Early Days learning Photography, Depth of field
ByIt’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
