Sunday, August 24, 2014

The New Mexico Badlands

About an hour and half outside of Albuquerque is a little know area called the El Malpais National Monument. The name El Malpais is from the Spanish term Malpaís, meaning badlands, due to the extremely barren and dramatic volcanic field that covers much of the park's area: which can rip you to pieces if you are not careful.
Wikipedia tells us that the lava flows, cinder cones, and other volcanic features of El Malpais are part of the Zuni-Bandera volcanic field, the second largest volcanic field in the Basin and Range Province. This volcanically active area on the southeast margin of the Colorado Plateau is at the intersection of the Rio Grande Rift Basin, with its deep normal faulting, and the ancient Jemez Lineament. These two features provide the crustal weaknesses that recent magmatic intrusions and Cenozoic volcanism are attributed to.

The rugged Pahoehoe and A'a' lava flows of the Zuni-Bandera eruptions (also called the Grants Lava Flows) filled a large basin, created by normal faulting associated with the Rio Grande Rift, between the high mesas of the Acoma Pueblo to the east, Mt. Taylor to the north, and the Zuni Mountain anticline to the northwest. Vents associated with these flows include Bandera Crater, El Calderon, and several other cinder cones; more than a dozen older cinder cones follow a roughly north-south distribution along the Chain of Craters west of the monument.

For me visiting El Malpais was another opportunity to carry on exploring my IR converted 50D, with a 10-20mm Sigma lens. Because of the IR conversion one has to be careful about ‘hot spots’ and flares. Luckily my Sigma 10-20mm f/3.5 EX DC HSM is ok regarding hotspots but may exhibit flares if I’m not careful:
I had been experimenting with Magic Lantern Auto-ETTR settings and had decided that a clipping setting of about 1% seemed to be a good compromise. However, after reviewing the RAWDigger data (see below), I’m now not so sure. Clearly I need to look into the clipping settings a bit more and will report on my experiments in the future.

The RAW image for the histogram above looks like this:

After processing in Lightroom, Photoshop and Silver Efex Pro II it looks like this:

Finally here is another image from the El Malpais shoot.

Wednesday, August 13, 2014

Update on the latest Magic Lantern Bulb ND LE module

In an earlier post I spoke about the new Long Exposure module from David Milligan ( ). David has now tweaked the module and it is now accessible under its own menu (under the ML Shoot menu) and has some new functionality: namely a way to calibrate your ND or ND stacks.
To calibrate your NDs, which you only need to do once, simply take a normal photo of constant exposure scene, ie one that is not going to change over the calibration and follow the instructions under the “Measure ND” sub-menu, ie dial in your manufacture’s ND Strength field, press Measure ND and follow the instructions (be sure to have the Canon Info screen on or be in LV).

For me I found the following:

  • ND1000 = 10Ev drop, calibrated at 10Ev;
  • ND 16 = 4Ev drop, calibrated at 3.5Ev;
  • ND 1000+16 = 14Ev drop, calibrated at 13.5Ev.

Knowing the calibrated figures, I can confidently capture LE exposures, which I do with the following workflow: 

  • Take off any filters, ie including any (UV) ‘sacrificial’ ones; 
  • Compose and focus without any ND filters on; 
  • Select aperture and ISO, ie for LE you will usually be using the base ISO of 100; 
  • Consider the need to select exposure lock in the ML Expo menu (this allows coupled adjustment of exposure settings); 
  • In the ML Bulb ND menu set your ND value (ie 3.5 or 10 or 13.5 for me).; 
  • Ensure ML Bulb ND is on and you are in M mode, ie not Bulb;
  • Select ETTR and ‘grab’ an auto-ETTR exposure, or choose your own exposure setting; 
  • Assuming you have the info screen on your camera’s LCD turned on (or be in LV), you will see the ‘ND exposure time’ in the top left hand corner of the camera’s LCD; 
  • Adjust the aperture and/or exposure time to ‘tune’ the ND time to achieve your artistic vision; 
  • Carefully attach the ND  filter (mine screw on); 
  • Press the SET button and hold until you see the ND bulb timer count down start.
Another great in-camera ML function: many thanks to David Milligan, one of the ML Hero members!

Tuesday, August 12, 2014

False Colour Digital IR Processing

In this post I want to talk about digital IR processing, and in particular how to ‘recover’ some of the colour in the scene.
Before discussing the process, however, it is worth saying that not everyone likes the IR false colour effect. If you’re one of those, then stick with the monochrome approach; hint use Silver Efex Pro II.

To recover colour you first need to ensure your IR conversion, or if you are simply using an external IR filter, still has some colour information being recorded. My 50D conversion from is a standard IR one, ie with only a hint of colour, but sufficient to get some colour recovery.

The first port of call is the camera. If you do nothing, other than leave the camera on its ‘normal’, RAW, ie don’t capture in JPEGs, settings, you will get a very red looking image. As you are shooting in RAW, this is not critical, it just makes in-camera reviewing a little more difficult.

To address this there are two things to consider. 

First set up a custom WB by filling the frame with green (living!) grass in sunlight; and use this image to set a custom WB.  

Despite the in-camera custom WB, the camera LCD review will still look weird, but at least you wont have a strong red cast! These two images show a normal sunshine WB compared to the (grass-based) custom WB. These also illustrate what the RAW looks like before post processing.

Remember these WB settings are only impacting the review JPEG. Such in-camera WBing has no permanent impact on the RAW file. In other words, it is questionable whether it is worth doing, especially if using ML’s Auto-ETTR (see below).

Sunshine WB
Grass-based Custom WB
Second, if the red-cast worries you, consider switching the image preview to monochrome. In fact, as an aside, try setting the image review to monochrome for normal colour photography as well: it will help you not be diverted in your composition by colour.

As for capture, be wary of two things: focus and exposure. Your auto focus mechanism will be thrown off by the IR spectrum; so use Live View or calibrate your focus mechanism to the IR-biased world. Note that the focusing Apps at allow you to factor in the IR dimension when calculating hyperfocal distances.

For me exposure is a non issue as I use Magic Lantern’s Auto-ETTR to nail the exposure: I find a 1-2% clipping works well.

Another trick is to set up a custom camera profile for initial use in Lightroom. The way to do that is to download the Adobe DNG Profile Editor and create a custom profile, which should be placed in the appropriate LR profiles folder for your system set up, eg Mac vs PC. Rather than go through it here, check out this link:
A final post processing trick, if you want some sensible looking colours in your IR image, is to carry out a Red/Blue channel swop in Photoshop, or some other image editor that allows channel swopping.  Hint set up an action to speed things up, ie I have allocated F12 for colour swopping and thus the process is a single click.

Having swopped the channels you can now post process further in Photoshop, Lightroom or your favorite Plug-in, knowing one of your image’s environmental anchours, the sky, is a sensible colour, ie blueish!

These final two images illustrate the ‘false colour’ IR effect: as I say, not to everyone’s taste!

Sunday, August 10, 2014

More experiments with IR

One advantage of living here in New Mexico is that the photons just rain down! Thus, at midday, when most photographers are running indoors and waiting for the evening sunsets, I’m out there with my IR converted 50D.

There was a custom car show this week at the Route 66 Casino, just outside Albuquerque, and the sun was bright: perfect for IR photography.

I’m still perfecting my settings, however, I tend to rely on Magic Lantern for the exposure and that means using Auto-ETTR. Focusing is a little more complicated, although it is made simpler by shooting at 10mm, ie it’s difficult to get an out of focus shot at this focal length.

As for post processing, I tend to create a ‘flat’ image in Lightroom, ie lower contrast, and fix the white and black points. Then to Silver Efex Pro II to look for that black and white vision.

The three images below are single captures, ie no bracketing, and finished off with the workflow above. Although with the third one I tried a different look.

I hope you enjoy them.

Another great Magic Lantern feature

As those who read my posting know, in addition to the increased functionality that Magic Lantern brings, it also allows us to travel lighter

For those that take long exposures using ND filters, you will most probably calculate the ‘ND shift’. ML can offer some automation via Auto-ETTR, but if you use high ND densities, eg 1000+, Auto-ETTR will likely not get a solution.

Now, thanks to one of the ML coders (David Milligan) we have a new, in-camera, module for the LE photographers.

For those that are interested this is how I use the new module: 

  • Rather than rely on the manufacture's data, calibrate your NDs or ND stack ups. You may find you didn’t need to do this, but it’s worth a one-off check. We’re only looking for ‘measurable’ differences, eg more than 0.5Ev, say; 
  • A simple way to do this is to focus on blank (single colour) surface, eg fill the frame with a wall. In my case with two NDs (1000 and 16) I took the following images on manual:
    • No ND filter (0Ev), Tv =x 
    • ND 16 filter + 4 stop adjustment on x 
    • ND 1000 filter + 10 stop adjustment on x 
    • ND 1000+16 + 14 stop adjustment on x 
  • Load the test images into LR, or eye-ball the histogram on the camera, look at the luminosity histograms and compare the peaks or the right hand side if you use A-ETTR to set the exposure. Note the deltas and, if significant, note the ‘corrected’ ND values, but don’t worry if less than +/- 0.5Ev; 
  • One final adjustment is to ensure that A-ETTR is not allocated to SET, as this conflicts with the ND module, ie move it to double-press; 

  • To use the new ML module it couldn’t be simpler than this: 
    • Focus, compose and set the exposure, either manually of using A-ETTR; 
    • Add on your ND; 
    • Enable the Bulb timer in the ML menu and enter your (corrected) ND filter value, note the new exposure is shown on the LCD screen, and press and hold SET until the ND module initiates its bulb countdown; 
    • Go and have a cup of coffee if you have a long exposure set.

As a final ‘extra’ from me, if you are doing really long exposures you may see ‘light contamination’ through the eye piece: some believe this happens other don’t. On the safe side use Garry’s ‘copyrighted’ ‘DLSR Eye Patch’; which is made from a piece of black fabric and a Velcro strip. It fits any DSLR, even non-Canon ones! Free user rights to friends :-o)