Archive for October, 2013

Syrian Unrest

Thursday, October 3rd, 2013


Two boys, I think brothers, at the protest.

I arrived late for Hands off Syria, a protest outside the US Embassy in Grosvenor Square, and more or less as I walked in the protest seemed likely to be disintegrating as a strong faction supporting the Syrian regime and President Assad began to erupt against a speaker who had begun to talk about the discrimination against the Kurds in Syria.

A number of protests in recent years by Stop the War have brought together groups with very different viewpoints. When they protested against our air attacks on Libya, there were both pro- and anti-Gadaffi groups who came, although then those against the dictator were mainly also in favour of the air attacks.

Here I think everyone was against military intervention by the West, but little else united the protesters. Taking place after the House of Commons vote had turned down any British intervention, the protesters were here to call on Obama not to attack.


I always like to show the US Eagle and flag when I’m at the embassy – and this is nicely not too obvious

Although I can’t feel much sympathy for those pro-Assad protesters – he’s a brutal dictator who should have been consigned to history long ago (and I suspect only kept in power by cynical Western support) and responsible for the massacre of many thousands of the Syrian people – they do provide some good images. And of course what they were saying about there being no discrimination against the Kurds in Syria, and the Syrian people being as one was total nonsense, as anyone who has done the slightest research would know. They must all read the Syrian equivalent of the Daily Mail and believe all its lies.

It’s hard to see any sensible policy towards Syria. Like most of the Middle East it isn’t really a country but an artificial construct that suited Western policy towards the area some time in the last century when the lines were drawn on maps.  We should have found ways to support democratic and progressive movements across the area  over the years, but instead chose to back some very reactionary monsters mainly on behalf of our oil companies. Which leaves us in the current mess.


A rather odd angle  was needed to include everything I wanted

But I was there to take pictures, not make political speeches, and I got on with it, stifling my disbelief at some of the speeches, particularly those that claimed that the recent vote was some kind of victory for the anti-war movement rather than arising from sheer stupidity by David Cameron in refusing to compromise with Labour.  If he’d done so the vote would have gone the other way – and what claims about success could have been made then?

The official Stop the War protest ended fairly soon after, and they started packing up, leaving most of the stage to the Syrians, who began a much more lively event.

There is something very odd about that image of Assad, somehow too smooth, too polished, too heavily retouched, something wrong with his eyes, and I do find the whole personality cult disturbing.

By this time the wind had dropped and the flag wasn’t playing the game, which was just a little disappointing.  This woman in particular was good to photograph, very demonstrative. There is often a problem with photographing a protest that people just stand there, doing nothing, saying nothing, but there was plenty of action at this one – as you can see at Hands off Syria.

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Lightroom Lens Profile Tip

Wednesday, October 2nd, 2013

I’ve just realised that I hid away a very useful tip in a rather long post the other day, one which its taken me rather a long time to realise. Which is:

With ultra wide-angle lenses, correcting distortion isn’t necessarily a good idea.

In particular, Lightroom’s default settings with the 10.5mm Nikon fisheye are quite unusable, and images taken at or near 16mm with the 16-35mm are often less pleasant.

The default profile with both lenses sets distortion correction to 100, but except in some special cases its best to set the default to 0.

Lightroom (and presumably ACR) lets you easily change the default. Here’s how to do it:

1. Go to the Lens Correction Panel, select the profile tab,
2. Make sure you have Enable Profile Corrections checked and the correct lens profile displayed.
3. Make the change you want – usually setting Distortion to zero.
4. Under the Enable Profile Correction line is the Setup, which will now be ‘Custom’.
5. Use the triangles to the right of ‘Custom’ to select ‘Save New Lens Profile Defaults.

The 10.5mm fisheye lens actually has very little distortion –  but it has a fisheye perspective (I think an equisolid angle projection), enabling it to have a pretty huge angle of view – around 180 degrees across the image diagonal and around 145 degrees horizontal. The profile assumes it ought to be rectilinear, and this really just isn’t possible for such a wide angle of view. Only about half the image is usable, and it simply negates the idea of using the lens.  You may occasionally want to use just a little distortion correction –  perhaps a value of 20 or 30, but generally its far better to leave it to zero. If you want at less ‘fishy’ result, try a plugin like Fisheye Hemi, which renders the verticals straight (though if the lens wasn’t level they will converge or diverge.) PT Lens will also ‘de-fish’ images but in a different manner which loses a little more of the image, or you could play with the free Hugin panoramic software. PTGui is rather more expensive and works very well too, giving a choice of projections and if you want to make panoramas is the software I’d recommend for that.

At 16mm the 16-35 has very noticeable barrel distortion. But it’s only really noticeable on buildings and similar subjects. But what we do get noticeably in any very wide angle rectilinear lens is a distortion that increases towards the edges and corners of the frame. It’s generally most noticeable in circular or spherical objects and you can easily see it by viewing a ball through the camera and moving the camera to put it in the centre and then the edges and corners of the frame. If you think of the circular object producing a circular ray of light that will look circular if it hits the sensor at right angles, but as you move it away from the centre of the image, the light ray is hitting the sensor at a more oblique angle, producing this ‘distortion’.

Barrel distortion actually makes this effect less obvious, stretching out the subject in the middle of the frame and compressing the edges. The 4% or so distortion the designers allowed in the Nikon is actually remarkably effective when applied to roughly spherical objects like heads, making them look more natural, and the little increase in size in the centre brings out that part of the image, making it seem closer – and the main subject of the picture is often fairly close to the centre.

It’s a distortion that I suspect Mr Nikon (or whoever designs their lenses) may well have deliberately allowed or even encouraged at the very wide end, knowing both that it would enhance many images, but also that because of its uniform nature it can easily be removed for subjects where accurate drawing becomes essential.

By the time the lens is at 21mm, distortion in the lens is generally pretty low, and at 24mm roughly zero, with a little pincushion distortion above that, seldom enough to be noticeable except in the most critical images.

Correction of distortion always comes with some loss of sharpness, though only generally noticeable at a pixel peeping level. It is seldom necessary to correct distortion for this lens, unless you are an architectural photographer, and for most of us the best default will be to set distortion to 0 and save this as the new default for the lens.

Marville’s Paris

Wednesday, October 2nd, 2013

I imagine that the US the National Gallery of Art  in Washington is currently closed (I’m writing this on 1 Oct 2013) courtesy of the US Republican Tea Party’s opposition to heath care. I can’t at all understand their opposition to what appears to be a very sensible if rather limited measure on public healthcare, any more than I can understand the current UK government’s push to privatise our NHS here – now well under way through various back doors. As a great supporter of our NHS I was sorry not to be at the march on Sunday when over 50,000 people went to Manchester to show their support. Or as one presenter on our BBC radio – once another great British institution but now sadly compromised in its coverage of UK events – put it ‘some people say as many as ten thousand‘.  If the police estimate was 50,000, you can be sure it was rather more.

Assuming at some point before January 5, 2014 US Republicans come to their senses and allow US Museums to reopen, those within travelling distance of Washington should make for the exhibition Charles Marville: Photographer of Paris which opened there on 29 September, the first major US showing of his work with a hundred photographs. The NGA page also has a link to a good set of 18 photographs, Paris in Transition, including work by Marville and others. It says the show is in association with The Metropolitan Museum of Art, New York, and a search on their site reveals around 20 works by Marville with images on line.

Back to public radio, NPR (it does photograph much better than the BBC) has a good report on the show by Susan Stamberg talking with curator Sarah Kennel, who has also produced what appears to be a very fine book, Charles Marville, Photographer of Paris, published by the University of Chicago Press (available in the UK in a couple of weeks.) The web site has a dozen large images from the book.

There is a good article about the book and the show by Luc Sante on The New York Review of Books, again with a gallery of images, and there are more pictures by Marville at MoMA and on Luminous Lint. Commercially many of his images are available in digital format through the Roger Viollet gallery, but I could only manage to see these as small thumbnails.

Also on line is a map of Paris with pins on it locating the sites where around 150 of his pictures were made, clicking on which gives a small version of both his image and a modern view from a similar position. There is also a PDF by Martin H. Krieger of the University of Southern California which explains the how and why this map was made.

[There may be collections of Marville’s work available on line from the large holdings of some Paris museums, but the French cultural establishment’s peculiar relationship with the Internet leads them to set up impenetrable web sites, perhaps stemming from their view of it as an ‘Anglo-Saxon’ institution and a devotion to a peculiar logic which requires a French education to understand – and certainly defeats Google.  Should anyone manage to find any, please post links in a comment below.]

Marville who became the official ‘Photographer of the City of Paris‘ is deservedly well-known for his roughly 500 images commissioned by the Commission Municipale des Travaux Historiques of Paris before and after the great programme of works before and after the ‘improvements’ made by Haussman. The great boulevards were pierced through the city, designed to allow free movement of troops  to put down the frequent insurrections by the people of Paris.  The narrow streets which they replaced were far too easily barricaded.

For many, including myself, this work has an added interest because of the work of a later photographer of Paris, Eugène Atget, for whom, despite my comments above, the BnF has a good web site, and even available in an English (US) version (and in French only, Regards sur la ville.).  Many of Marville’s better images are indeed hard to distinguish from the work of Atget, although as the latter site comments, while Atget shows only the ruins and destruction of a gutted city, Marville has an interest in its reconstruction.

Apart from some of those images of Paris, much of Marville’s work leaves me unmoved. The simple records of church doorways and statues fail to go beyond that, technically proficient but unless you have a particular interest in the thing photographed, rather boring.  I want more from photographs.

Improving Crappy Lenses

Tuesday, October 1st, 2013

PetaPixel’s title Researchers Develop Method for Getting High-Quality Photos from Crappy Lenses is certainly more down to earth than the original High-Quality Computational Imaging Through Simple Lenses to which it refers, and unless you a more of a mathematician than me you will find parts of the latter hard going. But it is worth going to the original, if mainly for the short video and the roll-over images showing how well the method works.

I took one of the sample ‘before’ images from their simple lens into Photoshop and tried my best to improve it. With a couple of passes through my normal sharpening plug-in, FocalBlade I could make significant improvements to image sharpness (I have an old version of the plugin, and used first DeBlur Pro mode, then Selective Sharpen Pro) without gaining too much noise in smooth surfaces, but was very clearly left with considerable colour fringing when viewed at 1:1, and could think of no way to significantly reduce this in Photoshop. This is a problem that the researchers “novel cross-channel term ” is designed to resolve.

The paper seems to be another chapter in a story we have already seen beginning where lens designers can rely on software to minimise some lens defects. Many cameras already incorporate this, particularly for their jpeg images, which can be corrected for vignetting, distortion and chromatic aberrations, and ‘post’ software such as Lightroom can provide similar functions for interchangeable lenses, automatically if it has a lens profile. For most of us such profile corrections have become a part of our normal working practice, applied automatically by the software, both for cheap and expensive lenses.

It’s hard to know how much of a breakthrough the work of the team at British Columbia University is, particularly as the point spread functions they use differ at different subject distances. While this may not be too much of a problem with cheaper compact cameras (or phones) there may also be a problem in achieving the necessary computational power in these devices – though what looks like some pretty tricky maths to me may not be too difficult to a chip – who knows?

I’d certainly love to have simpler, lighter and cheaper lenses for the Nikon. Particularly with the lower back pain I’m suffering at the moment, lighter would be good! The 16-35mm f4 is a great lens, hard at times to believe how sharp it is (after a little help from Lightroom) but at around 680 g or 1.5 lbs it isn’t light hung on a camera body around the neck. And at around 5 inches long, plus a lens hood, with a 77mm filter, it is big.  Good though the performance is, it still improves in Lightroom, which does a great job of removing distortion, chromatic aberration and vignetting.

This doesn’t quite all come for free, as the distortion removal does inflict a slight crop around the edges of the image, particularly noticeable at 16mm. Sometimes too, 16mm images can look better with the distortion, as when corrected to pure rectilinear there is actually more stretching at those edges. Round objects are actually closer to round with the distortion, and at 16mm most images actually look more natural without distortion correction – by setting the slider in the Profile sub-panel to zero.  It would probably be a good idea to make this the default setting for this lens unless you are an architectural photographer. Correcting distortions isn’t always a good idea with wide angle lenses.

Lighter cheaper lenses don’t always mean poor quality. The Nikon 18-105 is a pretty snappy lens and a little under a pound in weight as well as smaller in very dimension than the 16-35. As Photozone remarks, it has rather high distortion and chromatic aberration, but again with a little help from Lightroom the results are generally hard to fault.  Around a quarter the price of the 16-35mm, the biggest difference from the professional lens is in build quality. I can’t remember if the current lens I’m using is my third or fourth, though I did drop one of them. The low price means that repairs are seldom economic.