Thursday, 8 October 2015

October odds and ends

A couple of items for your interest.

Shutterbug published a lovely appreciation of Sir Simon Marsden on October 5th. I also found him very communicative and helpful at the time of the Centenary and really regret not meeting up, especially now I live a lot closer than I did in 2010. This has prompted me so that this year I've decided to desert Ansel Adams and get my 2016 calendar from the Marsden online shop.

Rather oddly, considering the piece dates back to August 2014, New Scientist just tweeted a link to an edition of their 'Last Word' column, which asks 'How far beyond the visible spectrum does a rainbow extend?'. The responses discuss both UV and IR extensions of what we see, and especially how those might be more dominant on other worlds such as Titan. It reminds me of the work of Robert Greenler who, having deduced that there should be an infrared component to a terrestrial rainbow, finally succeeded in photographic a natural one in 1970.

I recently had a visit from Ed Thompson and had a sneak preview of his upcoming book of colour infrared photographs. I'll write more about this when it's published but suffice to say there's lots of red and a delightful conceit in the way the book is packaged. In the meantime if you're in the vicinity of the Rough Print Gallery (14 Bradbury Street, Dalston in London) then images from the Red Forest and The Village portions of his epic Unseen project will be on show. The gallery Tumblr stream tells us that it's part of the White Rabbit Restaurant and the gallery is open 10-5 Wednesday/Thursday and during the restaurant opening hours. Starts 15th October and runs to the 21st.

I think that'll do for the moment.

Tuesday, 25 August 2015

Infrared Photography in Cuba

Cuba is a fascinating place for photography, with its blend of Spanish colonial architecture, old vehicles and picturesque scenery. It has an infrared legacy as well, if you recall the movie Soy Cuba. I took a roll of infrared film on my trip, almost 20 years ago, although the only place I used it was in Varadero, which is not necessarily the place to go to experience the real Cuba. The shot at the top of the page is from Varadero ... in the older part of town away from the tourists on the beach.

So, if you are based in the USA and fancy an infrared photographic trip before Cuba changes (which I hope it doesn't) then you could do worse that go in the company of Laurie Klein.

Camera Voyages have organised the logistics, flying from Tampa, Florida and visiting Havana, Cienfuegos and Trinidad between December 3rd and December 10th. Take plenty of dollar bills (the locals may ask you for some!), or pens or soap.

This isn't just an infrared trip, Bruce Byers will be exercising a Phase One digital back as well. Basically, as the trip promotion says ...
Laurie will help you find unique ways to capture the feelings, sights and sounds of a culture different then ours at home, through method acting, taping into your inner creative voice and having fun.

Bruce will help you capture the streets and the motion with in the frame. The culture is all around. He will help you tell the Cuban story with your camera.

[September 5th: Only one place left ...]

Monday, 10 August 2015

Concerning a visit to Bath

A recent visit to Bath included the Herschel Museum of Astronomy, which occupies a house where William Herschel and his sister Caroline lived and is also home to the William Herschel Society. This isn't the location of his famous discovery of infrared radiation (by then he had moved to Slough) but it is from where he first observed the planet Uranus in March 1781. If you're in Bath I recommend a visit. It should give you some measure of the man and his times and will also remind you of how important a scientist his sister Caroline was as well.

While there I discussed the infrared discovery with the staff and was shown a section of the Herschel Chronicles book (originally published in 1933 and now available in facsimile) which includes correspondence between Herschel and his patron Sir Joseph Banks. The Chronicle's author notes that Herschel, as was common at the time, thought radiant heat was fundamentally different to light. We now know that the two are different only in their wavelength.

Banks is encouraging Herschel to use the term 'Radiant Heat' rather than Caloric, which Banks linked to the 'French system of Chemistry'. Time has proved Banks correct and Herschel was glad to take his advice, saying he was 'very ready to change the word Caloric for Radiant Heat, which expresses my meaning extremely well'.

Tuesday, 2 June 2015

FLIR One Hands On

I've been hoping to have a closer look at one of the new breed of 'personal' thermal imaging cameras, and with the help of the Royal Photographic Society Journal I have been able to.

You may recall from earlier posts that this version of the FLIR One operates like a case for the iPhone 5 (more versatile versions are imminent) and uses the iPhone for viewing, operations and storage. The FLIR's case fits firmly onto the phone although it is in two parts so the thermal camera part can be easily unclipped if you don't want to carry it with you all the time. Fitting and removing the inner case to the phone is a little tricky and some users report breaking it ... so be careful. Clipped together the device is obviously heavier than the iPhone but not unduly so, and the whole thing still slips easily into a pocket. The two devices communicate via the Lightning connector and the thermal camera does not take any power from the camera; it has its own battery which is charged separately.

To operate the camera you pull down a slider switch half way until it clicks and turn on the free downloaded app. You are then prompted to pull and hold the slider a bit further, to calibrate the camera, after which you're ready to go. It's point and shoot, with options to change the colour palette, hold exposure, and select either a still photo, a panorama, time-lapse or a movie to shoot.

Thermal resolution is low, at 80 by 60 pixels, but the software neatly combines this with information from a coincident (almost) 640 by 480 visual camera, adding something like the Photoshop edges filter to form a hybrid image. For most purposes, this process, called MSX, completely ameliorates the low resolution thermal image. As the two cameras are not completely coincident there will be parallax errors if you shoot close-up. It is possible to correct for this (but sometimes I forgot). You can choose between several colour palettes. A thermal image is monochromatic but adding false colour can help show the distribution of temperatures. You can change the palette of a shot later, but for some reason the camera shrinks the image to 516 by 387 if you do this, which is weird. Another thing to note is that a FLIR logo is added to every image shot, which is slightly intrusive (imagine if Nikon or Canon did this) but is par for the course with their devices.

Straight out of the box you can shoot useful diagnostic images. For example, here is a shot that shows a cold carafe of water in the foreground and in the distance you can see a warm radiator and also the heat trace of warm pipes going up inside the wall above it. This uses a grey palette ... dark is cold and white is hot (relatively, the range is actually 12.8 to 21.2 degrees C).

Here's a shot with the temperature indicator turned on which shows heat spots of a group of transformers powering my broadband and phone equipment (iron palette). The FLIR One has a number of emissivity settings with a matte setting being the recommended one. Emissivity denotes how much infrared thermal radiation something radiates compared to what it should do if it were a theoretical 'black body'. Knowing the emissivity helps you know how accurate a remote temperature measurement is. The FLIR One has four settings for this, from matte to glossy, which is fewer that a fully professional thermal camera might have but is still useful.

I've no doubt a thermal camera such as this is a useful practical tool, especially in DIY for tracing heat loss and heating pipes ( buyers are notably enthusiastic about this kind of application), but I'm not so sure about its artistic possibilities. The low thermal resolution makes it difficult to take images as atmospheric as those that Joseph Giacomin takes, especially since I couldn't work out how to record only a thermal image with no visual embellishment. That said, it's easy to take fun thermal images and the images certainly attract attention.

I showed the FLIR One to a visiting heating engineer who immediately said he'd ask his boss for one, although for a professional with no need for panoramas or movies the new FLIR C2 [data sheet] is likely to be a better bet, especially since it is a self-contained unit with a similar price point and better analytical features.

The FLIR One in this form factor is available now from places such as the Apple store and Amazon (£180). I would wait for the newer model, which clips to the bottom of an Apple or Android phone or an iPad and should be a bit more future proof. From an artistic point of view I will pass, despite the low price. I think Joseph has convincingly demonstrated that a 640 by 480 thermal image has real artistic possibilities but I am less excited by the low resolution of the FLIR One. However this, and similar cameras, will show whether there is a market for less wallet-busting thermal cameras ... so I am delighted to see it and ignoring my arty pretensions I do think it's an impressive device and really easy to use.

To finish here are a few more results I got from the camera. Click for full size (640 by 480) versions.

The obligatory selfie. Normally with a thermal camera you wouldn't see my eyes through the glasses, but here the special processing does show them.

These thermal wavelengths (of the order of 10 µm) don't go through glass but they will go through some plastics. In this case you can see my hand inside a black bin liner. (The hand isn't touching the bag ... that would be cheating.)

The London Eye from Westminster Bridge. The thing growing out of the guy's head isn't a new tower block ... it's a lamppost on the bridge!

This shot, of the cab of a steam locomotive, demonstrates a colour palette that shows the very hot spots in red.

And finally some movie. Shooting a movie is straightforward, although in some circumstances you should lock the exposure (called span) to avoid changes to the palette mid-shot. The three scenes are of a London tube train (Victoria line) and a subsurface line (Circle etc) ... here you can see how the tube train, which runs deep underground, shows as warmer in relation to the platform than the subsurface one, which is at pretty much the same temperature. The wheels show very hot, as the trains are braking as they come into the stations. The third scene is of a loco at the Yarwell halt on the Nene Valley Railway, running to change ends before pulling a train towards Peterborough. I was surprised to see the hotspot at the front of the loco and by how relatively cool most of it was.

Thursday, 28 May 2015

Your veins are the key

Given that near infrared can penetrate a little way into skin, there are an increasing number of interesting applications that exploit that. I noted a medical system for locating veins last November.

Now a Swiss company is demonstrating a sensor that uses NIR to scan the pattern of veins on your wrist, which are apparently unique to you, to use as a biometric key. There's more on the BIOWATCH web site and also in a news item on the BBC web site.

After recent problems that Apple's watch infrared sensor found with tattoos, it'd be interesting to know whether they'd cause a problem for this sensor. Presumably unless there's total coverage, there will still be some vein pattern to use. I assume there's a patent and a quick search throws up some interesting examples, such as US 6799726 B2 from 2000, which uses near-field radio in a wrist-watch to access ski lifts, and WO 1988004153 A1 from 1987, which concerns biometric sensing. As this latter patent points out, often this requires a user to carry out a special action, such as looking into something or placing a hand on something. With the advent of sensors small enough to fit onto a wristwatch strap, the sensing can be genuinely unobtrusive.