Saturday, June 27, 2015

Virtual Photography

Keeping in the spirit of the last post, which focused on simulation, I thought I would say a few words about, what I call, ‘virtual photography’.

In today’s digital world, other than a few who still use ‘wet techniques’, the image is not made until we have finally ‘processed’ things in, say, Lightroom or Photoshop. There is, of course, a true final step, the ‘presentation’, eg online or on paper; but ignoring this for now, many photographers create their art in a computer, and most images stay there.

The statistics are clear. With digital we tend to ‘over capture’. That is the ratio of the number of images we present to the number of images we capture is small, ie 1 to 10 or 1 to 100 or more.

So what about all those ‘lost’ images? The ones that never get presented, at least to others. Like me, you most probably leave them on your hard drive: or should I say, your backed-up hard drive ;-)

To me, those images are not lost and this is where, what I call, ‘virtual photography’ comes in.

Virtual photography is simply photography without capture. That is trawling back through our old images, especially the ‘lost’ ones, and carrying out a virtual photography shoot. Or, in the extreme, one could imagine ‘using’ somebody else’s RAW captures (with approval, of course).

The process is simple: on a rainy day, say, when we are locked indoors; it is a simple matter to open up an old photo shoot in Lightroom and revisit those old raw images. Because of the power of LR, it is best to create virtual copies, say in a collection, and reset the exposures to their captures state: this way your mind is reset and not influenced by previous processing.

The first task is to re-envisage the image, ie a radically different crop for a different interpretation. Also, since you first looked at your old/lost images, there is a good chance you have new tools now, for example the new dehaze tool in LR & PS.

So, without leaving the comfort of your dry home, you can carry out a virtual photo shoot and use these ‘new’ images with some of your new tools, and your enhanced skills (since you first looked at the captured images).

As an example, this evening I was trawling through some old images of The Cobb at Lyme Regis Harbour.

The harbour at Lyme Regis is called the Cobb, although no satisfactory explanation of the name exists. The harbour has served as a refuge in Lyme Regis since at least 1313.

These two daytime images were captured with my Sony A6000 through a varable ND Throttle. Both exposures are ISO 100 at 30 seconds. These two images are different to my original processed versions, not only in their vision, but also because I used different post processing techniques, eg the dehaze.

In conclusion, in addition to ‘simulation’, which helps us in our planning; we should also recognise ‘virtual photography’ as a 21st Century form of photography, ie photography without (re)capturing an image.

Friday, June 26, 2015

Plan it, Take it, Make it

There are a lot of posts on-line regarding the difference between taking and making.

Most say you take a picture and make an image. Much of the debate seems to have roots in an Ansel Adams quote “You don’t take a photograph, you make it”

I think I am a taker and a maker.

I don’t think it adds much value ‘debating’ the semantics of the two views: in the end all we wish to do as photographers is show off our efforts: be that on an iPad with friends over a beer or with strangers when our image is hanging on a gallery wall.

I think a more important thing to discuss is ‘planning’; and I say this from experience: as I’m embarrassed about the number of times I’ve come away from a photo shoot with sub-optimal captures, because I hadn’t planned enough.

So the question is, with planning could I have increased my ‘hit rate’?

I believe so and in this post I’ll discuss some thoughts on planning. That is those times you are deliberately going out to try and create something.

For those times where you are ‘snapping’, you  ‘just’ need to ensure you know your craft: though practice and (equipment) knowledge.

I think we can usefully split planning into three ‘phases’: vision, equipment and simulation.

Some may be saying, as they read the above: What! Simulation? Well, we’re get there in a minute. Let’s deal with the first two phases first.

Vision is simply the planning we do in our minds-eye. That is, when we take the effort to go on a planned photography shoot, we carry with us a mental picture of what we are trying to achieve. What Ansel Adams called previsualisation: “Visualization is the single most important factor in photography”.

The vision (planning) phase is the most difficult to discuss, as it is so personal. Each photographer needs to find their own way through, what U.S. President George H. W. Bush called, ‘the vision thing’.

The equipment (planning) phase is relatively easy to discuss as, although it is related to the vision thing, eg having the ‘right’ lens with you, it is also about ensuring you have all the right equipment with you. For example, ensuring you have heated glove inserts if you need them (as I found out at a trip to Bosque Del Apache in winter.

Believe it or not, equipment planning is my biggest weakness. 

I know what to do; that is do what my wife does very well: create a list and check it off. But I’m not a ‘list person’. This is one planning ‘trick’ at which I simply need to get better. Especially as I get older and my memory begins to falter. There is nothing worst that hiking to a photo location and finding out you ‘forgot something’.

Which brings us to, what I believe, could well be a new phase of planning for many photographers: simulation.

Wiki tells us that “simulation is the imitation of the operation of a real-world process or system over time. The act of simulating something first requires that a model be developed; this model represents the key characteristics or behaviours/functions of the selected physical or abstract system or process.”

Ok, all a bit boring; but there are a few key words in the definition: imitation, real-world and model.

Today, we are ‘blessed’ with many great photography Apps, most of them costing only a few dollars. Being an iPad/iPod guy I regularly download Apps from the Apple Store and experiment with them, especially if they costs, say, a couple of cups of Starbucks coffee: which most/all of them do.

Some Apps allow you to simulate celestial mechanics, eg sunrise, sunset and the moon. Other Apps simulate cameras and lenses, eg depth of field. Then there are, what I call, the integration Apps: those that bring together many things and create a ‘virtual world’ for the photographer to plan in.

IMHO two of the best (simulation) Apps are The Photographer’s Ephemeris and PlanIt! For Photographers: and

Of the two, PlanIt! has the richest/widest feature set. For example you can estimate exposure as the sunsets at a particular location. You can plan how many images you need to take in a pano to ensure certain scene features are captured. Both Apps make full use of Google map data.

Rather than me boring you with my words, I suggest you download both Apps (I think they complement each other) and start simulating and planning you next photography trip.

Bottom line: although photographers have always thought about vision and equipment before a photo shoot, the new kid on the planning block is ‘simulation’; and, in my humble opinion, you wont go far wrong with TPE and PlanIt!

Monday, June 22, 2015

Lessons from the Road: Part 2

In the last post I spoke about how big the US is: really big!

But it has other ‘extremes’, that get your attention. So from Carlsbad it was a not so quick drive over to White Sands National Monument, before another long journey home.

Because of the limited time we had, we ended up visiting White Sands after mid-day! Luckily I had thought ahead and had my IR converted 50D with me :-)

Wiki tells us that the White Sands gypsum is rarely found in the form of sand because it is water-soluble. Normally, rain would dissolve the gypsum and carry it to the sea. The Tularosa Basin is enclosed, meaning that it has no outlet to the sea and that rain that dissolves gypsum from the surrounding San Andres and Sacramento Mountains is trapped within the basin. Thus water either sinks into the ground or forms shallow pools which subsequently dry out and leave gypsum in a crystalline form, called selenite, on the surface.

Groundwater that does flow out of the Tularosa Basin flows south into the Hueco Basin. During the last ice age, a lake known as Lake Otero covered much of the basin. When it dried out, it left a large flat area of selenite crystals which is now the Alkali Flat. Another lake, Lake Lucero, at the southwest corner of the park, is a dry lake bed, at one of the lowest points of the basin, which occasionally fills with water.

The ground in the Alkali Flat and along Lake Lucero's shore is covered with selenite crystals which reach lengths of up to three feet. Weathering and erosion eventually breaks the crystals into sand-size grains that are carried away by the prevailing winds from the southwest, forming white dunes. The dunes constantly change shape and slowly move downwind. Since gypsum is water-soluble, the sand that composes the dunes may dissolve and cement together after rain, forming a layer of sand that is more solid and could affect wind resistance of dunes. This resistance does not prevent dunes from quickly covering the plants in their path. Some species of plants, however, can grow fast enough to avoid being buried by the dunes.

Various forms of dunes are found within the limits of White Sands. Dome dunes are found along the southwest margins of the field, transverse and barchan in the core of the field, and parabolic dunes occur in high numbers along the northern, southern, and northeastern margins. From the visitor centre at the entrance of the park, we drove the Dunes Drive, which leads 8 miles into the dunes.

Unlike dunes made of quartz-based sand crystals, the gypsum does not readily convert the sun's energy into heat and thus can be walked upon safely with bare feet, even in the hottest summer months. Which was good, as I laid down several times to get the best angle for a shot.

Although I knew we would be arriving at the worst time from a photography perspective, I hadn’t really prepared myself for the shock of the environment: its white heat!

The air temperature was 100F and the brightness meant I initially struggled to use my camera. My ‘old eyes’ and glasses meant that reading my camera controls was a challenge.

Luckily, once I had set things up, in the relative shade of our car, I was able to forget exposure and focusing, ie using a wide angle hyperfocal approach and Magic Lantern’s ETTR.

Although I used my IR converted 50D, I was not happy with the results: so no images to share. It is clear that the lens I’m using has a lens hot spot problem I need to sort out.

As for my trusty 5D3, here are three interpretations, eg playing around with WB, of a place that I would love to visit at sunrise or sunset.

Bottom line: any photographers who have not visited White Sands, should seek out this unique wonder of nature: but plan ahead and think about visiting at sunset or sunrise!

Sunday, June 21, 2015

Lessons from the Road - Part 1

Some may think that being in the US means that I’m always on the road ‘doing photography’. Unfortunately, that is not the case; but not for the obvious reason, ie work.

The real reason is the fact that the US is big, really big!

As an example, the other week we took a ‘short’ two-night trip to see the Carlsbad Caverns and White Sands, which, from Albuquerque, ended up being over an 850 mile round trip!

The distance is one thing, but compound this with US driving styles, which are definitely not British, you have a long journey, punctured by a few hours doing photography.

Wiki tells us that Carlsbad Caverns National Park is situated in a bed of limestone above groundwater level. During cavern development, it was within the groundwater zone. Deep below the limestones are petroleum reserves (part of the Mid-Continent Oil Field). At a time near the end of the Cenozoic, hydrogen sulphide began to seep upwards from the petroleum into the groundwater. The combination of hydrogen sulphide and oxygen from the water formed sulphuric acid. The sulphuric acid then continued upward, aggressively dissolving the limestone deposits to form caverns.

Once the acidic groundwater drained from the caverns, speleothems began to be deposited within the cavern. Erosion above ground created the natural entrance to the Carlsbad Caverns within the last million years. Exposure to the surface has allowed for the influx of air into the cavern. Rainwater and snow-melt percolating downward into the ground pick up carbon dioxide; once this water reaches a cavern ceiling, it precipitates and evaporates, leaving behind a small calcium carbonate deposit.

From a photography perspective, I knew shooting underground, with lots of coloured/artificial lighting, was going to create surreal images, so I decided to build on that in post processing. I also decided on using long exposures, with no flash, and, as we had chosen one of the guided tours to start the day, which did not allow tripods, I decided to use my PlatyPod Pro, which meant I could place it the walk way floor or a manmade wall.

I used my 5D3 in the cavern and metered with ETTR, using the ‘Use Dual-ISO if needed’ setting. I chose my Sigma 12-24mm lens, and shot all of my images at the wide end. Exposures, at ISO 100, were up to 20 seconds.

Although I managed a few images on the guided tour, by being at the back; I found out the guided tours are not designed for photographers! So choose the self guided tour.

Therefore, after the guided tour, we kept going on a self-guided tour of other parts of the caverns, where we could go at our own pace, and stop at any time and at any place. Over all we were underground for over four hours.

One extra highlight of the trip was the evening bat flight, during which you sit and watch tens of thousands of bats leave the caves and go off on their evening hunt. Truly a wonderful sight.

Here are a few of the (surreal-locking) snaps from inside Carlsbad Caverns.

Bottom line: any photographer who has not visited Carlsbad Caverns is well advised to seek out this unique wonder of nature. In the caverns, try long exposures, rather that limited range flash; and use a Platypod-Pro, or something like that, ie that is a ‘tripod’ that is not intrusive. In a future post I’ll complete this road trip report and discuss the ‘inferno’ that is White Sands!

Friday, June 19, 2015

Sometimes all you need is Nature’s beauty: Amended

I came home from work early today, as it’s ‘poets day’ in the UK :-)

I wasn’t looking to do any photography, but as I turned into our drive way, my eyes where drawn to this enormous seed head.

It was perfect, with every seed attached; but it was obviously threaten by the wind; so I decided to capture it as one of the last records of our New Mexico life. After some three years at 7,000 feet we return to the UK and sea level, for good, in a few weeks time.

As I’m packing my camera gear this weekend, this was going to be one of the last images taken in the US.

I don’t know what specific weed I was photographing: I assume it is one of the Taraxacum, or dandelion, family. BTW the name dandelion's is derived from the French dent de lion, a reference to the irregular and jagged margins of the lance-shaped leaves.

To me I simply saw its beautiful symmetry and texture.

Although not shot with a macro lens, and not a macro image, ie 1-to-1 or greater capture; because the viewer is not aware of the scale, ie the seed head is some 5 inches in diameter, many would consider it a macro-class image.

For those that are interested I used my 5D3 in Dual-ISO mode (100/800) and my ring flash. The exposure was 1/160s at F/18, and I used my trusty 24-105mm F/4L lens at 60mm.

All post processing was done in Ligthroom (BTW I used the new LR CC (2015), which has a new dehaze feature that is worth checking out).

I hope, like me, you ignore the 'fact' it is a weed, and enjoy this beauty of Nature.

I was so intrigued by this seed head that I took a second image of it today: before its beauty simply falls away.

Tuesday, June 16, 2015

After the words...

I'm aware I posted a lot of words in the last post; so I thought I would make up for with a simple image of the storm around our house this evening.

I hope you enjoy the image.

Could this be the optimum focus stacking technique?

People often ask me about my Magic Lantern enhanced approach to photography, including landscape focus stacking. So I thought I would be bold and put down, what I believe, is the optimum approach to landscape stacking: care of Magic Lantern – sorry Nikon/Sony world!

Unlike macro stacking which is a simple, linear process, landscape focus stacking is a non-linear process. You cannot stack by simply moving the lens or camera relative to the scene in fixed increments.

In landscape focus stacking we are usually trying to get everything from the nearest focus of the lens to ‘infinity’ in focus; and our first port of call is usually the trusted hyperfocal approach.

Using the hyperfocal technique means that everything from half the hyperfocal distance to infinity will be acceptably sharp, or maybe more correctly, acceptably out of focus; as focus is only achieved at one point or plane, ie where we focus!

Note that, when using the hyperfocal approach, we can only bring the focus towards us by a maximum of half the hyperfocal distance. Thus if the hyperfocal is, say, 4m away, then my nearest point of acceptable ‘sharpness’ is about 2m away. Objects closer than 2m will be in the ‘unacceptably out of focus’ or ‘unsharp’ zone.

With Magic Lantern (the latest nightly version) we now have an inbuilt depth of field calculator that dynamically provides Live View feedback on the near and far depths of field. This feedback even accounts for diffraction and you can select the total blur (nee circle of confusion) according to your personal needs.

Rather than speak of circle of confusion on the sensor, I prefer to use the term sensor blur spot, as I’m attempting to account for lens ‘out of focusness’ and diffraction. Thus my blur spot is the combination of these two things in quadrature, ie SQRT( Out-of-Focus^2 + Diffraction^2).

If you look on line at the various depth of field calculators, you will normally be asked to specify a circle of confusion, and most of these calculators will ignore diffraction. Exceptions are the DOF apps I have previously written about.

For wide open apertures and ‘snaps’, we shouldn’t get that hung up over all this blur spot and circle of confusion stuff. However, if you are seeking out the ‘perfect’ landscape or shooting with a closed down aperture, and you desire is to sell this or hang it for others to see, then you will likely be trying to capture the ‘best’ image you can, eg exposure and focus.

So, let’s start by assuming we are creating a print: which is a more exacting need than, say, a JPEG for a blog page.

Informed wisdom, after trawling the web, may lead you to a ‘circle of confusion’ criterion of around 0.030mm (some will say 29 microns) for a full frame DSLR. By the way, if you are shooting a different camera format, the CoC will be different, eg for a cropped DSLR the CoC will be less, by the crop factor.

The first ‘problem’ we need to address is that the ‘normal’ CoC advice ignores our viewing conditions, or more correctly assumes a specific viewing arrangement, and ignores post capture cropping etc. It also assumes an average viewer, with average eyesight, ie not some eagle-eyed judge!

Although I'm not an optician, I have read that an average adult with healthy vision can resolve between 5 to 8 lp/mm (line pairs per millimeter), at a ‘normal’ viewing distance of 10 inches. If we take the more exacting value, and assuming a viewing distance of 20 inches, for example, we wouldn't need more than 4 lp/mm on the print.

Hence, the CoC, or blur spot, you select needs to be treated as a variable according to your presentational needs. Once again, I’m only suggesting this exacting approach for those ‘special images’, not for everyday snapping, where you can use a (generic) non-variable blur spot.

Rather than boring you with more theory and words, let’s jump to a simple formula that you can use to estimate the required blur circle in microns:

Blur Spot (microns) = (C x M) / (P x L)

Where C is the size of the (cropped) image on the sensor; M is the distance ratio compared to a ‘normal’ 10in viewing distance, ie if you intend to view at, say, 24 inches away, M would be 2.4; P is the print size; and L is the number of line pairs per mm that you are using as your ‘eye sight’ criterion (typically between 5 to 8). Note you should keep C and P in the same units, eg mm or in or whatever.

As an example, let’s assume we are looking to create a 16 x 20 in (ie about 500mm wide) print, that will be seen in a gallery (so we will use 8 lp/mm) at the closest viewing distance of, say, 24in, and that our image is taken from a slightly cropped area of our full frame image, with a cropped (sensor) dimension of about 30mm (out of the 36mm total sensor width).

The suggested blur spot may be estimated as: 30 x 2.4 / (500 x 8) = 0.018mm (18 microns).

Obviously this is much smaller than is suggested by the generic web number, ie some 29 microns. By the way, the 29 micron (generic number) may now be seen as indicative of 5 lp/mm viewed at 10in; in other words the web-based advice is at the lower end of our acceptable sharpness and eye sight. In other words, OK for snaps and blogs, but maybe not judges!

So what should we take from the above?

For ‘normal’ (print) photography needs, eg images presented on a PC you should use a non-lp/mm approach, ie simply use a 29 micron blur spot for a full frame (and scale down according to your camera’s crop), ie accounting for out of focusness and diffraction. If you need to manage your (print) image presentation to a more exacting standard, eg because you wish to account for cropping etc, or to cover a judge’s scrutiny, or ensure a gallery hanging is optimised, then start with the simple formula above to estimate your combined/total blur spot.

Let’s now return to the real point of this post: what is the optimum Magic Lantern based focus stacking workflow for (exacting) landscapes. BTW there is a key point here: we are not shooting fast moving or changing scenes. We are enjoying life and capturing images at a leisurely pace: taking in nature’s beauty as we capture some, hopefully, award-making images :-)

As I have discussed ML in some detail in previous posts, I won’t bore you by repeating all that ‘stuff’ again. I’ll also assume you are a Magic Lantern user and familiar with the power of ML. So here, based on my experience and experimentation, is the optimised focus stacking workflow for landscapes (based on my 5D3 set up). That is capturing the maximum sharpness your camera-lens system can achieve, over its entire focus range:

  • Using the simple formula above, estimate your case-specific blur spot. Or simply use the ‘default’ full frame blur spot of 29 microns; 
  • Go to the ML DoF sub-menu, under the focus menu, and enter the blur spot (unfortunately called circle of confusion in ML). Also ensure diffraction aware is selected. Note the ML nightly assumes a visible band camera. You will need to change the code for an IR camera (if you look in the ML source code I have suggested a number);
  • Also in the focus menu select follow focus and (under focus settings) select the follow focus controls that work for you, ie +/- or -/+. BTW this workflow requires a lens that reports focus length and distance, ie not a manual lens;
  • Ensure you have ETTR switched on. I personally prefer to not use the mid or shadow S/N options, ie I put these to zero and, usually, put % highlight to a low number, eg 0.1% or so. If you leave mid and shadow S/Ns at non-zero you will risk overexposing highlights. The reason I adopt this strategy is I can also decide, after a test image, to use dual-ISO or Auto-bracketing if I need to, ie if I have a very high dynamic range scene;
  • Switch to LV and you should see two things: depth of field and focus distance being reported, towards the lower right of the LV screen; and the follow-focus controls should be in the middle of the screen;
  • Take an ETTR reading and decide if this is acceptable. If you feel you are unable to capture the full dynamic content of the scene, then augment with dual-ISO or Auto-bracketing (see previous posts on how to optimise auto-bracketing or dual-ISO captures);
  • Compose your scene: this one is down to you!
  • Now the magic starts. Using the (on my 5D3) ‘joy stick’ toggle, move the focus to the macro end and until the soft stop is reached. Toggling up and down moves the focus faster than left to right;
  • The depth of field will now report the focus distance between you and your closest focus point, as well as the distance from you to the nearest and farthest depth of field points. Note the largest DoF number, ie the distance from you to the farthest DoF point;
  • Capture the first image;
  • Using the follow focus controls (note you could use the lens ring but the follow focus controls are more exacting) move the plane of focus such that the nearest DoF distance is now slight less than the farthest one you just remembered;
  • Capture another image and repeat the above until ML reports that your farthest DoF is infinity, Graphically you have achieved this:

It’s as simple as that!

All that is required now is for you to use your favourite post processing software to blend the images together.

As this has become one of my longest posts, I’ll simply stop writing here! As usual, I welcome feedback, including any questions you may have. Please feel free to comment below.

Sunday, June 14, 2015

We’re all human!

A friend from my camera club (thank you Stan) pointed out a silly mistake that weaved its way into my last two posts (now corrected). Namely that my ‘new’ Mamiya 45mm is ‘equivalent’ to a 28mm lens on my 5D3.


In my enthusiasm to talk about the LE potential, I made a silly extrapolation and didn't stop to think.

We are all aware of the so-called crop effect, ie when, for example, we use a 100mm full frame focal length lens on, say, a 1.6 crop APS-C body. That is the 100mm full frame lens on the APS-C body has the field of view of an 160mm lens on the full frame body. The lens, however, is still a 100mm focal length lens: on both bodies!

The thing that is changing is the sensor size: full frame vs APS-C.

So, my Mamiya lens, attached to my 5D3 by an adapter to ensure focus is achieved at the sensor plane, is still a 45mm lens, and because I’m not changing sensor size, the Mamiya 45mm on my 5D3 looks like a 45mm focal length on, say, my 24-105mm F/4L. 

Another way of looking at things is the Mamiya is acting like a tilt-shift lens with no tilt of shift! That is, I'm not using all the glass that is in the lens. 

Mistakes are the portals of discovery.
James Joyce

Saturday, June 13, 2015

Further LE Experiments

Note: this is a slight rewrite of the original post to address an 'error' that had crept into my thinking. 

There are two types of long exposure (LE) photographers: those that shoot up to 32s and those that go beyond the ‘barrier’. I spilt the LE world this way, rather than say those that use ND filters or don't use ND filters, as capturing up to 32s is relatively simple. Up to that exposure we can rely on the in-camera metering provided by the manufacturers. 

Beyond the 32s ‘barrier’ is the Bulb World!

One simple way to get into the Bulb World is to exploit the so-called exposure triangle. Thus, if I set an in-camera exposure of say, 4s at an ISO of, say, 800, this is the same as an exposure of 64s at and ISO 100. You can also use aperture to achieve a similar result. You still need to time things yourself, with or without the help of technology, eg the ML Bulb timer, ie Canon is of no help to you!

The problem with the above approach is that it assume the ‘test exposure’ can be achieved. At night this is likely to be the case. But what about in bright sunshine?

For example, let’s assume we are using the tried and test ‘sunny 16’ rule: shutter speed at F/16 is the reciprocal of the ISO. Thus at F/16 and a base ISO of 100, I would shoot at 1/100s; and be pretty confident this would a reasonable exposure: not optimum maybe from an ETTR perspective, but OK.

For bright conditions, where the base exposure can’t be pushed slower than, say, tenths or hundreds of a second, we need the help of neutral density filters (NDs).

Ignoring graduated NDs, there are two basic types of ND: a fixed density ND and a variable density ND. The advantage of the fixed is that it imprints no exposure artefacts, other than a colour cast sometimes, to the captured image. The variable ND, however, if used at the extremes and on a wide angle lens, may/will create the dreaded X-effect.

After various experiments I have settled on the following front ND set (used with step up rings):
  • 82mm ND 8 (3 stops)
  • 82mm ND 16 (4 stops)
  • 82mm ND 1000 (about 10 stops)
Together with a rear Vizelex ND 2-10 stop filter, which I need to use with my Mamiya 45mm 645 lens.

On my trusty 5D3 the combination, with the Varavon Multi Finder LCD Viewfinder, looks like this, which shows the rear mounted Throttle with a front mounted ND filter.

My base set up procedure is simple. According to the environmental conditions, and the end exposure I’m seeking, I choose the front mounted ND to create a base (ISO 100 and F/16) exposure of a seconds to a fews 10s of seconds, with my Throttle set at the lowest stop setting, about a stop down from an ND 0.

With this set up, I can use the rear mounted variable ND to dial in any exposure I wish. Although the Throttle has a 2 to 10 Stop range, because of exposure artefacts towards the max end, I don’t go above about 9 stops.

Thus, if, say, I wanted an end exposure in the 400s range, I would set my front NDs up to give me an ISO 100 base exposure (at ND min on the Throttle) of about 10-15 seconds. Then, once composed and focused, I would dial in the Throttle ‘stoppage’ to achieve the 400s (or more, or less) effect I was looking for.

It all sounds to simple: and it is! There are a few complications.

First, what about focus. Well, for me I tend to use a hyperfocal strategy. Thus at 45mm and F/16 I focus at about 22ft.  

This leaves setting the exposure and working around one problem with the Throttle: the variable Stop increments are not that linear.

I could revert to a trail and error approach, but why bother when you have Magic Lantern. There is an ND module, but this is not yet incorporated in the nightlies.

Then there is the ML Auto ETTR module, but, until now, that was limited to shutter speeds up to 32s; after that the ETTR algorithm would increase ISO. That is you couldn’t do LE work above 32s using Auto ETTR.

In the last few days, Alex (one of the ML gurus) has tweaked the Auto ETTR algorithms such that you can now dial in Bulb limits up to just over an hour! The Auto ETTR will now find a solution up to that shutter time, before increasing ISO. At the moment the tweak is only in an ML fork, so you need to compile things yourself: which is what I did this morning.

After a few false starts, working out how to use the new Bulb-based Auto ETTR, I converged on the following workflow:

  • Set a Canon exposure of a few seconds in M mode (this will be the exposure that the ETTR algorithm will use to estimate the LE);
  • Set Auto ETTR to AutoSnap (which will take a test exposure and then automatically the LE one, based on the ETTR calculations);
  • Press the shutter and the ETTR will take two images. The first will be at the shutter that you dialed in, which will usually be underexposed and then the ETTR LE;
  • Review the image and adjust the variable Throttle as required and take another image pair (note after ETTR the mode dial will be in M, but the Camera will be in B mode. To reset, simply move the Mode dial to B and back to M.
It is early days regarding the new ML LE ETTR mode and I will be carrying out more experiments. However, here is a crude test image, ETTRed at 240s on a windy, but bright mid-day, ie the trees are all moving! The Sunny 16 exposure would have been about 1/100s without any ND filters, ie I was using just short of 15 stops of combined front and back ND.

Thursday, June 11, 2015

Experiments with a different format lens

Note: this is a slight rewrite of the original post to address an 'error' that had crept into my thinking.

All photographers are aware that sensors smaller than a full frame 35mm, come with a ‘crop factor’. For instance, my 50D has a crop of 1.6, meaning that my 500mm full frame focal length lens on my 50D ‘looks’ like an 800mm lens, compared to the 500mm on my full frame 5D3.

For instance, a 645 format (56 x 41.5mm) has 2.6 times the area of full-frame 35mm (36 x 24mm), or a 0.62075 crop factor. In other words, a 100mm lens on 645 sees about the same angle of view as a 60mm lens does on my full frame 5D3. But, see below.

Although there have been adapters for 645 lenses, the latest adapter from FotodioxPro has the advantages of a built in ‘throttle’, ie a 2-10 stop variable ND filter.

So, intrigued with the technology as usual, I found a cheap Mamiya 45mm 645 lens on eBay and purchased the FotodioxPro 645-EOS Throttle.

It all arrived today and first impressions are favourable.

The 45mm Mamiya lens seems 'clean'. The lens is a manual aperture lens, which isn’t an issue as the throttle is passive. Ałso, as I'm not changing sensors, the 45mm Mamiya acts like a 45mm EOS lens on my 5D3.

Using Magic Lantern RAW histogram I was able to set up the desired exposure at, say F/2.8 and an ISO of, say, 400. Then simply ‘correct’ the exposure time for my F/16 image at ISO 100, ie 90s exposure.

Here is a B&W test image, taken in sunshine at 90s.

It’s early days and I’m sure I will find some problems: for example I have a second hand lens that I’m sure has some dust in it, but it seems clean from fungus. I’ll post more feedback in future posts.

Sunday, June 7, 2015

Simply sharing an image of a beautiful creature

As I had a few minutes spare this weekend,  I thought I would revisit some of my Bosque Del Apache images, and in particular those where master falconer Matt Mitchell flew some of his wonderful birds for us.

If you have not tried taking images of flying birds of prey, then seek out a falconer and try your luck: you won’t regret it.

For me I was lucky to have Matt and his rescued  birds. Matt is a native New Mexican, and also an artist, drawing his inspiration for his hand carved fetishes from his early love of wildlife.  He has been a master falconer for the past 40 years along with breeding hawks and falcons for over 20 years.

This capture of one of Matt's Harris Hawks, with it's square close in crop, was taken with my Canon 5D3 with a 70-200mm F/4L lens.  I used a base ISO of 100 and a Magic Lantern Dual-ISO setting at 100/800, with an aperture set at F/9. The shutter speed was 1/1000s.

I simply hope, like me, you just enjoy the beauty that nature provides us.

Wednesday, June 3, 2015

Looking for another ‘tripod’ solution?

Like many photographers, I have too many bags and too many tripods: I estimate about eight tripods, although to be fair some of them are rather toy-like. So it should be no surprise when I tell you I just took delivery of my ninth ‘tripod’.

I say tripod, however, this is pushing the meaning a little. Nevertheless, I believe my latest ‘tripod’ is a great find and one I can recommend. It is the platypod pro from a company rather innovatively called: :-)

Here is a picture of the platypod pro, which is not supplied with a head. Rather than attempt to explain it here, if you go over to their site you can see a video of the product.

Like many I think it is one of the best travel ‘tripods’ I have tried. It is small, robust and adaptable. It is ideal those places that don’t allow tripods, ie it will just look like a small pouch. Once through ‘security’ you can quickly get out the platypod pro and use it non-intrusively wherever you wish. Even in use it is unintrusive and should therefore survive scrutiny.

It is usable on ‘any’ surface and is great for the floor. The following (usual) boring image of our kitchen, which I just took with my 5D3 and my 24-105 F/4L on the ptalypod pro, shows one use case, ie a tabletop ‘tripod’. BTW the image is focus stacked image of three images, taken with the aid of Magic Lantern’s Auto-ETTR and the diffraction corrected DoF feedback. The exposure was 1.6s at F11 and ISO 100.

Bottom line: the platypod pro is a great addition to any photographer’s growing collection of tripods :-)