Sun/Sunlight 101 and Human Eyes 101

Sun/Sunlight 101
Our Sun, is a yellow dwarf, and specifically a G2V star, which means it's a spectral type G2 (based on color and surface temp) and luminosity class V (based on surface area).



Surface temp: 5800 ºK or 9980 ºF
Core temp: 15.6 million ºK or 28.1 million ºF
Mass: 4.38 x 10^30 lbs.
Diameter: 864,000 miles
Age: 4.57 billion years
Composition: 74% Hydrogen/24% Helium/2% other
Color: White (appears yellow due to refraction)



The Sun generates its energy by nuclear fusion of hydrogen nuclei into helium, with a net output of 383 yottawatts (10^24). The Sun lays approximately 93 mullion miles from us, and its light travels that distance in 8 minutes and 19 seconds, which is about my average speed while mountain biking. Sunlight is the total spectrum of the electromagnetic radiation given off by the Sun, and its wavelengths vary from 100 nanometers to 1 millimeter, and are divided into five regions:

Ultraviolet C or UVC: spans 100 to 280 nm
Greatly absorbed by the atmosphere, it has germicidal properties, and is more powerful than UVA and UVB, but they can be fatal to an organism.

Ultraviolet B or UVB: spans 280 to 315 nm
Mostly absorbed by the atmosphere, overexposure can cause sunburn and some forms of skin cancer, and they cause irritation to the cornea.

Ultraviolet A or UVA: spans 315 to 400 nm
Less damaging to the DNA, but are responsible for premature aging of the eye.

Visible light: spans 400 to 700 nm.
It is this range that is visible to the naked eye, and it represents 45% of Sunlight.
Bright and intense light, can lead to fatigue, temporary reduction of sight, and eye pain over prolonged exposure, and even with brief exposure the retina may be damaged and suffer vision impairment.

Infrared light: spans 700 nm to 1 mm
It is largely responsible for the warmth or heat that the sunlight carries, and it represents 48% of Sunlight. They heat the tissues, dry out tears reducing their protective qualities and can cause eye disorders.

Human Eyes 101
The human eye is a significant human sense organ. It allows humans conscious light perception, vision, which includes color differentiation and the perception of depth. The human eye has a 200° viewing angle and can see 10 million colors.


Eye Parts
Cornea: transparent protective envelope, 300 times more sensitive to sunlight than the skin.
Iris: colored membrane surrounding the pupil, determines eye color.
Pupil: central part of the eye varying according to brightness.
Crystalline lens: a transparent positive lens which adapts itself to object distance, reflects light.
Vitreous body: gelatinous liquid located between the crystalline lens and the retina.
Retina: a plate which is hypersensitive to light, transmits information to the optic nerve and to the brain.
Optic nerve: it transforms the images perceived by the retina into nerve impulses.

VHoldR ContourHD Review - First Impressions

I recently got the very sweet VHoldR ContourHD for a long term test, and after its first couple of uses, I am amazed of the exceptional clarity of HD. I have extensively tested the GoPro HERO Wide and the VIO POV 1.5 video cameras, and both have some special attributes they bring to the table, but that can't even hold a candle to the HD medium. This camera truly blows the doors off the other cameras!

Not only does the HD look good on the normal small screen format, such as YouTube, Vimeo, and others, but when it is seen in a full widescreen mode it still retains it clarity. The HERO is very grainy in a full screen mode, while the POV 1.5 is a bit better, it still doesn't have the crystal clear clarity of HD.

This is a general video test of ContourHD:

VHoldR ContourHD Test - Stoopid Trail Colorado from Brian Mullin on Vimeo.

Highlights

Video: HD (1280 x 720) at 30 fps or SD (858 x 480) at 60 fps, in H.264 Codec using a 5 Mega-pixel CMOS Image Sensor

Memory: MicroSD card (Maximum of 16GB, comes with 2GB), recording time of HD 30min/GB or SD 60 min/GB

Lens: HD 135 degree or SD 90 degree

Body: Water resistant, aluminum and fiberglass

Battery: Removable Litihium-Ion Battery, 3 hour record time


The unit comes with a 2GB microSD card which was good for 44 minutes of recording time in HD mode (20min per GB in HD). I went out and bought 8GB microSD card for maximum recording time, since at that point I will be bumping into the battery limit. I wanted to get a 16GB card, but they cost 3 times as much as the 8GB? I am still doing some battery and recording length testing, so no final iterations on them as yet.

Weight (measured)
101.5 grams (battery and card)
8 GB card .3 grams
battery 21.7 grams

Impressions
I have never used a VHoldR camera before so, so I had a few things to learn about the camera, but fortunately everything is fairly straight forward. The camera has some heft to it for such a small package, but the Aluminum body seems to be pretty tough so it should be able to take some abuse? Basically, the camera attaches to your helmet or bike using one of the mounts from the VHoldR Trail mount system. Unfortunately, it did not come with a vented helmet mount, just a goggle and a flat surface mount, what gives with that? I would like to see a version that comes with a vented mount as standard, that makes sense to me? I rigged up something while I waited for one of their vented mounts, so I used the goggle mount with a large Velcro strap swiped from one of my night lights.

This video test has a lot of shadowy areas, in which I was going in and out of the trees, from full intense Colorado sun to deep shade:

VHoldR ContourHD Shadow Test from Brian Mullin on Vimeo.

Here is a stability test in rough terrain:

VHoldR ContourHD Rough Terrain Test from Brian Mullin on Vimeo.

The camera has a simple On/Off button on the back of the camera, has two leds on the back that informs you of the memory and battery levels (green->yellow>red), an led in front that informs you of the camera is on (green) or in the record mode (red) and on the top of the camera is a slider that turns the recording on and off. On the back if you slide down the cover, on the inside there is the battery slot, a switch to change between HD or SD, a MicroSD slot and a mini USB port.


You just slide the camera onto one of the mounts, and then rotate the lens (90 degrees right or left of top center) to about where you think it is level, turn on the camera, click the switch until the dual laser beams come on that helps you level the lens. It can be a bit tough doing that in the field since the laser can be hard to see, so I suggest doing it at home, or step into a shady spot to level the lens. I freaked out the family the first time I turned on the lasers, and pointed them against the wall, which was kind of fun until the kids wanted to play with it, NOT!

After you get everything set up it is pretty easy to reach up on your helmet and turn the camera on or off, turn on the lasers or slide the record button. It makes a nice loud beep noise as things go on or off.


While it was on my head, I did notice the weight, but it wasn't significant, and it was nice not to have any wires (a big fault for the POV). It doesn't stick up in the air as much as the HERO camera, but it still got whacked by trees, and the softer slider material on the body seemed to get the abuse since it was showing gouges and scratch marks.


Once the camera is on and running, there isn't much to worry about. I only recorded in HD (1280x720) which is at 30fps, I have not tried it but the SD is at 60fps so it is supposed to give a smoother look? However, all of the video hosting sites cannot hold 60fps, so it is really only good for the VHoldR site.

One gripe I have is that if you don't clear the memory before your ride you are SOL to record much, especially if you are like me and max out the memory. The HERO is nice in this respect since you can delete an old recording, on the ContourHD, I was not aware of any method to do that?

It is really easy to open up the back latch, but it only bends so far so and tends to bow back and gets in the way. The microSD pops out easily, but the battery tends to get stuck in the slot.

Both the ContourHD and the HERO, like a lot of the CMOS video cameras use a Rolling Shutter, which makes videos seem a bit shaky and scattered (think sea sickness), due to motion artifacts (skew and wobble). The POV uses a Global Shutter technology like CCD's use, which helps alleviate the artifacts to a large degree. A Rolling Shutter exposes different portions of the frame at different point in time, hence "rolling" through the frame, while a Global shutter exposes the entire imager simultaneously. Neither does this in the physical sense. The degree that each camera exhibits the motion artifacts issue depends on a lot of factors. The GoPro due to its extremely wide camera angle (170 degrees) tends to compensate for some of those side artifacts, but it is still there.

This is a video of a multi camera shootout (ContourHD vs HERO Wide vs POV 1.5), I really strapped the helmet down hard so it wasn't sloppy on my head:

Multi Camera Shootout - ContourHD vs HERO Wide vs POV 1.5 from Brian Mullin on Vimeo.

This is my set up to try and test all 3 of my testing camera at once. Of course the HERO's batteries were dead, and the stupid cord on the POV got caught and pulled the lens to the side, so on my first test only the ContourHD worked properly!

When you get back home, or somewhere you have access to a computer, just open up the back latch, connect the USB cord and then either download the recording to the computer or watch them directory from the camera memory. I tend to download the video and the use my video editing software (current fave is PowerDirector Ultra) to create a short edited video that I upload to Vimeo. The indicator on the back stays red until the battery is fully charged, which can take a couple of hours depending on how much video was recorded.

Bottom Line
This is plain and simple one of the best sports specific HD (and non SD) video cameras on the market, and it makes the competitors look like wet noodles in comparison. The camera is light weight, durable and is intuitive to use. Its price is competitive and the HD benefits are simply amazing. It has a hint of motion artifacts like most CMOS Rolling Shutter cameras, and is a bit blurry with very distant background objects.

MSRP: $299.99

Purchase VHoldR ContourHD from REI





VHoldR ContourHD url: http://www.vholdr.com/contourhd/overview

Detailed Specs:

Video
HD (1280 x 720) at 30 fps
SD (858 x 480) at 60 fps
5 Mega-pixel CMOS Image Sensor
H.264 Codec

Memory
MicroSD card
Maximum 16GB (2GB included)
HD 30min/GB
SD 60 min/GB

Audio
Internal microphone
AAC Audio compression

Lens
HD 135 degree
SD 90 degree

Body
Water resistant
Aluminum and Fiberglass body

Battery
Removable Litihium-Ion Battery
3 hours record time
Charge via USB or Optional Charger
Charge Time 3 hours

Comes with
Countour HD camera
2GB MicroSD Card
Google Mount
Flat Surface Mount
Rechargeable Battery
USB Cable

Julbo Motion Review

Julbo Motion w/ unique ear loops

UPDATE: I Just found out that Julbo has currently discontinued this model, it is unknown if the model will later return into their sunglasses line?

I have been wearing and testing the new Julbo Motion sunglasses for a couple of months while mountain biking in all sorts of terrain and weather conditions. They have been in rain, snow, dense fog, and bright sunshine while on terrain varying from smooth singletrack to rough and tumble rock gardens. They offer incredible clarity, comfort and a panoramic field of vision.

Close Encounters of the Fawn Kind

I got up early on Sunday morning for my usual long weekend ride, mostly to beat the heat of the day and the crowds. Ok, there isn't much of a crowd up in Monument, but it is usually a bit quieter. Of course part way up to the Stoopid trail I came upon an entire herd of bikers. They were decent riders but a few of the stragglers were a bit out of their technical comfort range, and I passed them with ease. I got to my usual shortcut to the road to get to the upper trail systems, and one of the stragglers got out of my way just before the cutoff. I told her that she is just getting to the tougher technical stuff, and she had the gall to tell me was I skipping to the road because I couldn't handle the hard part coming up? Yah, whatever! Later when I was on the road, I could hear the people down below complaining about the trail, and I thought that was way too funny! Not a place to take an intermediate on a freakin' goat trail?

I can tell it's Summer time when the idiots on the road start to get worse, they come by you on a narrow bumpy dirt road and never let up on the gas, not even for a split second. Courtesy and safety people. I always wish I could flip out a Forest Service Ranger badge (as a fully deputized officer) and stop them for a severe lashing.

After the ugly road encounters, I was enjoying the solitude of some sweet singletrack on the Mule trail, and I had a nice pull up a long stretch of singletrack, that got the heart rolling up to a nice high level. I took a short food and rest break, and then got ready for the downhill fun. As I was cruising down the trail, and I saw this spotted object in the trail in front of me. At first I thought it's a dead rabbit or something like that.


I veered away from it, and as I passed it, I saw that it was a Fawn. I got off my bike and checked it out, and it was just sleeping and resting in the middle of the trail. I walked around the area thinking maybe the Doe (Mom) might be hurt or worse, but I never saw anything.




As I wandered around some more I see a second and much larger Fawn hidden a bit better in the nook of an Evergreen tree.



Figuring Mom was close by, I left the very cute Fawns to themselves. I figured they were around a 1-2 weeks old (my best guess). A very cool encounter!

They still looked healthy at the time, so I don't think they were orphaned? I hope they are fine and survive, that would be sad for them to perish, but rearing an animal is a task in itself and can cause other issues due to human interaction. It was at least a good 2 mile trudge to get to that spot where I found the twins, so it would be an arduous rescue.

Fawns are often found alone, because they do not flee from danger until about 14 days of age, and they do not forage with their mother until they are older. To escape detection a fawn lies motionless in tall grass or other cover. Its spotted coat helps it blend into its surroundings by imitating dappled sun on vegetation. Does leave their fawns unattended for several hours at a time.

I continued on down the trail and kept coming upon bark strewn across the trail in places, I am thinking perhaps a Bear was foraging for bugs? I am glad I did not have a close encounter with a Bear, and especially with some Bear cubs.

I was really enjoying the downhill section of the Mule trail. I love the slow speed braking on the tight switchbacks, the super skinny trail on the steep hillsides and the extremely fun shots deep in the trees. After getting back to Limbaugh proper, and following the trail around to Inspiration Point, I started up the long technical grunt up Colonels Revenge.


Sometime since the previous weekend some horse traffic has really trashed the trail. The trail is not wide enough for horses, nor was it ever created with a 1500 pound animal in consideration. In addition they tend to go up there when the trail is wet and leave very deep hoof marks, and it takes us weeks or months to get the trail back in shape after just a few encounters like that .

Well at least the flowers were out!

Continental Rubber Queen Review

I have been bashing away on a set of the Continental Rubber Queen 2.4's for around 4 months now, and I must say this is "Meaty Beaty Big and Bouncy". These are big suckers, that is just a blast to use, and they love to haul ass through the meanest territory you can throw at them. Yes, with these babies size does count!

UPDATE: Continental renamed the tire Trail King in the US instead of Rubber Queen

Flat tires, Adventures Race nuts and wacko drivers

It has been a while, since I had one of my daily musings, and since I have been having some interesting bike rides of late it was time to add a new one!

For several months, I have been testing a monster fat set of Continental Rubber Queen 2.4 inch tires, and I just switched to a set of Maxxis Ignitor UST 2.35/2.1, and these babies are scary skinny in comparison to the Queens. They can turn on a dime and roll really well, but they have no suspension characteristics since they are so tiny (more like 2.1/1.9). They actually make me want to miss rocks in a rock garden, and it hurts when you grab some air. I swear that the rims seem to get tweaked more, and I can actually hear the spoke's ping! I think the bigger tires are nicer on a decent wheelset, and these little skinny tires are detrimental, but that's just an early opinion. I have already missed using a big tire!

This last weekend I went out on my usual trails up in Monument and ran into an entire spectrum of people. I came upon a couple of family units that were bike riding up the Mount Herman road, and the scenario with each was that the parents had decent bikes with good gearing, while their teenage daughters were walking their bikes up the road due to a combination of lack of fitness and junk bikes with worthless gearing. I felt very sorry for the poor girls as I flew by them!

Next as I left the road proper and started on my normally serene and quiet Mule trail, I bumped into a couple that must have just broken down their campsite, since the gentleman was carrying everything out in a giant plastic garbage can! And it got only stranger as I rode further up the singletrack. I heard voices all over the place, up the trail and on the hillside. It turned out that there was an Adventure Race going on all over the Mt Herman area. Thank goodness they were not continuing up the trail I was on. I continued up and over the Mule trail into Limbaugh Canyon and then made my way over to Colonels Revenge, which I felt very stoked about when I cleared the entire thing! Yea! The thunderstorms were just barely starting, and I still had some time and energy, so I made my way over to the Burn Zone via the Black Pearl trail. Of course I again bumped into the Adventure Race, ugh! I stopped and spoke with a couple of groups of people, and they showed me the maps they were using. It appeared that they were doing an orienting session and had a number of points they had to find, and at each point, there was a punch that they used on their scorecard. At one of the punch spots, they seemed to be mixed up where to go, and they were wondering if the T junction on the map was the one I was getting ready to ride up? I took the map, pointed it north and showed them that the T junction was obviously a 1/4 mile south! Ok, I guess they can't read maps very well, or maybe I just have an innate sense of maps and I know where everything is anyway (it is my backyard). At least after I trudged all the way up the Burn Zone trail they all had left, and I got back the solitude!

Two weekends ago I went out for a ride, it started out nicely, and then it turned into a horror show. The start of the ride was a bit drizzly and humid, and then just as it got sunny I got 3 flats in a row. I have gotten flats before, but never in 20 years of riding have I had that many in a row. It turned out, I had picked up several roofing nails and they kept getting embedded in the tire and would puncture the tube! I had only one spare tube, and I couldn't get anything to seal up with my usual tricks, so I had to walk out 5 miles on a gnarly singletrack in a thunderstorm, and when I finally got to a road, some wacko job almost ran me over, ugh! The Mt Herman road was very quiet with no one around due to the weather, and this guy accelerates just as he gets near me and then veers slightly towards me, so I had to jump off the road into the mud for fear of my life or at least bodily harm.

I bumped into a guy the other day that offered some tips for emergency tire and tube fixes. The first tip was to over stuff pine needles into your tire and put it back on the rim, it will at least allow you to ride on the smoother sections of a trail and get you back home. The other tip was to cut the tube in the section that has the leak, then tie a tight knot using the cut ends. Yo then put it back in, pump it up, and it will still leak slowly, but it will at least hold air!