While the phrase depth of focus was historically used, and is sometimes still used, to mean depth of field, in modern times it is more often reserved for the image-side depth. Depth of field is a measurement of depth of acceptable sharpness in the object space, or subject space.

Depth of focus, however, is a measurement of how much distance exists behind the lens wherein the film or sensor plane will remain sharply in focus. It can be viewed as the flip side of depth of field, occurring on the opposite side of the lens.

Where depth of field often can be measured in macroscopic units such as meters and feet, depth of focus is typically measured in microscopic units such as fractions of a millimetre or thousandths of an inch.
The same factors that determine depth of field also determine depth of focus, but these factors can have different effects than they have in depth of field.

Both depth of field and depth of focus increase with smaller apertures. For distant subjects (beyond macro range), depth of focus is relatively insensitive to focal length and subject distance, for a fixed f-number. In the macro region, depth of focus increases with longer focal length or closer subject distance, while depth of field decreases.

It's the tripod that's the give-away. Tripods pose a potential liability issue for local councils when they are used in public places. Members of the general public might trip over them even though your know that it's unlikely. If you are shooting for a network it's best to make sure that you have releases from people who have identifiable  appearances in your footage.

There are a number of different styles of tripods available. Regardless of whether it’s the telescopic type or the dual tube type, always try to use a tripod/fluid head combination that has a "levelling head". A tripod that has a adjustable rising centre post is designed for stills photography – it has no place under a video camera.

Video and stills tripods consist of two parts – a tripod and a fluid head, however it is common to refer to the whole unit as a tripod or a tripod system.

Tripods with ultra-lite telescoping tubes are popular for use with video cameras – the height range is impressive and you can operate from almost ground level to over the top of crowds.  Setting up a tripod can be a little like setting up a deck chair, so it’s best to get in the habit of doing things in the right order. For this tutorial, we're using the Miller Solo DV 2-stage telescopic tripod which is the one of the best tripod systems available.

Stand the tripod on the floor, un-tighten the pan/clamp and raise the pan/tilt handle parallel to the ground. This gets it out of the way so you can proceed to the the following steps.

1. Lift the tripod and cradle it on one arm. Loosen the (larger) upper concentric lock on one leg and extend the tube to the approximate height that you’d like to work then re-tighten it. If you want to set the tripod to a higher position, then extend and lock the lower tube first then the upper tube. You can stand the tripod on the one extend leg to check if the height is right for you.

2. Once you’re happy with the height, hold the tripod as before and extend the other legs to match the length of the extended tube. Make sure that you tighten all three concentric locks. 

3. Grip two of the legs with both hands near the top of the tripod and place the foot of the third leg to the ground in front of you. Keeping that tripod leg in place and take a step backwards, drawing the other two legs towards you and placing them on the ground. Be sure that you pull the legs out to the limit of the leg angle limiters or built-in spreader.

4. Using a Miller DS10 system, you should firstly mount the rectangular camera plate onto the base of the camera with the supplied attaching screw. The screw should be tightened and there should be no slipping movement – the locating pin on the plate should prevent this.

5. Slide the attached camera plate (now securely attached to the base of the camera) into the recessed channel on the fluid head and make sure that the yellow securing lever has fully engaged to lock the camera onto the head. Tighten the smaller yellow slide channel lock on the side of the head to ensure the camera doesn't slide forwards or backwards in the channel.

6. Set the panning arm angle. Find a position where the pan/tilt handle feels comfortable. I find it handy to have an index mark on the head to find this position in the future. Try a few positions to see how it feels, but once you find the sweet spot, you should place an index mark on the head so you can angle the arm just where you like it every time. You’ll find that it feels comfortable and familiar when it’s set at the same position each time. 

7. You are now ready to level the tripod. You should do this by gripping the top camera handle in one hand, and loosening the main locking adjustment cup underneath the tripod head. You should now be able to roll the fluid head with the camera and adjust all angles so that the small spirit level indicator on the head is in the centre of it's circular index marks. At this point re-tighten the adjustment cup.

8. You now need to balance the camera on the head. This is done by loosening the black tilt lever on the side of the fluid head. This will let you tilt the camera on the tripod. You will probably notice that the camera will tend to naturally tilt backward or forward depending on the where the camera is seated on the fluid head. You need the camera to sit level to the horizen, so undo the yellow slide lock (near the camera mounting plate) and slide the camera forward or backward so that it sits in that horizontal position. Tighten when balanced.

You are now ready to set your tilt and pan drag settings with the small rotatable knobs. This is a personal preference, but when set correctly you should be able to make smooth slow or fast speed camera moves without jerking, and be able to start the move from a stationary position without having to apply excessive force.

This was a talk on lighting basics I gave to filmmakers about to shoot their first film for the annual Tropfest Film Festival held in Sydney in February each year. There are helpful suggestions on which lights are best for particular shooting situations (duration 05:22)

Sony RoughCut lighting talk from Pieter de Vries ACS on Vimeo.

The green screen should be set at around 3 meters from the subject and the larger the screen the better. Try to not compromise on this distance from the subject, even if it means choosing another location. 

This gives you separation from the screen and reduces the amount of green reflecting off the screen and onto the back of your subjects. This green contamination is a real no-no.

Light your screen separately. Lowel Tota-Lites are good for this however KinoFlos or Lowel Caselights are also very good. I position one to each side and run them through a dimmer to control the output. The plan is to get an even spread on the screen with each of the lights washing out any creases in the fabric if that's what you are using. Lighting the screen so that it's one stop darker than the subject is a good rule of thumb.

Once you are happy, light your subject separately using all the modelling with the light and shade that you would normally use. Keep in mind that strong back-light on the hair and shoulders can exaggerate the fact that’s it is a green screen shot when the final composite is done. When you have finish lighting the screen, turn off the lamps lighting your subject so you can check to see if any green is reflecting back onto the backs of the subject. A small amount of back lighting will generally take care of this problem. It's important to make sure that there is no reflected green from the screen falling on the back of your subject – if there is, it will come back to haunt you as the production manager coughs up the extra dollars for the editor to clean up the problems.

Even lighting

As an on-camera light, the Lite-Panel LED is hard to go past. The ability to trim the brightness for any given lighting situation is important and this light allows you to do that. The daylight balanced 50 degree model works best as an on-camera light in my experience.

Use a piece of CTO correction gel for the tungsten lighting situations but you will loose some output as you'd expect. It's perfect for a night shoot inside a car and the wider beam of the two is more versatile.

Rosco LitePads also work nicely and have the ability to fix any lighting holes; those places where you find hard hide a light. Interior scenes in vehicles at night are nicely taken care of with LitePads along with so many other potentially tricky situations. These are my favourite light because of the different shapes and sizes that are available.

The great thing is that when you use it, nothing feels lit. It just appears like you've gotten lucky with soft natural available light every where you point the camera and we all know life's not really like that. It's the balance of light's output on the subject compared to the background that's the key to making it work.

As long as you can get the light reasonably close to your subject, remembering that if it’s a daytime exterior interview it’s a little harder to fill; the ambient daylight level will probably be quite high in the first place. The small on-camera light panel is even good used as a key light in low ambient light situations. It’s in the great sunny outdoors that you find there is not sufficient output.

I’d go for the wider beam version. It performs better as an all round camera light, but you'll have to power it from a separate battery (9v to 19v) in say a waist bag, as the battery provided clips onto the back of the light and makes the camera far too top heavy. It's no Sun-Gun, but a beautifully subtle lighting tool for video.

© 2013 Pieter de Vries ACS

Photographic tripods consist of two primary parts – a tripod and a fluid head, however it is common to refer to the whole unit as a tripod or a tripod system. 

To get precision pans and tilts, you have to take the time to balance the camera once it is mounted on the fluid head. Australian manufacturer Miller Camera Support design and build a broad range of tripod systems so I will discuss the Miller DS10 Carbon Fibre system here. 

On the Sony PMW-EX1R and some other digital video cameras, you must be sure that  ALL OF THE MANUAL ADJUSTMENT icons are active if you want to have full manual control over your camera.

Iris, Gain, Shutter Speed and White balance settings and icons must all be in seen along the bottom of the screen. Do this by pushing the corresponding Iris, Gain, Shutter Speed and White balance buttons on the camera.

Here is why

The camera software assumes that any parameter that you don't see on the screen must be automatically adjusted by the camera. For example, if you have all of these settings active except the GAIN, the camera will automatically make a gain level adjustment for you when the picture is too dark. Even though you have control of the IRIS, it appears to be adjusting the light level automatically when panning to dark area of the scene. 

It's not the IRIS that is automatically adjusting here, it's the GAIN.

Finally, remember, "locking" the manual adjustments by sliding the switch to the HOLD position locks out ALL the adjustments, including the iris, which is the one thing that you usually need to have control over.

© 2013 Pieter de Vries ACS

A few years back I was filming a documentary with Mark Strickson a natural history director with Bristol based UK production company, Partridge Films. We were shooting sequences for Discovery Channel in Far North Queensland in Australia, and were at the tail end of a six week stint shooting "Deadly Crocs" with then relatively unknown Croc Hunter, Steve Irwin. Steve was the same then…and I claim little more than to have introduced him to the art of making and drinking decent strong coffee while we were camping. This may have been a catalyst to his rather odd presenting style.

Having finished most of Steve's sequences, Mark and I set up our tents by the South Kennedy River in Far North Queensland, Australia. We planned to leave early in the morning for a pleasant filming trip up the river in our small tin boat in search of Salt Water Crocs. The next morning we slowly motored up river heading north towards the mouth of the river. There were a large number of "Salties" sunning themselves on the muddy banks. This was encouraging. The river ahead divided, and on the bank where the river split, there was a large lifeless salty taking in the sun. Mouth open and rock solid, it lay motionless in the distance.

I decided to shoot initially from a distance to get a safety shot. This is the shot to get in case I the subject takes its leave. He or she could become shy and quickly slip into the water. I asked Mark to give me some forward motion with the motor to help stabilize the boat and then suggested he switch it off and allow us to drift quietly towards the croc. The resulting footage was smooth as I had my Miller Arrow HD tripod straddling the uneven floor of the boat. It appeared that this animal was very much at ease in the sunny spot and as I knew that I already had a few great shots in the can, I thought we go for the cream. With the tiny outboard switched off, we drifted into the bank with some assistance from the oars. The bow of the boat wedged into the muddy bank around two meters from our croc who was still very much in relaxed mode. 

I found an even closer handheld shooting position at the bow and decided to stabilise myself by quietly placing one foot onto the bank. The plan here was; one foot on the bank and the other in the boat. This prevented the tinny from sliding back off the bank. As I put my foot onto what I though was solid bank, my whole leg sank down, into the mud, all the way to my thigh making an obscene squelching noise! I couldn't pull it out – my let was in too deep and the suction was too strong. 

I whispered loudly to Mark to fire up the outboard and reverse rapidly to yank my leg out. I was there with one foot on floor of the tinny with the other leg buried and seemingly permanently imbedded in three feet of mud. The nine footer was only two meters away and now getting wary – I had nowhere to go. The outboard motor didn't start (have you ever know an outboard to start first go?) and by now I was making way too much noise. Had the croc decided to strike, it would have been curtains.

I'm happy to say that the option of grabbing me, a meal for the taking, was mercifully, not as enticing as the joy of continuing to lie in the warmth of the tropical sun. I can recall his/her eye slowly opening, a slow look to me then…. closing again and back to the business of sleeping. There is truly no way that I could have escaped. I did eventually extract the leg and so here to tell the story.

The trip back to the camp site was interesting. The tide had retreated and the river level by now was dramatically lower. What water there was, was a torrent that flowed the wrong way! We ended up having to carry the boat full of 16mm camera equipment over the rocks . Then we ran out of fuel!

Almost dark and in full view of the many crocs now forming a peanut gallery along the banks, we must have been a site for sore eyes. None of them moved off the bank to take us. I think by now they just felt sorry for us.

© 2013 Pieter de Vries ACS

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For a night shoot, often full of mixed light sources, use the pre-set tungsten/indoor camera setting. This will cover you for the lighting nasties that can play in the scene and it will look the most natural.