I didn’t actually take any pictures at our Thanksgiving get together. I just enjoyed it. I did however carry the camera around on a family trip to the River Walk in San Antonio with my parents and Adrian.

My parents sit for a spell on the river walk on the Friday after Thanksgiving.

Dinner at Las Canarias. Despite its name, this is a French Resteraunt, and an exceptional one at that.

The Passing of a Barge. The River Walk isn't just for walking. Tour and dinner barges run up and down it carrying tourists.

The Crowds. The river walk was quite crowded on the day after Thanksgiving. I didn't mind this time, which is out of character for me.

Tower Life Building. This building sits along one of the less heavily traveled sections of the river walk and it is much more interesting than the more modern all glass monstrosities.

RAID stands for Redundant Array of Independent Disks and names a set of methods for distributing data across multiple hard drives. In most cases, the RAID array is designed to recover from at least one drive failure. This ability leads some to believe, incorrectly, that is a appropriate solution to the backup problem. RAID arrays have a level, generally 0, 1, 5 or 6. Raid 0 and 1 are the most common for consumers. Raid 0 is called “stripping” and offers no redundancy at all. It is all about performance. Raid 1 is called “mirroring” and as the name implies, it is about keeping 2 identical copies of your data.

So, with a RAID 1 array, with the data mirrored (exactly the same data is on both hard drives at all times) on two drives, why isn’t it a backup system?

1. RAID can not protect against local disaster or theft. What happens if someone steals the entire computer? What about a fire or lighting strike?
2. RAID can not protect against software errors like bugs in the file system drivers.
3. RAID can not protect against virus or mal-ware that delete your data.
4. RAID can not protect against human error (fat-fingers, overwrites, delete all, etc).

Of course that isn’t even the entire story. Even with a plain old hard drive failure – the thing RAID 0 is designed to protect against – the array often fails completely. Why? Because the existing “good” drive is subjected to considerable stress for several hours while the only existing copy of your data living on it is copied to the replacement drive. This often leads to a second failure of the “good” drive.

On a side note, the proper use of RAID is actually to maintain uptime and/or to increase performance. RAID allows many commercial systems (web servers, factory automation systems, etc) to survive one of the most common failures – a hard drive – without interrupting their users… most of the time.

Home User Backups

Backups are about surviving the worst case scenario.

The key to a good backup system is to maintain recent copies at a different location than your computer. The farther the better. Your next door neighbors house is better than nothing but isn’t ideal. Consider that you probably live in an area prone to some natural disaster that will wipe out a neighborhood, not just your house. For example flooding, tornadoes, hurricanes, earthquakes and wildfire all come easily to mind.

There is no one right solution. Instead, consider the following rules:

Rule 1:

Keep at least one copy of your backup off line (powered down and disconnected) at all times.

Rule 2:

Test your backup. However you create them, whether using automated software, or by simply dragging the folder to your backup drive, take time after each backup, or at least monthly, to verify that recent data is actually on the backup drive and usable.

Rule 3:

Use an incremental solution if at all possible. Incremental backups are a form of backups where only new and changed data is backed each time a backup happens. Generally older incremental backups are kept for sometime before being removed to free space. Using incremental backups does two things.

1. Backups are faster because only new and changed data must be copied.
2. You can recover older versions of files that have been changed and then backed up more recently (i.e. you can get to older versions if something corrupts the most recent version).

Rule 4:

Keep the backup copy(s) safe. That means as far from your computer as possible when a backup is not going on.

1. Store the backup drive at your work place and only bring it home on your backup day (say every Tuesday).
2. Purchase 2 identical external drives (they are cheap now!) and rotate them on a monthly basis. Keep whichever drive you are not currently using off-site at an office or friends house, or in a safe deposit box. Keep the other locally in a fire safe.

Rule 5:

Use more than one backup system. This sounds like over kill and for some it may be, but for others (those who answer “oh god, I’d be done for” to the question “what would you do if you lost all your data”), it is a must.

Your primary system should be something simple and understandable that requires your interaction. Why? Because then you are paying attention to it and not just ignoring it only to realize when your hard drive fails that the automatic backup system you use stopped working 3 months ago.

You should also have a secondary system. It should be automated. One of the on line backup systems (“in the cloud”) is a good option here. The reason this isn’t good enough to be the primary is that it is totally out of your control and it relies on having a fast data connection when you need to do backups or, more importantly, restores. How long will it take to download 100Gb or even several Tera-bytes of data? What if you need to do it on a really slow connection (say after a major disaster when telecom services are iffy)?

You should also have special case backups. These are for the most important files – the “I can’t live without it” files -  such as your almost finished dissertation, that manuscript for your killer novel, or your customer contact list and accounting data. Backing these things up individually and regularly independent of your other backups is one more way to make sure you don’t loose them (and to sleep better). And because the set of things that fall into this category is usually very small, there are some really simple ways to handle this, such as emailing them (properly encrypted for security) to your gmail/hotmail/yahoo account and then leaving them there in case you ever need them.

Hand Held Stitch Panorama of the US Capital Basement. Some visual defects are obvious even at reduced resolution.

Closeup of Misalignment

This misalignment results from parallax error, which is caused by the viewer shifting locations. This error can NOT be fixed in post processing. There is no way to align this image so something isn’t misaligned. In this case, the camera was hand held so my location moved quite a bit from shot to shot. In a shot like this, with many elements at different distances, parallax error was unavoidable without the use of a tripod and offset head that had been properly calibrated for the lens in question.

The Problem – Parallax Error

Illustration of Parallax Error

Notice that when the observer (the eye) moves, the foreground object (the red ball) obscures a different portion of the background as indicated by the blue sight lines. You can demonstrate it yourself. Hold your finger up at arms length, close your left eye and note what your finger covers on the background. Then without moving your finger, open your left eye and close your right eye. Notice that your finger shifted relative to the background.

The shift happened because the position of the observer moves left about 1.5 inches when you switched from the right to the left eye. We are so used to this happening that we don’t even notice it most of the time. For stitched panoramas, where the background isn’t uniform (for example, if the background is layers of people and columns), it makes a difference in the resulting stitched images.

Using a tripod alone won’t fix the problem entirely most of the time. Unless your camera and lens combination happens to have the nodal point directly over the tripod screw you will need a slider or offset plate. Once you have properly shifter the camera so the nodal point is on the tripod’s axis of rotation, the effective location of the observer will no longer change as your swing the camera between frames.

Use an Offset Plate or Slider and Calibrate

We need to slide our camera back from the point of rotation on the tripod so the nodal point for the lens moves over the center of rotation for the tripod. In principle this is simple. In reality, it requires the right equipment and caution.

Because you will be moving your camera away from the tripod’s center of rotation, it could become unbalanced. Always carefully check the balance and stability of the setup to make sure it won’t fall over. When in doubt, keep a hand on it!

Each lens has a unique nodal point dependent on the lenses optical design. To find your lenses’ nodal point, create a setup similar to the illustration except that we use a background object with regular markings – a ruler!

A light stand and craft ruler used to calibrate the nodal point for a lens.

My foreground object is a light stand, but anything that is stationary will work as a foreground object. It should be placed about 1/2 between the camera and the ruler. Of course, even with the significant depth of field of a wide angle lens, either the ruler or foreground object will be out of focus. I choose to focus on the ruler. It is easy to tell where the out of focus foreground object is hitting the in focus ruler.

Once you have everything setup, simply look through the view finder and swing the camera left and right. As you do, note any shift in relative position between the ruler and the foreground object. If there is any, pick a direction (forward or back) and shift the camera that way. If the relative motion gets bigger, you picked wrong. If it gets smaller, you picked right. Continue to shift the camera until the foreground object no longer shifts its position relative to the ruler as you swing the camera left and right.

Foreground object in center of frame.

Foreground object swung to left of frame.

The two frames above show a (nearly) correct offset for my 28-70 Nikon lens. Notice that the light stand is adjacent to the same line on the ruler in both frames. There will be little or no parallax error in stitch panorama using this offset.

Equipment

If you are curious, here is the rig I’m using:

Nikon D700, 28-70mm f2.8, Velbon Super Mag Slider and Arcatech GP-s Ball head in Leveling Configuration

• Nikon D700
• Nikon 28-70mm f2.8 Lens
• Velbon Super Mag Slider
• Arcatech GP-s Ballhead setup in leveling base configuration
• An inexpensive hot shoe bubble level because with the slider mounted, I can’t easily see the bull’s eye level on the GP-s

Notes

• I chose to use a ruler, but I could have placed the light stand so that it was centered over the edge of the door. As long as it stayed over the edge without shifting, I know have the correct location.
• You can tell if you need to move forward or backwards by the way your foreground and background objects move relative to each other, but that requires to much thinking. I just guess and if it gets better, I picked right!
• The larger the relative distance between your foreground object and background object, the better. I did this in my apartment. It would be more accurate to do it outside with the light stand 2 or 3 feet away and using a building or tree 100s of yards away.
• For zoom lenses, the nodal point depends on the current focal length. In the case of my 28-70mm, the nodal point moves almost the length of my slider from 28mm to 70mm.
• Modern aspherical lenses, particularly zoom lenses, will probably not have an actual nodal point. There may be no single point of rotation that can remove all parallax error. For lots of reasons, this isn’t to big of a deal, including the fact that panorama stitching programs try to use the center of frames where the calibration should be best (and where a wide angle lens is sharpest).

Annie performs an aerial during her showcase routine.

I had planned to compete in the Jack and Jill but decided when I got there that I would rather take pictures and stay late for social dancing. I didn’t want to have to deal with trying to make the really early competitors’ meeting on Saturday morning at noon. That turned out to be the right answer for me this year. I had many many many incredible social dances. It was a great weekend of dancing.

Todd and Naomi during the Strictly Lindy competition.

Elaine and Adam

Skye and Frida

Chandrae and Stephen

In the Jam Circle

Swiveling

Swing Out! Sometimes showcase routines only have a few swing outs in favor of lots of fancy moves. Not this one. Jumpin' at the Woodside with swings outs galore!

For those interested in the results and some videos, see the official results page. For more images seem my facebook albums: Part1 and Part 2.

The Liquorice Stick

Piano Man

Friday started with The Boilermakers Jazz Band at the bumper car pavilion at Glen Echo Park. The Jam Cellar brought them in and oddly enough didn’t publicize it very well. I ended up hearing by word of mouth on Facebook. The crowd was healthy, but not as large as it should have been for a 1st rate lindy band like The Boilermakers. Their lead female vocalist is a world champion level lindy hopper for Pete’s sake! The lack of publicity meant SPACE to swing out, which is something lacking at many of the dances here with bigger bands.

When you've been around for 55 years, you have a lot of material at your disposal.

Swivels

Been There, Done That

There is normally a dance in the Spanish Ballroom with a pretty big name on Saturday nights and the floor is usually crowded. This Saturday the dance was organized by Gotta Swing and the music was provided by The Glenn Miller Orchestra. Tom and Debra of Gotta Swing do a great job promoting their dances. The floor was packed.

The Glenn Miller Orchestra

Trombonist

Winds

Gotta Swing’s bigger dances usually include at least one performance and an organized jam. This particular night there were 3 or 4 performances (I didn’t take notes so I don’t remember exactly who performed) and a jam. It was all good fun.

Performing

Paying Attention

Exit Strategy

This coming weekend is ILHC – THE International Lindy Championship – here in DC. It is going to be huge and I’m looking forward to seeing some of my old dance friends from Houston again.

A bull rider comes out of the gate at the Rodeo.

I grew up in a small town in Texas named Seguin. Every year in October the county held a fair and rodeo and every year I would go to the midway for my birthday. It has been a few years (well, quite a few) since I’ve been to a small town fair and rodeo.  When we decided to go to the Loudoun county fair I wasn’t expecting the that type of experience. Loudoun county is only an hour from our apartment and my (all be it limited) experience with things an hour from DC is that they are overrun by city dwellers (like myself) trying to escape the city.

Masters of Chainsaw working on a wood carving.

Start 'em Young, Hanson's Acrobatic Show

Many of these larger escapy oriented events seem overproduced and fake. They feel more like a block buster movie with hundred-million dollar budget tailored to the superficial wants of the crowd rather than independents film made by inspired and hungry producers and actors who genuinely want to make something wonderful that isn’t about the superficial experience.

The fair included a petting zoo as well as camel and pony rides.

Super Farmer Competition

The Hay Bail Toss. It is harder than it looks.

The Loudoun county fair surprised with a crowd that appeared to be mostly local. It was a great small town affair with events like beef-musical-cones, Agricadabra the agricultural magician and Hanson’s Acrobatic Show featuring the Hanson family, including their two young duaghters. The entire fair was a hometown master piece full of well thought out and genuinely fun activities and shows, none of which would ever be considered in a “big time” affair.

Agricadabra. You can have all sorts of fun with a weed blower.

Legos are Fun

An uncooperative cow during "Beef Musical Cones".

The rodeo was great fun too. Unlike larger scale events, access was pretty much open and I ended up walking around the rider’s area while they prepped. I stood and photographed from the fence during the bull riding itself and on several occasions could have reached out and touched the rider and bull.

Fire Safety Training

Fireman Trainee Race

Animal-Owner Costume Contest

Of course, the massive you-know-whats aren’t limited to the bulls and riders. The bull fighters are about as fearless as they come. They are the people keeping the riders alive after their ride ends for better or worse. And really, better and worse are about the same at the end of a bull ride. You fall off and try to avoid being gored to trampled to death by the bull. Luckily for the riders, there are two guys who dive in to help pull them away and also put themselves between 2000+ lb of pissed off animal and the guy who it just threw off like a rag doll.

Flag Rider

Bull Rider Prayer

Bull Riders Prepare for a Bull Ride

Unfortunately, modern rodeos have become mostly about the bull riding. Rodeos arose as a way for cowboys to show off their work skills and most of the historic events stem from real skills they used daily. Barrel racing is about horsemanship and riding around obstacles quickly. Calf roping is about capturing cows that need branding. Riding wild broncos is a required to break wild horses. All of these, and more were (are) skills a cowboy needs to do the job.

Dust control prior to the rodeo starting.

Off the Bull. And yes, the bull fighter is nearly touching the bulls head.

Bull riding doesn’t fit that pattern. It seems like the type of event that came out of a drunk dare rather than a desire to practice and show off working skill.  You never really need to ride a bull as a part of being a cowboy (unless I’ve missed something, which I suppose is possible).  I mean no disrespect to the professional bull riders. Those guys have you-know-whats as large as the bulls’ they ride and they are competing in the event the crowd wants to see.

Round and Round

Now would be a good time to run.

But, the crowd wants carnage, not cowboy skills. Nascar is the same way. Very few people watch to see the driving and engineering skills involved. If that is what they wanted to see, they would watch other forms of racing, not because the drivers and engineers in Nascar aren’t skilled, but because the competition isn’t set up to show off those skills. It is set up to create carnage to sate the appetite of the masses. It is the modern equivalent of two guys in a ring trying to kill each other with swords. At least they let the girls barrel race still and it was pretty impressive. Unfortunately, it was late enough where the light had gone completely so I didn’t take many pictures.

Barrel Racer

Of course, a county fair wouldn’t be a county fair without a midway. By the end of the rodeo it was full dark so I had some fun with long exposures.

Cotton Candy and Popcorn! What could be more fun?

Puke-O-Matic

All the Rides

The edge of Iguazu' falls.

To visit the falls, we flew into Beunos Aires via Ezeiza airport and then had to transfer via taxi to Aeroparque Jorge Newbery about 30 minutes away. We had a short layover and were on the last flight of the day to Iguazu’ so there was some question of whether we would make it. We did, partially thanks to the refreshingly non-TSA-insane security. It was nice to enjoy a flight instead of being treated like a convicted criminal as we are in the US.

The entire area seemed like a lost world, especially our first overcast and rainy day.

Iguazu’ is more than just falls. It is a national park and wild life refuge. There are 100s of colorful birds, including the Tucan Grande and parrots all around the park as well a monkeys and coati. I’ll post some of those images later this week.

Rafted up in the middle of our trip, we enjoyed a snack and a wonderful view. This image was taken looking towards the Tasman sea.

During our day of kayaking we experienced Sterling Falls from up close as well as New Zealand fur seals playing in the water and lounging on rocks. The operator we chose motor boated us out 6 km and then we spent the day paddling back. Many of the other operators have you paddle out and back so you only get to experience half the area we were able to explore.

Sterling Falls

Our second day on Milford Sound was a different experience. We took an overnight cruise which allowed us to view more of the sounds all the way out to the Tasman sea and back. The boat made two trips around the sound, one in the evening after we boarded and another at sunrise the next morning. Most passengers ate a relaxed dinner and breakfast during these circuits, I ate as fast as I could and headed out on deck.

Other Worldy

A Little Perspective. The small white thing in the middle ground is a cruise ship.