Long time no post

Haven’t really had the time and stuff feels so clunky. WordPress feels quite old-fashioned. With modern blogging platforms you ought to be able to drag photos to upload in the background and whatever. I have valtteri.openphoto.me for occasional photos but it lacks one core functionality: to actually show the photos in any reasonable size. As a result it’s almost useless.

Maybe I should install something else than wordpress, but I don’t want to spend time in configuration hell…

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Flynano prototype shown to public

Flynano, the sub-70 kg carbon fiber seaplane designed to go around regulations by sheer lack of mass. Their first prototype that was retired and is now exhibited at verkkokauppa in Jätkäsaari, Helsinki, Finland. I took a few photos, more after the break.

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Cameras and physics of light

This should be highschool level deduction.

The basics

In short:

Assuming equivalent sensor technology where read noise or thermal noise doesn’t dominate:

1. Low light performance (low noise in low light photos) is dependent on absolute aperture size

2. Dynamic range (avoiding saturation in bright areas while still lighting dark areas) is dependent on pixel size

In slightly more length:

1. You catch more photons from the same target with a bigger aperture. With more photons, there is less randomness.

2. A small pixel saturates with less photons than a large one. If you have low dynamic range, you either blow highlights or lower the exposure so that highlights are not blown, but then you get more noise in the shadows.

What this does not mean

A larger sensor by itself does NOT improve low light capability. The lens with a certain aperture diameter (mm) can only catch so many photons*

You have to enlarge the optics to get a good low light performance, not the sensor. You can keep a smaller sensor and just enlarge the optics to reach the same result as with big optics and big sensor.

What you are being sold

Let’s see what cameras are sold with:

A. Zoom factor. More of this usually includes the lens design tradeoff of making the aperture much smaller so it hurts low light performance.

B. Megapixels. More of them means the pixels are smaller and that lowers dynamic range.

As a result we get cameras that have blown highlights and/or noisy dark areas outdoors (too small pixels) at best, and completely noisy images everywhere when used inside (too small aperture).

The fix would be:

1. Enlargen the aperture. So throw away the zoom lenses and go with well designed primes. Immediate improvement in low light performance.

2. Lessen the amount of megapixels. People have to resize down for web anyway. 2 megapixels could be good. 1000×2000 is bigger than almost any web graphics. One could go down to half a megapixel, 500×1000.

The results could be phenomenal. The photos could be indistinguishable from full frame DSLR photos at the same half megapixel resolution and modest focal lengths! Except maybe for background defocus. Even a 0.7 megapixel image won’t fit here, you have to click it:


A 0.7 megapixel image by Jean-Marie Huet. WordPress isn’t very good with images I’m afraid so you have to click the image. It’s shot with a 5 D mark II.

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Winter Bicycling in Style

http://kristakeltanenblog.com/2012/02/winter-tweed-run-helsinki-2012/

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How are we going to heat our cities in the future?

Changed the title picture again. Air happened to be in such a configuration that the smoke from the hood district heating plant travelled horizontally. It uses fuel oil and isn’t in use most days. Only when it’s quite cold like today (about -10 C).

Making coal electricity and using the waste heat for district heating apartment buildings is quite effective and has a pretty low workload compared to separate houses and oil heaters or what you have.

There isn’t any really good “green” solution for this. Making district heat with wood has its problems for example, and having heat pumps everywhere is inefficient and even inelegant in many senses. First making electricity with a low efficiency and then using that to make heat again with a low multiplier. You need magnets and bearings and whatnot in both devices. Are there even enough rare earths?

Building nuclear plants close to cities isn’t nice either. If you built them far away, you’d need to build really long pipes and that gets inefficient again. It also hurts the nuke’s electricity output surprisingly much. You could probably optimize the plant for better district heat production though, and the Russians have done that in some cold cities. But you can’t have a single nuclear plant as the only thing that’s heating a city: it would be devastating if an unplanned break left a million people cold in their homes.

In the future though, buildings can be much more energy efficient, so that’s the biggest saver. That too can be overdone, and I don’t like many modern buildings which have tiny awkwardly placed windows. A human produces about 70 watts of heat, and electronic equipment produces some waste heat too. “Zero energy” houses can take the heat from the exiting air and use it to heat the incoming air (like penguins do with the blood in their feet), making large savings (and at the same time making it hard to retrofit some old buildings.)

Dividing Finland’s yearly energy consumption with all the seconds in the year and all the people, we get nine kilowatts of constant power, day and night, summer and winter, for each person. That’s huge.

One big part of that is heating. It’s also a big missing part of the discussion.

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English Winter

even though it’s Finland. No snow so far.

Been riding the bike to work almost every day.

Also noticed that the blog had been hidden from search engines with some option. That should be cleared now.

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Holy Crap – Quantum Locking

Quantum levitation of a superconductiong coil (I assume it’s a coil) on something “locks” it, doesn’t just push it like a magnet. And it looks very very strange. It looks so fake.

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Nature Photo of the Year 2011

http://palkitut.vuodenluontokuva.fi/palkitut.htm

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Video Testing…

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Oh boy, lenses and cameras

The previous post got old immediately. Sony released a couple of cameras (NEX-5N and NEX-3C) and lenses and Panasonic released a small lens and leaked two high grade ones.

What beats me is how the Sony 16-55 mm F2.8 can only cost 600 dollars. The aperture has to be physically big. The 30% smaller M43 sensor in the Panasonics and Olympuses should result in smaller lenses for equal fields of view and F-numbers, meaning less material cost, less surface area to polish and inspect etc.

So far, M43 has enjoyed an advantage over Sony because of a greater lens selection, especially in the pancakes section. Panasonic continues to build on that with the interesting 14-42 pancake-storable powerzoom. But Sony’s new sensors seem to be frighteningly good. I don’t know about dynamic range, but at least high ISO performance has seemed very good in tests.

The Panny high grade lenses 12-35 and 35-100 of yet unknown f number (but rumored to be bright) are big and don’t give so much advantage compared to NEX in that regard. If you couple that with an old Panasonic 12 megapixel sensor, it’s possible you’re not that much smaller than a NEX.

You could get around that by using pancake primes. You could also improve the sensor and or processing somewhat. Could Fuji join M43 and bring some kickass sensors? (Are they even bleeding edge anymore? The Sony A77 is rumored to be better than the 5D Mk II in low light) Everybody’s been waiting for that to happen for years…

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