It has been observed that a single glass lens produces higher quality images compared to a pinhole. However, the sharpness of the image tends to be inconsistent, even when the subject is at a constant distance. Single lenses may introduce shape distortions, color fringing, or a general haziness. These effects can impart a unique, often described as “atmospheric” or “romantic,” quality to the images, giving them a surreal or otherworldly feel, as opposed to the classical sharp and detailed photography.
Typically, such qualities are not desirable, so a lens capable of producing high clarity and detail is preferred. Some of the effects achieved with pinhole or single-lens cameras can be replicated with diffusers or filters, or through digital manipulation in post-processing or during printing. However, the results differ, and it is advisable to explore all options before deciding on a specific approach.
The primary goal in the design and manufacture of photographic equipment is to create lenses that minimize optical defects while maximizing image detail and brightness. To achieve this, camera manufacturers employ a variety of specialized optical lenses, each made from different types of glass with specific refractive and dispersion properties. A photographic lens typically consists of multiple elements of varying shapes and glass types to correct aberrations. Standard camera lenses usually have between five to eight elements.
Regarding focal length and angle of view:
- The natural field of view of the human eye is approximately 45 degrees, making a lens covering this angle a “standard” or “normal” lens. This is roughly equivalent to the diagonal of the camera’s frame format.
- For a 35mm (24×36mm) camera, a standard lens has a focal length of around 50mm.
- For a 60×70mm roll film camera, the standard lens is about 80–105mm.
- For APS (17×30mm) cameras, the normal lens is 25mm.
- Compact digital cameras with a 4.8×6.4mm sensor typically use a standard lens of 6–10mm.
- Professional digital SLRs with larger sensors (around 15×22.5mm) use a standard lens of around 28mm.
- High-end professional digital SLRs with full-frame sensors (24×36mm) use a 50mm lens as standard, similar to a 35mm film camera.
- For a 5×4 inch plate camera, a standard lens is 150mm.
