Friday, December 24, 2010

Vaporizing some aluminum, taking some pictures

Part of our bachelor project was working with a small scale single turn coil apparatus for creating high magnetic fields. This allowed for some nice plasma pictures!

The principle of single turn coils in a nutshell: you dump a whole lot of energy from a capacitor bank in a (single turn) coil. Once you get a few kiloAmperes flowing, you get a pretty high magnetic field, but the coil also endures intense magnetic stresses and a lot of Joule heating. Ultimatly the coil snaps after the peak field is reached and the vaporized metal turns into a nice plasma. The remains of the coil fly off outwards, keeping the sample intact.

I photographed the plasma and pieces flying off with a long exposure in a dark room. I was slightly worried about frying the sensor, as there is a lot of high energy UV light coming from the plasma. I actually stacked on two UV filters just for some peace of mind. I was still constantly checking the sensor during the first few images.

This is the best picture, it's an aluminium foil completely flying to pieces on our little testing apparatus (Click for deviantArt page where you can see the full resolution version)

This was done as a long exposure in a dark room with a 250mm lens stopped down to f/11 on ISO 100. It was one of the first photos I shot, I did some f/32 shots at first (to protect sensor), but those coil shots were less bright, so I opened up the aperture. Then this one blew up much brighter then before and kind of took me by surprise. The sensor is still OK though!

These pulses can reach about 2T, hence the catchy title 'Two Tesla Plasma' (go ahead, say that out loud. It has a nice ring to it, right?)

I also tried to get a 3D image by using a second camera from a friend of mine. Click the image below to see the effect (WARNING: I can NOT be held responsible for possible epilectic seizures)

The parallax looks a bit odd because both images were shot at 250mm on a cropped sensor. Using a focal lengtch that matches the human eye more closely would probably have made the effect much better, but I'm not too fond of getting the cameras that close to the glowing metal pieces flying everywhere.

So, everyone go and study physics: where you can blow stuff up and get pretty pictures -- for science!

[Edit] For those interested in more info, you can skim through the paper hosted at github (Don't mind the bleek results, we had some problems and serious time constraints).

Sunday, November 28, 2010

Highly Entropic

In case you were wondering why this blog is titled "Highly Entropic", this is the deal:

Entropy is a physical (thermodynamical) property. It's one of those things that can be pretty hard to understand. Roughly speaking, one can say that it is a measure of the "disorder" of a physical system. If something is "Highly Entropic", it is said to have a lot of "disorder".

The reason this blog is titled "Highly Entropic" is partly because I intend to blog on various (unrelated) things (for the moment it's mostly (DIY) photography, but I also plan on doing computer/Linux related posts, maybe somethings food-related, wine making, etc...).

A second reason is that I am quite "entropic" myself. Since a picture says more than a thousand words, I'll just leave you with this panoramic view of our garage (click for the deviantart link, click "Download" there for the full resolution photo)

Some things worth mentioning: This shot was made with the parnoramic mount I blogged earlier. On the bottom left, you can see some pieces of my ring flash. On the right side, you can see the rear of a wooden recumbent bike I built several years ago (there may be a blogpost about this in the (far) future).

The original picture is 250 megapixels large and was stiched together from 42 images using hugin. Doing so required around 9GB of memory at its peak -- one of the very few times I actually needed to setup a swap file (I only have 6GB of RAM). The resulting (8bit) compressed tiff file is 560MB.

On panoramic mounts and entropy

Still going strong in the DIY photography category (even though there has been some delay). This time it's a panoramic tripod mount!

With current software it's extremely easy to make a panoramic picture out of a set of overlapping photo's. (I use the excellent free and open source tool hugin.) There are, however, some things you should be aware of. Of course, the pictures should be taken from the same spot. The logical thing to do is to use a tripod. This gives good results for distant landscapes, but if you include near objects in the scene, you will encounter some problems stitching togenther the panorama. This is due to parallax and can be resolved by using (building!) a panoramic tripod mount like this:

(If you find the shadow on the above photo a bit weird, it's because I shot it with my ringflash, no particular reason)

Instructions and lots more after the jump!

Friday, November 26, 2010

On using the mandoline when really really hungry


I did, however. Picture below sums it up.

Warning: slightly graphic images after the jump (involving a small slice of flesh that once belonged to my thumb)

Tuesday, October 19, 2010

Yet another DIY ringflash

Sorry for the long delay between posts -- college has been eating my time. In my post about re-using an old strobe (which got referenced on lifehacker -- cool!) I told you I was working on a (macro) ring flash. It's been finished for about a week now, but I didn't have much time to try it out in the field. I thought I'd just go ahead and post the build process already.

Self shot in mirror with DIY ringflash

Monday, October 4, 2010

Downside of shooting RAW: the thirst for diskspace -- Linux RAID adventures

With my photo directory easily breaking the 100GB limit after about a month of shooting, I needed some more space. Given that disk space is pretty cheap these days, I went for two 1TB drives in software RAID1 (I don't have the discipline to make decent back-ups, hence the RAID). It turns out to be pretty easy to set up a software RAID on Linux -- if you read the documentation properly (I didn't).

Friday, September 24, 2010

End of red wine pulp fermentation and bottling of rhubarb wine

Two days ago, the red wine had been pulp fermenting for a full week. It became time to strain off the liquid from the pulp. At the same time we bottled the rhubarb wine that had been clearing for a few months, now.

Wednesday, September 22, 2010

Don't throw away that old flash yet!

To continue with the DIY-photography-on-a-budget theme from last post, I present you a way to use that old 2.5mm jack triggered flash you might have laying around!

Monday, September 20, 2010

Remote shutter trigger for the round price of $0*

*if you have stuff laying around

Whilst searching for remote camera triggers, I came across this link. Of course, I had to try this out myself. I salvaged some old parts from junk I had laying around and made my own version. It's not the most aesthetically pleasing, but it does the job and it does it well. It features a (DIY) two-modes focus/shutter button and a shutter toggle button for long bulb exposures.
The remote trigger

Saturday, September 18, 2010

Started first red wine

Ok, so I'm into amateur winemaking. So far I've made two rhubarb wines (the first of which was aweful, the second one turned out much better and is about ready to be bottled).

Once I started those rhubarb wines, I also planted a couple of vines to do the real stuff. This year came the first (small) harvest of those plants.

The grapes about a month ago, not fully ripe yet
Last Wednesday I harvested the grapes and prepared to crush them. Luckily (or sadly?) enough I didn't need stomp them with my feet, for someone at the local wine making (and tasting) club came to the rescue with this gem:

First harvest, ready to be crushed
Note the many small green grapes. Those are grapes that weren't fertilized (common among local winemakers this year, it started raining at the wrong time). Hopefully they won't affect the end-product too much.

Whizzing the grapes through the machine
The juice had a nice acidity but only slightly more than half of the required sugar. Corrections will be made after the pulp fermentation. That fermentation has been going on for a few days now (started with a Port yeast).

Pulp fermentation
I'm exited to see (taste) how my first red wine turns out!

Thursday, September 16, 2010

Size matters

My adapter to mount my old Helios 44-2 (M42 mount) in reverse in front of my Canon 55-250mm came in the mail today. Perfect opportunity to fill the current voidness of this blog.

Shipment took 12 days, but heh, the ring was only $4.79 with free worldwide shipping, so I'm not complaining! (got it from dinodirect).

the old Helios, the adapter ring and the 55-250mm
the entire thing mounted

Fully extended, it's about 10 inches -- now if that won't impress the ladies, I don't know what will.

I do worry a bit about the weight of the (all-metal) Helios in front of the (pretty much all-plastic) Canon 55-250mm. It's a relatively cheap telelens, but -- being on a student's budget -- I still don't feel like ruining it.

As far as pictures go: I haven't had the opportunity to try the setup out 'in the field'. The damn wind won't go down.

Maiden Post

So yeah, I started a blag...

It's still pretty empty in here at the moment. Let's make this post to give the google spiders something to parse. Just to give this first post at least some content, I present you:

The roadmap:
I'm planning to blog about some of my interests and hobbies that are hopefully interesting enough for other people to read, or even to motivate them to do something similar. Also I'm just showing off the incredibly awesome and interesting person I truly am *cough*.

So, let's see how this goes along in the future.