Colorfoto.de Wide angle lenses

Objective lenses with large image angles are visually complex. Above all, the very strongly refracted edge beams that occur with these models require a high correction effort. At the same time, small-picture lenses are characterized by an unnecessarily large image circle for the typical “APS-C” large SLR camera sensors. This forces the correction effort up again. If, on the other hand, the wide angle is calculated exclusively for the smaller image circle, a good imaging performance can be achieved with little effort. In digital SLRs, two problems are added: in contrast to the smooth film, a CCD or CMOS sensor is constructed from several superimposed structures including the Mikrolenses. In the case of oblique beams, this increases the vignetting in the corners, in that the structures shadow a part of the pixel areas or the microlenses do not bundle the light optimally. In the short focal lengths of the mirror box, an optimal lens design interferes with the problem: Because the distance between the rear lens and the sensor is larger than the focal length, the optical calculator has to move the rear main plane behind the lens. Canon EOS 20D The 8-megapixel APS sensor of the EOS 20D results in an apparent focal length extension by a factor of 1.6. The actual focal range remains unchanged. Only the image angle depends on the sensor size, so that a 20 mm lens at the Canon provides the same angle of view and motif as a 32 mm lens on a Kleinbildkamera. Typical for all curves are the kinks, which are not caused by the optics, but by the electronic re-sharpening. Nikon D200 Nikon currently uses APS-C image sensors in all SLR models. Since the 10 megapixel CCD of the D200 is similar to the D80 and the D40x, you can transfer our results very well to these models. Olympus E-400 Olympus has also entered the 10-megapixel class with the E400. However, Olympus has to accommodate the 10 million pixels on the smaller sensor area of ​​the 4/3 format. The sensor, which is called because of its aspect ratio 4/3, has half the diagonal of the picture format, ie a quarter of the KB area, which leads to correspondingly short focal lengths. The data are also valid for the new 10-megapixel Olympus models E-410 and E-510. Pentax K10D and Sony Alpha 100 In the Pentax and Sony similar 10-megapixel sensors as in the Nikon D200, again 10 megapixels on a 24 x 16 mm CCD chip as well as an extension factor of 1.5. However, both manufacturers rely on moving CCDs, which compensate the light wobbler of the photographer by counter-movements. Basically, Pentax tunes its cameras less contrast than Nikon or Canon, but synonymous as Sony from, which leads to lower scores. Therefore, it makes no sense to compare a Pentax lens directly with a Nikon, Sony or Canon lens. Because of the different camera settings, the absolute point level is greatly shifted, and this must be taken into account in comparisons. If you take this into consideration, take a look at the Nikon results for other lenses that we are not testing on either Sony or Pentax. Because of the similar sensor geometry, you can assume that a third-party zoom with a good Nikon result on the Pentax or Sony well. The tendencies are therefore similar, although the absolute results differ significantly.