Due to the unexpected redundancy of one of my guests I am now looking to sell on a couple of places on my Northern Lights expedition in January on his behalf.
The trip starts and finishes in Alta, Norway. Food is included for most of the trip. We spend 4 days up on the Finnmarksvidda where we normally get amazing Northern Lights viewing opportunities. I can also help guide anyone that wants to learn how to photograph or video the Aurora.
This is a real adventure and a lot of fun. The only way up to the cabins by snow scooter, crossing frozen lakes along the way. We eat a campfire lunch in a Sami style tent, we go ice fishing, exploring by snow scooter and enjoy traditional sauna nights.
This post follows on from my previous post about sensors and was inspired by one of the questions asked following that post.
While sensor size does have some effect on low light performance, the biggest single factor is really the lens. It isn’t really bigger sensor that has revolutionised low light performance. It’s actually the lenses that we can use that has chnge our ability to shoot in low light. When we used to use 1/2″ or 2/3″ 3 chip cameras for most high end video production the most common lenses were the wide range zoom lenses. These were typically f1.8 lenses, reasonably fast lenses.
But the sensors were really small, so the pixels on those sensors were also relatively small, so having a fast lens was important.
Now we have larger sensors, super 35mm sensors are now common place. These larger sensors often have larger pixels than the old 1/2″ or 2/3″ sensors, even though we are now cramming more pixels onto the sensors. Bigger pixels do help increase sensitivity, but really the biggest change has been the types of lenses we use.
Let me explain:
The laws of physics play a large part in all of this.
We start off with the light in our scene which passes through a lens.
If we take a zoom lens of a certain physical size, with a fixed size front element and as a result fixed light gathering ability, for example a typical 2/3″ ENG zoom. You have a certain amount of light coming in to the lens.
When the size of the image projected by the rear of the lens is small it will be relatively bright and as a result you get an effective large aperture.
Increase the size of the sensor and you have to increase the size of the projected image. So if we were to modify the rear elements of this same lens to create a larger projected image (increase the image circle) so that it covers a super 35mm sensor what light we have. is spread out “thinner” and as a result the projected image is dimmer. So the effective aperture of the same lens becomes smaller and because the image is larger the focus more critical and as a result the DoF narrower.
But if we keep the sensor resolution the same, a bigger sensor will have bigger pixels that can capture more light and this makes up for dimmer image coming from the lens.
So where a small sensor camera (1/2″, 2/3″) will typically have a f1.8 zoom lens when you scale up to a s35mm sensor by altering the projected image from the lens, the same lens becomes the equivalent of around f5.6. But because for like for like resolution the pixels size is much bigger, the large sensor will be 2 to 3 stops more sensitive, so the low light performance is almost exactly the same, the DoF remains the same and the field of view remains the same (the sensor is larger, so DoF decreases, but the aperture becomes smaller so DoF increases again back to where we started). Basically it’s all governed by how much light the lens can capture and pass through to the sensor.
It’s actually the use of prime lenses that are much more efficient at capturing light has revolutionised low light shooting as the simplicity of a prime compared to a zoom makes fast lenses for large sensors affordable. When we moved to sensors that are much closer to the size of sensors used on stills cameras the range and choice of affordable lenses we could use increased dramatically. We were no longer restricted to expensive zooms designed specifically for video cameras.
Going the other way. If you were to take one of todays fast primes like a common and normally quite affordable 50mm f1.4 and build an optical adapter of the “speedbooster” type so you could use it on a 2/3″ sensor you would end up with a lens the equivalent of a f0.5 10mm lens that would turn that 2/3″ camera into a great low light system with performance similar to that of a s35mm camera with a 50mm f1.4.
Every now and again I get asked how to adjust the color matrix in a video camera. Back in 2009 I made a video on how to adjust the color matrix in the Sony’s EX series of cameras. This video is just as relevant today as it was then. The basic principles have not changed.
The exact menu settings and menu layout may be a little different in the latest cameras, but the adjustment of the matrix setting (R-G, G-R etc) have exactly the same effect in the latest camera that provide matrix adjustments (FS7, F5, F55 and most of the shoulder mount and other broadcast cameras). So if you want a better understanding of how these settings and adjustment works, take a look at the video.
I’ll warn you now that adjusting the color matrix is not easy as each setting interacts with the others. So creating a specific look via the matrix is not easy and requires a fair bit of patience and a lot of fiddling and testing to get it just right.
I’m running a digital film making workshop in Dubai, December 15/16th 2017.
This 1.5 day course will take you through composition, lighting, and exposure (including color, gamma and exposure index) as well as post production including different grading techniques including LUT’s, S-Curves and color managed workflows. It will focus on how to create high quality, film-like images using the latest digital techniques. It will also cover one of the hotest topics right now which is HDR.
Day 2 will include practical sessions where different shooting techniques can be tested to compare how they effect the end result.
Just a very quick note that the last UK event of the Sony Pro Tour for 2017 will be in Glasgow on Thursday the 7th of December. I’ll be there to answer any questions and to give an in depth seminar on HDR including how to shoot HDR directly with the Sony cameras that feature Hybrid Log Gamma.
The event is free, there will be a wide range of cameras for you to play with including FS5, FS7, the new Z90 and X80 as well as monitors, mixers and audio gear.
More info here: https://www.sony.co.uk/pro/page/sony-pro-tour-2017
Our current video cameras are operating at the limits of current sensor technology. As a result there isn’t much a camera manufacturer can do to improve sensitivity without compromising other aspects of the image quality.
Every sensor is made out of silicon and silicon is around 70% efficient at converting photons of light into electrons of electricity. So the only things you can do to alter the sensitivity is change the pixel size, reduce losses in the colour and low pass filters, use better micro lenses and use various methods to prevent the wires and other electronics on the face of the sensor from obstructing the light. But all of these will only ever make very small changes to the sensor performance as the key limiting factor is the silicon used to make the sensor.
This is why even though we have many different sensor manufacturers, if you take a similar sized sensor with a similar pixel count from different manufacturers the performance difference will only ever be small.
Better image processing with more advanced noise reduction can help reduce noise which can be used to mimic greater sensitivity. But NR rarely comes without introducing other artefacts such as smear, banding or a loss of subtle details. So there are limits as to how much noise reduction you want to apply.
So, unless there is a new sensor technology breakthrough we are unlikely to see any new camera come out with a large, actual improvement in sensitivity. Also we are unlikely to see a sudden jump in resolution without a sensitivity or dynamic range penalty with a like for like sensor size. This is why Sony’s Venice and the Red cameras are moving to larger sensors as this is the only realistic way to increase resolution without compromising other aspects of the image. It’s why all the current crop of S35mm 4K cameras are all of very similar sensitivity, have similar dynamic range and similar noise levels.
A great example of this is the Sony A7s. It is more sensitive than most 4K S35 video cameras simply because it has a larger full frame sensor, so the pixels can be bigger, so each pixel can capture more light. It’s also why cameras with smaller 4K sensors will tend to be less sensitive and in addition have lower dynamic range (because the pixel size determines how many electrons it can store before it overloads).
I few years ago I was privileged to have Jean Mouettee and Thierry Legault join me on one of my Northern Lights tours. They were along to shoot the Aurora on an FS100 (it might have been an FS700) in real time. Sadly we didn’t have the best of Auroras on that particular trip. Theirry is famous for his amazing images of the Sun with the International Space Station passing in front of it.
To be able to “see” the Aurora in 3D they needed to place the camera rigs over 6km apart. I did try to take some 3D time-lapse of the Aurora a few years back with cameras 3Km apart, but that was timelapse and I was thwarted by low cloud. Jean and Thierry have gone one better and filmed the Aurora not only in 3D but also in real time. That’s no mean feat!
I’d love to see these projected in a planetarium or other dome venue in 3D. It would be quite an experience.
Jean was also in the US for the total Eclipse in August. He shot the eclipse using an FS5 recording 12 bit raw on a Atomos Shogun. He’s put together a short film of his experience and it really captures the excitement of the event as well as some really spectacular images of the moon moving across the face of the sun. I really shows what a versatile camera the FS5 is.
Please don’t take this post the wrong way. I DO understand why some people like to try and emulate film. I understand that film has a “look”. I also understand that for many people that look is the holy grail of film production. I’m simply looking at why we do this and am throwing the big question out there which is “is it the right thing to do”? I welcome your comments on this subject as it’s an interesting one worthy of discussion.
In recent years with the explosion of large sensor cameras with great dynamic range it has become a very common practice to take the images these cameras capture and apply a grade or LUT that mimics the look of many of todays major movies. This is often simply referred to as the “film look”.
This look seems to be becoming more and more extreme as creators attempt to make their film more film like than the one before, leading to a situation where the look becomes very distinct as opposed to just a trait of the capture medium. A common technique is the “teal and orange” look where the overall image is tinted teal and then skin tones and other similar tones are made slightly orange. This is done to create colour contrast between the faces of the cast and the background as teal and orange are on opposite sites of the colour wheel.
Another variation of the “film look” is the flat look. I don’t really know where this look came from as it’s not really very film like at all. It probably comes from shooting with a log gamma curve, which results in a flat, washed out looking image when viewed on a conventional monitor. Then because this look is “cool” because shooting on log is “cool” much of the flatness is left in the image in the grade because it looks different to regular TV ( or it may simply be that it’s easier to create a flat look than a good looking high contrast look). Later in the article I have a nice comparison of these two types of “film look”.
Not Like TV!
Not looking like TV or Video may be one of the biggest drivers for the “film look”. We watch TV day in, day out. Well produced TV will have accurate colours, natural contrast (over a limited range at least) and if the TV is set up correctly should be pretty true to life. Of course there are exceptions to this like many daytime TV or game shows where the saturation and brightness is cranked up to make the programmes vibrant and vivid. But the aim of most TV shows is to look true to life. Perhaps this is one of the drivers to make films look different, so that they are not true to life, more like a slightly abstract painting or other work of art. Colour and contrast can help setup different moods, dull and grey for sadness, bright and colourful for happy scenes etc, but this should be separate from the overall look applied to a film.
Another aspect of the TV look comes from the fact that most TV viewing takes place in a normal room where light levels are not controlled. As a result bright pictures are normally needed, especially for daytime TV shows.
But What Does Film Look Like?
But what does film look like? As some of you will know I travel a lot and spend a lot of time on airplanes. I like to watch a film or 2 on longer flights and recently I’ve been watching some older films that were shot on film and probably didn’t have any of the grading or other extensive manipulation processes that most modern movies go through.
Lets look at a few frames from some of those movies, shot on film and see what they look like.
The all time classic Lawrence of Arabia. This film is surprisingly colourful. Red, blues, yellows are all well saturated. The film is high contrast. That is, it has very dark blacks, not crushed, but deep and full of subtle textures. Skin tones are around 55 IRE and perhaps very slightly skewed towards brown/red, but then the cast are all rather sun tanned. But I wouldn’t call the skin tones orange. Diffuse whites typically around 80 IRE and they are white, not tinted or coloured.
When I watched Braveheart, one of the things that stood out to me was how green the foliage and grass was. The strong greens really stood out in this movie compared to more modern films. Overall it’s quite dark, skin tones are often around 45 IRE and rarely more than 55 IRE, very slightly warm/brown looking, but not orange. Again it’s well saturated and high contrast with deep blacks. Overall most scenes have a quite low peak and average brightness level. It’s quite hard to watch this film in a bright room on a conventional TV, but it looks fantastic in a darkened room.
Raiders of the Lost Ark does show some of the attributes often used for the modern film look. Skin tones are warm and have a slight orange tint and overall the movie is very warm looking. A lot of the sets use warm colours with browns and reds being prominent. Colours are well saturated. Again we have high contrast with deep blacks and those much lower than TV skin tones, typically 50-55IRE in Raiders. Look at the foliage and plants though, they are close to what you might call TV greens, ie realistic shades of green.
A key thing I noticed in all of these (and other) older movies is that overall the images are darker than we would use for daytime TV. Skin tones in movies seem to sit around 55IRE. Compare that to the typical use of 70% zebras for faces on TV. Also whites are generally lower, often diffuse white sitting at around 75-80%. One important consideration is that films are designed to be shown in dark cinema theatres where white at 75% looks pretty bright. Compare that to watching TV in a bright living room where to make white look bright you need it as bright as you can get. Having diffuse whites that bit lower in the display range leaves a little more room to separate highlights from whites giving the impression of a greater dynamic range. It also brings the mid range down a bit so the shadows also look darker without having to crush them.
Side Note: When using Sony’s Hypergammas and Cingeammas they are supposed to be exposed so that white is around 70-75% with skin tones around 55-60%. If used like this with a sutable colour matrix such as “cinema” they can look quite film like.
If we look at some recent movies the look can be very different.
The Revenant is a gritty film and it has a gritty look. But compare it to Braveheart and it’s very different. We have the same much lower skin tone and diffuse white levels, but where has the green gone? and the sky is very pale. The sky and trees are all tinted slightly towards teal and de-saturated. Overall there is only a very small colour range in the movie. Nothing like the 70mm film of Laurence of Arabia or the 35mm film of Braveheart.
In the latest instalment of the Pirates of the Caribbean franchise the images are very “brown”. Notice how even the whites of the ladies dresses or soldiers uniforms are slightly brown. The sky is slightly grey (I’m sure the sky was much bluer than this). The palm tree fronds look browner than green and Jack Sparrow looks like he’s been using too much fake tan as his face is border line orange (and almost always also quite dark).
Wonder woman is another very brown movie. In this frame we can see that the sky is quite brown. Meanwhile the grass is pushed towards teal and de-saturated, it certainly isn’t the colour of real grass. Overall colours are subdued with the exception of skin tones.
These are fairly typical of most modern movies. Colours generally quite subdued, especially greens and blues. The sky is rarely a vibrant blue, grass is rarely a grassy green. Skin tones tend to be very slightly orange and around 50-60IRE. Blacks are almost always deep and the images contrasty. Whites are rarely actually white, they tend to be tinted either slightly brown or slightly teal. Steel blues and warm browns are favoured hues. These are very different looking images to the movies shot on film that didn’t go through extensive post production manipulation.
So the film look, isn’t really about making it look like it was shot on film, it’s a stylised look that has become stronger and stronger in recent years with most movies having elements of this look. So in creating the “film look” we are not really mimicking film, but copying a now almost standard colour grading recipe that has some film style traits.
BUT IS IT A GOOD THING?
In most cases these are not unpleasant looks and for some productions the look can add to the film, although sometimes it can be taken to noticeable and objectionable extremes. However we do now have cameras that can capture huge colour ranges. We also have the display technologies to show these enormous colour ranges. Yet we often choose to deliberately limit what we use and very often distort the colours in our quest for the “film look”.
HDR TV’s with Rec2020 colour can show both a greater dynamic range and a greater colour range than we have ever seen before. Yet we are not making use of this range, in particular the colour range except in some special cases like some TV commercials as well as high end wild life films such as Planet Earth II.
This TV commercial for TUI has some wonderful vibrant colours that are not restricted to just browns and teal yet it looks very film like. It does have an overall warm tint, but the other colours are allowed to punch through. It feels like the big budget production that it clearly was without having to resort to the modern defacto restrictive film look colour palette. Why can’t feature films look like this? Why do they need to be dull with a limited colour range? Why do we strive to deliberately restrict our colour pallet in the name of fashion?
What’s even more interesting is what was done for the behind the scenes film for the TUI advert…..
The producers of the BTS film decided to go with an extremely flat, washed out look, another form of modern “film look” that really couldn’t be further from film. When an typical viewer watches this do they get it in the same way as we that work in the industry do? Do they understand the significance of the washed out, flat, low contrast pictures or do they just see weird looking milky pictures that lack colour with odd skin tones? The BTS film just looks wrong to me. It looks like it was shot with log and not graded. Personally, I don’t think it looks cool or stylish, it just looks wrong and cheap compared to the lush imagery in the actual advert (perhaps that was the intention).
I often see people looking for a film look LUT. Often they want to mimic a particular film. That’s fine, it’s up to them. But if everyone starts to home in on one particular look or style then the films we watch will all look the same. That’s not what I want. I want lush rich colours where appropriate. Then I might want to see a subdued look in a period piece or a vivid look for a 70’s film. Within the same movie colour can be used to differentiate between different parts of the story. Take Woody Allen’s Cafe Society, shot by Vittorio Storaro for example. The New York scenes are grey and moody while the scenes in LA that portray a fresh start are vibrant and vivid. This is I believe important, to use colour and contrast to help tell the story.
Our modern cameras give us an amazing palette to work with. We have the tools such as DaVinci Resolve to manipulate those colours with relative ease. I believe we should be more adventurous with our use of colour. Reducing exposure levels a little compared to the nominal TV and video – skin tones at 70% – diffuse whites at 85-90%, helps replicate the film look and also leaves a bit more space in the highlight range to separate highlights from whites which really helps give the impression of a more contrasty image. Blacks should be black, not washed out and they shouldn’t be crushed either.
Above all else learn to create different styles. Don’t be afraid of using colour to tell your story and remember that real film isn’t just brown and teal, it’s actually quite colourful. Great artists tend to stand out when their works are different, not when they are the same as everyone else.
Just to let you know that from next month Sony we will be holding a tour in selected European countries to showcase their Handheld camcorder range, and as a result starting from November they will visit 4 locations across the UK, as detailed below. I will be in attendance at the UK events offering free advice and info, so if there is anything you are struggling with why not drop in and see me:
Electronics and water are two things that just don’t match. We all know this and we all know that dropping a camera into a river or the sea probably isn’t going to do it a great deal of good. But one of the very real risks with any piece of electronics is hidden moisture, moisture you can’t see.
Most modern high definition or 4K pro video cameras have fans and cooling systems designed to keep them operating for long periods. But these cooling systems mean that the camera will be drawing in air from the outside world into the cameras interior. Normally this is perfectly fine, but if you are operating in rain or a very wet environment such as high humidity, spray, mist, fog etc it will mean a lot of moisture circulating through the camera and this can be a cause of problems.
If the camera is warm relative to the ambient temperature then generally humid air will simply pass through the camera (or other electronics) without issue. But if the camera is colder than the airs dewpoint then some of the moisture in the air will condense on the cameras parts and turn into water droplets.
A typical dangerous scenario is having the camera in a nice cool air conditioned car or building and then taking the camera out of the car/building to shoot on a warm day. As the warm air hits the slightly colder camera parts moisture will form, both on the outside and the inside of the cameras body.
Moisture on the outside of the camera is normally obvious. It also tends to dry off quite quickly, but moisture inside the camera can’t be seen, you have no way of knowing whether it’s there or not. If you only use the camera for a short period the moisture won’t dry out and once the fans shut down the cameras interior is no longer ventilated and the moisture stays trapped inside.
Another damaging scenario is a camera that’s been splashed with water, maybe you got caught in an unexpected rain shower. Water will find it’s way into the smallest of holes and gaps through capillary action. A teeny, tiny droplet of water inside the camera will stay there once it gets inside. Get the camera wet a couple of times and that moisture can start to build up and it really doesn’t take a lot to do some serious damage. Many of the components in modern cameras are the size of pin heads. Rain water, sea water etc contain chemicals that can react with the materials used in a cameras construction, especially if electricity is passing through the components or the water and before you know it the camera stops working due to corrosion from water ingress.
Storing you delicate electronics inside a nice waterproof flight case such as a Pelicase (or any other similar brand) might seem like a good idea as these cases are waterproof. But a case that won’t let water in also won’t let water and moisture out. Put a camera that is damp inside a wateproof case and it will stay damp. It will never dry out. All that moisture is gong to slowly start eating away at the metals used in a lightweight camera body and some of the delicate electronic components. Over time this gets worse and worse until eventually the camera stops working.
So What Should You Do?
Try to avoid getting the camera wet. Always use a rain cover if you are using a camera in the rain, near the sea or in misty, foggy weather. Just because you can’t see water flowing off your camera it doesn’t mean it’s safe. Try to avoid taking a cold camera from inside an air conditioned office or car into a warmer environment. If you need to do this a lot consider putting the camera in a waterproof bag ( a bin bag will do) before taking the camera into the warmer environment. Then allow the camera to warm up in the bag before you start to use it. If driving around in a car from location to location consider using less air conditioning so the car isn’t so cold inside.
Don’t store or put away a damp camera. Always, always throughly dry out any camera before putting it away. Consider warming it up and drying it with a hairdryer on a gentle/low heat setting (never let the camera get too hot to handle). Blow warm dry air gently into any vents to ensure the warm air circulates inside to remove any internal moisture. Leave the camera overnight in a warm, dry place with any flaps or covers open to allow it to dry out throughly.
If you know you camera is wet then turn it off. Remove the battery and leave it to dry out in a warm place for 24 hours. If it got really wet consider taking it to a dealer or engineer to have it opened up to make sure it’s dry inside before adding any power.
If you store your kit in waterproof cases, leave the lids open to allow air to circulate and prevent moisture building up inside the cases. Use Silica Gel sachets inside the cases to absorb any unwanted moisture.
If you live or work in a warm humid part of the world it’s tough. When I go storm chasing going from inside the car to outside in the warm to shoot is not healthy for the camera. So at the end of each day take extra care to make sure the camera is dry. Not just any obvious moisture on the outside but dry on the inside. So this normally means warming it up a little (not hot, just warm). Again a hair drier is useful or leave the camera powered up for a couple of hours in an air conditioned room (good quality aircon should mean the air in the room is dry). I keep silica gel sachets in my camera bags to help absorb any surplus moisture. Silica gel sachets should be baked in an oven periodically to dry them out and refresh them.
Fogged Up Lens?
Another symptom of unwanted moisture is a fogged up lens. If the lens is fogged up then there will almost certainly be moisture elsewhere. In the case of a fogged up lens one thing that sometimes helps (other than a hairdryer) is to zoom in and out a lot if it’s a zoom or change the focus a lot. Moving the lens elements backwards and forwards inside the lens helps to circulate air inside the lens and can speed up the time it takes to dry out.
Camera setup, reviews, tutorials and information for pro camcorder users from Alister Chapman.