Etikettarkiv: temperature

English

Suunto Core Outdoor Watch

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Some of you already know my fascination for wrist watches and therefore I thought I should share with you my latest aquisition, the Suunto Core outdoor wristwatch. Suunto is Finnish and means direction and this is a good name for these watches. There are many different models to chose from and I decided to get the Suunto Core model which seems to get you lots of functions for small money and the most all-round watch there was. Or, sorry, wristtop computer as these watches are sometimes referred to.

I am a guy who like walking in the woods, hiking, trekking and just generally being outdoor when possible especially in the summer time. I try to make at least a few day trips and if possible an overnight in a tent as well every summer as a minimum, it is something special when you are cooking in the wilderness, sleeping in a tent and generally having to struggle a little more than you normally do every day to and from work. If nothing else you appreciate a nice bed when you come home again :)

On top of that I am an unchangeable gadget-guy, and I really enjoy knowing the altitude I am on right now, the bearing I am walking in, my position, the time, when the sun rises and sets on the latitude that I am right now and many other things. So my latest addition to things I won’t leave home without now is a Suunto Core wristwatch.

This little gem can do a lot of things and it is a watch specially designed for outdoorsmanship more than anything else. This is not the first ”trekker’s watch” I have owned, I also have an ”Origo” watch but after a particularly rough outing in the United Arab Emirates a couple of years ago the altimeter broke on that one. So I have decided to get myself a new watch and now I recently bought it.

The Suunto Core watch keeps two times, good for traveling and it has what you expect from a modern digital watch, countdown (99 min max) and works wel as a stopwatch (24 h max). On top of that you can program it with the closest city and it will show the time the sun rises and sets for the date, something that changes drastically right now, the day becomes longer with about 6 minutes every day now and the nights shorter here in Stockholm.

The watch also contains three interesting functions for the hiker not normally found on wrist watches and they are altimeter that shows how high over the sea you are at the moment, barometer showing the air pressure (sea level equivalent) and an electronic compass.

Suunto Core
Suunto Core, outdoors sportswatch

The altimeter and barometer are actually two faces of the same coin here. You can select the profile yourself, if you want the watch to be in altimeter mode when you climb, then you can set it to barometric mode when you stop for the night and the watch will tell you the air pressure and assume that you are staying on the same level. You can not get both at the same time though because both the barometer and the altimeter works from the same air pressure sensor. If you climb a mountain the air pressure lowers with every meter you climb, the watch senses this change in air pressure and can therefore know how many meters you have scaled. In barometric mode you fix the altitude and the watch instead registers the changes in air pressure that preceeds an oncoming storm or weather front.

The watch can automatically shift between altimeter and barometer mode, it understands when you start climbing because the air pressure shifts too fast and then it switches to altimeter. If you stay it will after 12 minutes of no change in the altitude (or very small changes) shift back to barometric mode. Brilliant. Over a full days walking around I generally don’t have to recalibrate it for more than 20-40 meters error by the end of the day.

In barometric mode it can also tell you if there is a sudden drop in air pressure. This might signify an oncoming sqall or storm and you can set an audible and visible alarm on the watch to go off if this happens. There is also a 24 hour trend graph that will show you the changes in barometric pressure over the last day and night. There is also an arrow indicator showing you if the air pressure is stable, tends to rise, tends to drop and the attitude for the last 3 and 6 hours. Great for checking if the current weather is stable. I have observed the barometric pressure alarm go off twice. In both accounts it started snowing heavily hours later so I believe it is working pretty well!

The last function of the pressure gauge is the ”snorkeling feature” where it can tell you when you snorcle in the hot waters of the Maldives or some other nice place how deep you have been as maximum and how deep you are now. Not quite a diving instrument (watch should not be submerged more than 10 meters really) but it is still a pretty fun feature.

A logging function can be used to keep track of your climbing and descending over time if you want. It will log the altitude and the current time as often as you want and you may also save the log for a later review. You can also set a reference altitude and the watch will show you how much above or below your reference you currenly are.

You can also have it show accumulated inclines declines, something that I thought was pretty neat in a ski slope…

There is also a temperature measurement but since the watch is warmed by your arm it generally does not show air temperature. If you take your watch of and leave it for 30 minutes or so it should give you a pretty good temperature reading though. The temperature is also necessary for the accuracy of the air pressure measurement.

The compass is great, works well but uses battery more than other thngs and because of this the watch will turn it off after one minute of operation; you will then have to press a button to turn it on again for another minute. If you have the backlight lit during compas operation it will flash as it goes dark for each measurement that is done – about 2 per second. The compass can be set to try to stay in a certain direction, it will show with arrows how much in error your current direction is and point you in the right direction and the precision is actually pretty good in the woods. Calibration is simple, turn it on, slowly spin a full circle clockwise and it will recalibrate itself. In urban environment there are sometimes problems where there are heavy electrical machinery and other ferro-magnetic materials at work that will confuse it – try looking at it while a metro train in the underground drives past… but most of the time it can be used there as well.

All in all I really love this watch. I recommend it for everyone who loves to be outdoors, hiking, fishing, hunting, climbing, skiing… this is for you!

I rate it 5/5.

English

Warm Light / Cold Light

Do you answer yest to one or more of these questions?
  • Do your indoor photographs come out red or yellow?
  • Do your winter photograph seems very blue?
  • Do you get weird colours in people’s faces when you shoot portraits in fluorescent light?

You need to learn more about white balance!

When you take photographs the camera records what it sees. This is a difference to our eyes where the eyes themselves and the brain actually processes what we see before we experience it. Light comes in many different aspects. It can be coloured light or it may be even distributed ”white light” across the spectrum. However the distribution across the spectrum can be uneven and the light is then said to have a certain ”color temperature”.

This temperature is measured in a scale called Kelvin, the same that physiscists use to talk about temperature. And when we speak about light temperature we are speaking about something that the phycisists call ”black body radiation”. The explanation for this phenomenon is somewhat complex and out of the scope here so let’s just say that when you heat something up enough it starts to emit light.

If you think about a piece of iron when it is heated enough the light from it is white almost with a blue streak. And when it cools off it becomes first yellow, then orange, then red and after that you can not see the color any more. So physicists talk about various colours as they are related to objects and what colour the radiate at different temperatures. Now we can relate temperature with colour.

Kelvin is not so different from degrees Celsius. There is however an offset of 273,15 (273 will do for us) degrees between the Kelvin scale and degrees Celsius. That is because Celsius has it’s zero point when water freezes (at sea level) and Kelvin has it’s zero point when there is a total absence of energy, the coldest there can be. This point is -273,15 °C so therefore room temperature is close to 300 K. Now, to see something glowing it is generally around 2000 K or more. Light from the sun at mid day can be estimated to have a light temperature of about 5 600 K.

In the evening and in the morning the tones go more pronounced red and yellow, the golden hours as they are called in photography takes place roughly one our after sunrise and one hour after sunset and they are great for nature photography. Light from a light bult is usually somewhere around 3 200 K giving a much more red-yellow light than the sun.

Indoor where we use electrical light the light radiated from these are much colder compared to the sun. Our brains adjust to this automatically but not our cameras necessarily. There is a control on the camera called White Balance. This control tells the camera what the temperature should be of the main light source in the picture and the camera will adjust the red-blue balance of the picture accordingly.

Today most cameras have automatic detection of white balance but this can sometimes be wildly wrong so it is always a good thing to try to learn to set this yourself. Most cameras today have several settings for white balance, here are some that are common on most cameras:

  • Automatic mode
  • Sunny
  • Shadow
  • Bulb light
  • Fluorescent light
  • Flash light

If you are photographing in RAW format you don’t need to worry about these, because you can always set them in your post processing of the pictures. But if you are shooting in JPEG format you should take care and try to get the white balance right from the beginning. If you fail to do this you may compensate a little bit in your post processing software (Google Picasa, Adobe Lightroom, Photoshop, GIMP or the tool of your choice) but when you do that to a compressed picture such as a JPEG there will be artefacts introduced. Slight adjustments are okay but if you need to change it more than a few hundred Kelvin then you will notice you start getting strange things in your picture.

One example is the sudden appearance of bright blue pixels in dark or black areas. It does not look good.

At the same time there really is no need to fully compensate for white balance, sometimes the blueish or reddish tone can actually make the picture a very nice picture but if you are tired of having every picture you shoot indoor come out as yellow-orange then you need to find and adjust your cameras white balance setting.

It should be fairly obvious which setting goes where, after all the names says it all. At this point I want you to look up your camera’s manual and find the chapter on white balance. Take a few test shots with different settings and learn the difference between them.

Sun and Ice
Snow and Ice. Example of the colour of light at sunset.
Micro Ice Forest
Micro Ice ForestExample of mid day colour of light.