Ghost cat!

8 December 2006 — dan

Our youngest cat, Millie, in near-infrared.

Ghost cat

This shot was taken at night (f1.8, ISO 800, four seconds), by the light of two 500 watt halogen floodlights that I couldn't quite angle down enough to light Millie up really well. They still threw enough heat on her that she was squirming cheerfully around on the chair, though, which made it hard to get a shot of her that didn't look like a many-legged blob.

Millie the draught excluder

Here she is in visible light. She serves as a useful metaphor for the wave-particle duality of light, actually, since she is simultaneously spotty and stripy.

Millie and Joey, a still life

She gets on well with Joey.

Posted in Animals, Photography. 2 Comments »

White trees, black sky

6 December 2006 — dan

Herewith, the shatteringly gorgeous results of my first venture into infra-red photography.

IR photo

That's how it looked out of the camera, whose red photodetectors are most strongly tickled by near infrared, but whose green and blue ones see it too.

They don't see a lot of it, mind you, because like all normal digital cameras these days, my EOS-20D has an IR-blocking filter inside it, over the sensor. It's there because digital sensors are very sensitive to near-IR light, in the same way that normal film is very sensitive to ultraviolet. If something in the camera doesn't block that invisible-to-humans light, it'll haze up your photos.

(Lots of people put UV filters on digital cameras, too. That's just because UV filters are really cheap, so you can use them to protect the lens. You can get non-filtering protectors now as well, that're just a piece of glass in a filter frame. I don't think they're much cheaper, though.)

The anti-IR filter is not, however, perfect. A little light gets through. So if you put an IR-pass filter on your camera, you can still take IR pictures. You just have to use a pretty long exposure - eight seconds at f/3.5, ISO 800, for the above example.

It's traditional to cancel out the meaningless colour cast from digital IR images, giving a result that looks like a black and white IR film picture, so I monkeyed with it a bit, and did.

Greyscale IR photo

The human eye can't see a thing through the viewfinder when the IR-pass filter is on, because on an SLR like my camera, the viewfinder looks out through the main lens. Cameras with separate "rangefinder" viewfinders don't have this problem.

I was still pleased to note, though, that the autofocus actually worked. The phase detection autofocus can see near-infrared light with no trouble - indeed, a lot of cameras use an IR beam as their AF-assist light.

The autofocus didn't quite get it right, though, because it assumes you're taking a visible-light picture, and infrared light doesn't refract as much as visible (many older SLR lenses have a red dot on their focus scale as well as the standard white one; the red one is the one you use when you're shooting IR).

You can compensate for that by cranking down the aperture to get more depth of field, but that increases your exposure time even further; the above eight second shot would have had to be 42 seconds if I'd taken it at the usually-suggested f/8. An alternative strategy is to just take a few pictures, manually bumping the focus in a bit for each one. Or, if you've got a choice of things to focus on, you can try focussing on something closer than the actual subject.

These problems almost all go away if you get yourself a camera adapted for proper IR photography (from here or here, for instance - or you can do it yourself if you're brave), with the internal filter replaced with an IR-pass, everything-else-block one and the autofocus recalibrated for IR. Now you can use the viewfinder as normal, and autofocus works. Given the plummeting price of DSLRs, it's not actually crazy for ordinary photographic hobbyists, amateur astronomers and so on to do this; it also only costs a bit of time to do a similar trick with a toy digicam or webcam. I don't have that strong a need to see the world of white trees and black eyes, though.

(Have you ever wanted to get married in a black-skied nightmare world? Now you can!)

Incidentally, if you've got a camera with an electronic viewfinder that shows you what the sensor sees, then an IR conversion will give you a live near-IR view of the world. So will a camcorder converted in the same way - actually, the 52mm filter I bought was sold for use on camcorders, but works fine on the 52mm threads of my Canon 50mm lens.

I think fully converted cameras can grab a little bit of colour in IR scenes, too. My simple screw-on filter just makes everything a shade of the same pink, so there's no data lost when you drop the image to monochrome.

The filter I bought, by the way, is an allegedly 850nm-pass model from here that cost me only $AU22.98 delivered. I've no idea what its actual spectral performance is like, but it seems to work fine, and is a lot cheaper than many brand name options.

If you want something even cheaper, you can try using layered theatrical light filters or fully exposed and developed (and thus black) colour film or something, but unless you can get offcuts of theatrical gel for free, you'll be paying more for the big sheets of the stuff that you don't need.

(I've made those goggles, by the way; they're cool. Note the new photo gallery!)

Posted in Hacks, Photography. 3 Comments »

Russhuttle

28 November 2006 — dan

All nerds worth their salt know about the Buran. It was the Russian Space Shuttle, that looked like a straight knock-off of the US original a la Concordski, but which actually had considerable improvements over the American horse-designed-by-a-committee.

(In this regard Buran was, arguably, also like Concordski, despite that aircraft's distressing tendency to fall out of the sky.)

Buran wasn't completely liberated from the stupidity of the Shuttle's design. It still sat dangerously on the back of its giant fuel tank rather than in the obviously-more-sensible on-the-nose-of-the-tank position, despite the fact that it didn't have the rear engines that force the Shuttle to be where it is, getting smacked by foam and blown to bits by booster failures.

But the Buran was still better. The Soviet Shuttle program didn't get off the ground, but the hardware was just fine.

Anyway, six years ago I was working at the end of Darling Harbour (I didn't stay there a lot longer...), and was reviewing the then-remarkable, now-pointless Sony Mavica MVC-CD1000 digital camera (it used 77mm CDs for image storage, which was a good idea when a megabyte of memory card cost five bucks, but is ridiculous now that the price is three cents).

And someone came along and parked the OK-GLI Buran aerodynamic test vehicle next to my office.

So I took a picture of it with the Sony...

...and here that picture is.

Click for the full sized version, complete with antique EXIF headers.

After this, that poor old bird got dragged all over the place, and has I think been stuck in Bahrain for some time now. OK-GLI is, however, apparently eventually going to take one last boring sea-and-land trip to a German museum, where it can rest in peace with a Concorde, a Concordski, an enormous Cock, and lots of other neat stuff.

Posted in Nerdery, Photography, Science. 6 Comments »

Panoramitude

19 November 2006 — dan

I was going to just blog about the most excellent, if quirky, panorama-photo-stitching program Autostitch, which I have only just discovered because I am much lamer than these people, but the post ended up being so big that I ran it as a Dan's Data review instead.

If you've got any +5 Insightful things to say about panorama-making with Autostitch or anything else, or would just like to link to your awesome browser-paralysing 10,000 by 10,000 pixel QTVR image, please comment below!

Posted in Photography, Software. 8 Comments »

Further VPC-C6 observations

1 November 2006 — dan

I've played more with the VPC-C6 now. Some hints and tips:

It takes at least a few seconds after shooting a clip before you can start shooting another one. I don't know how much impact card speed has on this, but if interesting things seem at all likely to keep happening then you should keep the camera rolling. That's standard video-making advice anyway; people who maniacally try to save tape by toggling pause and play all the time are likely to end up with lots of footage of them saying "C'mon, guys, do it again!"

Incidentally, these new-fangled cameras which (a) make no noise and (b) can take still images as well as videos give a new way for amateur videographers to screw up when recording important events.

The old fashioned way is misreading the setting of your record/pause control, so that you're paused when you think you're recording and recording when you think you're paused. Thus are hours of magnificent "foot shots" created.

With a silent solid state photo/video camera, though, masterful users gain the ability to simply press the wrong button when attempting to record an important event. They, therefore, take one still picture at the beginning and another at the end.

Getting back to the hints - the C6's teeny lens goes to a maximum aperture of f/3.5, which does not let a great deal of light into the camera.

This is a normal problem for consumer digicams, though most of them do at least offer f/2.8, which lets more than 1.5 times as much light into the camera. The C6's particular problem is that its auto-exposure mode, when you've got the flash turned off, seems to like to keep the ISO sensitivity down, so you get nice smooth un-noisy pictures.

That's great, and all, but not when it means you have to take pictures with half-second shutter speeds. The C6 will cheerfully do this, even in rooms that're lit to a normal indoor daytime light level.

Turn the flash on and the C6 happily drops to a generally-OK 1/30th of a second (and often winds the ISO up to about ISO 250 anyway, presumably to compensate for the weediness of its little flash), but on-camera flash makes everything look flat as a pancake. It's a last resort if you care at all about taking good-looking photos. And it flattens the battery, too.

The solution to this problem is to use the C6's menu system (which works very nicely - it's not cluttered with unnecessary settings, and it remembers what you changed last and starts up again in the same spot) to wind the ISO sensitivity up - to 200 for most indoor shooting, and all the way to the camera's noisy maximum 400 for night-time indoor flash-free shots, because that's the only way you'll avoid hideous blur, stabiliser or no stabiliser. Use exposure compensation (also easy to access) to wind the exposure down by about a stop as well, if you like; that'll speed up the shutter a little more again, and you can brighten the images up in a fraction of a second in post processing.

The result is lots of crunchy noise, of course, but better a grainy picture of something than a smooth picture of nothing, if you ask me.

(If you leave the C6 on auto-everything mode then its flash will allow it to salvage many low to medium light shots, more or less, but don't expect it to be able to light a large room.)

In my MiniReview I mentioned being perfectly happy to use good old VirtualDub to do basic editing of the C6's clips, without actually mentioning that it can't, in point of fact, load the MP4 files the C6 produces.

You can still use it, though.

MP4Cam2AVI can rapidly convert MP4 video into an AVI file that VDub can load, and it can also convert the non-VDub-compatible AAC audio to MP3 or uncompressed PCM, which gives you a 100% VDub-compatible file.

VirtualDub still can't save MP4, though. If you'd like to avoid format conversion and just want to chop clips out of MP4 files, YAMB works well enough. Play the clip separately, find the start and end of the clip you want (in plain old seconds-from-start if you like, or full hh:mm:ss:ccc timecode), enter numbers, click button; bing, smaller MP4s.

YAMB can also extract video from an MP4 to a soundless, VDub-compatible AVI, and separately extract the audio as an AAC file (C6 audio is 48000 bit per second two channel allegedly-VBR LC-AAC), and then you can convert the AAC to WAV or MP3 (I use Winamp's stock Disk Writer Output plugin for that), and then load that as the audio track for the soundless AVI in VDub.

Or, like I said, you can just use MP4Cam2AVI.

If you really want to get devious, you can trick VirtualDub and various other software into dealing with MP4 files without knowing it by doing all this. Well, apparently you can - I'm buggered if I'm going to try it.

MP4 may be a bit of a pain to edit on Windows (there are various full-featured editing packages that can handle it on load and save, but they're massive overkill, not to mention expensive, if all you want is cut-cut editing with the occasional soundtrack replacement), but it's widely compatible elsewhere. Modern Macs can play it natively, and you can also upload it straight to Google Video, no problem.

(Yes, I know the title has an extra R on the end. I changed it right after I uploaded it, but the change has not yet appeared.)

Posted in MiniReviews, Photography. 2 Comments »

MiniReview: Sanyo Xacti VPC-C6

30 October 2006 — dan

Sanyo Xacti C6

Sanyo's Xacti VPC-C6 (which may be known as the DMX-C6 in your country) is a great little gadget.

Close-to-DVD-quality video recording (640 by 480, 30fps) straight to SD card in MPEG4 format, and decent still image performance too. And there's a not-too-bad digital image stabiliser, and passable low light performance, and you even get quite good sound from the built-in stereo mic, which is just as well because there's no way to plug in an external mic.

Cameras with a tape or disc transport in them can't help but record their mechanism noise if you use their internal microphone, but the C6 is silent when you're not zooming, and the zoom's very quiet too.

It's good for the other things it lacks, to. It's not cluttered with zillions of stupid special effects modes you'll never use, for instance. It doesn't come with any of those gaudy stickers that remind mainstream camera buyers about the resolution and lens specifications of their purchase. And it's got voice prompts, but they're not very annoying and can, of course, be turned off.

Another thing the C6 lacks is size. It's a tiny little thing...

Size comparison

...as you can see in this comparison. The red box is just the C6's external dimensions; the actual camera is slopey and round-cornered and highly pocketable, but still manages to cram in a two inch screen with the usual fold-and-flip movements and a sturdy-feeling hinge.

The C6 is about a year old now. Since its release, Sanyo have come out with an underwhelming HD version, and apparently then a somewhat better HD version, and a splashproof version, but nothing terribly much better. The C6 is still very much worth buying, for the right price.

The C6 sold for about $US655 when it launched. At that price, it was going up against a lot of excellent camcorders. They're all bigger than the C6, of course, but there are plenty of MiniDV and mini-DVD camcorders that're quite compact enough for most people, and have extra stuff like lots of optical zoom (the C6 only has a 5X zoom lens, plus the usual pile of useless digital zoom to go with its useless interpolated ten megapixel maximum resolution still image mode; it's got a genuine 6MP sensor, and it can actually resolve, oh, maybe half of that), external mic connectors, et cetera.

This, for instance, is a couple of months younger than the C6, but much better value at $US399 than the C6 was for $200 more.

But that was then, this is now, and I bought this C6 for $AU414 including delivery on eBay. They're about five bucks cheaper again, now, so we're talking about $US315 delivered, as I write this.

My money bought me the standard C6 kit, a spare (off-brand) battery, a little bendy tripod, a soft bag, and a very manly bright pink neck strap. I bought it all from DigitalRev on eBay, who bundle those extra "gifts" with pretty much everything they sell. The bendy tripod is actually a rather good match for the featherweight C6, if of course you don't mind it being only about two inches off the ground.

There are a few local dealers here in Australia who sell C6s for something approaching this price, but they all look dodgier than DigitalRev to me. US dollar prices, FedEx delivery and the option of "import duty insurance" from dealers who claim to be Australian? Riiiight.

(All of the really good C6 prices seem to be in Hong Kong, so eBay's probably the way to go for most buyers. If you're in the USA, though, Amazon currently have the C6 for $US449.99 including delivery, which ain't bad for a camera with a local warranty. Beards And Hats have it for ten bucks more, not including delivery, which is less exciting. I'm sure there are many more exciting deals available from NYC's more salubrious establishments.)

DigitalRev will sell you a memory card along with your camera, but their prices for those aren't the best, so I bought a 1Gb card separately. 2Gb is the largest the C6 can accept. You get well over 40 minutes of video per gigabyte - Sanyo say "up to one hour" - and a ceiling of an hour of video record time per battery.

Even with a 2Gb card, the C6 still ends up costing about the same as a decent MiniDV camera, but it's much easier to use with a computer. Just plug it in via USB, or stick the memory card in your card reader, and you've got computer-ready video files right there. It comes with some kind of software package, but I've ignored that completely - VDub's good enough for me.

And, I remind you, the C6 is just so small. It's a grown-up version of those baby-cams that're still on sale all over the place.

Baby-cams are great, if you know what you're getting. The modern versions shoot proper smooth 25fps-plus video in standard formats, and their fixed focus, no-zoom, webcam-type lenses are fine for shooting happy little 320 by 240 clips; they even go some way towards resolving 640 by 480. For well under $US100 (toy-cam experts Aiptek have prices right there on their front page), they're a great deal.

But then there are things like this.

Lousy camera

This is from the last K-Mart sale catalogue. They're selling this cheap-lensed piece of plastic crap for about the same price as the metal-cased C6, and should be ashamed of themselves for doing so.

I can't quite identify the precise OEMmed yum cha camera this is, but it seems to have the same specs as the Aiptek MPVR, which is currently a $US170 item direct from Aiptek, and rather cheaper elsewhere.

At that price, the MPVR is not a bad product. And its camera specs are right in line with the Aiptek/Mustek/whatever cameras that're going for $US95, tops; they're good for the money, too.

At the equivalent of more than $US300, though, the K-Mart camera is daylight robbery.

Aaaaanyway - if you like the idea of a teeny-tiny digital video camera that's practically purpose-built for video-podcasty sorts of tasks, not to mention light enough that you could easily loft it with a kite if you're brave, then get yourself a C6 while the getting's good. It's a decent choice for anybody who wants an ordinary still/video camera with the emphasis on the video; it's an excellent choice if you've already got a DSLR and want something that fills the two gaps in the DSLR's feature list - movie recording, and smallness.

If you'd like to read a proper C6 review, the one at Steve's Digicams is good.

(One more note. Is your brand new shiny C6 apparently stone dead? That's because you've put the battery in the wrong way around. Most battery packs are keyed so you can only insert them one way; the C6 battery isn't. Fortunately, Sanyo weren't daft enough to make the battery able to short out if you stuck it in backwards - just turn it around and you'll be fine.)

(Update: Find a few hints and tips here!)

Posted in MiniReviews, Photography. 4 Comments »
Newer posts »