Digital cameras are amazing but one thing they don’t do particularly well, is cope with scenes where there is significant variance between the bright and dark areas (highlights and shadows). A classic scenario is the landscape photo and the sunset.  Have you ever photographed this type of scene and been left a little disappointed with the results? What normally happens is that the sky looks ok but the foreground looks dark or visa versa – the foreground looks good but the sky is overexposed, too bright and all that lovely detail that your eye saw, is lost. Our eyes and brain are much better at interpreting this type of scene. We have a high dynamic range (HDR) in our natural visual system. Digital cameras don’t however; They operate best where there are no extremes between light and dark. So why is that?

Cameras use metering to measure the amount of light in a scene and then either set or suggest an appropriate exposure depending on whether you’re in automatic or manual mode.  The way a camera meters is limited however! If you want to meter a landscape scene for example, you might set the metering mode to evaluative whereby the camera averages out the light in the entire scene. Alternatively you might use spot metering using a point at the centre of the viewfinder to measure light. With spot metering, you could point the camera at the foreground. The camera would determine the scene to be quite dark and set a bright exposure, or you could point the camera at the sky. The camera would then determine this to be very bright and set a darker exposure. Either way, whatever way you go about it, your final image will either have very dark areas in the foreground (dark areas such as fields) or very bright (blown out) areas in the background (areas such as sky).

One solution, HDR

High Dynamic Range (HDR) is a way to overcome this problem. This involves the photographer taking several exposures (shots) of the same scene. The images are then loaded into a dedicated software program that merges them together extracting the optimum exposed area from each. Typically, a photographer will set the camera on a tripod, set focus, aperture and ISO, then take an average meter reading which might suggest a certain shutter speed. The photographer will now take a range of shots using the shutter to adjust exposure. Typically 5 or 7 shots are taken across a range from under exposed to over exposed. The underexposed shots will render the sky beautifully while the over exposed shots will bring out the foreground. The shots in the middle of the range will render the mid-tones.

Where would the world be without examples

Disclaimer: This is my back garden, not known for it’s scenic beauty but nonetheless a great place to practice HDR:)  I setup the camera on a tripod around 4:30pm this evening. It was already dusk and so a decent landscape was a challenge. I set the ISO to 400, worked for a minute on a quick composition and get the shot in focus. I then put the camera into P mode, and took a meter reading. The camera suggested an exposure of f11 at 1/30th of second. I then put the camera into manual mode and decided I would take 5 or 6 shots at f11 ranging from 1/125th of a second (dark, under exposed) to 1/4 of a second (bright, over exposed). I ended up with the following.

(Click to enlarge)

You can see from the above that the under exposed images retain the detail and contrast in the sky but render the foreground as dark, while the over exposed images render the sky as blown out but retain the details and contrasts contained in the foreground.

When I was done, I came back inside and downloaded one of many HDR software packages. I chose Photomatix as it seems popular with photographers and gets good reviews around the web. The software itself is very easy to use. You just install it, load it, click ‘Generate HDR Image’, load in you range of exposures and from there follow the wizard. I had a few go’s and eventually started to get some nice results from playing around with the presets etc.

The result (click to enlarge)

I think you’ll agree, we have an amazing rendering of all the light range from dark shadows to highlights. You can see the foreground and its detail – it’s no longer a dark silhouette but you can also see the sky and all its glorious tones and details. I like landscapes, particularly sunsets. I met a couple of folks from boards.ie this morning and we went out to Renville to take some shots. The two lads gave me loads of pointers that helped me to produce this article so thanks Mark and Mike for all the help.

I came across light painting while searching YouTube for tutorials on photography and flash. The concept is pretty simple, put your camera into open shutter or bulb mode. Then within the area of focus use whatever light source you wish such as a torch to light your subject. Because the shutter is open, the ambient light needs to be as dark as possible (pitch dark if you can). If you light a torch and move it around in front of the lens, the streaks are recorded as just that – streaks or strokes.

I decided to use my faithful guitar once again for this experiment. I put it on its stand and setup the camera on a tripod. I set the camera to bulb mode, and focussed on the guitar with the room lit. Another of my cheap Ebay purchases that I was keen to try was a cable shutter release (about $10). I plugged that into my camera PC port and that allowed me to open and close the shutter without ever having to touch the camera (although being in a dark room it didn’t matter so much).  Then I got a small bicycle torch and taped some paper round it to better focus its light beam. Through trial and error it was continuously too bright so I diffused it a bit by taping tissue paper over it.

 
The bicycle light I used, I taped some card round it to focus its beam, then covered the opening with some tissue paper to soften or diffuse the light.

The setup, Camera set sideways on a portrait rig on the tripod. I composed and focussed the shot with the lights on, then turned them off before taking the actual shot. 

Once I had everything setup, it was just a case of turning off all the lights, then fumbling my way to the guitar stand, placing the light at the start point near the bottom of the guitar and carefully tracing my way round the guitar body and fret board. I found that best results were achieved if I pointed the light in towards the guitar rather than pointing it directly at the camera. It took some trial and error to determine how fast I needed to move the light round the guitar body but after some practice I started to get some reasonable results. When I had traced round the guitar with the small bike lamp, I then got a bigger torch and shone it round the base and floor, a little behind the guitar and a little in front (again very much trial and error). Finally after reviewing many results I decided the shot needed something else so I put my flash unit behind the guitar facing it and trigged that remotely. 

So to recap, while the shutter is open, trace round the body of the guitar with a small focussed light beam (bike torch), then shine a bigger torch down from above and light various parts of the guitar and the floor. Finally trigger a flash positioned behind the guitar – then close the shutter. All this is done in a pitch dark room so be careful. I will admit that at one stage I knocked the tripod over and my beloved camera went crashing to the ground. It seems to be ok but knowing my luck, some critical element inside the box will fail soon.   I really could have done without that!

The results

I ended up taking about 20 shots before I finally settled on one. Some of the discards are beautifully lit but too chaotic or whatever. For example I love #1 below because of the way its lit, shame about the mess of trails. Only for that it would be winner. The one I finally settled for is #2.

#1 (Click to enlarge)

#2 (Click to enlarge)

This is the one that I posted on my flickr page. I love the way the floor came out and the flash was pretty subtle causing a sensation being spot lit from above as well as casting shadows outwards from the guitar stand legs.

It’s been a while since I wrote, my apologies but all kinds of stuff got into the works and at one stage I nearly ground to a complete halt. But anyway here I am back with a new hobby – photography. When I say new I kinda mean it. I have been taking photos for years with point & shoots and digital bridge cameras but literally just aiming and pressing the shutter release. So I have a disk full of flat jpegs with blown out skies, graining, edge distortion and less than perfect focus. I have always been fascinated by photography, I’ve done quite a bit of reading on the subject. I remember a few years back discovering Bryan Peterson’s ‘Understanding Exposure’. I read it, read it again and then I knew I wanted to take up photography properly.

Enter the kit

I have a Canon 50D and recently invested in a few bits and bobs such as a Manfrotto Tripod and separate tilt and swivel head, I got my hands on a Speedlite 430EXII flash unit and that pretty much forms the basis of the hardware. I got the 50D with the 17-85mm f4.0 kit lens. Its ok but really I am saving for my first lens that I hope to have before Christmas which has to be the Canon EF 50mm f1.4 prime. It’ll give me razor sharp results if I stay above f1.8 but I cant wait to try out a few extreme DOF’s at 1.4 and see what its like to take photos in poor light situations such as gigs.

A few weeks ago I spent an hour on Ebay and picked up some lens hoods, a wireless Flash Trigger kit, a shutter release remote controller, a multi colour light reflector board and a battery grip for the 50D. Would you believe that the entire lot came to about $100, god bless Hong Kong. Mind you, during the week, I got the dreaded letter from Revenue in Dublin stating that I owed them import duty on the package and looking for me to send them the PayPal Invoice. I sent them “a” PayPal Invoice and got away with paying them €15 to release my package so no harm done. But buyer beware! If you are importing anything from outside the EU over €22, your package will be intercepted and you will be charged tax.

My first project, Depth of Field

Sounds great eh…my first project, Truth is I have been messing with the camera for a few weeks and trying out all sorts of experiments especially when I got my hands on the Speedlite, the wireless triggers and the reflector board – so calling this my first project is a little inaccurate. The truth is that its my first project to write about but I promise you I am an absolute beginner to using cameras in anything other than fully automatic mode.

Depth of field is all about the area of the photo that is in acceptable focus. You will often see portrait shots for example where the subject is in sharp focus and the background is nicely blurred, well that in a nutshell is depth of field. You control DOF by adjusting the cameras aperture which refers to the size of the hole used to allow light to pass through to the sensor or film. Aperture is measured in f stops and is a little counter intuitive. The larger the number – the smaller the hole. So f4.0 is actually a much bigger hole than f22. As you increase each f stop, you are halving the amount of light that gets into the camera. i.e. f5.6 lets in half as much light as f4.0, f8 lets in half as much light as f5.6 etc so it is a key element in exposure setting. Why is it counter intuitive like this?  Well very basically, f stops are measured by taking the focal length of the lens and dividing this by the size of the aperture, so a larger hole gives us a smaller number.  There are a few basic rules to remember

• The smaller the f number, the shallower the depth of field you’ll achieve.
• The closer you are the the subject, the shallower the depth of field you’ll achieve.
• The more zoomed in you are, the shallower the depth of field you’ll achieve.
• Depth of field refers to the area of the picture that is in acceptable focus with one third being in front of the subject and two thirds being behind.

I’m sitting here in my living room tonight, I look at my guitar and I figure, I could get a nice DOF shot looking down the fret board. I might put my left hand in focus and my strumming hand in the background out of focus. The room is badly lit with cold white light from an overhead bulb. So lets look at the setup and as they say a picture is worth a thousand words. This is a photo of the setup taken on my mobile phone.

The Setup (Click to enlarge)

 
Sorry its a bit dark, best I could do with the phone. On the left is the camera, mounted on the tripod. In the background I have setup the reflector board using its gold sleeve to reflect a nice warm light. I placed it in the guitar stand which allowed me to position and control it.  On the floor in front of the reflector board you can see a little black device, that’s the flash unit plugged into the wireless trigger receiver. The transmitter is sitting on the camera’s hot shoe. The guitar is lying on the table where I sit and strum it when the photo is being taken. I focussed the camera on the corner of a cardboard box that I aligned with the corner of the coffee table. So I knew then when posing, I should place my left hand and fret board roughly over the corner of the coffee table. I pointed the flash unit towards the reflector board at a shallow angle. I set the camera up to shoot 10 seconds after pressing the shutter release button.

So lets talk about settings. This photo is as much an experiment in lighting as it is about DOF. I have a reflector board and a reasonably decent flash unit so I am keen to learn how to use them. I have read many articles about flash and how to achieve better results through bouncing light off a surface and back onto the subject rather than blasting the subject directly which can result in harsh light and shadows. The flash wireless units are cheap little devices ($30) so you’d hardly expect them to transmit TTL and indeed they don’t, so the flash was set to manual mode. I toned it down almost two stops (1/2 – 0.7). The way the wireless trigger works is that it fires when the camera fires. The flash is pointing towards the reflector board at an angle so that when it fires, the light gets bounced off the board and back to the guitar / subject. Using the gold surface gives a nice warm light that is a little diffused or softened hopefully. I took the shot at 1/6 second with an aperture of f5.6 @ 85mm. I kept the ISO right down to 100. Of course the camera registered severe underexposure as it was unaware of the flash settings but through trial and error, the above combination started to give me some nice results.

The next challenge was to position myself correctly within the 10 second countdown to shutter release. I kept getting that wrong – the depth of field was quite shallow so the margin for error was tight but I kept at it. I think the shot I ended up with works. I am posting it here with absolutely no post production whatsoever. I have never pp’d a photo (yet) and that will be my next learning curve if I can get my niece Niamh (a Photoshop genius) to spend a few hours with me and get me started. It’s also been pointed out to me that as a student I can pick up a copy of CS4 cheap so that’s where I’m headed.

Enough already, show us the dam photo (Click to enlarge)

 
A quick word about some of the kit used. I got all the bits and pieces from Ebay. The stuff from Hong Kong is cheap as chips but it works just fine. The flash wireless unit works 100% of the time, it literally never misfires unlike some units I have come across.  Cheap and cheerful, at these prices if anything goes wrong – so what.

• Reflector board (It has 5 different coloured surfaces and folds away into a small pouch)  – $6
• Wireless Flash trigger unit. This is a little Gem, it allows you to remove the flash unit from the camera and place it anywhere while controlling it wirelessly. This particular unit is the CTR-301P – $27
• Lens hood for Canon 17-95mm Lens – $5