Infrared photography – Nunhead Cemetery

Not having been out and about photographing for the fun of it for a while the thought came to me a while ago that I’d like to give another go at doing some IR photography. I’d bought a Cokin IR filter a while ago and so had the kit already.

Also – living close to it but never having visited I thought that Nunhead Cemetery would be a good spot – Graveyards always look good in IR.

If you’re not interested in techie photography ramble and explanation – just jump to the end to see my photos.

 

Equipment

Equipment used (and had already):

• Nikon D800
• Nikon 24-70mm
• Cokin P-series filter holder + 77mm adapter
• Cokin P-series IR filter (P007)
• Remote shutter release (3rd party wired from eBay)
• Tripod

The problem with trying to shoot Infrared with standard D-SLRs is that in front of the sensor they have a IR/Low-pass filter. Although it doesn’t block ALL IR  light – it blocks much of it.  So if you’re not going to go to the effort/expense of converting a camera and taking this out – you need to use an IR filter, which only allws IR and near-IR light in, and have a fairly extended exposure time.

There are numerous filters on the market – I just happen to have a Cokin P-series filter. I bought this a while ago as the advantage of Cokin filters is that you buy adapter rings for the holder and so you can use the filters (panes of glass) for different sized lenses – thus saving on the expense of buying multiple filters. At the time I invested in this system Cokin were only doing A and P-series filters – A being small and P larger in size. They now also have Z and X series which are even larger. P-series are rated up to 82mm – but there are issues when shooting wide-angle lenses.

Reading up online it seems that the Cokin filter isn’t the best of the IR filters available commercially – but it’s the one I have. Sometimes they’re rated in terms of light frequency they will block.

 

Setup

So – I have a D-SLR with a filter to cut out IR wavelengths, and in front of it I have a filter to only allow IR in. This means that exposure times need to be quite long to get enough IR light to give a decent exposure – hence using a tripod and remote shutter release to reduce/stop any camera movement.

I found that when shooting wide-angle alas the Cokin filter holder would cause a vignette – although shooting IR and the camera warm – the Vignette would be light rather than dark.

 

Taking a picture

Tripod – check

Remote shutter release – check

Eventually I changed the camera setup so that it would shoot after a Mirror lock-up just in case that cased vibration.

After a while (it was light out – seeing the LCD screen wasn’t great) I realise that there was some lens flare happening on the filter. Due to the filter holder I was unable to put a lens hood on. Additionally – because there is a slight gap between the filter and the lens – the lens flare (or filter flare) was even happening when pointing away from the sun – the sun was getting into this gap. So I would stand in-between the sun and the camera. However thinking it might be interesting – I also took shots allowing some flare to happen.

Focusing : Because the IR filter is so dark – the camera has no way of focusing using traditional methods – so you have to focus before putting the filter on.

So my procedure for a new shot was:

1. Set-up tripod + camera
2. Frame shot (without IR filter)
3. Focus
4. Switch focusing to Manual (if using autofocus originally)
5. Put IR filter in the holder
6. Close viewfinder cover (in case extra light got in)
7. Take a picture
8. Check Picture on LCD. However this was hard to judge in the light so often viewed the histogram and trusted this.
9. Repeat with exposure changes, and sometimes compostion/orientation changes, and on occasion – allowing flare.

I found that the exposure values I often used were:

All:
ISO: 100
Focusing: Manual
White Balance: Auto (I think – didn’t change it.)
File type: RAW

Wide depth of field:
Aperture: f8
Shutter speed: 20-30seconds

Shallow depth of field:
Aperture: f2.8
Shutter speed: 6sec-10sec

Of course – these values will vary for other cameras depending on their IR sensitivity and the amount of IR light/heat etc.

Should have done:

LCD Loupe: It would have been handy to have a LCD loupe (e.g. Hoodman Loupe) to be able to see the results on the back of the camera.

White Balance: After reading sites online on how to process IR images I realised that I should have, or at least tried to, set a white balance on the camera. With IR filters a little red light still comes through and so pictures usually appear with a red tint. It seems it might be possible to remove this using a custom white balance. It obviously won’t be the standard light colours but should be more interesting than just white. More of this in Processing section.

Focusing: Have read somewhere that focusing should be done differently from my method of focusing without the filter initially – the reason being is that the IR wavelength is significantly different from visible light. Not sure how much of an effect this is. I did notice that if I switched to live-view that the LCD did actually show an approximation of the picture I’d get rather than just dark red! So maybe live view may have done a better job of focusing.

 

Processing

In the past I just converted IR photos to simple Black and White images, probably through Photoshop. However I thought I’d look up alternative methods – or at least the best way of doing it – possibly within Camera Raw – this lead me to all kinds of options – and included the tip about White Balance I mentioned above.

As per so many other things with digital photograph editing – there are SOOO many ways to edit things and so I won’t go into the options here – instead I’ll just cover what I did.

 

White Balance

In the past I’ve accepted the fact that the picture will look totally red because of the near-IR light getting in through the filter. However various guides online suggest it might be possible to set a custom white balance to correct for it in the camera – possibly using Live View. However….. I didn’t do this.

So the usual way I set white balance is with Camera Raw – however within itself Camera raw isn’t sufficient on this occasion - the slider will only go so far – not far enough to correct for the VERY red picture. So this calls for an additional process. Some online guides suggest using an alternative RAW converter but another couple I read pointed at the method I eventually used : Creating a DNG profile, applying this first, then using Camera Raw’s own White Balance correction.

To use a DNG profile you need to:

1. A create a DNG file.

You can convert one of your RAW files to a DNG file using Adobe’s. There’s one for Windows, and one for MAC. It’s free but you need to register with Adobe and get a AodbeID. Creating a DNG file is fairly straight forward.

2. Create the Profile file

To create a profile I used Adobe’s DNG Profile Editor. Again free if you have a Adobe Labs ID, or after you register.

To create the Profile (also known as Recipe):

1. Open one of your DNG files
2. Change the controls on the right to the Color Matrices tab
3. Move the “White Balance Calibration” setting – “Temperature” slider all the way to the left. So the red picture turns more orange.
4. Export the Profile using “File -> Export” to the Camera Profiles folder of Adobe. Initially it selected the correct folder for me but trying just now it didn’t. On Windows 7 this is : C:\Users\<USER NAME>\AppData\Roaming\Adobe\CameraRaw\CameraProfiles\ Using a name that represents it’s use i.e. for IR.
5. Close the editor.

Here’s a picture of the slider:

Also the picture pre and post doing this.

To use this profile you then open your RAW picture in Camera Raw, go to the Camera Calibration tab – and select your new profile there – it should be in the list, e.g. (bottom of the drop-down) :

See profile: Nikon D800 IR Recipe.

After that the picture in camera RAW looks orangey. You can then use the White Balance sliders as normal – or the white balance sampler tool. Depending on where you sample this will turn parts of your image orange, and parts blue.

 

Standard Raw Processing

After the White Balance work you can continue with RAW editing as you normally would, for me this includes:

• Clarity
• Exposure
• Highlights
• Blacks

To get the most of the image.

Then open the image into Photoshop.

 

Channel Swap

A lot of blogs/guides then suggest swapping the red and blue channel. Not sure why – but this just works – maybe because it has a tendency to turn the sky blue rather than orange – which makes sense to our unconscious mind.

To do this either create a Channel mixer adjustment - or better a Channel Mixer Adjustment Layer. Then on the

Red Channel:  Change Red to 0% andBlue to 100%

Blue Channel: Change Blue to 0% and Red to 100%

So from:

To:

This changes a picture from:

 

To:

 

There were a couple of images that I didn’t do this to – they just seemed to work in their original state.

 

Other Editing

Then continue with your other editing.

Mine varied from picture to picture but some common edits included:

• Levels
• Curves
• Sharpening
• Adjusting Saturation (mostly reduced)

And that’s it really.

 

 

Pictures

And so finally – my pictures.

As mentioned above – these aren’t perfect – some have accidental lens-flare and some are on purpose – as after all I think it looks quite nice.

Click on them to see a larger image.

 

April 15, 2013 | Categories: Editing, Shoots | Tags: Camera Raw, Channel mixer, Cokin, DNG, DNG converter, DNG Profile, FIlter, infra-red, infrared, IR, Nikon D800, Nunhead cemetery, photoshop, post-processing, processing, Raw | Leave A Comment »