Tuesday, July 29, 2014

Long-Exposure Photography

There are many blogs out there with information on how to do Long-Exposure (LE) photography and the bottom line is simple: get yourself some Neutral Density filters. Of course the next question is how many? But before discussing this, there is another question to answer: why not a single variable-ND filter?
Cutting to the chase: it all comes down to how wide your lens is. In 35mm equivalence terms, if your lens is wider than about 28mm, you will likely see uneven skies. The reason is that the variable ND filters use two polarizing filters and if you move them to the maximum, you will likely be disappointed. So, although you can go from, say, an ND of 2 to 10 in a single filter, if shooting wide, just be warned.

So, as a wide angle shooter I decided to stay away from the ‘all in one’ solution and elected to buy two NDs: a 10-stop and a 4-stop, ie what many call an ND-1000 (really 1024) and an ND-16. Together giving me a 14-stop capability, which put in terms of exposure time would mean a 1/50 sec exposure being stretched out to some 330 seconds!

BTW for those of a mathematical disposition the governing equation is: tnd = to x 2ND

Where tnd is the exposure after the application of the filters and to the base exposure without the filters.

If you are reading this, I don’t need to tell you why you may wish to consider LE photography, eg: eliminating people from a scene or blurring water and skies for artistic impact. So the question is: how to go about it?

As usual with me, I look for ways Magic Lantern can assist me; and I’m pleased to say it can.

First ML comes with a built in bulb timer. Simply put the camera on its bulb setting and enter the desired shutter time. To initiate the LE time, do a half press of the shutter release for a couple of seconds, and ML does the rest.

The second place ML helps in in the matter of exposure estimating. 

Without ML, the usual approach, unless you are good at math in your head, is to use an App or a look up table. Simply note the exposure without the filter and look up the new exposure for the ND you are using. Or, if using an ND14 stack, double the shutter time 14 times in your head!

If you don’t wish to carry and App or a look up table, then ML can help you…at least a little bit.

For low NDs you will usually find you can use auto-ETTR, which is good out to short of 30 seconds. However, if you are using an ND-14 stack, ML ETTR will struggle to find a solution and certainly will fail beyond 30 seconds. 

But all is not lost if Auto-ETTR fails. You simply switch to using the ETTR Histobar hint and estimate the exposure manually: 

  • Compose and focus; 
  • Put the aperture wide open; 
  • Put the ISO at 100; 
  • Put on your ND filter, but if you have two as I do, only put on the densest one at this stage, ie ND1000 for me, unless I only need to use my ND16; 
  • Go to LV and adjust the shutter time until you see something sensible as an exposure, ie not 30 seconds, where it has maxed out, but up to, say, 10ish seconds, and an ETTR hint between 1-3 Ev; 
  • By noting the ETTR hint you know by how many stops to adjust your exposure, with or without the addition of a second ND, in my case the 4 stop ND16; 
  • So if my ETTR hint said 2Ev and my shutter was 0.5s, I would know I could comfortably increase my shutter speed by 2 stops to 2s, ie 6 clicks for me as I have set third stop increments on my camera. If this wasn’t enough I could then adjust my aperture, by another 2 stops, ie 6 clicks, and my shutter speed another 2 stops to account for the aperture shift, ie ending up at 8s. Finally, if I wanted to go further I could screw on my ND16 and adjust the shutter speed by 4 stops to 128s.

Below are a couple of experimental LE IR exposures taken at midday, ie for maximum IR impact. The base exposure on my IR converted 50D was about 1/100 second, ie easily handheld with my 10mm lens, but with the ND14 stack the exposure ended up at 150 seconds, ie I was on a tripod! You can clearly see the cloud and tree movement over the two and half minute exposure.

Bottom line: LE photography, a bit like timelapse, allows you to explore the world from a different perspective. Once again, Magic Lantern, in-camera, functionality has shown its worth, ie LE estimation and setting without the need for me to carry Apps or look up tables.

Sunday, July 27, 2014

Infra-Red Macro

As reported in a previous post, my IR converted 50D allows me to look at the world through a different part of the spectrum, ie the solar IR reflected world that normally we can’t see with our eyes

The beauty of an IR conversion, rather than using an IR lens filter, is that the camera can be used in a relatively normal way, hand held shutter speeds.

The other advantage of an IR conversion is that I can use all my lenses, including my Canon 100mm F2.8L Macro.

I’m still exploring our solar reflected IR world, however, it is clear from my early tests there are some unusual and mysterious images to be seen

 Gladioli #1

Friday, July 25, 2014

We miss the sea

Although we enjoy living at 7000 ft in the Albuquerque East Mountains, we also miss the shimmering seashore.
But that’s what Photoshop is for.

So, as I was trawling through my Lightroom memories this evening, I came across some images from last year’s Albuquerque balloon fest: the largest balloon convention in the world. 

So I imagined what the balloon fest would look like if it took place on the coast.

Just a bit of fun you understand!

Architectural Beauty

Many photographers have a natural affinity for landscape photography as it provides multiple layers of enjoyment, eg travelling, admiring a new vista, capturing the moment and then in post-production realizing your vision.
As a photographer who does not rush to capture a ‘mirror-image’ memory, ie a documentary record, I see the ‘data’ I capture in the camera as just that, data to be used in my digital ‘darkroom’.

Recently, I was therefore particularly fortunate to be allowed to photograph in a rather unusual landscape, ie an urban one. I will keep the location ‘secret’ for now, as I have only just started processing ‘the data’.

Due the nature of the buildings in the area, I have decided to process the data into two portfolios. The first will lean towards exploring the colour and angularity of the landscape; and the second will explore the landscape through black and white abstractions.

As is always the case with my post processing, I always ensure the data is mine, although not all the data is necessarily captured at the same time! I have said before, a single ‘raw’ photograph rarely captures feelings, it needs the maker to add something.

The image below is one of my first experiments in the colour and angles portfolio. I’m still searching for ‘the look’, but I feel that I’m on the right path. I would welcome feedback on this experimental image, as I’m sure there is more I can do with this rather unusual landscape.

Friday, July 18, 2014

Blue Hour at Buffalo Thunder

This week, whilst on a business trip, I stayed at the Buffalo Thunder Resort (BTR) just outside Santa Fe. This time of year in New Mexico is known for its monsoon storms, which typically begin in early July after several complex and dynamic weather phenomena collide. New Mexico receives up to half of its annual precipitation during the monsoon season. For me all this means clouds!
So I was particularly fortunate to be at the BTR, as the building’s lighting makes for a 'theatrical' foreground to the weather’s dramatic background, especially during the Blue Hour.

According to Wikipedia: “the blue hour is the period of twilight each morning and evening when the sun is a significant distance below the horizon and the residual, indirect sunlight takes on a predominantly blue hue. This effect is caused by the relative diffusability of short blue wavelengths of light versus the longer red wavelengths. During the blue "hour" (typically the period is about 40 minutes in length), red light passes straight into space while blue light is scattered in the atmosphere and therefore reaches the earth's surface.” So there!

But you don’t need to understand the physics to get the most out of the Blue Hour, although knowing when it occurs is important: http://www.bluehoursite.com/
As usual I was keen to see if my Magic Lantern additional functionality was going to be of any help; and I think it did. For instance, I didn’t need to bracket, so I set an ETTR exposure first and used Dual-ISO on some of the images, ie to handle the dynamic range.

One facet of Blue Hour photography is that it allows us to exploit complementary colours, which, unlike ‘harmonious colours’, that lie close to each other on the colour wheel, are opposite each other on the colour wheel. Thus we should be on the lookout for reds and oranges during Blue Hour.

The following single image captures provide a feel of the Blue Hour; well certainly at the Buffalo Thunder Resort during the New Mexico Monsoon season.