Category: Photography

It was our annual village Fun Run, 7 kilometres along village roads and countryside. The first back, as ever was Finn Johnson. I believe his time was 23 minutes, 57 seconds. Also, as ever, I took a few snaps…more photos in my Facebook Gallery.

Some of you will know that Northumberland was famously a coal-mining region. My paternal grandfather, whose story I capture in my song “Coaldust and Seaspray” was a miner, just sayin’.

There were countless collieries and undersea mines as well as also open-cast mines. Surface mining near Cramlington was accompanied by art in the form of what is claimed to be the largest landform sculpture of the female form – Northumberlandia (the “Lady of the North” or “Slag Alice” to some).

Northumberlandia was designed by American landscape architect Charles Jencks and was made from 1.5 million tonnes of earth from neighbouring Shotton Surface Mine on the Blagdon Estate owned by fellow science writer Matt Ridley. NB Most science writers don’t own estates other than the vehicular type and any that they live on tend to be (ex) council. Anyway…

Shotton has operated on Blagdon almost continuously since 1943. The sculpture meanwhile is 34 metres high and 400 metres long, and set in 19 hectares of public park. Landscaping was undertaken in part by Cambridge Direct Tree Seeding (CDTS).

The neighbouring Shotton mine was granted government permissions to start mining in 2007 (despite opposition from the local council). It is still active, although it should have ceased operations in 2016. It provides 8% of UK coal output amounting to several million tonnes of coal.

A Wildlife Trust representative at the Northumberlandia site told me that the company had been granted an extension but it would definitely close in 2018. The mine is continuously back-filled and ultimately will be landscaped and trees planted to make a much larger public park and nature reserve.

The Cambridgeshire village of Cottenham is famous for a lot of things – cheese, fires, the Pepys family, community activities, and, of course, being the source of the idiom “Hobson’s choice”. Hobson having stabled the horses for his Cambridge business at the foot of Lamb’s Lane, back in the day.

The village is also quite well known for its Anglo-Saxon or Mediaeval site, Crowlands Moat. The moat lies at the heart of the Broad Lane “birds” housing estate. The site was listed by English Heritage as a “scheduled ancient monument”. The moat originally surrounded the long-gone Crowlands Manor.

The moat is home to a significant breeding population of great crested newts (Triturus cristatus), a rare, and protected species. In the UK and across Europe it is generally illegal to kill, injure or take a northern crested newt, to possess or control any live or dead specimen or anything derived from them, to recklessly damage, destroy or obstruct access to any structure or place used for shelter or protection by the species, or to recklessly disturb its home or breeding grounds. The moat is also home to smooth newts (Lissotriton vulgaris).

On a typically wet and grey Bank Holiday Monday we went looking for newts…and saw at most two, there were presumably many more lurking in the murky waters of the moat. Just the Common Newt though, no Great Cresteds…

Several people have asked about my photo on the cover of the January/February issue of the Cottenham Newsletter. They’re curious as to where I took the photo, how I got the church and the lode in the frame like that. A couple of people have even suggested that it must be a composite and have walked along the bank to see if they can see how I took it.

Well, it’s not a composite, there was no photographic trickery. It was snapped with a 600mm zoom lens on the 30th December 2017, just after 11am. I “developed” the photo in Paintshop Pro and cropped it to frame it nicely for the cover of the newsletter. The lode was almost full, which perhaps messes with one’s perspective. But, more than that zoom lenses notoriously compress the depth of an image, making the most distant object seem not only closer but also making it seem as if they’re the same sort of distance away as closer objects. It’s a useful effect and gives rise to intriguing and puzzling photos like this one.

Anyway, to settle any arguments, the photo was taken from the dog-leg in the Cottenham lode where the little wooden bridge emerges from Rampton Spinney. So, about 1.2 km from the Broad Lane Bridge (seen in the right of the photo) as the crow flies. All Saints Church (pictured in the left) would be about 2 km from that point.

Other technical details: Canon 6D, Sigma 150-600mm zoom, f/10, t 1/500s, ISO 1200.

I was given a nice 1:1 macro lens for Christmas (Tamron, 90mm f/2.8). It was giving excellent results out of the box, but having realised that my DSLR does allow one to tweak the autofocus micro adjustment in-camera. I thought I would calibrate it as I had with my 600mm Sigma zoom (albeit that was done off-camera with a USB adapter). There’s a much easier way to verify that your lens isn’t back focusing or front focusing with lenses of shorter focal length as you don’t have to be so far away from the calibration targeting; at least 50 times focal length, which for a 600mm lens is 30m but for a 90mm lens is just 4.5m. I also opted for the moire fringing method described here.

Basically, you set your camera on a tripod, manually focus in Live View on a pattern on your computer screen, then switch to autofocus in the viewfinder and watch how much and in which direction the focus ring moves to “focus”. Your camera may be front or back focusing and for most DSLRs above the prosumer level from Canon and Nikon you can micro adjust this to fix it and make the AF sharper. If I remember rightly, my DSLR will remember micro adjustment settings for 42 different lenses, which is an order of magnitude than I possess so plenty of data slots.

The bottom line is that if your camera allows you to, you should calibrate your lenses in-camera. There will almost always be tiny discrepancies between what the camera thinks the lens is focused on and what it is actually focused on forward or back. My 50mm prime lens needed a -2 adjustment, whereas the Tamron macro needed +10 (out of a range of -20 to +20). This was sufficient to bring the lenses up to snuff. With these adjustments, there is no focus ring movement from manual focus to autofocus. They’re calibrated.

It’s going to be harder to calibrate the big zoom lens as our garden is a lot less than 30m even across its diagonal and I also don’t fancy the chances of the camera nor a laptop with the moire pattern in this rain, so I’ll leave all that for another day.

Meanwhile, here’s another macro shot of the poinsettia cyathia, this time carried out with focus bracketing. It’s a useful technique, but I can see some artefacts where the leaves and/or camera moved ever so slightly between frames. Or, it’s just a side effect of the way Picolay works with a focus stack of images.

These micro-adjustments and calibration can make only a tiny and sometimes barely perceptible difference to sharpness at 100%, but useful if you’re going to enlarge or do a really tight crop. Of course, given the awful compression websites like Facebook apply when you upload to them, it might seem pointless. Indeed for some uploads, it’s probably fine to just apply an unsharp mask to areas of interest in a photo. But, given that the micro-adjustments are relatively easy to do, I’d say do them anyway.

UPDATE TO ANOTHER UPDATE: The Canon utility was hopeless, luckily I found a bit of open source software that takes back control much better and used it to focus stack yesterday morning’s moth and then combine the images, to much better effect.

ANOTHER UPDATE: It seems that the Canon EOS Utility should allow me to automate the process focus bracketing with my 6D…just installing and will test with tomorrow’s moth…assuming there’s another stunning species to photograph…may give it a miss if it’s just another Clouded Drab.

UPDATE: Been taking another look at this and applied focus stacking to my latest moth photo. There are several programs for focus stacking (Photoshop has it built in), Helicon Focus, Zerene Stacker, Picolay, and CombineZP (there are many others just search for focus stacking software). There’s also a tool for Canon dSLRs, DSLR Bracketeer, that lets you do the focus bracketing automatically and then you do the stacking in an app of your choice. There’s also a tool that lets you do the focusing on a bigger screen, like a tablet or computer, CamRanger, but you need a wireless tethering device. (Then there are camera rails!)

A narrow depth of field (DOF) has its pros and its cons in photography. Portraits often benefit from a nice sharp focus on the subject’s eye, but everything out of the plane of the face being out of focus so that backgrounds are blurred. In landscapes, the opposite is often required: foreground, middle ground and distance all needing to be nice and sharp (depending on your artistic wont, of course).

Fundamentally, DOF depends on the focal length of the lens, where you focus it and more importantly the f-stop you choose. The f-stop is the size of the aperture, essentially the hole that lets light into your camera. f-stop is given as a fractional ratio to the lens’ focal length of the maximum size it can be opened. So, f/2.8 is a big hole letting in lots of light (and needs to be balanced against a shorter shutter speed and/or lower ISO to get a properly exposed shot). Conversely, f/22 is a smaller hole and lets in far less light so requires a longer shutter speed (see my starburst article for diffraction effects possible with such an f-stop).

A larger aperture (smaller f-stop number, meaning a bigger fraction of the maximum size) means more light but a shorter DOF. This is part of the reason why things look blurry under water – there’s less light and so the pupils of your eyes open wider meaning a shorter DOF for your vision. Children who spend a lot of time swimming underwater without goggles can grow accustomed to the light levels and find that their pupils narrow and they can see sharper detail. I wrote about this effect among the Moken people for Discovery Channel back in the day.

Anyway, when you’re shooting close-ups of flowers and insects and such DOF becomes a real issue. With a 1:1 macro lens you are hoping to get the most detail possible but if the lens is within a few centimetres of the subject, then parts of the subject a few millimetres in front or behind your focus will not appear sharp. A top-notch lens with the possibility to shot with a slightly smaller aperture, provided there is sufficient light and without pushing the ISO to noisy high levels might get around the problem. But, there is another way.

You can focus stack your subject. Bracketing the point of focus from the closest to the farthest points on the object of your photographic desire. This is akin to creating genuine HDR (high dynamic range) photos where you expose for the dark, the mid-tones, and the highlights, stack the images together and create a composite that is neither under- nor over-exposed on any of those regions. Focus stacking brackets the focus and creates a composite.

There are plenty of HDR apps available, indeed some cameras and smartphones have an HDR mode that takes a series of photos very quickly one after the other with the bracketed exposures, stacks them together and erases the areas that are too dark or too bright, to give an even exposure. Works wonderfully in cathedrals when photographing the knave and altar and bright stained-glass windows in a single shot.

There are fewer “apps” for focus stacking, but there are some available (as discussed here). I found a piece of software called Picolay, which seems to do a nice job. It has lots of settings, but you can let it run on autopilot. You take a series of photos with the focus at different points on your subject (preferably done with a tripod and remote shutter to make them as near identically positioned in the frame as possible, focus aside).

You load the focus bracketed photos into the software and hit “go”. It calculates where the sharpest regions are in each photo, stacks them all together and essentially erases areas that are not sharp, giving you a composite that has an apparent DOF much greater than has any of the individual photos in the stack.

I plucked a crumpled leaf from our grapevine, set it up on a black plinth, put the camera on a tripod close to the leaf and moved the latter to frame it nicely. I then manually focused the macro lens on different areas of the leaf and snapped a dozen or so shots.

The shot below shows the software’s analysis of the stack of photos, I am assuming brighter colours meshes with sharper focus.

The following shot shows the processed stack, where much more of the leaf is in focus compared with any of the individual photos.

Here’s a photo of the leaf in which I’d focused on the upper portion of the frame rather than the main vein

And, here’s one where the main vein is in focus, you will notice that neither of these shots is wholly sharp, whereas the stack above looks mostly crisp across the whole frame.

It’s not perfect and there are artefacts where the frames didn’t match perfectly. I did the experiment quite quickly. For a proper photo shoot, I’d spend more time setting things up just right and probably use a diffuse light source and maybe I ring-flash. Ensuring each source photo is pin-sharp, each region of focus is vital. The potential is there. I suspect, and I haven’t checked, but some smartphones with multiple cameras and such probably have such focus stacking built in and ones that supersede the Lytro focus-free camera can presumably take this to the next level.