daily averages:

Daily averages for two years.

Something happens Thursday nights and over the weekend. It's really not a mystery.
  • On Thursday nights, I go to Jubeck's, a microbrewery where I've been a member for over five years, since even before they opened. I typically drink two ales and snack on the free peanuts, Chex mix, and other goodies.
  • Over the weekend, my wife and I often eat out, sometimes multiple times, and I don't walk to school.
In January to early May, it's typically poor weather for riding my scooter, so I walk more. I also shovel snow. And I keep myself on a regular routine. In summer and early fall, I ride my scooter, walk less, have no snow to shovel and the grass seldom needs mowing after July or so. I like to cookout, and I keep beer in stock. The extra calories add up.
Still, from when I started to the current date, I've lost about 35 pounds. My blood-test results have improved, and I feel a significant difference when I walk. Uphills are easier without the 35-pound pack I carried on my stomach and hips. So what have I learned about my body and weight loss?
  • Walking helps everything---weight loss, blood work, and mental health.
  • Cutting out everything white matters---no white sugar, white rice, white flour, white potatoes, white supremacy, white privilege---all of it has to go. (The latter is the hardest to get rid of.)
  • I can eat as many salads and fresh vegetables as I want as long as I don't slather them or fry them in oils.
  • The improved feeling that comes with weight loss is itself an incentive to continue losing.
  • I need to watch the beer consumption, especially as it easily gets tied to increased snacking. That said, I'd rather die young than drink light beer. Even if I didn't live longer, it would seem that way.

Sunday, January 5, 2020

Portrait Photos

In previous posts, I've explained the impact of aperture upon depth-of-field.  When taking portrait photos, a commonly desired featured is a blurred background, as shown in the following photo:
My daughter, Tess, before her senior prom.
1/125 sec, f5.7, ISO 125, focal length 155mm
There are still more features in the background than I prefer, but they are fairly blurred so that the focus is literally upon her.   Better yet is the following image in which the background is completely blurred:
My daughter, Tess, before a previous prom.
1/1600 sec, f5.7, ISO 1250, focal length 300mm
Notice that in both cases, the aperture was f5.7, not extreme.  Instead, the shallow depth-of-field and resulting blurring of the background was due to using a longer focal length, 155mm in the first and 300mm in the second.  In both cases, I was using a Canon T6 with a zoom lens.

This narrowing of the depth-of-field is a strong reason for using a longer lens for portrait images.  A second reason is that the photographer need not be very close to the model.  I was probably 20 feet or more from my daughter in both cases and could take multiple candid shots without her being painfully aware of my presence.  Depending on the comfort of your model with being photographed, this may be a tremendous advantage.

The weakness of using a long lens is the general need for better light or a more expensive lens.  Many photographers who specialize in portraits will spend the money on a fixed-link lens (prime lens) of 80 or 90 mm.

Another reason for using a long lens is simply to take photos at a distance, such as when my older daughter was on the field at a track meet:
Ananda (left) and her friend, Kat.
1/500 sec, f8, ISO 400, focal length 300mm
Notice the lack of detail in the grass behind them.  That said, if you depend on the camera to do the focusing, the shallow depth-of-field may result in something other than your intended subject being in focus.  We'll leave focus issues for another post.



Shutter-Priority Effects

In my previous post, I showed examples of how by changing aperture settings the photographer can alter the depth of field.  In this post, I'll show the effect of setting your camera to Shutter Priority (Tv on Canon cameras) and experimenting with fast and slow shutter speeds.

When you set your camera to Shutter Priority (instead of fully manual), your camera will automatically set aperture and iso.  So, as in the previous post, the depth of field will change.  But by setting the shutter speed very fast or very slow, you can stop or blur movement, respectively.

With a very fast shutter speed in the image in the left below, individual drops of water are visible.  With the very slow shutter speed on the right, the water falling is blurred, as are the resulting ripples. (Both images were shot while using a tripod and a 50mm lens.)

left: 1/2000 second exposure, f1.8, ISO 400                  right: 1 second exposure, f23, ISO 100 

Note also the difference in the shadow on the rock in the upper-right of each image and the difference in detail in the water upstream.

Sports and live-arts photographers may also wish to use fast shutter speeds to capture images without blurring.  Note, however, that the price of high shutter speeds is either small f-stop values or high ISO values.  Very small f-stop values (large aperture) generally mean expensive lenses.  Very high ISO values generally mean graininess in images.  Such are the tradeoffs.



Wednesday, December 18, 2019

The Effect of Aperture upon Depth-of-Field

Though I teach science for a living, I have for years enjoyed taking photographs.  For much of that time, I  depended on the camera to determine the settings, leaving everything on Automatic, even when I had other options.  Finally, I got a decent DSLR camera and have begun teaching myself a bit more about photography.  I plan to create a series of posts demonstrating the effects of settings.  For the first, I want to show the power of shooting in Aperture-Priority mode (Av on a Canon camera).

When your camera is set to Aperture-Priority mode, everything is still determined for you by the camera except for the aperture.  (Thus, the name.)  Setting your aperture determines how big an opening in the lens lets in light.  Big opening = small f-stop = small (narrow) depth-of-field.  It's easier to look at this comparison of two photos shot a few seconds apart in Aperture-Priority mode with the f-stop at its smallest (left) and at its largest (right):

left: Aperture set to f1.8 (automatic setting of ISO 100 and shutter speed 1/1024 second)
right: Aperture set to f20 (automatic setting of ISO 800 and shutter speed 1/64 second)

(Click on the image to enlarge it.)  Notice that on the left, only the larger seed pods closer to me are in focus.  Everything behind is blurred.  However, in the image on the right, most of the grassed are in focus.

The effect of blurring the background, referred to as bokeh,  is commonly used in portrait photography to eliminate distracting details, keeping the person being photographed as the focus of the image.

Even a small change in aperture can have a significant impact:

left: Aperture set to f5 (automatic setting of ISO 3200 and shutter speed 1/32 second)
right: Aperture set of f1.8 (automatic setting of ISO 1250 and shutter speed 1/64 second)

Notice the blurring of the pot and window frame at the lower f-stop.

One thing to keep in mind as you reduce your f-stop/depth-of-field.  If you are using automatic focus, it may be difficult to get the items in focus that you wish:


Both photos used f1.8, but the auto-focus chose different items to focus upon.  
You can learn to control this but, for now, start by being aware of it.

Aperture-Priority mode is a good first step away from simply depending upon whatever logic is programmed into your camera---a first step in taking more control over your photographs.

Wednesday, October 30, 2019

Disconnected

I often carry my camera on my daily dog walk to help me get out of my head and pay attention to the physical world. From my home street, I take a public sidewalk 600 feet or so along Highway 20, a busy four-lane highway. As the sidewalk gives way to the parking lot of Harbor Freight, a ramp smooths the transition.



That ramp is largely due to the Americans with Disabilities Act (ADA, 1990) which recognized the need for public infrastructure to provide accommodations for those who would otherwise be excluded from the use of public facilities, even those privately owned. It also set standards for new construction. Changes in the law were no doubt crucial, but they were accompanied by changes in our mindset---if you ever make friends with someone in a wheelchair, you'll never see curbs the same again. The ADA greatly improved the odds of making such a friend.

This summer, a new VA clinic opened in part of what had been the K-Mart, once the anchor of the shopping center before becoming a hulking dead weight as it closed. As the east corner of the building was repurposed, the old garden center and an older and never-used-in-my-time auto shop were demolished. Newly built interior walls divided the space into offices for the VA. Near the old auto shop, a new ramp led to a side door equipped with a passcard reader. A new parking area hugged the side.

As I strolled, I pondered the disconnect that seems to dominate the U.S. currently. Can we no longer love someone we disagree with? Have we lost our ability to care for someone less fortunate than ourselves? And as I walked, the VA parking lot began to bug me.
Note how the ramp leads from the door to a crosswalk to... a curb.




To be fair to the VA, quite a few parking spots are handicap-accessible. But the curb seems to say, ""Park elsewhere, if you're disabled." It's almost arrogant, unwelcoming. And so unnecessary. Why not put a smooth transition to the crosswalk, maybe even at asphalt-level and wide enough to easily clear of snow?

I can only assume that the VA and the contractor who built the parking lot were not communicating very well. Did the contractor even think about the disabled veterans who might use the space? I bet if the contractor had a son in a wheelchair, he might have questioned the curb design.

I believe that on some level, the contractor would be ashamed if confronted with the way he constructed the curb. But if made ashamed, he'd probably resort to excuses, "There's plenty of other places to park," or "I was just doing what I was paid to do." Shaming him won't make things better. Introducing him to some of the people the VA serves, welcoming him like a family member, might.

Saturday, June 8, 2019

Grading Papers

Most of my students know that I hate grading papers.  To force myself to do it in a timely fashion, I promise them that I will have their tests graded b the following Monday or they all make an A.  So far, I haven't had to do that---but I've ruined some Sunday nights.  However, occasionally grading has its interesting points.  Take a look at the female student's drawing below.  By the point in the semester when this test was given, I knew her well enough to know she wasn't trying to tweak me.


Sunday, May 19, 2019

Just As I Am

On Friday night, I was invited to read an essay I wrote for the Dubuque Area Writers Guild's Gallery 2019.  Each year, the release of the Gallery marks the opening of Dubuquefest.  The Gallery is now in its 41st year.  The piece I read, Just As I Am, is about my experiences growing up Baptist in the rural South and is available [here.]