Scorhill Stone Circle panorama

I wanted to try out panoramic photography at Scorhill stone circle near Gidleigh in Dartmoor as well as tinkering with radio. I didn’t have much time there, it’s a tough drive through winding roads and Google maps had already warned me that I had about an hour on site tops if I wanted to make a meeting in Exeter in the afternoon. It’s worth a rematch, because there’s quite a lot of interesting stuff within a mile, what with the Shovel Down stone rows and possibly another circle to the northwest.

A long time ago I had ambitions to take panoramic pictures of stone circles.  The moving panorama thing really sings with megalithic stone circles, they don’t move so much so you don’t need video for the immersive experience, and we have 900 stone circles still extant in the UK, mainly in the west of the country. Those were the dotcom days of Apple QTVR and plugins, and hardware that was only just up to the job. QTVR is pretty much dead now. Backwards compatibility isn’t really in Apple’s DNA. The problem with QTVR was these had to be encoded in that format, because computers weren’t hard enough to do the processing of the source file on the fly like Panellum does. So these images are lost in Apple-history-land, although the source files I do have show just how poor digital cameras were1 in the 2000s, the pictures won’t particularly benefit from being QTVR un-munged and re-munged to whatever is the panoramic tech of the moment. On the plus side, the stones are still there so a reshoot is possible 😉

Panoramic photography images are big – the panorama is 1Mb in size, so I’ve put it after the read more break. They aren’t as big as John’s trig point images, but the great advantage of a stone circle is that all the action is in the near field, you don’t have to zoom in so much.

dogs and dappled light

I shot these pics raw, because there was a weak sun through the haze, so I thought I could push some of the shots, However, the weak sun came through dappled cloud, and Sod’s law seemed to say that in one direction the cloud closed in again just as I passed the same direction the second time2.  I have a Kaidan Kiwi-L and it is sweet, compared to trying to spin round a stone circle on a monopod with the integral level. Some of the win is that the click stop forces you to take enough pictures, and you can mount the camera vertically. There are much cheaper ways of doing this now – well, after you have amortised the cost of the 3D printer.

Kaidan made a big fuss of how you should adjust your camera so it spins around the nodal point, and early software used to be critical on that. I do still try and match that, but either Autopano Pro is a lot less critical of getting that right or I have become a slovenly panorama maker because it seems less critical now. With a stone circle much of the action is at a reasonably constant distance from the lens and the foreground is often miscellaneous grass so maybe a bit of parallax error in the foreground isn’t seen so much as when doing a panorama in a building, with all its straight edges calling out a poorly centred camera.

Scorhill has a lot of human traffic – dogwalkers abound, and I waited about 10 minutes while a lady did her callisthenics in the stone circle. This shortened the photoshoot, I just about took the Kaidan twice round the circle in varying light before some more hikers with a huge hound hove into view and I figured I needed to clear site to head off to Exeter. I could push the exposure for the darker pics, but the problem is the light is different as the sun went in, so they don’t match well.

lighting for panoramas

I need to think differently about lighting for panoramas, since they’re inherently more tricky. You can’t keep the sun behind you with a panorama by definition, and the golden hour is also not ideal. What looks great on a still in one direction will be the sun low in the sky and great big long shadows in the other. Exposure is easy with an overcast sky, but that sky is so boring. It’s probably safe to say too much contrast is a problem in panoramas, because many of the photographer’s tools to minimise it can’t be used through 360 degrees

Probably the best light for stone circle panoramas is a blue sky with plenty of fluffy clouds, one of which is over the sun for the entire duration of the panoramic spin. Panoramas may be more suited to the mid-morning and mid-afternoon, a little bit off the ghastly high-contrast sun overhead at noon time and get some shadows to give modelling but before shadows get out of control.

Look ma, no Linux

Getting away with modest zoom ranges is just as well, because you seem to need Linux to run the splitting program generate.py to get multiresolution images. I don’t have a GUI on my linux box and have already had to rebuild it three times when some software digs itself into a hole I couldn’t get it out of. So when I spot requirements like so

To be able to create multiresolution panoramas, you need to have the nona program installed, which is available as part of Hugin, as well as Python with the Pillow package. Then, run

I think, right, move along now, nothing to be seen here…

When I tried Hugin years ago there was some hoohah about the patented SIFT algorithm, so you got to manually select the tracking points, involving lots of swearing when it didn’t work. Life is too short for that sort of thing.

So I bought Autopano Pro, and they were  nice enough guys to trace my license key even though 11 years have passed and I have a new email address, so that is how I process my panoramic images. Kolor is now closed.

It appears that the SIFT patent will expire next year, which is good. Software patents suck. If they exist at all, they should be on a much shorter scale – software and Internet time is shorter than dog years so a maximum term of five years would let you get dominance without jamming progress in a field for over twenty years.

Continue reading “Scorhill Stone Circle panorama”

Sainsonic AP510 APRS tracker experiments

I bought an AP510 some time ago, at the time results were disappointing, but the firmware has improved over the years. Using 20141215 I was getting signals out to about 8 miles from the typical white stick omnis like Diamond X50, and up to 20 miles from near Chagford on Dartmoor when it was mounted in a backpack. As you can see from the header picture, I had a great RF takeoff and not much vegetation in the way from pedestrian height 😉

Thank you G6SQX and G0MAS for running high performance APRS IGates! The difference in performance with the antenna taped to the fibreglass shell at the back of my campervan is visible in the paucity of reports near G0MAS around Uffculme, range was only a quarter of that as a pedestrian. Despite having steady power and a USB lead as a counterpoise to the aerial. Maybe taping the aerial to the fibreglass detuned it, this thing is marginal enough at 1W output.

My track and the stations G0MAS and G6SQX it reached

Some of the idea of getting this was to play with radio on the hills so it’s good that it performs better in pedestrian mode. I’d like to have a better feel of why exactly that was.

Continue reading “Sainsonic AP510 APRS tracker experiments”

A moment by a Dartmoor Stream

A lovely little stream near the path to Scorhill stone circle, it was worth a longer recording. Starlings are starting to mass in the Autumn, and they provide some counterpoint to the running water in this binaural recording. Nice not to have to filter anything – straight out of the recorder apart from trimming the timeline and bringing the gain up a little bit.