ewa marine - tips & tricks

Contents:

Which time of day is most suited for under water photography / filming ?
Wide angle adapters - when and how should they be used ?
UW-colour correction filters - when and how should they be used ?
UV-filters - why and for which cameras ?
water droplets on the front port.
How to stop condensation from forming on the inside of the front port.
Photo- and video-lead - what they are and which ones fit your housing.
How to stop the camcorder from moving inside the housing.
More questions? Send us am e-mail !

Which time of day is most suited for under water photography / filming ?

In contrast to film and photography on dry land, where the best light is generally found early in the morning, or late in the afternoon, noon offers the best light for under water footage.
The reason for this can be found in the light filter properties of water. After only 5 m (15 feet) the ray of light passing through water has already noticeably lost some of is red spectrum. For that reason we tend to use that time of day for our footage in which the light has the shortest distance to travel through the water on its way to our lens. That is the time, when the sun is directly above and generally speaking between 11:00 a.m. and 2:00 p.m.

Wide angle adapters - when and how should they be used ?

There are at least four good reasons, why an additional wide angle adapter lens should be fitted to the camcorder when filming under water (In the case of SLR cameras the standard 30mm focal length are generally sufficient):

	1.	Water is a most effective filter for light. After only 5 m (15 feet) the ray of light passing through water has already noticeably lost some of is red spectrum and after 10m (30 feet) all red has vanished from the scenery. Yellow and green follow shortly as you descend. In other words, if a camera man wants to film an object 5m infront of him and 5m under water (=10m for that ray of light) the colours of that object will be dull and blue. No matter how colourful that little fish really was.... The solution: use as wide an angle as you can. The colours are only right infront and around you. Give the standard wide angle of the camcorder some extra width with an additional adapter lens.
	2.	The border between air and water acts light a natural lens and makes objects appear closer then they are. In actual fact it eliminates the effect of your factory fitted wide angle by a factor of x0.7 !
	3.	Water is a seldom clear medium. Sand, plankton and minerals suspended in the water obscure objects further from the lens and make them appear unsharp on the footage.
	4.	A diver rarely stands perfectly still in the water (and please do not touch those corrals. It will kill them and spoil the fun of those who follow, including yourself next season !) It is therefore unlikely, that you will actually get that moving fish perfectly where you want him in the picture. The results of your work will only be the odd fin and lots of background...

For this reason ewa-marine has developed the WW6 wide angle adapter lens. This product is ideally suited for under water use, and due to its very short length, will not only fit into most ewa-marine housings, but into aluminium and poly-carbonate/Lexan housings of other manufacturers as well.
(specs: 80mm (3.15 in) diameter; 18mm (0.71 in) length; 58mm filter thread; factor x0.6)

UW-colour correction filters - when and how should they be used ?

UW-colour correction filters can be used in conjunction with photo and video equipment to markedly improve the quality of the results. Water changes the natural colour balance and even at very shallow depth starts to remove the red light. The result are those well known bluish pictures of under water photography. The reddish UW-colour correction filters help solve this dilemma reintroducing the red just as the light is about to enter the lens
The colour and other properties of the water will, alas, also influence its filter properties. We differentiate between "blue" (in the tropics) and "green" (in lakes and the sees of the temperate zones, including the northern Mediterranean) water.
For this reason, ewa-marine has developed two distinct UW-colour correction filters:

	FUW-b	for blue water
	FUW-g	for green water

Both systems come with the following filter threads:
37mm, 46mm, 49mm, 52mm, 55mm, 62mm, 67mm
The autofocus will register the light about two settings lower with the filter in place. So there should be as much light as possible, e.g. around noon. Also do not try to use the filters above a depth of 5m (15 ft), where there is still enough light for conventional work.

Please note: Do not take any pictures with a flash or other external light carried by the diver while the filters are in place, as they will turn out overly orange.

UV-filters - why and for which cameras ?

The UV- Filter (ultra violet light filter) will remove the invisible UV-light and the haze occasionally resulting from this light. Results are normally crisper and clearer. The filter is also a perfect protection of the lens from fingerprints, scratches and general dirt.

The UV-filters are not necessary for under water use, as the UV-light is the first spectrum to be filtered out of the light after only a few feet.

water droplets on the front port.

Whenever you want to take a half & half photo (half the picture under and half over the water level), you will find some drops sticking to the front port above the water level.
To avoid this, rub the outside of the front port gently with a slice of apple. The fruit acid in the apple will break the surface tension of the water and stop the drops from forming. Depending on the water (salt or fresh water) the application must be repeated after about 3-5 minutes and can be repeated as often as necessary.

How to stop condensation from forming on the inside of the front port.

When you insert your camera or camcorder into the housing, you are also "inserting" fresh and usually moist air. If you then enter water that is slightly cooler then the air above it, this will cause the air inside the housing to cool as well and as cool air can carry less moisture, drops of condensation can appear on the front port or the camera.

This can be alleviated by adding a drying agent into the housing (ewa-marine CD-5). Many of our housings have a special pouch for the CD-5 or just insert it next to the equipment. As the silica needs some time to act, give it about 10-15 minutes after closing the housing before entering the water.

Also try to find a dry place to install the camera into the housing: preferably cooler than average air-conditioned) and away from open water.

Photo- and video-lead - what they are and which ones fit your housing.

ewa-marine has developed special photo-, BF1 and video-, BV2, lead weights to be used in conjunction with our housings. These weights can be used to trim the housing to be neutral at a depth predetermined by the diver.

	BV2 (2x0,7 kg)	The video leads can either be inserted in the lead-belt included in some housings or strapped to the lead-belts fitted under some units. (please do not hang lead to housings that are not in the water. This will cause unnecessary extra wear to the housing an decrease its life expectancy. Clip the weights on as the housings reach water level) These lead weights are also suitable for use with the U-AXP autofocus SLR housing
	BF1 (1,5 kg)	The photo lead has the same shape as the foam included in the U-A, U-AX, U-AXP and U-AZ. This foam piece can be replaced by the lead. The BF1 is coated with a soft latex to ensure, that it will help protect your equipment.

Please note, that the flexible housing behaves just like the organs of a diver with regards to water pressure. As stated by the law of physics of Boyle-Mariotte (pressure x volume = constant) the volume of air in the housing (just as that in the lungs, diving jacket and the air inclusions in the diving suit) decreases as it descends. In other words, a housing that is positively buoyant on the surface will be neutral at a certain depth and thereafter even show a tendency to sink. This point can be "adjusted" by adding weights to the housing, the amount of air included in the housing and some practice...

also read: "how much air should there be in the closed housing?"

How to stop the camcorder from moving inside the housing

As most of our products were designed to fit a multitude of similar camcorders and cameras, it can happen, that in your case the camcorder seams to be lose in the housing and actually moves around by itself! Although the fit should be lose, to allow for safe and easy access as well as a reservoir of air, the camcorder should definitely not move.
In most cases the solution can be found by positioning one of the foam pads supplied behind or next to the camcorder. Feel free to add additional padding (which will double as shock protection on land)
In some cases the reason can be traced to too much air in the housing. Close the housing lightly and press it gently against your chest to allow the excess air to escape. But please note: NEVER open the housing under water! And remember to leave some air in the housing to be compressed as you dive.