02 April 2014

New film: Scarborough & Whitby

Not exactly new anymore (shot and edited in August-September 2013) but this film was popular with the other members of Huddersfield Film Makers Club when it was entered into our annual competition last month.

Techniques used

For the first time I used exclusively Manual mode with a variable ND filter to keep exposures consistent, and slow enough to capture motion blur -- which I find looks great for fast-moving subjects like people and vehicles. The filter tends to confuse the camera's metering as to what the correct exposure should be (I think it errs on the side of underexposure) so I would use aperture-priority mode set to maximum aperture size, get a rough idea of what shutter speed would be suitable, and adjust to suit and take a few test shots. (For the shot of the fishers on the harbour wall at about 2:00, I must have left ISO on Auto by accident and it was adjusting exposure slightly, resulting in a mild flicker.)

Shots that didn't make the cut included a test with a Canon 75-300mm lens. This model was unstabilised and everything was mounted from the camera body, which meant it was very front-heavy. Even a gentle breeze would cause enough wobble to ruin the footage (with some odd motion blur as the lens bobbed up and down). Perhaps using long lenses would work if a rig was made where the lens was mounted, similar to Canon's large zoom lenses, but perhaps even more solid with a mount near the front glass.

29 March 2014

Judge dread: building up or knocking down

Creatives and judges have argued over subjective details of their work since the dawn of time, and the world of amateur film making is no different. This post is about judges' feedback and its value to the film maker.

23 August 2013

Crib sheet: ND filter effect on shutter speed

This week I had more numbers floating about in my head, this time about ND filters.

About ND filters

'ND' refers to 'neutral density', meaning that the filter reduces all wavelengths (i.e. colours) from passing through in equal amounts. Looking through the viewfinder the photographer sees a darkened image with no particular colour cast. ND filters are available in various strengths. Below I consider the effect of plain ND filters, rather than the graduated ones (which are used when you want to darken a particular part of the image, such as the sky). More info in the Wikipedia entry.

Stops, light reduction, filter numbers

I've always found it difficult to grasp the concept of 'stops' of light. When looking at various ND filter strengths I was getting confused by how much a stop was, when referring to shutter speed. The numbers below explain how to figure out what effect a given ND filter will have on shutter speed.

Daylight conditions

On a recent time-lapse shoot in changeable daylight conditions, I found when shooting in Aperture Priority mode at f/8, the shutter speed would vary from 1/640 in bright sun to 1/320 when cloud passed over. Afterwards I considered what effect on shutter speed and whether it would introduce any motion blur.

ND filter numbers

Hoya and many manufacturers quantify their filter strength by using a set of numbers that double: 2, 4, 8, 16, etc. Tiffen uses a different scale of numbers: .3, .6, .9. I was researching the Hoya style when I put together the numbers below.
  • ND2, ND4, ND8, etc refer to how much light passes through, as a fraction. So ND4 allows 1/4 of light to pass through. ND16 allows 1/16 through.
  • If you test your exposure without a filter, you can calculate what effect the ND will have. In my example above, an ND8 filter (in bright conditions, exposure normally 1/640) will slow the shutter to 1/80. ND8 allows 1/8th of the light through, which would extend the shutter time by 8 times: 640 / 8 = 80. In the lower light conditions, normally 1/320, with the ND the shutter speed would be 1/40: 320 / 8 = 40.
  • If you want to measure the effect of the filters in the units of stops of light, this is also easily figured out: 2 to the power of [stops] equals the ND number (and therefore division of light), for example ND8 is 3 stops: 2^3stops = ND8. ND32 is 5 stops: 2^5 = 32.

In practice

When shooting you need to know what the normal shutter speed for exposure would be. Then you can calculate what effect a given ND filter would have on the shutter speed. You're unlikely to have a vast array of filters so you'd have to make a judgement call on what is to hand.

What if you want to hit a target shutter speed? Say you want a shutter speed of 1/2 and you only have a ND16 filter. From the calculation above you can see that normal exposure should occur at a shutter speed of 1/32, which is quite slow for daylight. Perhaps you could achieve that with a tiny aperture, or if you were exposing for a dark area of the scene and didn't mind over-exposed areas elsewhere in the picture.

Maybe you're shopping for an ND filter to use in daylight conditions. Using the same f/8 aperture as above, you'd need the equivalent of ND320, something you can't buy off the shelf. There are ND128 filters available, but in square sheet form rather than screw-in filters, so you could use two of those stacked together (equivalent of ND256) and close the aperture slightly. However using multiple filters can introduce ugly reflections between the elements if the sun catches in a certain way. And using very strong ND can introduce a colour cast, which is more prevalent in cheaper items.

I hope this guide is useful. If you are looking for professional film making services (including time-lapse shooting of any duration from one day to several years), see the website for my new company: Construct Films.

14 August 2013

Crib sheet: Time-lapse calculation

While on a day long time-lapse shoot today, I wondered about how long my various cameras' card space would last and how much video I'd end up with. I had various memory card sizes. In the past I'd just work it out on the fly but today I thought a quick crib sheet would be useful.

Calculating video length

(assuming playback is 25fps, as it always is here in Europe)
  • 30 seconds interval = 5 seconds of video per hour of shooting
  • 10 sec interval = 14 seconds of video/hr shooting
  • 5 sec interval = 29 seconds of video/hr shooting
  • 1 sec interval = 144 seconds (2min 24secs) of video/hr shooting

How long before the memory card is full?

(assuming 1.7Mb per picture and actual card capacity is ~90% of nominal capacity)
(1.7Mb is the average file size of 'Medium Normal' quality on the Canon 600D, YMMV etc)
  • 30 seconds interval: 4Gb card in 17 hours, 8Gb card in 35 hours, 16Gb in 70 hours
  • 10 sec interval: 4Gb in 5.8 hrs, 8Gb in 11.6 hrs, 16Gb in 23.2 hrs
  • 5 sec interval: 4Gb in 2.9 hrs, 8Gb in 5.8 hrs, 16Gb in 11.6 hrs
  • 1 sec interval: 4Gb in 35 minutes, 8Gb in 70 mins, 16Gb in 141 mins (2hrs 20mins)

How long before the battery is flat?

Canon (or your camera manufacturer) will have their own claims about the number of shots the camera will make on a single battery. The typical battery capacity in my various Canon SLRs is 1200mAh.
In recent months I've been experimenting with battery technology, and I have a custom-modified battery pack which has a capacity of 6500mAh, and in my tests will last for 3700 shots. I also have a 9800mAh pack which I will test soon.

11 April 2013

The importance of having engaging characters

I regard the two Star Wars trilogies like many other fans: great original films, disappointing prequels. Until this week I'd never thought much about why that is, beyond the obvious facts that Episode I's political story is tedious and the vast majority of its acting is wooden.

This time last year a comprehensive review of Episode I: The Phantom Menace appeared on YouTube courtesy of RedLetterMedia. It is delivered alongside crude comedy and regular swearing but it also (unexpectedly) offers sound film making advice.

04 April 2013

Recent video experiments

A couple of new video clips of experiments I've been playing with recently:

'A Month of Rust' is a 30-day time-lapse shot in 1.5:1 scale macro; what you see in the frame is about 5mm across.

'Orbs' is my first attempt at combining CG animation and live action video.

28 March 2013

Video file containers

Anyone who uses video on a computer, from editors to casual users, knows that sometimes different video formats can be incompatible with software. Luckily all the major video player applications that come with a computer (e.g. Windows Media Player, QuickTime Player) or are downloaded from the Internet (e.g. VLC, MPEG Streamclip and many others) can play almost any video we throw at them. But if you want to know more about formats and their peculiarities, read on.

06 March 2013

New film: In Flight time-lapse

It's been a lengthy hiatus since my last post, and a while since I've edited and finished a film. Here is a brief compilation of time-lapse clips from a recent flight from Manchester to Shetland.

Music: "Interlude VII" by Ending Satellites (endingsatellites.com).

All footage is from stills shot on an iPhone 4S using the TimeLapse app. There is a free version which allows 50 shots to be taken at a time, which equates to about 2 seconds of video. Upgrade to the paid version to shoot unlimited images. The app works well, allowing you to choose image size and to lock the exposure and focus. The app recommends you switch on Airplane Mode to prevent any notifications or calls interrupting the shooting (and you'd have Airplane Mode on anyway during a flight); an interruption can stop a shot being taken or can rotate the image 90 degrees, but then shooting resumes thereafter. For one of the sequences I was shooting for about 20 minutes without a problem.

All shots were taken from behind windows. Sometimes I set the phone on the window ledge, or held it as solidly as I could against the glass for short periods. Later I found that my sat-nav suction mount could be used as a makeshift shelf on the window, and the phone would sit there happily with a bit more freedom for composing the angle. Luckily I didn't have many problems with reflections, even when the sun was shining in through the window.

28 August 2012

Discs, media and encoding

Recently I've seen more folk try burning AVCHD discs as they've started using high definition camcorders and have balked at the cost of Blu-ray burners and blank BD-R discs. Unfortunately there's a bit of confusion about what an AVCHD disc is, which is not surprising since it is a strange hybrid of things, and (for most of us) arrived quite unexpectedly.

The key to it all is understanding the difference between what is disc media, and what is encoding ("encoding" is often informally referred to as the format of the disc).

26 August 2012

New film: Burpee Mile

Recently I helped edit a film for a friend. Caroline Birkinshaw, a personal trainer from Leeds, decided to do the Burpee Mile, a full mile of one of the most gruelling exercises ever imagined. Dave Hackney was on hand to shoot the event, getting some great shots of the hard work and the struggle Carrie went through to complete her task. After a bit of a delay Dave and I sat down to review the footage and I put together an edit.

Going through the raw clips I could see there was plenty of great material to use, and seeing them chronologically there was a plot arc of sorts emerging. Caroline begins alone on the running track but is soon joined by her parents, more family and friends and by the end she had a small crowd cheering her on, jumping burpees alongside and celebrating when she made it over the one-mile mark. This slow build up of momentum was a key feature I wanted to preserve in the edited film. The latter shots of Caroline feeling the strain contributed to the film reaching the peak of tension before the relief at her achievement.

Originally it was discussed this film would be set to rousing music, but when I saw those raw clips I was certain that a documentary style would suit it better, lending more gravitas to Caroline's achievement. A little comedic relief is provided by interviews with Caroline's dad and some spectators who were impressed by her determination.

25 August 2012

Fun with a variable ND filter

A little while ago I set out to do a bit of casual filming using my stabilised 18-55mm lens. I wanted to shoot wide open for narrow depth-of-field so I screwed on a ND8 filter (which blocks 8 stops of light), but at the maximum aperture of f/3.5 the picture was underexposed. The weather was a little overcast but mostly bright. So I swapped the lens for my 50mm f/1.8 and the picture was exposed enough, but I was shooting hand-held so the unstabilised 50mm wouldn't do.

Back on the computer, I ordered a variable ND filter. Comprising two polarisers that darken considerably when their orientations are crossed (see video at the bottom), these filters are great when you want fine control over exposure in bright environments. As soon as it arrived I tried some experiments in my back yard.

Shot at f/3.5 with variable ND filter
f/3.5 with variable ND filter

Shot at f/18 without ND filter
f/18 without filter

These two stills are grabs from video clips I shot with 1/50th shutter. In the first picture I set the aperture first, at the maximum of f/3.5, and then adjusted the filter so that the highlights were just below clipping. In the second picture the filter was removed, and then I adjusted the aperture to retain the highlights, which turned out to be at f/18. Quite a difference, which is demonstrated in the noticeably narrower depth-of-field in the first picture.

One other noticable difference is the colour tone. With the filter, the picture looks cooler with a blue tint, and possibly desaturated. I have found with cheap ND filters that the optical quality is not perfect and colour shifts can occur, usually pushing towards blue. The effect varies with the severity of the light loss, and the quality of materials used -- one time I tried a plastic filter and the effect was something akin to picture taken with a Lomo/Diana toy camera, or something tweaked with Instagram. In the case of this variable ND filter, the colour shift is not so bad that it can't be corrected during editing.

A short video to demonstrate:

20 August 2012

After Effects CS3 performance comparison

A while back I had an After Effects project with 640 layers of footage. I've had to learn patience with my ancient Power Mac which struggles to render anything in real time, even simple comps, but I shouldn't have been surprised to find that 640 layers took about 40 seconds per frame. The entire 90-second animation took 23 hours.

25 June 2012

Rapid film making

I've made an entry for a video competition run by Viking office supplies:

It was shot in about 30 minutes in our tiny office at the end of the day. Luckily my boss Gareth was willing to act in front of the camera, or it would have been just me!

Setting up the camera and leaving it to record takes a bit of practice, as can be seen in a few wonky shots. We didn't have time to re-shoot anything so a bit of clever editing hid the problems to some extent.

Jumping into a project and shooting it quick is incredibly liberating. Knowing that the project doesn't have to be your best work frees you to try things with little expectation. It's been the first time in a few months that I've just gone out and shot something; it was very satisfying and good skills practice. A while back I read a blog post explaining there's no speed limit to learning things, and it certainly applies here.

03 June 2012

Time-lapse: what is it?

When we think of a time-lapse clip, we think of seeing action at high speed. Plants growing, clouds passing overhead, buildings being constructed, vegetables rotting. What we are seeing is a disparity of time; the rate of playback of the action is different to the rate it was shot. Action that really takes hours or days or months is being seen in a few seconds or minutes, and it can be captivating in a way unlike live action footage.

18 May 2012

New film: Vintage Kino promo

For the past six weeks I've been working with organisers of the Kinofilm Festival based in Manchester. The festival has been in existence for many years but has recently been subject to a rejuvenation, with regular showings of local and international short films, feature films, and 16mm curiosities from the archives. (For news on upcoming events, see the Kinofilm page on Facebook).

This promotional film is for the Vintage Kino events where a programme of shorts are projected from the original 16mm celluloid. The films vary from documentaries such as We Are The Lambeth Boys, to public information films on the dangers of drug abuse, to short cartoons and comedies. Each event aims to focus on a particular year and includes Pathe news reels that summarise the year's events.

It is the first film I have produced under my new brand, aenimated films. It serves a basic function of giving my films a shared identity, and a website that collects all my various scattered media across the web into one place. It was chiefly motivated by working on the Vintage Kino promo, which may be seen by people interested in my other short films.

Post processing

All the shots in the film were heavily colour-corrected in After Effects, usually with Curves effects. The captured projections usually needed to be squared up and brightened; some needed work to remove a colour cast. The outdoor shots on Oldham Street had some 're-lighting' effects to draw attention to the murals and signage.

Camera settings

The film was shot using a Canon 600D (T3i). The material in the Three Minute Theatre we mostly shot using a 50mm f/1.8 lens (the brightest I have) and some were with a 10-24mm f/3.5. ISO was set to 800 except for the occasional shot where it needed to be pushed to 1600, along with 1/30th shutter. Interview sound was recorded separately using a Zoom H4n with a Rode VideoMic plugged into the mini-jack.

17 May 2012

After Effects CS3 crashing on save

I recently found a bargain-priced copy of Adobe After Effects CS3 on eBay. It's the full professional version for my Mac so I didn't foresee any problems. I'd been using it for a few weeks before I ran into what seemed like a terminal issue...

26 April 2012

BIAFF 2012

I'm pleased to report my two entries to the British International Amateur Film Festival (BIAFF) this year, Brew-hoo and The Wheels, were both awarded three stars! My short comedy Brew-hoo was screened on the Saturday.

27 February 2012

New film: Lock Gates

This short video depicting the hand-construction of a pair of canal lock gates is a natty combination of time-lapse sequences and live action clips. I helped shoot the time-lapse for my work during the three week process, and went back to the workshop to shoot some extra live action video, up close to the materials and the craftsmen who work them.

20 February 2012

A fix for Final Cut Studio crashes

One of the Macs in our office has just been updated to Snow Leopard (yeah, we're a bit behind the rest of the world) and we found that Motion 4 and Compressor 3.5, the versions in Final Cut Studio 2, were crashing. Compressor would hang or crash if you tried to change the output location from the default 'Source', and Motion was particularly frustrating because you couldn't even save a project, or export from an unsaved project, without it crashing and losing all your work.

After a bit of searching I eventually found a fix. It was tricky to find because it's not an issue specific to Motion or Compressor, but across all of Apple's Pro applications after Mac OS has been updated to 10.6 Snow Leopard. The fix is here:

It requires a bit of typing in Terminal which can be a bit scary due to using the superuser commands. Copy and paste the lines in the instructions if you're not a confident typist!

17 February 2012

New film: Timelapse 2011

A compilation of all the little time-lapse clips I made last year.