Archive Page 2

22
Nov
16

KOTM – Matte Boxes

Matte Boxesmattbox

 

Hi, folks, today I want to talk about Matt Boxes and before I get started I must admit that they are something that falls right into a gap in my knowledge. Being a stills kind of guy I am used to using lens hoods to avoid lens flare and apart from using the correct one for the lens there really is nothing much to learn about them, however, as normal the moving image world is somewhat more complicated. Luckily I have an entire department of camera wizards to help me out so I thought it was about time I got myself educated in this important accessory.

 

So firstly a Matte box is used for much the same reason as a lens hood, and that is to stop unwanted light from hitting the front of the lens and causing issues such as lens flare, they differ from photographic lens hoods but essentially do the same job. Matte boxes tend to be more generic than lens hoods that are generally lens specific. This is an advantage as you only need to lug around one matte box for all the lenses on a job as opposed to carrying a different lens hood for each and every lens that may be used (I always seem to forget the lens hoods when I pack my equipment and then need to find room for them which is a pain as they are bulky, fragile and certainly not cheap for a plastic tube.

 

The first thing I notice is that matte boxes are not circular as lens hoods are but are oblong (my mission to revive the word oblong as it’s so much better than a rectangle). This is due to the matte box being a generic hood designed to fit a multitude of lenses as compared to a lens hood that can be manufactured to an exact field of view for the lens in question.

They also tend to have adjustable flaps on the front edge just like a set of barn doors on a light. These are known as French Flags or occasionally French Flaps (I prefer flaps as I think it’s an Australian expression). Now don’t start, French flaps is actually a bookbinding term originally and not rude at all. They allow for more flexibility to block light than the fixed form of a lens hood, this is necessary when the one box is to be used with many different lenses.

 

The other main difference between hoods and boxes is that matte boxes are designed to hold filters. Us stills guys tend to screw our filters directly onto the front of the lens and if we need more than one we stack them together sometimes causing vignetting, Cinematographic filters tend to be larger and square or oblong in shape allowing for multiple amounts to be used without this problem arising, they are inserted into slots or trays in the matte box itself.

 

Now we can separate matte boxes into a couple of types, clip on being ones that attach directly to the front of the lens and others that attach to a rod system. For those uninitiated in the cinematographic world, a rod system is literally two metal rods that attach under the camera and offer support for accessories such as batteries and of course matte boxes. The clip on matte boxes are light in weight and normally have fewer filter slots than the rail system equivalents that are generally larger and heavier. We need to use the rail system with these larger matte boxes due to their weight that lenses are not designed to support.

 

Now remember that rod systems come in two main diameters 15 and 19 mm and needless to say some matte boxes will fit on both but some will only fit on one or the other so this is something we need to check before selecting a particular unit.

 

Another thing to think about is how many filters you are going to need to use at any one time and ensure that the matte box you select has enough slots.

 

Various adaptor rings are available to fit between the front of the lens and the matte box or a flexible fabric alternative can be used, these are known humorously as nun’s knickers! (I could not possibly do a blog about matte boxes and not mention these).

For obvious reasons, the lighter smaller clip on units is recommended for hand-held work and the larger heavier ones for when the camera is on a tripod etc.

 

One thing I have learnt is that most matte boxes come with a set of mattes, these are thin black plates with various sized holes cut into them (letterbox style) and they can be fitted to the matte box to help adapt it to the particular lenses field of view, bigger hole for a wider angle and Visa-versa, this is so simple that I think it’s clever, as a firm believer of the KISS principle that is.

 

So that’s about it I will put a list together of what matte boxes we carry and how many and what size filters they can hold and so on for all our reference.

Clip On 15mm Rods 19mm rods Filter size Number of trays Other
Chrosziel MB 450

 

NO YES NO 4 X 5.46 2
Arri LMB 25

 

YES NO NO 4 X 5.46 2 OR 3 ONLY HAS TOP FLAG
Arri LMB 15

 

YES NO NO 4 X 5.46 2 OR 3
Arri LMB 6

 

YES NO NO 6 X 6 2 OR 3 HAS STEP DOWN FRAME TO PV SIZE

GOOD FOR WIDER LENSES

Arri MB 29

 

YES NO NO 4 X 5.46 2 OR 3 AND 138 MM CIRCULAR
Arri MB 20

 

YES YES YES 5.65 x 5.65 1, 2, OR 3 GOOD FOR WIDER HD LENSES
Arri MB 19

 

YES YES YES 4 X 5.46 2 OR 3 AND 138 MM CIRCULAR
Arri MB 18

 

YES YES YES 4 x 4 , 4 x 5.65 AND 4.5 ROUND 2, 3, or 4

 

AND 138 MM

Arri MB 16

 

NO YES NO 4 X 5.46 3
Arri MMB 2

 

NO YES YES 4 X 5.46 MORE FOR STILLS
Arri SMB 2

 

NO YES YES 4 X 5.46 1, 2, OR 3
Arri SMB 1

 

YES YES YES 4 X 5.46 1, 2, OR 3
VIV 3 stage

 

YES YES YES 4 X 5.46 1, 2, OR 3

AND 138 MM

Missfit Clip on 3 stage

 

Backlight 6

 

YES NO NO 6 X 6 3 GOOD FOR WIDER LENSES
4 x 4 Van Dieman Mosquito

 

4 X 4 1 or 2
Bright Tangerine Atom

 

YES YES 4 X 5.46 2 GOOD FOR MOVI / RONIN, OUR LIGHTEST WEIGHT MATTE BOX

 

Now remember this pearl of wisdom I found online “While nobody will notice that you’ve used a matte box, the important thing is that nobody will notice that you didn’t use one but should have”, wise words indeed.

 

Now Matte boxes don’t really warrant a BCR collectively but I feel that French Flaps and Nuns knickers deserve some score in their own right so let’s rename the BCR from Brucie Coolness Rating to Brilliant Crude or Rude and give them 5 points each making the score a maximum 10.

 

Cheers guys merry shooting BB.

 

06
Oct
16

KOTM- Cambo Actus DB2 View Camera

Brucie Blogger is back with Kit of the Month!!

Actus DB eh so what do you think the DB stands for?

cambo actus.jpg

Well, I presume its “Digital Back” and nothing to do with “the canine’s orbs” as I first thought. Having said that the latter would also suffice as a good description, as this really is the DB’s when it comes to modern view camera offerings.

 

The Actus DB2 has evolved from Cambo’s Actus series of view cameras that are designed to be used in conjunction with mirror-less cameras and DSLR’s. The new DB2 can still be used with a DSLR on the back but as it is equipped to take a Phase one IQ3 100 mp back I don’t suppose we will see a DSLR attached very often. In fact,we are not going to rush out and buy an adaptor for DSLR’s unless one of you has a mega hire needing it and then perhaps we could have our arms twisted.

camboa2.jpg

Despite my vintage, I came into photography towards the end of the view camera era, I remember selling off the ones we had in Australia while they still had some decent value and recall being gutted as I wanted to play with one more myself.

Great quality tilt shift lenses by Canon and Nikon and have gone some way to replacing them but can only go so far, nothing can really compete with the ultimate image control that a good view camera can deliver.

 

So Cambo has been clever by coupling a modern take on the view camera with today’s megapixel top end digital backs and they seem to have done a lovely job of it too.

 

 

camboa3.jpg

Small size and a beautiful mover

 

 

 

 

mradams.jpg

Not exactly a compact Mr.Adams is it?

The first thing you notice about the DB2 is its size, far from sticking out like, well like the DB’s it’s rather diminutive, fitting nicely into the palm of your hand. It’s a far cry from the cameras used by Mr. Adams and his counterparts back in the day.

 

But don’t let its size fool you this really is a well-equipped camera featuring.

 

 

360 degrees of front swing

19 degrees of front tilt

27mm of rear shift vertical

40mm of rear shift horizontal

150 mm maximum extension with standard monorail

295mm with long monorail

445mm with macro monorail

Available in a range of colours so long as you want anodized black that is.

 

All very impressive but what does that mean for your photography, well the highlights are below.

 

View camera movements allow for selective sharpness / selective un-sharpness

Rear shift movements for stitching wider angle images.

Focal plane shifts to increase file size

Image centered landscape / portrait selection

Built in macro extension.

camboa4.jpg

So as a view camera you can see that the DB2 really is a great piece of equipment but when you couple it with one of our IQ3 100mp digital backs from Phaseone then it becomes a truly awesome camera system. You now have a medium format, full frame sensor view camera with a resolution of 100 mp (more if you start stitching frames together) coupled with all the versatility that you could ever need.

 

Now one thing I recall about using view cameras in the past was having to check my focus by using a loupe on the rear glass and that was a pain, to say the least. Well, I’m pleased to say that those days are well and truly gone. My very expensive loupe has retired, now only making an occasional appearance to aid in the removal of splinters and the like, thank goodness. Today we have it much easier, by using the live view mode on the IQ3 back and viewing at 100% we can get that focus absolutely perfect.

 

But if that’s not quite easy enough for you how about using the WIFI ability of the IQ3 to give you live view on your iPad making the most of its large screen. Shutter release and full control over the back can also be accessed via this WIFI system thus removing any risk of camera shake spoiling your results, so that’s the cable release gone from your kit bag too.

 

So calling all the photographers who need the versatility of a view camera and the resolution of a modern top end digital back we now have you covered, dust off your Sinar lenses or hire ours and GET SHIFTING.

 

10 out of 10 for the BCR this camera is lovely and with the IQ3 on the back and some sexy glass on the front it’s even lovelier, come in and give it a go and please don’t forget to show us your beautiful moves (and tilts too).

Cheers all BB

 

camboa5.jpg

 

20
Jul
16

Volte Face by Oliver Curtis

Volte Face by Oliver Curtis.

 

Oliver Curtis has turned his back on convention and just about everything else with his upcoming exhibition and book titled Volte face, roughly translated as about-face.

 

The expression volte face originally stems from the Italian word “voltafaccia” with volta meaning turn and faccia meaning face. Imagine for a moment what the Mona Lisa must look out at every day from her vantage point on the wall in the Louvre or Lincolin from his giant stone seat in Washington and you will have some idea of what Oliver has been shooting since changing his outlook on a visit to the pyramids of Giza in 2012.

 

Oliver recounts how after walking around the base of the pyramids he found himself stood with his back to the tomb looking out over the city of Giza under a vale of smog on the horizon and a selection of “human detritus” adorning the desert sand immediately in front of him. Now for most of us that would be a cue to turn round and take some pictures of what we flew to Egypt to see in the first place but not for Oliver, instead he saw something else, a new perspective.

 

This is the mark of a great photographer, having the ability to see and to see things the rest of us miss or just overlook it’s a skill that cant be taught in my opinion you either have it or you don’t and that explains why I am sat here writing a blog I guess.

 

The exhibition is taking place at the Royal Geographical Society from the 19th of September until the 14th of October and Pixipixel are proud to be amongst the sponsors and look forward (or even backward) to seeing many of you attend. At this point it can’t hurt to point out that admission is free.

 

Oliver is also producing a rather nice book of this project that I have yet to see, but presumably is best read from the back to the front in the spirit of the whole idea.

 

In reflection on this project Oliver explains that “Volte face is an invitation to turn around and see a new aspect of the over-photographed sites of the world – to send our gaze elsewhere and to favour the incidental over the monumental.

He continues to explain that “despite the landmark not being present in the photograph, the images are still suffused with the aura of the construction, the camera lens effectively acts as a nodal point and by giving the photograph the title of the unseen partner this duality becomes a virtue.”

 

By visiting the exhibition you will see that Oliver has produced some stunning images of familiar places in a way that we have never seen before and that itself is no easy thing, so we would like to congratulate him on his creativity in putting this outstanding body of work together.

Brucie BloggerScreen Shot 2016-07-08 at 18.08.14

 

04
Jul
16

Introducing Genevieve

Now it’s quite an unusual name Genevieve especially in the present day, I don’t think I have ever met one to be honest. I recall an old film about a car race back from Brighton and I happen to know Sainte Genevieve (Saint Geneviève de Loqueffret )is the patron saint of Paris. I didn’t know that she is said to have saved the city from Attila the Hun and an outbreak of ergot poisoning (very nasty) not to mention being appointed as the guardian of the “consecrated virgins of Paris” so the name has some interesting and amusing history but it is still very unusual.

So having said that, I would like to introduce you to the newest Genevieve in London, She hails from Belgium which is very nearly Paris in my book, so it will suffice as a introduction and she is most definitely without any doubt whatsoever UNUSUAL.

 

Now Genevieve is a big girl she is quite heavy, but tall with it and she is delightfully quiet so you can take her home to meet the folks and she won’t embarrass you, but none of that is what makes her unusual. She is unusual, because of her power and she has heaps of it, she puts a 1970’s female Soviet Block weightlifter to shame and without the steroids!

 

Ok, I’ve had my fun and before I put you off Genevive all together, I should point out that she is a truck, a 4 x 4 wheel drive truck and she carries with her a 100kva generator!

 

Yes, Genevieve is our shiny new Mitsubishi Canter generator truck and you won’t find another lady like her in London.

genevieve 1

So lets start with Geneviève’s body, as I said she is a Mitsubishi Canter truck so has constant four wheel drive, high ground clearance, locking hubs, heavy duty axles and off road tires in fact many councils use the Canter as a base for their snow ploughs so she is a tough go anywhere kind of girl. She weighs in at about 6.5 tones so she’s not exactly anorexic and requires a taco (no not as in like a burrito) as in a tachograph! But don’t let that put you off, we can always find a driver if required and a spark (electrician) for that matter.

 

One quick glance inside her shapely rear end reveals the mother of all generators producing 100 Kva at your demand for anything from charging your IPhone to bringing Frankenstein’s monster back to life. With more outlets than Costa Coffee you won’t be short of places to plug into whatever you are using in fact she has:

One each of 125 and 63 amp single phase outlets and a brace of 32 and 16 Amp ones too. If you are after 3 Phase then she is equipped with a power lock and a 125 amp socket. Ok so no USB port but you can plug your phone into the cigarette lighter like everyone else.

genevivepower.jpg

 

A modest amount of storage is available for kit at the very back but if you need 100Kva then I don’t think this will be enough room for everything you are running still it’s better than a poke in the eye!

genevieve load.jpg

But by far the most impressive thing about this lady is how quiet she is, I had Toby start her up for me yesterday and even with the rear service hatch wide open I swear she made less noise than a little Honda 2Kva generator and they are renowned for being quiet.

 

So if you like your women tall well built, adventurous, powerful and silent then Genevieve is the girl for you. Why not give us a call and arrange a date?

genevieve2

The only improvement I would make is a huge set of bull bars and a winch but I’ve spent too long down under so ignore me, she is a perfect 10 as Kevin Bloody Wilson would say (those easily offended should not look up Kevin or his music)

13
May
16

KOTW-Arrimax 12/18 kW High Speed Ballast.

Arrimax 12/18 kW High Speed Ballast

 

So lets face it no matter how much I try to make this sound exciting it not going to be.

This is a fabulous bit of kit but it’s never going to score highly in the wow factor despite it’s cost and weight, I would say that its most popular feature is going to be the wheels!

Arri_562814_Arrimax_18_12KW_Electronic_Ballast_1336488694000_417450.jpg

 

I guess in the interest of spicing things up a little I should look into what a ballast actually is. Now although probably heavy enough this is definitely not the sort of ballast used to keep a boat the right way up or a balloon on the ground it’s something else entirely.

 

Put very simply, (to suit me) a ballast is an electronic device designed to limit the amount of current in an electric circuit. It automatically allows for a higher current at start up (striking) to allow for an arc to form between the electrodes in your bulb but then immediately limits that current to an optimum level, thus allowing for the bulb to produce the desired level of luminance whilst retaining its rated lifespan. Interestingly without a ballast a thing called a “negative differential resistance artifact” would cause the current in the bulb to very quickly “RISE TO DESTRUCTIVE LEVELS” and BANG. You get the idea, no more bulb, no more light.

 

So despite my obvious temptation to blow things up I guess that a ballast is a fairly important bit of kit, unless of course your dad owns Osram. So what’s so special about this one then? other than the wheels that is.

 

Well its what’s known as a high-speed ballast and no that’s got nothing to do with the wheels, for a start they would be alloys and have low profile tyres on them if this was some kind of racing machine. No high speed refers to the ability of the ballast to produce a virtually constant output over the entire AC cycle, allowing for flicker free operation and in turn filming at higher frame rates without a problem.

 

Ok so I bet you are itching to know how this is done, well it’s all about the shape of waves. A normal AC power supply has a nice curvy wave pattern, if you care to look at it on your oscilloscope (what do you mean you don’t have an oscilloscope, call yourself a photographer but don’t have an oscilloscope for goodness sake!) it looks something like this.

c1

 

Now, a normal “magnetic” ballast does a pretty good job in smoothing this out but if we look at the image below you can see that the light output fluctuates or flickers.

c2

That flicker plays havoc when we are shooting at high frame rates so is not ideal.

 

A high-speed ballast like the Arri 12/18 kW squares off the wave pattern and in turn produces a far more constant light output see below.

 

c3

Clever Stuff eh??

c4

 

 

 

 

With this consistent output high frame rate filming becomes possible without issue. Arri says that frame rates up to 3000 fps are possible when using multiple sources due to the ability to use up to 1200Hz lamp operation. With a single source the new 1000Hz ballasts are fine for lighting at frame rates of 1000 fps and in many cases even faster.

 

Happily for us this square wave format should increases the life of the bulb by around 20% and you will be pleased to know it can also increase the light output by 6-8% so it is hip to be square after all.

 

Now with every up side it seems a down side must follow and surprise surprise this is no exception. The issue with square waves (other than being useless to surf) is noise. The square waves can cause the globe and igniter to buzz, the head becomes a resonating chamber and the noise, now amplified is projected out of the front of the light (because it has a big hole at the front) straight towards the set. This is not an issue unless you are recording sound and then it’s a nuisance to say the least. But an answer is at hand and it involves cutting corners!

 

By using a special circuit in the ballast the corners of the square waves can be “rounded off” this prevents the buzz and keeps the sound guys happy. This does have an effect on the Hz that you can run at unfortunately but the Arri unit still can put out a very respectful 50-60Hz for low noise environments.

c6

So that was exciting wasn’t it I hope we are all now fully trained as far as waving is concerned and I would expect to see a marked increase in oscilloscope sales in the near future.

 

But back to the ballast in question I’ve had a bit of a look at its technical specifications and it has a couple of nice features beyond its wave changing trickery, how about cold striking and hot re striking and dimming from 100 -50% of power, oh and did I mention wheels?

 

This ballast also features DMX remote dimming capabilities (that’s fairly self explanatory) and an Active Line Filter for Power Factor Correction (a what for what?). from what I can understand about this it results in a more efficient power use and also assures a consistent colour output despite dimming or mains voltage fluctuations.

 

Full safety protection for over heating, short circuit and over voltage issues is built into the circuitry making for worry free operation. ABS and a drivers side airbag are not included however so be careful when pushing it around.

 

Well, I got through that without too much brain ache and I hope you did too?  Ballasts are never going to rock your world, but without them we would be in the dark (literally) so I am glad people like Arri are putting so much effort into making them better. I am hesitant to give a BCR Brucie coolness rating as its not going to score high enough on the cool side of things so on this occasion I will use my special BCR Ballast Capability Rating and award a 10 out of 10 to this beast.

 

Oh and it weighs about 49kg so if you have an assistant to punish let us know and we will take the wheels off!!!!

b6q516k

Cheers BB

26
Apr
16

Something a little different again -Chroma-keying

Chroma-keying

chroma1.jpg

Chroma-Keying is the technical term for what most of us refer to as Green Screen shooting and for some of you that is probably the only thing I can teach you on the subject, however for the rest of the world here is my take on this popular and great fun technique.

Firstly the term “green screen” is confusing as the process of Chroma-keying can be done with various colours other than green, but more on this later.

So before I get too into it, let’s just have a quick think about what the process of Chroma-keying actually is and why we use it so often. The Chroma-keying process basically allows you as an image or filmmaker to remove a specific chosen colour in the image and replace it with another colour or background. Probably the most often seen use of this is the weather person and his or her map at the end of the news. Chroma-keying has allowed the weather forecast to be a far more immersive and polished presentation but I must admit to missing the likes of Michael Fish struggling with magnetic cloud and rain icons, obviously this keying technique is not limited to the daily precipitation forecast and is in fact used far more often than you might expect.

 

fish1

       BBC prior to chroma keying, lots has changed except the weather it seems

 

It may be obvious when you see a flying superhero at the movies that some trickery has taken place and this would often be done using chroma-keying but how often do we see a car scene with dialogue in a TV show? Well take it from me a very high percentage of those car scenes will have been shot against a green screen. This is down to the sound created by a moving car, even one on a trailer, this sound can interfere or drown out the actors lines causing the need for separately recording the dialogue and syncing it back to the film later with all the expense incurred. By filming in a stationary car in a nice quiet film studio and then chroma-keying in the background a lot of time and expense can be saved.

 

Right, I think we all know what chroma-keying is now so how do we do it? Well firstly get yourself a good digital operator as I wont be going through the computer side of things on this occasion. I’m going to concentrate on backgrounds and lighting for chroma-keying as that’s what we hire out. Having said that you can get the digital operator from us along with all the computer hardware and software required oh and the camera too….. needless to say.

 

To set up a Chroma-keying shot you first need to set up a background in whatever colour you are choosing to use, be it chroma green, chroma blue or something else. This can be as simple as hanging the appropriate colour background paper roll up or slopping some paint onto a cyc (someone else’s cyc preferably). But take care at this stage, ensure that the background has no nasty marks or scuffs, no wrinkles or creases and so on. Any imperfections in the background can have a negative effect on the keying process.

 

Background options are numerous ranging from that pot of paint to colorama paper rolls or fabrics, we carry various size fabrics from 6 x 6 ft up to 20 x 20 ft in chroma green and up to 12 x 12 ft in chroma blue. Appropriate goal post systems, frames and stands are here in abundance too so hanging the background is no problem at all.

 

One word of warning in regards to using a painted background and that is to be mindful of reflections, a painted surface is far more prone to this than a paper or fabric backdrop. In fact to make your life easier one of our fabric backdrops made from Rosco Digital Cloth is the ideal solution, it gives no bounce back and the perfect key when lit with green.

 

The next stage would be to light this background and the thing to look out for here is to light it evenly with no hot spots, shadows or fall off. You are looking to light the background about 1-2 stops less than your subject will be. Keep it soft and try not to blast the hell out of it as you may end up reflecting the background colour onto the rear of your subject causing fringing around the edges (not what you are after)

 

In practice the easiest way to get a consistent light across your green screen is to light it from both the left and right hand sides using matching lights, this way the lights will overlap each other creating a uniform brightness across the entire backdrop.

lightgreen

Again we have lots of options for lighting the background and many of you will have your own preferences but a couple of good options include Kino Flow lights with 2 x 4ft 4 bank units sufficient to light a 12 x 12 ft screen or for larger arrears our 8 x 4 light flo units are great. However if you want to really spoil yourself then try our very sexy new Cineo HS mk2 led panels (just back from some Wonder Woman chroma keying). All of these lights can all be provided in chroma green output specifically for green screens or in daylight or tungsten for lighting other colour backgrounds. If none of these tickle your fancy give us a call and we can work through your requirements with numerous other lighting options available.

 

kino

Kino 4ft 4 bank

kino2

Light flo 4 x 8

 

 

 

 

 

cineo hs2

Next light your subject, but just have a think at this point as you need to emulate the lighting required in the finished shot, so don’t do a 3 point daylight set up if the end result is someone driving a car at night and so on. Remember direction, quality, colour and power of light here and try to pre-visualize the finished shot.

 

Where possible and appropriate some kind of hair or rear light is great to separate your subject from the background. Positioning your subject at a distance to the background will help with this separation and also reduce the possibility of shadows on the background cast by the subject. If you have to have the subject close to the background you can try to light from a higher angle thus putting those shadows onto the floor and hopefully out of shot but this will only work if the end result calls for the light coming from that same high angle (getting the idea?)

 

As far as what lights to use for your subject its really down to the “look” you are after but whatever that is we have what you need to achieve it so just touch base and we can recommend some options.

 

This one may be obvious but I had better mention it, your subject needs to be a different colour to the background, so don’t shoot a Smurf against chroma blue or a bottle of Grolsch against chroma green ok.

 

smurf

Why not to shoot a Smurf against a Blue Screen?

Whilst shooting be mindful of reflections from the background in jewelry, watches and glasses etc these can spoil your day if you fail to notice them so take care.

Also consider shooting with a large aperture if possible as this will throw the background out of focus and that helps keep it a uniform colour and brightness whilst hiding any imperfections thus aiding with the keying process.

 

Now just before I go and let you all get on with some serious keying, I did mention using different colours to chroma green earlier and said I would expand on that. The go to colour for chroma keying is green but blue, yellow or red can be used instead, care must be taken with red and yellow as these can cause issues with skin tones. Chroma blue works extremely well but lots of people like to wear blue so this can cause you grief too. Back in the days of Mary Poppins and Ray Harryhausen, subjects were shot against WHITE but sodium vapor lights were used due to them having a narrow colour spectrum, this was part of a photochemical process and won an Academy Award back in 1965 so we aren’t doing anything new really are we, they used to call it yellow screen shooting.

marypoppins

Not bad keying for 1964 eh? I am particularly impressed with the shadow!! No wonder they won a Oscar!!!

 

The most convincing reason for using a “GREEN” green screen that I know of is to do with resolution, many cameras use a CMOS sensor topped with a bayer filter and this contains twice as many green sites as it does red or blue ones thus a 4k single chip camera recording at say 4:2:0 would record green at 2k and red and blue at 1k. So green is popular due to it capturing the highest resolution. Back in the film days blue was the go to colour for the same reason, as the blue layer in film stock had the finest grain. Remember with keying it’s the edge detail that makes or breaks the effect so the better resolution the better and more convincing the end result will be.

bayerpattern

 

Green screens also require less light than the blue ones to illuminate and this can be a bonus but on some occasions however the use of a blue screen may still be preferable, for example if the end result is a night time scene then any excess green will stand out against the blue hue that these scenes often have but any excess blue light will blend in nicely.

 

Ok, so I hope to see some amazing stuff from you all, why not let us know if you do anything fun or exciting as we are always on the look-out for something cool to blog about.

 

Cheers folks and happy shooting

 

BB

 

 

 

23
Mar
16

Something slightly different-Sunlight

Sunlight

sunlight1.jpg

I don’t know about the rest of you, but everyone here at Pixipixel is well and truly over winter. Short cold and dull days are not exactly the stuff of great photographs or location shoots are they? This has however given me an idea……….

As a departure from my normal rambling “Kit Of The Week” blogs I’m going to try something a little different, more along the lines of a how to guide, and what better place to start than how to recreate sunlight?

So please don’t take this the wrong way, I know many of you will be well versed in this but you never know you may pick something up even if it’s only a nice tan.

Firstly a small bit of Brucie theory:

Sunlight (I’m talking about a bright blue sky sort of sunlight not an overcast miserable day) is a hard light. You can see this if you look at your shadow on a bright day, it will be well defined with hard edges and a high contrast between it and the surrounding ground, in fact often exactly what we try and avoid as image makers. So why is this?

 

Ok, so back to photography basics for a moment, a hard light is produced by a small light source like the sun!

Yes I know the Sun is big (1392000 km across ish) but it is also a long way away, so to us it appears fairly small in the sky. This would be different if we stood on Mercury, but we aren’t so stop being awkward.

Now with the light source being small and far away the light rays that “hit” us are reasonably parallel to each other and this is what gives us the hard edged, high contrast shadows that we associate with summertime. With me so far?

 

So it makes sense that to recreate sunlight we either need to find a massive flaming orb and install it at the center of our solar system and pray for a break in the clouds or use a small light source in the studio itself. I know which option is easier, but exactly which light source should we use?

 

Now up until this point I’ve been thinking in general terms but obviously you moving image types are going to need a continuous light, whereas us stills guys can use flash or continuous. This is no big deal because we have numerous options for everyone.

 

Starting with us stills guys and looking at flash lighting we have a couple of options. Firstly and most simply a bare head will work fine, provided it is positioned at a reasonable distance from the subject. The trouble with this is that the light rays will be scattered causing a more diffused effect and also any stray light will bounce around the studio, becoming unwanted ambient light and further softening the effect. A small reflector or even a snoot will greatly help with this, however a purpose built modifier will yield much better results.

 

Both Profoto and Broncolor produce Fresnel lensed attachments for their lights and these help to bring those pesky light rays under control and more parallel to each other creating a beam of hard light (much the same as a lighthouse). This is a great starting point and works very well. The Broncolor attachment is called a “Flooter” and the Profoto version is the “Fresnel Spot”.  Both are fairly large so will need to be positioned at a distance from the subject. Very small versions are available such as the Broncolor Picolite Fresnel Spot Attachment but they are best used for tabletop macro sort of work, also we don’t carry them at the moment, so best you forget I ever mentioned them.

 

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Happily this Fresnel approach works well, but it can be done better and both the big names in flash have specific light shapers for this, they are radically different to each other but both work superbly.

 

Profoto have the “Hard Box” this is essentially a T shaped tube with the flash head inserted into the bottom, it decreases the size of the light source and eliminates unwanted stray light giving a light rich in contrast and very similar to sunlight.

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Broncolor have gone down a different path with their “Satellite” reflector. It’s a highly polished disc reflector into which a standard head is fired this reflector concentrates the light giving the daylight effect, it’s a bit like burning ants with a magnifying glass back in the schoolyard and must not be left in the back of a car on a bright day (I learnt that one the hard way myself).

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Both the Profoto and Broncolor solutions work better if the flash heads protection glass is replaced with a special purpose one. Just to confuse us the Profoto frosted dome should be replaced with a clear one and the Broncolor clear dome should be replaced with a frosted one!!

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The next method to consider is the use of a parabolic reflector, now these “Para” reflectors are designed to bring those light rays parallel again and do a far better job than a spherical reflector, I won’t go into detail why but it’s all to do with internal angles of reflection and is also probably why rugby is a better game than football!!!

Briese make a really magnificent version specifically designed for the recreation of sunlight, it produces a spectacular fresnel like light that is also very enveloping and it can be used with flash or continuous lights.

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See how I made the move from flash to continuous so smoothly…….. I think that’s called a segway. I’m getting the hang of this I think??

 

Ok so you moving image people have been very patient with me again, thanking you, now it’s your turn.

 

Nothing changes as far as light modifying is concerned between flash and continuous, I am pleased to say so all that stuff about a small light source with parallel rays of light giving a hard light is still correct.

You can use numerous lights to give you the “sunlight” look. Traditionally an 18k hmi Fresnel has been the go to fixture for film crews looking to recreate sunlight but with recent improvements to lights we no longer always require so much power. A good alternative is the Arri max 12K or the Arri m90 9k both of which have the unique MAX reflector giving a light quality similar to a fresnel but without the lens.
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With the extra power delivered by the Arri Max range of lights you can afford to use diffusion to “take the edge off” so for an exterior shoot often an 18k or 12k unit will be used with a 9k through a scrim (1/2 stop) as a fill. In studio the smaller Arri M series units often will be employed and Kino’s or LED’s used to fill in.

The Alpha 18K K5600 is another very powerful light that could be employed to recreate daylight/sunlight, with its clear front it will give a slightly less hard light than a Fresnel but it comes with a Fresnel lens too if you need to harden up a bit so it gives you some options.

 

It’s worth mentioning at this point that despite recent improvements to cameras 18k is still the goto strength required to override sunlight, yes the Arri max range will give you the equivalent oomph at a slightly lower power rating but the sun is the sun and its not getting any duller just because the chaps at Arri are getting smarter. Film crews use 18k for one very important reason, clouds, if they appear and you don’t want to hear “cut” then you need the power of 18K to keep shooting. From what I understand this is not going to change no matter what improvements are made to cameras, well not until the sun goes super nova anyway and I think we will be safe from that for a couple of years yet.

 

Now one last thing to consider is the good old inverse square rule (remember that) it states that the strength of a light is inversely proportional to the square of the distance from its source. Now when you think about the Sun itself, it is so large and so far away from us that any exposure drop over say the length of a room is negligible, therefore a larger light positioned further away is going to give you more consistent light levels across your set than say a smaller one positioned closer. Now I don’t think I am contradicting myself as a large light positioned at a greater distance becomes a “smaller” light source just like the sun and hence retains the hard light characteristics.

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(I had to include this pic as it proves the inverse square law can also apply to people’s intelligence in relation to the distance from a tattooist shop.)

 

Ok so that’s how to recreate sunlight, easy eh it’s all about recreating the same characteristics in your light that would be present in real sunlight and in a studio when you don’t have real sunlight to work with it’s an extremely useful thing to be able to do, but once outside in the real sunlight is it a redundant skill, does it still have a use? Well to the uninitiated you would think that bright sunlight at lunchtime on a nice day would be about as good a light as you could get and it certainly is hard, high in contrast and powerful but that doesn’t really help us as photographers does it.

 

Bright sunshine is (somewhat counter-intuitively) not great for us image-makers. The high contrast nature of this light can cause us problems with tonal range and correctly exposing our subject and the background at the same time. Think about a beach scene on a bright summers day, you want to take a nice picture of the kids running out of the surf so you grab your snapper and shoot only to find that.

You have a beautiful blue sky and silhouettes for children or nicely exposed children and a washed out sky. “Damn it I spent a small fortune on this camera and  I can’t even get a snap of the kids!”

So how do we get round this problem?

Simple, you overpower the sun!

Now you can stop short of creating a small fusion reaction in your speedos to do this, as the sun is surprisingly easy to overpower (well for us stills guys it is anyway).

 

Essentially all we need to do is to meter for the background exposure and then add in some fill flash to light our subject. This flash needs to have the same characteristics as the sun to keep the feel, but we know how to do that now don’t we? Using flash for this is easy as we don’t actually need a particularly powerful flash, we as stills people only have to overcome the sun for a fraction of a second and flash equipment is good at that, it has the ability to push out large amounts of power (light) for very short amounts of time.

 

For you filmmakers however it’s a different story, yes the theory of exposing for the background and then filling the subject is the same but you need this light on for the full duration of each frame and for the entire shot. Therefore you need a lot more punch to do the same thing as us stills guys, traditionally an 18k Fresnel or similar is used for this (try running that off 4 AA’s) oh and if the kids are running any distance you’re going to need more than one to “keep them in sunlight”.

 

At this point I realize how lucky I am to be a stills guy, it puts me in mind of watching the odd orchestra walk through the green channel back in my former life, I always wondered if the double bass player was jealous of the flautist at airports.

 

That’s all folks,  let’s make this year’s summer brighter than last year by everyone using artificial lighting lots n lots. Perhaps we can bluff the sun into shining a bit more!!!!

Now before I go, the shrewd folks amongst you are probably jumping up and down screaming what about colour temperature but that’s something for a future blog I think as it’s a subject all on its own and depends a lot on what sort of sunlight you are simulating, be it midday or evening and so on I’ll get back to you on that.

Likewise if you are trying to recreate a diffused sunlight (overcast) look then we need a chat about scrims and so on, again that’s for another day.

 

I hope you all learnt something if only how to brighten up a miserable English “spring” day, or how to avoid work by reading a verbose and slightly silly blog?

Cheers for your time…… Now get back to work!

 

Merry Lighting BB




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