Depth of Field

Although I use Ebay quite a bit, I rarely bid in the auctions. It annoys me too much how the price always seems so low and then jumps up exponentially in the closing minutes of the auction as everyone leaves bidding until the last possible moment. But when I saw a Sigma 20mm/f1.8 EF lens I couldn’t help myself and it was me that pounced at the last minute with my bid and won the lens.

The Sigma 20mm/f1.8 on my Canon 600D
The Sigma 20mm/f1.8 on my Canon 600D

What’s so great about this lens? I already have a Canon 18-55mm zoom – what’s wrong with that? The answer is: it’s all about depth of field.

Every filmmaker knows what depth of field is – the range of depth within an image which is in focus. Those of us cursed by tiny budgets to shoot on prosumer video formats have spent many years bemoaning how everything’s always in focus. Then HD-DSLRs came along and suddenly it all changed. Now you can control your depth of field. Now you can throw your background beautifully out of focus and keep your subject crisp and sharp, just like in real movies. But you can’t just turn on your DSLR and expect to get stunning depth of field straight away. So how can you make sure you’re always getting the shallowest possible focal depth? (Not that that is always the best look for every shot, but it’s nice to have the option.)

Let’s go back to basics and look at what affects depth of field. Most of us learnt all this when we first started making films, but let it drain from our brains over the years as our photographic dreams were crushed by the obstinately sharp backgrounds of a thousand Mini-DV frames.

1. Image size.  The larger the image, the smaller the depth of field. That’s why DV cameras with their tiny image sensors give such large depth of field, while at the other end of the scale a 35mm celluloid frame will permit lovely narrow focal depth. It’s also why a “full frame” DSLR like the Canon 5D Mark II will supply smaller depth of field than a “crop chip” DSLR like my Canon 600D.

2. Lens length.  The longer the lens, the smaller the depth of field. We all know this one well enough. How many times when DPing on DV have I heard the director ask me to zoom right in so the background goes nicely out of focus? But in the DV days it never went as out of focus as we wanted it to.

3. Subject distance.  People commonly forget this one. The closer the subject is to the lens, the smaller the depth of field. This is why sometimes you can achieve shallower focal depth by using a wide lens and placing the camera close to your subject than by zooming right in and moving the camera back. It’s also why miniatures will have a tell-tale small depth of field (the distance between lens and subject is miniature, just like everything else in the set-up) unless you take steps to counter it.

Depth of field varying with aperture
At f5.0 (left) almost all of the DeLorean is in focus, but at f1.8 (right) the depth of field is much smaller.

4. Aperture size.  The larger the aperture (i.e. the smaller the f-stop number) the smaller the depth of field. This is the crucial one with DSLRs. This is why I jumped on the Sigma f1.8 lens and why the f1.4 I borrowed on Field Trip was so beautiful. Of course, if you’re shooting in a bright environment then an aperture of f1.8 will give you a very over-exposed image, even with your camera on the lowest ISO. (Remember that you can’t compensate by changing the shutter speed, because that will also change the amount of motion blur in your footage, which unless you’re remaking Saving Private Ryan you normally don’t want to do.) The solution is to use an ND (neutral density) filter to cut down the amount of light entering the lens.

Of course there are far more technical details behind all of this, which frankly I don’t understand but fortunately I don’t need to in order to make films. I hope this post has refreshed your memory or tied together what fragments you already knew. I’ll let you know how I get on with the 20mm Sigma in the field. No pun intended. Well, maybe a little.

Depth of Field

Sneak Peak

See how that’s a clever pun? No? Well, if you read on you will discover that this post concerns the PEAK District. Ahahahaha! All must bow down to my comedy genius. Seriously though, my least favourite thing about blogging in WordPress is that it makes you give your posts titles, and I always waste at least five minutes trying to come up with a pun-based title.

Right, so on Monday my wife Katie – who is the costumer and wardrobe supervisor for Stop/Eject – and I travelled to Derbyshire to meet with Tom and production designer Sophie Black, discuss the look of the film and recce locations. Sophie lives in the small town of Belper in the Peak District (Sneak PEAK – remember! Hahahaha!), and it was while dropping her home during the Wasteland trailer shoot that I got my first glimpse of Belper and decided to shoot most of Stop/Eject there.

The village’s most notable landmark is an old redbrick mill which looms over a weir on the River Derwent, and this was our first port of call. We considered the merits of the riverside gardens for happy scenes with the film’s central couple, and scouted about for somewhere they could safely paddle. After looking at a nice cobbled street we travelled on north to Matlock to see Magpie, Sophie’s prime choice for the charity store central to the film. Unfortunately it was closed, but we had a good peer through the window, noting that it had great character but was very small and could prove hard to light.

After lunch we went in some more shops both in Matlock and Belper, and though many were far more suited to the practicalities of filmmaking, none was as visually interesting as Magpie. Next week I’ll get to recce the inside of Magpie and make a decision.

The other location we checked out was Belper Cemetery, which has lovely views across the valley and will add a lot of value to the film, providing of course that we can get permission to shoot there.

All in all, things are going pretty well so far, but since my films are more cursed than Will Turner’s twice-cursed pirate father I’m sure it won’t be long before it all goes spectacularly wrong.  In the meantime, enjoy the second Stop/Eject podcast featuring lead actress Kate Burdette – not that she needs any introduction to followers of The Dark Side of the Earth.

Sneak Peak

Born of Hope

Friday was primary casting day for Stop/Eject; thanks to everyone who came along. We should be reaching a decision very soon on at least one of the characters.

On Saturday I ventured up to Debden in Epping Forest, where three years ago I helped out for a few days as a cameraman on Born of Hope. Born of Hope is a very ambitious feature-length Lord of the Rings fan film, directed and produced by Kate Madison. The finished piece impressed me far more than the official film trilogy, and I very much related to Kate’s struggles and determination to get it to the screen on a microbudget.

Kate Madison
Born of Hope producer-director Kate Madison

I attended Saturday’s cast and crew reunion in order to do my first bit of shooting for a new documentary feature I have in the works. Currently saddled with the terrible working title “Living in a Fantasy World”, this doc will follow several amibitious UK filmmakers as they make or try to raise finance for their independent fantasy/sci-fi projects. Kate was one of the first people I thought of when I came up with the idea, and I look forward to following her and her partner Chris Dane as they develop their next projects, The Last Beacon and an untitled fantasy web series.

Living in a Fantasy World is very embryonic at the moment and little else is likely to happen on it until next year, but rest assured that you’ll always be able to hear the latest news on it here at neiloseman.com

Born of Hope

Dark Side update

Benedict Cumberbatch as Max
Benedict Cumberbatch as Max (photo: Richard Unger)

Carl and I have decided we need to change tack a little with The Dark Side of the Earth. We had some interest from a major Hollywood studio, but the suggestion was that the dialogue is too period, too archaic. I just don’t have the mental capacity to tackle another draft, so we’re looking for a writer who can do a polish and make it a little more mainstream, ideally someone with experience of writing for Hollywood. I’ll let you know how that goes, but it definitely seems like if this film is going to be made it will not be by a UK company.

In other news, I’m now casting for Stop/Eject, the short fantasy drama I’m shooting next month. And if anyone reading is in London this Friday afternoon and fancies helping me out running the auditions, please get in touch.

Dark Side update

Wasteland FX walk-through: Empty A50

Here’s a look at how I created one of the FX shots in the Wasteland trailer. Tom, the director, wanted to see the central character, Scott (Shameer Seepersand), walking along a deserted dual carriageway to show his isolation in the post-apocalyptic world.

We started by shooting the A50 from a bridge (image 1). Traffic was light, but we were never able to get a clean, car-less shot. (While filming we were interrupted by a couple of blokes from the Highways Agency who wanted to cover their arses in case of accident, so gave us a safety briefing: “Be careful when you cross the road, lads.”)

The next day we drove around looking for a footpath or cycle path with similar tarmac to the A50 which could be shot from a bridge to get the same elevated viewpoint. Having located one, we filmed Sham walking (2).

Shrinking Sham down and feathering the edges of his element into the shot was the work of moments (3), but the illusion wasn’t complete until this element had been colour-corrected to match up the tarmacs.

Next the cars had to be erased, which I achieved partly by overlaying cropped sections from later in the footage (when the cars had moved on, leaving a space behind) and partly by exporting a frame to Photoshop and using the clone tool. The former technique is preferable because using a motion element retains the movement of picture noise; the lack of this movement can be an FX giveaway. Therefore I kept the Photoshopped sections small – just way in the distance where the cars were tiny.

At this point (4) the shot is essentially complete, but I added some extra touches in the form of smoke elements from an FX library, a faint one in the distance (top left) and one on the van which I had left frozen in the picture as if it had been abandoned. I also duplicated the van’s smoke and distorted it to create a shadow for that smoke (5).

All images copyright 2011 Light Films.

Wasteland FX walk-through: Empty A50

Play

Here’s the first in what I hope will be a series of podcasts covering the making of my new short film Stop/Eject. This one features producer Tom Wadlow discussing how the project originated, and provides a glimpse of the first pre-production meeting.

Play

Wasteland trailer online

You can now watch the trailer for Wasteland, the zombie feature I’m DPing and editing. And if you missed it first time round, why not read about how I lit this trailer?

Wasteland trailer frame
A frame from the Wasteland trailer (copyright 2011 Light Films)

 

Wasteland trailer online

SLR Learner

Shooting director Patrick Coyle in his role as Buck
Shooting director Patrick Coyle in his role as Buck

You learn something with every job you do. On last weekend’s intensive shoot for Field Trip, I learnt a hell of a lot. Aside from one day filming the Wasteland trailer and a morning filming a corporate, it was my first use of my new Canon 600D and Pro Aim shoulder rig. Four days, up to seventeen hours each day, and every shot handheld: I could not have asked for a tougher crash course in HD-DSLR cinematography.

Between takes
Between takes

The director wanted a documentary style: lots of ad-libbed camera movements including crash zooms. It quickly became apparent that SLRs are not the right format for such a style, prone as they are to the rolling shutter “jelly” effect, and given that the lenses we were using noticeably adjusted the exposure – even in manual mode – whenever we zoomed. So that was the first lesson: choose your camera to fit your movie, and don’t just follow the crowd.

Aside from that, perhaps the key thing I realised is that I’ve bought into a system, a system which I can adapt to my needs and finances. This is true of both the rig and the camera. In the case of the former, I left off the follow focus and frequently the matte box and sunshades too, since these slowed down lens changes and made it harder for me to pull focus on the fly.

My lenses
My lenses

With the latter, lenses were the big revelation. To keep costs down, I didn’t purchase any lenses with my camera. I already owned Canon’s basic 18-55mm and 55-250mm zooms, and an adaptor would allow me to use my old 28, 50 and 70-210mm Minolta lenses too. None of these are particularly great, and crucially none of them are very fast. When I borrowed some f1.4 andf f1.8 primes from a helpful runner, I was blown away by the tiny depth-of-field. Conclusion: I’m wasting my camera’s potential with my current set of lenses, and I must get hold of some nice fast ones pronto.

Other things learnt or reinforced on Field Trip include: always make very sure the data has all been transferred before you wipe a card; you get what you pay for (one of my cheap third party batteries packed up); and I need some nice ND filters.

As ever, you’ll be the first to know when I get the new kit and how it stacks up. Thanks to James Byrne for the Field Trip photos.

SLR Learner