Schierer Space

On Friday we planned on going to the zoo, but when we arrived the parking lot was filled with school buses and grade-school aged children as far as you could see. 83 buses worth according to a harried zoo employee. And there were more coming.

We bailed out to the Fort Worth Nature Center and Refuge for some walking around in nature and much opportunity for Nate to burn off some energy. He poked at rocks and ran around. A generally a nice day was had by all.

Well, the fam is back home after our late but relatively smooth return from Texas yesterday. We were down to visit with my G-Ma C. in honor of her 90th birthday (which was actually today).

We visited (and stayed with) my Aunt Bren, Uncle Ray and some zombie-hunting madman.^[1]

At Aunt Bren’s request I pushed through some pics of Jonny and his gf, since they were looking all dapper. ^[2] K has those up on Facebook and they’re also in the gallery.

The rest will be a while. 467 images made it home after some rare on-camera deletions.

So that’s how far I am at this point… ending in a romp in the Texas wildflowers for Nate. Coming soon, visit to the Fort Worth Nature Center and Refuge, G-Ma’s B-day celebration and the Fort Worth Zoo.

1. Picture shows him in his natural habitat. [↩]
2. Ha! I called you dapper! [↩]

K’s folks were in town this past weekend to see Nate. We occasionally talked with them too. Actually, we had some fun playing Ticket to Ride with K’s folks and K’s Grampa D.

Here are a few pics. Enjoy.

So I had a password protected PDF file which unfortunately I had forgotten the password for. Knowing some attributes of the password, I had a feeling it would be fairly quick to perform a brute-force method to crack the password. So I used the power of Google to find a free PDF password cracking tool. Yes, this is perfectly legal.

It turns out that this particular tool was originally written for Linux, but someone had graciously used CygWin to compile a Windows version so I could run it on my Windows PC. ^[1]

So background for the non techies: A brute-force method is one that essentially tries every possible combination until it succeeds. For something like a PDF file, which is resident on the computer running the algorithm, it can be quite fast.^[2] In fact, it is SO astonishingly fast that I was inspired to write this blog post.

So my relatively fast, but far from state-of-the-art Pentium 4 machine clocks in at 3.4GHz and has 3GB of RAM. ^[3] This is pretty quick for a single core computer, but quite slow relative to the multi-CPU machines that are readily available today. Anyhow, my ordinary PC can test approximately 41 thousand passwords per second. To put that in perspective, consider a 5-digit random password containing upper-case letters, lower-case letters and numbers (62 different characters per digit). There are precisely 916,132,832 different passwords that can be made this way.^[4] At the speed of my computer, I can crack ANY 5 digit password following these rules in just over 6 hours. Smaller passwords take less than 6 minutes. Consider that a typical 4-digit numerical ATM card PIN would take a mere quarter of a second to crack.^[5]

The lesson here is that with a room full of computers (or networks of computers), cracking even significantly longer passwords comes into reach. Using lists of common words, names, etc. (i.e. dictionary attacks) are obviously even faster. This is why your passwords should be A) long, B) contain lots of different characters C) not be common words or phrases and D) not be the same everywhere you use them.

Oh, I remembered that the passwords on the PDF files were numerical and relatively short, which makes for a pretty weak password, but it was sufficient for this need. It took far longer to install the software than it did to crack the password.

1. Yes, I know, I really should have been able to do this myself, but after a couple of weird linking errors I decided to move forward. As a pet project, I intend to reproduce this work myself just to make sure I still remember how. [↩]
2. It would be slower if the system was remote and the password attempts had to be sent over the network, or if the system being ‘cracked’ prevents more than a few password attempts before locking the account. [↩]
3. Actually 4GB of RAM, but WXP can’t see all of it. [↩]
4. 931,151,402 if you include shorter passwords. [↩]
5. Fortunately, you have to have the card AND the ability to enter 10000 PIN numbers without getting your card eaten by the machine. [↩]

K snapped a few more pictures this evening before Nate went to bed. On principle I just have to be caught up… so here goes.

First, K made this scrumptious two-layer pineapple upside down cake for dessert after Easter dinner. YUM!

Second, Nate’s been sick the last week or so with various typical toddler ailments. Currently he’s suffering from nostrilus firehosium. In any case, it tends to make him pretty much emotionally unstable. These pics were taken no more than 2 seconds apart.

Look! I’m actually posting images from this weekend for a change (and some from last week too).

Nice weather has been long in coming to central New York, and even though it looks nice, it can still be pretty chilly. K went outside with Nate this week and got some pics with the new cam. He also showed off his new solo-ladder climbing skills. Look out El Cap!

We got out yesterday too for more fun in the cold windy sunshine.

And of course, the highlight of the weekend was watching Nate search for the brightly colored M&M filled Easter Eggs that somebody hid around the house. Nate also enjoyed the one-week late donkeys at church this morning.

When we were out in PA last weekend we went to the Erie Zoo. It’s a lot nicer than I remember with much more respectful enclosures for the animals. As I mentioned in my updates post a few days back, there was much snapping of shutter. We also stopped in the greenhouse for some great flower pics. Here are some highlights. You can, as always, clock through to the gallery.

Enjoy.

In film cameras, one would select the film speed to correspond to the expected lighting conditions. The faster the film the less light was required to produce a satisfactory image. Unfortunately, faster film generally had larger grain size in the emulsion leading to speckling in the image. Digital camera sensors are quite similar, except that the sensitivity can be adjusted on the fly. However, the electric sensors are subject to noise, and the more sensitive you make them the more noise will be captured. For astrophotography and other high-sensitivity applications the sensors are often cooled to reduce noise.^[1]
The 40D has a newer sensor and processor relative to the 20D. Here’s a quick comparison of the sensor specs.^[2].

Ok, enough already, lets get to the comparison. I setup a pen and ink art piece in front of the tripod in low light last night. All images were exposure corrected by the same process in Photoshop. There is a slight color cast difference between the cameras which could very well be legit. Of course the first thing I noticed was the difference in field of view between the two images. All four images are cropped to a fixed dimension in pixels. So 900 pixels on the 20D sensor covers more viewing area than 900 pixels on the 40D sensor. Or said a different way, each 40D pixel contains the information from a smaller area of the field of view, so when you put 900 of them together you get a smaller portion of the complete image than you did with the 20D.
The noise, however, does not appear to be significantly different to me. Certainly the ISO 1600 images are much noisier than the ISO 200 images, but the 20D compared to the 40D does not seem to be significantly different. Note that the horizontal banding is actually texture on the original art paper and is not a noise feature. I didn’t have a clear night, or I would have made some longer exposures under truly dark conditions to magnify this up a bit. Perhaps a future post.

1. Image noise is partially caused by random energy variations in the electrons within the semiconductor. The cooler the semiconductor, the lower the energy of the electrons and the less likely they are to jump over the critical threshold that produces a detection on that pixel. Sometimes noise is referred to as thermal noise because of this relationship with temperature. Want to learn about other noise sources, check out “What is… Noise“. [↩]
2. Stats taken from DPReview since none of these specs changed between the 20D and 30D. [↩]

As seen on Digg, an EPSN top ten of shootout goals. Watch first, some serious dexterity there.

So as sweet as these are, I need a hockey expert to help me out. How are some of these shots legal?

So the official NHL rule book says in Rule 89 Tied Game:

b. (NEW for 2005-06) During regular season games, if the game remains tied at the end of the five (5) minute overtime period, the teams will proceed to a shootout. The rules governing the shootout shall be the same as those listed under Rule 30 – Penalty Shot.

Rule 30 Penalty Shot says:

a. Any infraction of the rules which calls for a “PENALTY SHOT” shall be taken as follows:

The Referee shall ask to have announced over the public address system the name of the player designated by him or selected by the Team entitled to take the shot (as appropriate). He shall then place the puck on the center face-off spot and the player taking the shot will, on the instruction of the Referee, play the puck from there and shall attempt to score on the goalkeeper. The puck must be kept in motion towards the opponent’s goal line and once it is shot, the play shall be considered complete. No goal can be scored on a rebound of any kind (an exception being the puck off the goal post, then the goalkeeper and then directly into the goal), and any time the puck crosses the goal line, the shot shall be considered complete.

Only a player designated as a goalkeeper or alternate goalkeeper may defend against the penalty shot.

There are two things that confuse me. First, in number 4, the spin-o-rama shot. Unfortunately, ESPN has their stupid title bar right in the way, but it seems unlikely that in all of these shots the puck continued in its motion toward the goal. When the player stops at the crease (otherwise there would be a crease violation), the motion of the stick would seem to swing an arc away from the goal then back into the side of the net. Thoughts?

The second is the ‘once it is shot’ rule, I guess its not a shot if the goalie hasn’t touched it yet? In number 3, it would seem that the player shoots, then reaches back across the goalie to tap the goal home. Many of these highlights seems to have deke after deke, so there certainly isn’t any shortage of repeated trigger pulls. Is this just an extended pass-to-self?

Bow down to the refs who have to watch this stuff in real time and make the right call. Wow.

So one of the lenses in the mucho-extra-gear-and-accessories pack (mega-pack) is the EF 28-135mm f/3.5-5.6 IS USM. In non-lens speak, this is a mid-range zoom lens with image stabilization (IS). IS is a feature where a group of lens elements are rapidly adjusted by a computer to compensate for the camera shake cause by hand-holding the camera. Under optimal lighting conditions, it’s unnecessary because the shutter speeds can be high enough to prevent the hand-shake from affecting the image. At lower lighting, shutter speeds drop, and this is where the IS can make a difference. I’ve seen various reports stating that this feature can make up for anywhere from 1/2 to 2 full stops. ^[1] You can certainly see the image in the viewfinder ‘lock’ when the IS turns on (half-shutter press), so it’s clear that it’s doing something. The question is whether it’s doing enough to warrant the extra weight (and cost). So I decided to put this lens to the test.
Beyond the geeky fun of generating a test, I have decisions to make between the lenses I had prior to buying the mega-pack and the ones I just acquired. ^[2] The primary competition for this lens is the EF 28-105mm f/3.5-4.5 II USM that I already have. This lens covers slightly less territory (105mm vs 135mm), but has more light collection ability at the long end (f/4.5 vs f/5.6). ^[3] Unless the IS can make up for the lost light, the 28-105 is the better lens. Combine that with the fact that the 28-105 is shorter in length (75 vs. 97mm), considerably lighter (375 vs. 540g), and shares filters with two other lenses I have (the new one doesn’t); my existing lens isn’t looking so bad. So lets see what IS can do.
I set some sheet music on a music stand about 2 meters away and set the lens to maximum zoom (135mm). I took a series of shots with IS off, then on to compare the results. All images were corrected for exposure in Photoshop, so some were brightened more than others. (more…)

1. A ‘stop’ is camera lingo for a doubling of light collection. So changing the shutter speed from 1/100th of a second to 1/50th of a second would increase the exposure by one stop, since the shutter will be open twice as long. Likewise, doubling the sensitivity of the sensor (or film) will increase the exposure by one stop. [↩]
2. Yes, I can certainly keep them all, but I can’t CARRY them all, so I still have to decide what to put in my bag. [↩]
3. Recall that the higher the f-number, or focal ratio, the smaller the aperture of the lens relative to its focal length. The smaller the aperture the less light, and because the is f-number is in linear units, the aperture area goes with the square. So f/2 is 4 times more light than f/4, that is, two stops. f/4.5 is about 2/3 of a stop higher than f/5.6. [↩]