How faithful are digital images?

The processor in a digital camera can reveal or change the appearance of the information coming into the camera and we may notice it or not.

The processor may alter the distribution of darker and lighter areas, taking out some of the subtleties. And we may see this alteration as making the image look artifical or unnatural.

If it is a good camera it may show all these subtleties of tone, and do so in a way that film camera technology struggled to do.

Lighting
And using a flashlight and a mirror it is very easy to appreciate what is going on. Standing in front of a mirror in a darkened room and playing the beam from a flashlight on your face, we can notice how very small changes in the angle at which the light hits the face can make it appear narrower or broader, and can make features appear more or less pronounced.

Every woman who makes herself knows how lighting affects the appearance of things, and of course studio portrait photographers use lighting to build a ‘light picture’ that best suits the subject. Lighting for film and television is an art form of building the preferred image with light.

Altering information
But the image processors in some cameras do more than just block up tones. They actually change the details of the subject I recall, some years ago, seeing crops at 100% of images from a digital SLR, where the camera had produced an image that did not reflect the subject.

The processing engine in the camera had ‘moved’ darker and lighter areas around in the small details, and effectively altered the subject. An eyebrow appeared turned up at the edge, when it did not do so in the person being photographed.

Digital technology has come a long way in the past few years in producing images that are both more film-ic and natural looking, and which accurately reflect the subject.

Which is not to say that it is only the current crop of cameras that can deal with subtlety in tonal distibution. This is a crop from a studio shot taken several years ago with a Nikon D70 , which under good lighting, could produce good tonal subtlety.

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What is good lighting?
There is no doubt that current cameras can handle poor lighting conditions better than earlier models, whether it is bright and contrasty light or low light with deep shadows. But ‘handling’ poor light and using the best light are not the same thing and do not give equal results.

The essence of studio lighting is that it controls the brightness range, and the photographer makes sure the range from the lightest to the darkest areas is within the capability of the camera’s processor.

That restricted tonal range applies to daylight shots as well, which is why light but overcast days are better for photography than harsh sunlight.

Lighting is described as specular or diffuse.

Lighting from a small light source is specular and it casts a harsh shadow. The sun may be big but it is far away and it casts harsh shadows.

Overcast days means the lighting is bounced of the clouds and diffused over the sky.

With diffuse lighting the range from the brightest to the darkest areas is small. In full, bright sun, where there are harsh shadows and burned-out highlights, the range may be too great for the camera, and importantly, even if it is not, the tones have to be compressed, making for a less pleasant image.

Many nature photographers put their gear in the cupboard throughout the summer season. Most shoot early in the morning or late in the afternoon to avoid the harsh unflattering overhead sun.

Portrait photographers shooting outdoors use reflectors, overhead diffusers, and fill-flash to even up the lighting and reduce the overall contrast range.

Overhead diffusers may seem an impossibility, bearing in mind how big the sky is, but take a look at some of the products from California Sunbounce.

3 thoughts on “How faithful are digital images?

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