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    3. Pink flamingo. In spite of abrupt contrast of light and dark even in small details, good optics smears the blurred background beautifully. Bright colours create an illusion of third dimension, though the sun is straight behind the camera. Camera Name Model - Nikon D2X. Sensitivity 100 ACA. Camera lens 70-200/2,8. Exposure 1/1250 sec. Aperture value – 4,5.
At first, eyes accustomed to film pictures perceive digital photos with hostility. Some photographers and specialists who prepare the pictures for printing in magazines aspire to modify digital photographs and restore their habitual film aesthetic by means of Photoshop. Some of them do this on a hunch, others – consciously. Other photographers liked the new type of acutance and use the innovative technologies, enjoying the new almost unlimited power over the image. Their life has turned into an absorbing struggle for acutance of an image or, on the contrary, against it.
Let’s try to clear out how to obtain a maximum acutance of image in practice.
    Though the thought seems trite, struggle for acutance starts in a shop. Before buying a lens or camera with internal optics you should examine characteristics of the sophisticated equipment. Without going into technical details it’s possible though to formulate some regularity.
   1. Expensive camera lenses with fixed focal length depict better than cheep lenses of the same class.
   2. Camera lenses with changeable focal length (zooms) have lower acutance. They also often blur the image at the edges of shot; they function differently at extreme values of focal length. For instance, a very expensive zoom Nikon 17-55/2,8 violates image stability from one sample to another. It can depict small details badly on condition that aperture is open at wide end 17 mm, yet it can demonstrate perfect acutance at focus of 50 mm. Another sample of the same camera lens can function properly at any focal length. Don’t think that the information mentioned above relates only to camera lenses of the named brand. Unfortunately, lenses of most camera makers have such defects nowadays.
   3. There are no multi-purpose lenses. All of them have properties peculiar to their class. For example, wide-angle camera lenses (lenses with taking angle from 180° to 40°) have higher depth resolution than standard lenses (i.e. lenses with taking angle from 40° to 55°). Portrait and telephoto lenses (lenses with taking angle from 55° to 1°) always have lower depth resolution than standard or wide-angle lenses.
Soft-focus lenses are specially designed to produce image of reduced contrast and acutance. This effect is obtained by means of increase of spherical aberration (optics defect when a halo or glow arises around any point of the image). This causes reduction of image acutance and micro contrast. These are expensive portrait camera lenses with aperture ratio from 1,4 to 2,8.
   There are also macro camera lenses in the shops. These lenses are specially designed for small objects shooting applying high degree of enlargement. Lens carriers preclude from setting acutance on objects which are situated close to the camera. Optics marked as macro is saved from such drawback. It allows enlarging small objects several times more (See photo 4).