Exposure
Exposure is the amount of light per unit area. This light hits the cameras light sensor and can be controlled, allowing more or less light to enter the camera when recording video. This is not to get confused with aperture, although, the f-stop number can effect the exposure levels too. It's important to get a good understanding of exposure as it essentially allows you to lighten or darken your video - but you have to get the balance right. Here is a brief description of how to correctly set exposure on the HRV-Z1E: http://www.urbanfox.tv/workbooks/sonyz1/z1exposure.htm
METHOD 1: Does it look right!
Yes – simple as that. Look at the LCD screen (or a monitor) and decide whether you like what you see. Unfortunately, this method has two downsides. Firstly, you need to set up your viewfinder (and monitor) correctly. If your viewfinder is set too bright or too dark you could get false positives. Secondly, if you're new to camera operation, you're probably unsure what "right" is anyway. But, as you get more experienced with your kit and after shooting in a range of conditions - you'll just sorta know when it is right.
METHOD 2: Ask the camera.
Zoom in to the subject - go to auto iris and let the camera decide the subject's exposure - go back to manual iris - now zoom out to frame your shot. You must zoom in to the subject to prevent the auto function under or over compensating for the surrounding light levels. Remember, there will be times when the subject will be correct but the background is too bright or too dark. That's the nature of video – it is unable to accurately show a wide range of contrast in one shot.
Neutral Density Filters
The Sony HVR-Z1E has 2 neutral density filters. A neutral density filter or ND filter is a filter that modifies the intensity of all wavelengths of light equally, giving no changes in hue of colour rendition. Using the ND filters on the Z1E does not affect the white balance – because they are neutral. The two types of filters on the kit are ND1 and ND2.
ND1 reduces the amount of light entering the camera to about 1/6.
ND2 reduces the light entering the camera to around 1/32.
There are four reasons why you may need the ND Filters
1. TOO BRIGHT ND filters act like sunglasses for the camera. Certainly a good rule of thumb is… if you think you need to wear sunglasses because it is a sunny day then the camera will need them too. So, generally you will need to use the ND filters if… it is sunny you are by the sea you are on a sandy beach or working in snow.
2. F11 IS A BAD PLACE TO BE
If you turn the Iris ring you will see that F11 comes just before CLOSE and close results in no picture at all. So, F11 is a dangerous F stop to work with as you might accidentally turn the iris ring too far and loose picture completely. To solve this problem select ND1, which reduces light to about 1/6th (i.e. about 2 ½ stops) open the iris by 2 ½ f-stops to compensate and now you are not working at that dangerous F11 but nearer the middle of the range.
3. F11 IS A VERY BAD PLACE TO BE F11
is a very small aperture. These small apertures can exhibit something called diffraction. Diffraction causes light to bend as it enters the camera through the iris. The result will be pictures that look soft and out of focus. Plus, the image will look low in contrast. All in all pretty bad. To cure this we use the ND1 filter again, which forces you to open the iris to compensate – and so work at an aperture that won't cause diffraction.
4. DEPTH OF FIELD
Depth of field is the distance between the nearest and farthest “in focus” objects in the picture. It is used as a tool in picture composition… If the camera lens is stopped down (e.g. f11) then both near and far objects will appear in focus - the depth of field is deep. If the camera lens is opened up (e.g. f2) then the depth of field will become shallow. A shallow depth of field can look good on an interview. Your interviewee will be in focus – but, with a shallow depth of field, the background will be out of focus and less distracting. To decrease the depth of field in a picture open the iris (ie make the aperture larger – e.g. around f2 ). Now, every stop you change doubles the amount of light entering the camera. This means the picture will become overexposed. To counteract this add in some ND filter.
Taken from: http://www.urbanfox.tv/workbooks/sonyz1/z1exposure.htm
Gain
Gain or ISO is a crucial thing to consider when filing. When you click record on the camera, light travels into your lens, through your aperture, and your shutter controls how long each frame of video is exposed to the incoming light. Gain or ISO boosts your sensors sensitivity to light. By using this, it can increase the voltage in the pixels of the photo taken, increasing its overall brightness. However, this can increase the noise levels within the photo, making the blacks seems distorted and green, not smooth and black. By keeping the overall sensitivity low, around 200, this should keep the noise levels down. You should only really increase the gain when you're in low level lighting such as night time or indoors.
White Balance
White balance (WB) is the process of removing unrealistic colour, so that objects which appear white in person are rendered white in your photo. White balance has to take into account the "colour temperature" of a light source, which refers to the relative warmth or coolness of white light. Our eyes are very good at judging what is white under different light sources, but digital cameras often have great difficulty with auto white balance and can create unsightly blue, orange, or even green colour casts with your footage. Understanding digital white balance can help you avoid these colour casts, thereby improving your photos under a wider range of lighting conditions.
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