Category Archives: Shooting Tips

cameras, Shooting Tips, shoots, Travel

Tips for shooting in very cold weather.

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(Updated 12/2023)

With winter well upon us I thought it would be good to share some of my arctic shooting experience. I’ve shot in temperatures down to -45c in the arctic in winter.

Overall modern tapeless cameras do OK in extreme cold. The most reliable cameras are generally larger solid state cameras. Larger cameras cool slower than small ones and larger cameras will hold on to heat generated internally better than small ones. Cameras and electronics with lots of cooling vents can sometimes also be troublesome as the vents allow them to cool more quickly. But cold is not necessarily going to be the biggest problem.

IMPORTANT NOTE: It is EXTREMELY dangerous to charge normal  lithium batteries that are below freezing. Below freezing the lithium in the battery migrates to the anode of the battery cell. This cuase permanent damage to the battery shortening its life and if enough builds up around the anode it can short the battery out causing a sudden fire/explosion. Each time you charge a very cold lithium battery more lithium builds up. It is possible for a lithium battery that has been charged when very cold to suddenly burst into flames some weeks/months/years later if bumped or knocked causing the lithium build around the anode to shift. Always warm up any lithium batteries before attempting to charge them.

Filming in a remote arctic area. Photo by Jan Helmer Olsen.

Condensation:

Condensation is the big deal breaker. When you take the very cold camera inside into a warm house/hotel/car/tent you will get condensation. If the camera is very cold this can then freeze on the body of camera including the glass of the lens. If there is condensation on the outside of the camera, there will almost certainly also be condensation inside the camera and this can kill your camera.

To prevent or at least reduce the condensation you can place the camera in a large ziplock or other sealed bag BEFORE taking it inside, take the camera inside in the bag. Then allow the camera to warm up to the ambient temperature before removing it from the bag. Peli cases are another option, but the large volume of the pelicase means there will be more moisture inside the case to condense and the insulating properties of the case mean that it could take many, many hours to warm up.

I don’t recommend storing a cold or damp camera in a Pelicase (or any other similar waterproof case) as there is nowhere for the moisture to go, so the camera will remain damp until the case is opened and everything dried out properly.

Rather than moving a camera repeatedly from outside to inside and repeatedly generating risky condensation you should consider leaving the camera outside. You can leave the camera outside provided it does not get below -30c. Below -30c you risk the LCD panel freezing and cracking. LCD  panels freeze at between -30 to -40c. If you are using a camera in very cold conditions and you notice the edges of the LCD screen going blue or dark you should start thinking about warming up that LCD panel as it may be close to freezing.

LCD displays will become slow and sluggish to respond in the cold. Your pictures may look blurry and smeary because of this. It doesn’t affect the recording, only what you see on the LCD.

Very often in cold regions houses will have an unheated reception room or porch. This is a good place to store your camera rather than taking it inside into the warm. Repeatedly taking a camera from cold to warm without taking precautions against condensation will shorten the life of your camera.
If you can, leave the camera on between shots. The camera generates some heat internally and this will prevent many issues.

BATTERY LIFE:

Li-Ion batteries are effected by the cold but they are not nearly as bad as Nicads or NiMh batteries which are all but useless below freezing. li-Ion battery life gets reduced by between 25 and 50% depending on how cold it is and the quality of the battery (very cheap cells may have a higher water content which can freeze causing the cell to dramatically lose capacity and the ability to deliver power).
Down to about -10c there is only a very marginal loss of capacity. Down to -25c you will lose about 20%-30% below -25c the capacity will fall away further and it becomes impossible to use the full capacity of the battery.

Keep your spare batteries in a pocket inside your coat or jacket until you need them. After use let the battery warm up before you charge it if you can. Charging a very cold battery will reduce the lifespan of the battery and it won’t fully charge (see note above – DO NOT CHARGE a battery that is below freezing, it is very dangerous). One top tip for shooting outside for extended periods is to get a cool box. Get some chemical hand warmers or better still electric rechargeable handwarmers and place them in the cool box with your batteries to keep them warm. If you don’t have hand warmers you can also use a hot water bottle. Chemical hand warms typically use an iron powder mixed with salts. The heat comes from the iron rapidly rusting. This process needs moisture to work. A chemical handwarmer will work great in a pocket close to your body moisture but when it is very cold there isn’t enough moisture in the air for a chemical warmer to work when it is away from your body moisture. As a result chemical warmers inside camera covers or in a cool box might not actually produce any heat.

Watch your breath

If your lens has and snow or ice on it, don’t be tempted to breath or blow on the lens to blow the ice off.  Do not to breath on the lens when cleaning it as your warm breath will condense on the cold glass and freeze.  Also try to avoid breathing out close to the viewfinder.  When it is very cold and if you are warm in your nice thick winter clothes even standing close to the camera can lead to frost and ice building up on it.  Small amounts of sweat from your body will evaporate and this moisture will find its way to the camera, even if you are a few feet (1 or 2m) from it. If doing a timelapse of the Northern Lights, once the camera is running you should move away from the camera.

A small soft paint brush is good for keeping your lens clean as in very cold conditions you’ll simply be able to brush and snow or ice off. Otherwise a large lens cloth.
Your lens will get cold and in some conditions you will get frost on the front element. To help combat this wrap some insulating fabric around the body of the lens. Wrist sweat bands are quite good for this or an old sock with the toes cut off.  For time-lapse long sessions in very cold weather you might want to get a lens heater for the lens. These are normally 12 volt or USB powered and wrap around the lens. They don’t use lots of power but they do warm the lens just enough to keep the worst of the condensation, dew and frost off the lens. They are sometimes also called “dew heaters” and are sold by most good telescope suppliers.

Covers.

Conventional plastic rain covers become brittle below about -15c and can even shatter like glass  below -20c. The clear plastic panels in other covers can also suffer the same fate. So use if you use a cover use one made out of fabric. Special insulated cold weather covers often called “polar bears” can be used and these often have pockets inside for chemical heat packs (although when very cold these don’t work, use a USB hand warmer instead). These are well worth getting if you are going to be doing a lot of arctic shooting with a larger camera and will help keep the camera warm. But for very small cameras the bulk of a thick cover can make it almost impossible to use. As an alternative wrap the camera in a scarf or cut the sleeves of an old sweater to make a tube you can slide over the camera. If you have a sewing machine you could make a simple cover out of some fleece type material.
For DSLR’s and stills cameras a balaclava can be used to cover the camera body to provide some protection. However unheated covers don’t make a big difference when the camera is outside in very cold temperatures for extended periods unless it is always left turned on, eventually the cold will get to it.

Brittle Plastic.

Plastics get brittle at low temperatures so be very gentle with anything plastic, especially things made from very hard, cheap plastic. The plastic Sony use appears to be pretty tough even at low temps. Wires and cables may become as rigid as a steel rod. Be gentle, bend then too much and the insulation may split and the cable break. I try to avoid bending any cable once it has become very cold.

Other considerations are tripods. If outside in very low temps for more than 30mins or so the grease in the tripod will become very thick and may even freeze, so your fluid damping will become either very stiff or freeze up all together. Contact your tripod manufacturer to see what temperatures their greases can be used over. Vinten and some of the other tripod companies can winterise the tripod and replace the normal grease with arctic grease. If you are unsure put your tripod head in your deep freeze at home for a few hours and see if it still works when you take it out.

Looking after yourself.

I find that the best way to operate the camera is by wearing a pair of large top quality mittens (gloves are next to useless below -15c), Consider getting a pair of Army surplus arctic mittens, they are very cheap on ebay and from surplus stores and will normally have an additional “trigger finger”. This extra finger makes it easier to press the record button and things like that.  If you can get Swedish or Finnish military winter mittens, these are amongst the best. I wear a pair of thin “thinsulate” fleece gloves that will fit inside the mittens, i can then slip my hands in and out of the mittens to operate the camera. If you can get gloves with finger tips compatible with touch screens this will allow you to use any touch functions on a camera or your phone. Get extra large mittens, then it is easier to slip your hand in and out.

I keep a chemical hand warmer inside the mittens to warm my fingers back up after using the camera (or use heated mittens powered by a USB battery pack).

The hardest thing to keep warm is your feet. If you’ll be standing in snow or standing on ice then conventional hiking boots etc will not keep your feet warm. A Scandinavian trick if standing outside for long periods is to get some small twigs and tree branches to stand on and help insulate your feet from the cold ground. If your feet get cold then you are at risk of frostbite or frost nip. Invest in or hire some decent snow boots like  Baffin’s.  There is almost nothing worse than having ice cold feet when working. Don’t forget that if you do get cold, moving around, running on the spot etc will help get your circulation going and help you to warm up. Also consider some high energy food and snacks, you will burn a lot more calories in the cold than you would do normally. Also a flask with a hot drink is always welcome.  I have an arctic clothing guide here; Arctic Clothing Guide |

Shooting Tips, Uncategorized

Back to Basics; White Balance.

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While chatting to a few people at IBC it was brought to my attention that some people find my blog a little too advanced and intimidating. So in order to try to address that I’m going to go back to basics and write about some of the basic principles of digital video. The plan is to look at some basic concepts and then expand on these so that even beginners will gain a deeper understanding of these topics.

To kick off I’m going to look at White Balance.

What Does it Do?

Accurate white balance ensures that white objects in your video appear white, in addition it ensures that colours look natural and similar to the colours you see with your own eyes while shooting the scene.

How do I set it?

You can use the cameras auto mode, often called ATW (auto tracing white balance), a preset white balance, calibrate the white balance using a white or grey object or manually dial in the white balance.

Background:

Colour Temperature

Different light sources have different colour temperatures. For example an incandescent light bulb, the type with a glowing filament has a low colour temperature while an arc lamp which is much hotter will have a higher colour temperature. Low colour temperature light sources like a filament light bulb are at the red or orange end of the visible light spectrum while hotter light sources like an arc lamp or the sun are at the blue end of the light spectrum. Our own visual system will adapt to these varying colour temperatures but a video camera needs to be set to the correct colour temperature to reproduce colours correctly. The colour temperature of a light source is measured in “degrees Kelvin” or “K”. Lower numbers will be at the red end and higher numbers at the blue end. So a filament light bulb will glow orange at typically 2,300k while the mid day sun will be around 5,500k and the light from a clear blue sky is around 9,000k. If you shoot with a camera set for a low colour temperature i.e. 3,200k outside on a sunny day your pictures will be very blue. If you shoot with a camera set for a higher temperature like daylight, typically 5,600k under filament lamps the pictures will be very orange.

Different Types of White Balance Setting.

Full Auto, ATW, Auto Tracking White, Auto White: This is generally a fully automatic mode that tries to guess the correct white balance. It normally works by assuming that the brightest parts of the scene are white objects and will try to correct these objects so that they appear white. As a result ATW is often easily fooled especially by bright slightly off white walls. As ATW is always active if the scene you are shooting changes then so may the white balance and this can be seen as a colour shift during the shot. ATW can be a little unpredictable and trying to later correct a shot where the white balance changes part way through can be very difficult. One advantage with ATW is that if you move from one place with one colour temperature to a place with a different colour temperature, for example moving from an interior room lit by filament lights to outside daylight then the ATW should compensate for the change in colour temperature automatically. On many pro  cameras ATW can be assigned to the white balance “preset, A, B” switch “B” position.

Preset White: Preset White allows you to pre set the colour temperature manually. Normally this preset will be for 3,200K (Tungsten filament lamps) or 5,600K (average daytime exterior). Many more recent Sony cameras will have a switch to select preset white and then a further button to alternate between 3,200 and 5,600K.  Preset white is useful when you have a multi camera shoot to get all cameras matching or for setting the white balance when shooting under coloured lights such as stage or concert lighting where ATW would really struggle or manual white balancing may give an incorrect colour balance. It’s is also often the white balance method of choice on projects that will be colour graded in post production as it gives a constant setting from shot to shot, scene to scene which colourists often find easier and faster to work with.

White Balance Switch and White Balance Set Button on FS700

Manual White Balance: This is sometimes misunderstood, but when done correctly will give the most accurate results. This is where you have a 3 way switch marked “Prst” (preset) “A” and “B”. When in the “A” or “B” position (assuming ATW has not been assigned to the “B” position) a white balance memory is used to determine the colour balance of the camera. To get the correct colour balance the camera needs to be sample and memorise the colour temperature of the light in the scene you want to shoot. This is done using a white or grey card or object. It doesn’t really matter which you use provided the card or object is not coloured in any way and can be correctly exposed. Be careful what you use, a lot of paper is dyed slightly blue to make it appear brighter. If you have a choice the best thing to use is a grey card designed for photography or video exposure and white balance. Place the card at the center of your shot, you want the primary light source for your scene to be falling on the card. Point the camera at the card, it should fill at least 50% of the frame and expose it so that it is around the middle of your exposure range, not bright white and not dark grey, right in the middle. Then with the white balance switch in the “A” or “B” position press the “white balance” button (often found on the front of the camera under the lens or close to the white balance switch). The camera will then adjust the gain of the red, blue and green channels so that the grey/white card shows no colour and will often display the measured colour temperature in the viewfinder or a simple “OK” message. If you get a “NG” or error message you may need to adjust your exposure up or down a little. Look at the pictures on a colour screen and check that they look OK. If not, check that the grey/white card is in the centre of your frame again and try repeating the process. You can store two manual white balance settings one in the “A” memory and one in the “B” memory and switch between them as needed.

Advanced White Balance Techniques: Sometimes it can be useful to use a white balance colour temperature that may be different from the actual colour temperature of the scene. For example if you are shooting a sunset the colour temperature of the actual light might be around 2,000 to 3,000K. If you were to white balance the camera to match this it would neutralise the orange glow of the sunset making it much less colourful. So to shoot a sunset you might want to have the camera set to a higher colour temperature to accentuate the orange sunset light. Setting the camera to preset 5,600k might work, but perhaps this takes things too far and makes it too orange. In this case you might want to dial in an in between value for your white balance like 4,400K. Some cameras will allow you to do this by changing the preset white value (in picture profiles or scene files on most Sony cameras). Alternately some cameras will allow you to add an offset to your manually set white balance, but do remember if you do this to remove it again once your done with it.

Another way to white balance the camera with a warmer or cooler white balance than the actual lighting conditions is to use a coloured card instead of a white/grey card. If you use a card with a slight blue tint then the camera will think the scene is bluer than it really is. This results in a final image that is warmer (more orange) than if you had used a white/grey card. If you use a card with a slight orange tint then the camera will think the ambient light is warmer resulting in a final image that looks cooler (more blue).  Instead of using coloured cards (often called warming or cooling cards) you can achieve exactly the same effect by doing your white balance through a blue or orange lighting gel or filter.

What to avoid: Try to avoid mixing different light sources with different colour temperatures. For example a person sat close to a window, lit by a filament light will be illuminated by the orange 3,200K light from the lamp as well as the blue 5,600K light from outside. This can result in some strange colours and the scene may look odd (of course you may deliberately choose to have this colour contrast to enhance your scene). Some light sources contain peaks and gaps in the light spectrum that they emit and this can result in odd colour reproduction. A common example of this is fluorescent lights used in homes and offices that often have a pronounced green tint to them that white balancing alone will not remove.

 

cinematography, Shooting Tips

Why Nailing Your Mid Range Will Make Post Production Happy. Even with Cingammas and Hypergammas.

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One of the concepts that’s sometimes hard to understand is why mid range exposure is so critical with most video cameras, even cameras with extended dynamic range. Cameras that use Cinegammas, Hypergammas  may give you great dynamic range and extra latitude but it’s still vital that you get your mid range exposed correctly. In many cases, the greater you cameras ability to capture a wide dynamic range the more critical mid range exposure becomes. I’ve often heard comments from users of XDCAM cameras complaining that they find it harder to work with cinegammas and hypergammas than the standard REC-709 gamma.
So why is this, it seams counter intuitive, surely a greater dynamic range makes exposure more forgiving?

Typical Standard Gamma

First lets take a look at a standard gamma curve. These graphs are not accurate, just thrown together to illustrate the point. The standard gamma for HD, REC-709 can be considered to be near linear. Certainly in terms of “what you see is what you get” the idea behind REC-709 is that if the camera is set to 709 and the TV or monitor is 709 compliant then we will get a linear 1:1 reproduction of the real world. However REC-709 is based on the gamma curves used at the very beginnings of television broadcasting where TV’s and cameras had very limited dynamic range. True REC-709 only allows for about 6 stops of dynamic range and as a result the version of REC-709 used in most video cameras is tweaked somewhat to allow a greater dynamic range in the region of 8 to 10 stops while still producing a pleasing image on most TV’s. Another way of increasing dynamic range is to introduce some form of signal compression. The simplest form of this in common use is the cameras knee circuit. This simply takes anything above a certain brightness level (typically between 80 and 95%) and compresses it. We normal get away with this compression because it’s only affecting highlights like clouds in a bright sky or a bright window or lamp in the shot. Our own visual system is tuned primarily to mid tones, faces, plants and things like that so we don’t tend to find highlight compression overly obtrusive.
When considering your post production workflow and grading in particular, it’s important to remember that in most cases whenever anything is compressed then some of the original data is being discarded. In addition if the amount of compression is non-linear (increases or decreases with amplitude) then when we add a linear function to that, like adjusting the signal gain the non-linearity is also increased.
Based on these assumptions, you should be able to understand that anything exposed in the linear part of a gamma curve will grade very well because there is no extra compression and gain adjustments will behave as expected. Now if you look at the graph of a typical standard gamma curve (as above) you can see that everything below the knee point is pretty linear, so anything exposed in this range will grade easily and well (assuming it isn’t actually overexposed). For this reason standard gamma can be very forgiving to small over exposure problems as a slightly bright face should still be in the linear part of the curve. However overexpose to the point where the face starts to enter the knee area and all is lost, you’ll never make it look natural.

Typical Cinegamma or Hypergamma

Now look at the curve for a typical Cinegamma or Hypergamma. You can see that this curve starts to become more curved and less linear much earlier than a standard gamma. This is how the extra latitude is gained. Compression is used to allow the camera to record a greater brightness range. This extra compression though comes at a price and that is linearity. The further up the exposure range you go the less linear the response (it’s actually becoming logarithmic). The result is that even though you have more dynamic range, if you do overexpose faces and skin tones by even just a small amount they will start to creep into the non linear part of the curve and this makes them harder to grade naturally. You may be less likely to get those ugly blown out highlights on a shiny face typical of video knee compression with cine/hypergammas, but you must still be very careful not to overexpose.

So there you have it. Greater dynamic range does not necessarily equate to more exposure tolerance. In fact it’s often the opposite. You might get better highlight handling, but you may find you need to be even more careful with how you expose. As we go forwards (or sideways at least) and linear raw becomes more common place then you will be able to shift you mid tone exposure up and down with a lot more flexibility as with a linear raw camera the last stop of exposure has the same linearity as the first, so in theory your mid tones can sit anywhere in the exposure range. Sony’s F65 is a great example of this. It has 14 stops of linear dynamic range. A face lit with a 3 stop range could be placed in stops 11-14 and would grade down to wherever you want just perfectly.

cinematography, Shooting Tips, Technology

Calibrating your viewfinder or LCD.

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One of the most important things to do before you shoot anything is to make sure that any monitors, viewfinders or LCD panels are accurately calibrated. The majority of modern HD cameras have built in colour bars and these are ideal for checking your monitor. On most Sony cameras you have SMPTE ARIB colour bars like the ones in the image here. Note that I have raised the black level in the image so that you can see some of the key features more clearly. If your using a LCD or OLED monitor connected via HDSDI or HDMI then the main adjustments you will have are for Contrast, Brightness and Saturation.

First set up the monitor or viewfinder so that the 100% white square is shown as peak white on the monitor. This is done by increasing the contrast control until the white box stops getting brighter on the screen. Once it reaches maximum brightness, back the contrast level down until you can just perceive the tiniest of brightness changes on the screen.

Once this is set you now use the pluge bars to set up the black level. The pluge bars are the narrow near black bars that I’ve marked as -2% +2% and +4% in the picture they are each separated by black. The -2% bar is blacker than black so we should not be able to see this. Using the brightness control adjust the screen so that you can’t see the -2% bar but can just see the +2% bar. The 4% bar should also be visible separated from the 2% bar by black.

Color is harder to set accurately. Looking at the bars, the main upper bars are 75% bars so these are fully saturated, but only at 75% luma. The 4 coloured boxes, 2 on each side, two thirds of the way down the pattern are 100% fully saturated boxes. Using the outer 100% boxes increase the saturation or colour level until the color vibrance of the outer boxes stops increasing, then back the level down again until you just perceive the color decreasing. I find this easiest to see with the blue box.

Now you should have good, well saturated looking bars on you monitor or LCD and provided it is of reasonable quality it should be calibrated adequately well for judging exposure.

I find that on an EX or F3 the LCD panel ends up with the contrast at zero, colour at zero and brightness at about +28 on most cameras.

PMW-F55, PXW-FS5, PXW-FS7, Shooting Tips, Uncategorized

When should I use a Cinegamma or Hypergamma?

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Cinegammas are designed to be graded. The shape of the curve with steadily increasing compression from around 65-70% upwards tends to lead to a flat looking image, but maximises the cameras latitude (although similar can be achieved with a standard gamma and careful knee setting). The beauty of the cinegammas is that the gentle onset of the highlight compression means that grading will be able to extract a more natural image from the highlights. Note than Cinegamma 2 is broadcast safe and has slightly reduced recording range than CG 1,3 and 4.

Standard gammas will give a more natural looking picture right up to the point where the knee kicks in. From there up the signal is heavily compressed, so trying to extract subtle textures from highlights in post is difficult. The issue with standard gammas and the knee is that the image is either heavily compressed or not, there’s no middle ground.

In a perfect world you would control your lighting (turning down the sun if necessary ;-o) so that you could use standard gamma 3 (ITU 709 standard HD gamma) with no knee. Everything would be linear and nothing blown out. This would equate to a roughly 7 stop range. This nice linear signal would grade very well and give you a fantastic result. Careful use of graduated filters or studio lighting might still allow you to do this, but the real world is rarely restricted to a 7 stop brightness range. So we must use the knee or Cinegamma to prevent our highlights from looking ugly.

If you are committed to a workflow that will include grading, then Cinegammas are best. If you use them be very careful with your exposure, you don’t want to overexpose, especially where faces are involved. getting the exposure just right with cinegammas is harder than with standard gammas. If anything err on the side of caution and come down 1/2 a stop.

If your workflow might not include grading then stick to the standard gammas. They are a little more tolerant of slight over exposure because skin and foliage won’t get compressed until it gets up to the 80% mark (depending on your knee setting). Plus the image looks nicer straight out of the camera as the cameras gamma should be a close match to the monitors gamma.