jueves, 15 de diciembre de 2016

Raw foodies: Europe's earliest humans did not use fire

Raw foodies: Europe's earliest humans did not use fire

December 14, 2016
Dental hygiene, caveman style
Cluster of starch granules in microfossils extracted from dental calculus. Credit: Karen Hardy
Studying dental plaque from a 1.2 million year old hominin (early human species), recovered by the Atapuerca Research Team in 2007 in Sima del Elefante in northern Spain, archaeologists extracted microfossils to find the earliest direct evidence of food eaten by early humans.
These microfossils included traces of raw animal tissue, uncooked starch granules indicating consumption of grasses, pollen grains from a species of pine, insect fragments and a possible fragment of a toothpick.
All detected fibres were uncharred, and there was also no  showing inhalation of microcharcoal - normally a clear indicator of proximity to .
The timing of the earliest use of fire for cooking is hotly contested, with some researchers arguing habitual use started around 1.8 million years ago while others suggest it was as late as 300,000-400,000 years ago.
Possible evidence for fire has been found at some very early sites in Africa. However, the lack of evidence for fire at Sima del Elefante suggests that this knowledge was not carried with the earliest humans when they left Africa.
The earliest definitive evidence in Europe for use of fire is 800,000 years ago at the Spanish site of Cueva Negra, and at Gesher Benot Ya'aqov, Israel, a short time later.
Taken together, this evidence suggests the development of fire technology occurred at some point between 800,000 and 1.2 million years ago, revealing a new timeline for when the earliest humans started to cook food.
Dr Karen Hardy, lead author and Honorary Research Associate at the University of York and ICREA Research Professor at the Universitat Autònoma de Barcelona, said: "Obtaining evidence for any aspect of hominin life at this extremely early date is very challenging. Here, we have been able to demonstrate that these earliest Europeans understood and exploited their forested environment to obtain a balanced diet 1.2 million years ago, by eating a range of different foods and combining starchy plant food with meat.
"This new timeline has significant implications in helping us to understand this period of human evolution - cooked food provides greater energy, and cooking may be linked to the rapid increases in brain size that occurred from 800,000 years ago onwards.
"It also correlates well with previous research hypothesising that the timing of cooking is linked to the development of salivary amylase, needed to process cooked starchy food. Starchy food was an essential element in facilitating brain development, and contrary to popular belief about the 'Paleodiet', the role of starchy  in the Palaeolithic diet was significant."
Dr Anita Radini, PhD student at the University of York said: "These results are very exciting, as they highlight the potential of dental calculus to store dietary and environmental information from deep in the human evolutionary past. It is also interesting to see that pollen remains are preserved often in better conditions than in the soil of the same age. Overall this is a very positive step in the discipline, in terms of preservation of material in the calculus matrix."
More information: Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe's oldest hominin at Sima del Elefante, Spain, Naturwissenschaftenlink.springer.com/article/10.1007/s00114-016-1420-x


Read more at: http://phys.org/news/2016-12-raw-foodies-europe-earliest-humans.html#jCp

The Five Most Essential Camera Settings and How to Use Them

The Five Most Essential Camera Settings and How to Use Them


Modern cameras, from phones to high-end DSLRs, are designed to make decisions for us. And for the most part, they do a pretty darn good job of it. Slap your SLR into AUTO mode and more often than not you’ll get images that are sharp with decent exposure. If you are just looking to document your world, then go for it, snap away. The drawback is that images taken in AUTO tend to look similar to one another, with a uniform depth of field and exposure. If you want to move beyond the automatic camera settings, you need to understand your camera, how to use it, and most importantly, what impact changing those settings will have on your final image. Here are five of the most essential camera settings, what they mean, and how they impact the photograph.
Five Most Essential Camera Settings

ISO

Five Most Essential Camera Settings
This night image required I use a fast shutter speed to retain detail in the flame, so I had to use a high ISO (3200). In the next detail shot, you can see the noise, in the original RAW file. (By the way, this image shows what happens when you free methane from a bubble in the ice of a frozen pond in the boreal forest, and then set it alight.)
First, the acronym ISO is terrible, because it’s basically meaningless in terms of photography. It stands for “International Standards Organization” a European non-governmental organization that makes sure industries apply the same standards. In the case of photography, they want to make sure that an 800 ISO on a Canon is the same as on a Nikon, Sony or Fuji. If that standard didn’t exist, then settings wouldn’t be applicable across camera brands. So if I set my Canon to make an image at 1/100th sec at f/2.8 and ISO 400, and you set your Nikon to the same setting, we wouldn’t get the same exposure. Thankfully all the major manufacturers do subscribe to the ISO standards.
Yeah, yeah, but what is ISO? It is the measure of the sensitivity of your camera’s digital sensor to light. The lower the number the lower the sensitivity, the higher the number the more sensitive the sensor becomes. If you are shooting in a low light situation, say a poorly lit room or a dusky evening, an ISO setting of 100 will require that more light reaches the sensor than if you were to use a setting of 400, 800, or 1600.
Five Most Essential Camera Settings ISO
Note the noise in the detail of the person’s clothing and in other shadowed areas.

Drawbacks of high ISO

So why not shoot at high ISOs all the time? Two reasons: 1. High ISOs often create digital noise on the image, (though camera sensors are getting better and better) and 2. Sometimes you may want to force a slow shutter speed, in which case you want low sensitivity to light. This may be the case when you are trying to capture blurred motion such as water, wind or to create pleasing blurs in sports photography.
  1. High ISOs often create digital noise in the image, (though camera sensors are getting better and better)
  2. Sometimes you may want to force a slow shutter speed, in which case you want low sensitivity to light. This may be the case when you are trying to capture blurred motion such as water, wind, or to create pleasing blurs in sports photography.
In short, ISO is one of the three tools you have at your disposal to manipulate your exposure.

Shutter Speed

The length of time your camera’s sensor is exposed to light is the shutter speed. Many cameras have a mechanical shutter that snaps open and closed allowing light to reach the sensor, others use a digital shutter that simply turns on the sensor for the set period of time before switching it off again. Shutter speed has a huge impact on the final image. A long shutter speed will create blur in moving subjects. As a landscape photographer, I use long shutter speeds often to blur water, expose starlight, or capture wind motion.
Five Most Essential Camera Settings
For this image, I used a 0.5 sec shutter speed to blur the waves somewhat, but retain detail.
Five Most Essential Camera Settings shutter speed
A 30-second shutter speed blurred the Yukon River in this image, into a mirror-like surface.
Short or fast shutter speeds have the effect of stopping motion. Use a shutter speed of 1/2000th of a second and the motion of a runner or a cyclist will be stopped dead.
Five Most Essential Camera Settings shutter speed
This image of a bike passing used a shutter speed of 1/500th of a second. It was just enough to be sharp overall while retaining some sense of motion in the spinning tire.
Your use of the shutter has to be thoughtful to create a good image. Think about the final image you want to create. Does it have blurred components or is it all sharp? Do you want to stop, or convey the sense of motion? Consider, experiment, then decide on your shutter speed.

Aperture

Five Most Essential Camera Settings aperture
An f-stop of f/11 at 17mm was sufficient to make the entire image, from inches in front of the lens to the cliffs in the distance, sharp.
The aperture, or f-stop, may be the most confusing aspect of photography for many photographers because it affects images in unexpected ways. Essentially, the aperture is how big the hole in the lens is. The smaller the hole, the less light is allowed in, the larger it is, the more light gets through. What often confuses people is the numbering system: the smaller the number, the larger the hole. So f/2.8 is a larger opening than f/4, f/5.6, f/8, f/11 and so on. Lenses with a wide maximum aperture (a small number like f/2) are considered “fast” meaning they are capable of allowing in more light.
But it’s not just about light, and how wide a lens can open. The aperture also affects image sharpness. Most lenses (dare I say all?) are sharper, a few stops down (called the sweet spot). A lens with a maximum aperture of f/2.8 will create a sharper image at f/8, then at f/2.8. The higher quality the lens, the less this matters, but it is noticeable on most lenses.
Five Most Essential Camera Settings aperture
A very shallow depth of field in this image brings the grouse hiding in the brush into focus while the surrounding chaos of branches blurs into a haze.

Depth of Field and application

Next, the aperture also controls the Depth of Field. The DoF is the amount of the image from close to far that is in focus. A lens, when set wide open, say f/2.8, will have less DoF than when the same lens is set to f/11.
Like shutter speed, your use of aperture should be purposeful. Have a landscape image that you want in focus from front to back? You better select a high f-stop (like f/11). How about a portrait where you want a clean, soft background but a tack-sharp eye? Then use a small f-stop (like f/2.8 or f/4) and watch that focus point.
The aperture has a direct impact on shutter speed. A large f-stop will require you to use a longer shutter speed to attain proper exposure. Just as lower f-stop, will allow you to use a fast shutter speed. These two are completely interrelated, there is no escaping it, so you NEED a strong understanding of both.

White Balance

White balance, like ISO, relates to the sensor, but in this case, it has to do with the color of the light, rather than its brightness.
Different light sources have different color tones. Our eyes often don’t detect these differences, but you can bet your camera will. Have you ever seen a photo of a home interior lit by soft-white bulbs, but including a window? Usually, the interior of the room looks natural while the light outdoors looks artificially blue. That’s white balance. The camera (or photographer) decided to use the interior light (the warm-toned bulbs) as the natural color, but then the natural light
The camera (or photographer) decided to use the interior light (the warm-toned bulbs) as the neutral color, but then the natural light outdoors appears blue. When the white balance is set wrong, the colors are off. They look too yellow, blue, or orange. When it’s correct, everything looks natural, or as our eyes detect it.
Five Most Essential Camera Settings white balance
Here is the camera’s AUTO selection for the White Balance. The colors of the aurora borealis appear too purple and yellow.
Five Most Essential Camera Settings white balance
In this version, using the same post-processing for exposure, I adjusted the white balance further into the blue range, making the colors of the lights appear more natural and pleasing.

What about Auto White Balance?

I’ve got a confession to make here. I almost always use the AUTO white balance setting on my cameras. Cameras are pretty darn good at assessing color tones and deciding on the appropriate white balance. When it does get it wrong, I can check the image on the LCD and make the correction for the next shot. Second, I shoot exclusively in RAW format which means that I can make adjustments to the white balance in the computer. I trust the image on my computer screen more than I trust the tiny LCD on the back of my camera.
That said, there are times to adjust the camera’s white balance settings. The first is if you are shooting JPEGs. That image format will not allow you to effectively adjust white balance later, so it’s got to be right in the camera. The second is when stacking images either for high contrast scenes or for panoramas. When stacking images, slight changes in color tones will make combining them into HDR or panoramas much more difficult or impossible. You can also use White Balance if you purposefully want to make an image look cool or warm, or if you are using artificial lights. (Now THAT subject warrants an article of its own…)
Be mindful of your White Balance, know what it does and how it will impact your image, then decide how, or whether to use it.

Exposure Compensation

ak-homer-109266-sunset-139
Here I used Exposure Compensation to make sure that the image was bright enough to show details in the foreground while assuring that the bright sunset in the background was not blown out.
These two images show how useful Exposure compensation can be. The image below was made in bright sunlight, but a purposeful underexposure of three stops reduced the mountains to black but retained detail in the sky, making a surreal image.

Know your camera well

Exposure Compensation is a tool you should know how to adjust without even lowering the camera from your eye. Exposure compensation allows you to very quickly, add or subtract light from an image. Too dark? Use Exposure Compensation to add a stop of light. Too bright? Exposure Compensation can quickly reduce the exposure. How it is set depends on your camera settings.
I use Aperture Priority mode most often on my camera. That means I select the aperture, and the camera decides the shutter speed. If I adjust my Exposure Compensation, the camera will retain my chosen aperture and simply adjust shutter speed up or down to get the desired exposure. If I were to use Shutter Priority, as I sometimes do, the camera will adjust the aperture. In AUTO the camera will make that decision for me.
I use Exposure compensation constantly. It is my go-to method for fine-tuning my exposure in the field. On my Canon DSLR, I can adjust it with a simple twitch of my thumb on the rear wheel of the camera. Other cameras have their Exposure Compensation controls on the front, a wheel near the shutter button, or some other system of buttons on the back. Know how your camera works, and learn to adjust this quickly and efficiently. Understanding this important tool will mean you don’t miss your chance to get the shot right when you are working in the field or studio.

Conclusion

These five camera settings are the most important things to understand on your camera. Experiment with them so you know how they affect your final image, and know how to change each quickly and without fuss. Once you do, you’ll have taken charge of your photography, and be on your way to creating purposeful images.
If you have comments or questions please share post them below.