Kelv2888
9th of May 2005 (Mon), 23:13
I have a Canon 20D with 2 L lenses.
Some browsing on the net about digital lenses like EFS lenses are making me wonder.
It is stated that for a digital sensor, the light needs to hit the sensor at a very specific and precise angle for a optimum image.
Is the image with a regular non digital lens inferior to a image taken with a specialized lens for digital?
Heres some of the things I've read.
http://www.warehouseexpress.com/PHOTO/digicameras/olympuse/001.html
Anders Uschold, a lecturer on digital imaging and digital photography, a respected journalist and an expert court witness for analogue and digital photography, carried out a special scientific test in 2002. He examined three six megapixel cameras with high-quality lenses designed for analogue models and a five megapixel camera with a lens optimised for digital photography. The aim was to investigate the capabilities of digital cameras and compare 'analogue' lenses (designed for 35mm systems) with those optimised for digital capture.
The result was, that the camera with fewer pixels but using a lens system optimised for digital photography was more effective than the higher-resolution models with lenses made for analogue cameras.
http://www.popphoto.com/article.asp?print_page=y§ion_id=2&article_id=849&page_number=1&preview=
This extra reach is a real plus, but what about other possible side-effects, such as lower corner resolution, contrast, and brightness, that some manufacturers claim you get when older lenses are used on digital SLRs? Are these real problems or a marketing ploy?
According to Olympus and several other manufacturers, resolution and light falloff around the edges of an image are caused by the extreme angles of light from a non-aspheric lens striking the smaller image sensor found on a typical digital SLR (see our test of the Olympus E-1 (http://www.popphoto.com/article.asp?section_id=2&article_id=742), November 2003). This is particularly noticeable at wide apertures on wide-angle lenses. Image contrast is also lowered by increased lens flare, which is caused by two things: First, light bouncing off the internal components and sides of a lens adds unwanted light to shadow areas. Second, light striking the protective glass filters on the front of a CCD or CMOS sensor reflects back to the rear lens elements and is mirrored back to the image sensor, again adding light where it doesn’t belong. On film SLRs, a coating on the back of the film minimized this part of the flare problem, so few lenses were designed with anti-reflective coatings on the rear elements. Newer digital lenses include more aspherical lens elements to straighten out the light path and more anti-reflective coatings on rear elements.
http://www.photoxels.com/tutorial_focal_length.html
Digital Lenses
Digital camera manufacturers are now working on lenses that are made specially for digital cameras ['Digital' lens is really an unfortunate misnomer]. Film can be properly exposed with light incident on it at any angle. An image sensor, on the other hand, consists of a matrix of light-gathering photosites set in "wells" and pretty much requires that light be incident on it at right-angle. This means that lenses made for 35mm film cameras may not be always adequate to the job.
http://www.shutterbug.net/test_reports/1204zuiko/index1.html
Unlike lenses originally designed for film photography, all Zuiko Digital lenses are engineered to produce optimal image quality with the “Four Thirds” CCD with its three-dimensional surface structure. According to an Olympus rep, the digital optimization starts with higher resolving power, “to get the most out of the imaging element.” The lenses also benefit from improved polishing technology, low dispersion or aspherical elements, and superior coatings to suppress internal flare caused by the highly reflective sensor. In addition, each barrel lens includes an Olympus exclusive, called “smart lens design.” A built-in CPU and special firmware enables the lens to transfer data to the camera, allowing for correction of aberration and darkening at the corners of the frame. (For vignetting correction, the camera’s Shading Compensation feature must be enabled; this is also unique to Olympus.) Any distortion can be easily corrected later using the Olympus Viewer software.
Short focal length lenses, such as the 11-22mm zoom, particularly benefit from the new design that causes all light rays to strike the CCD sensor at a near perpendicular angle. In older wide angle lenses, light entering near the edges strikes the sensor plane at increasingly oblique angles. That’s not a problem when shooting film, but in digital photography it can produce softness and darkening at the periphery of the frame
Thanks for the replys
Some browsing on the net about digital lenses like EFS lenses are making me wonder.
It is stated that for a digital sensor, the light needs to hit the sensor at a very specific and precise angle for a optimum image.
Is the image with a regular non digital lens inferior to a image taken with a specialized lens for digital?
Heres some of the things I've read.
http://www.warehouseexpress.com/PHOTO/digicameras/olympuse/001.html
Anders Uschold, a lecturer on digital imaging and digital photography, a respected journalist and an expert court witness for analogue and digital photography, carried out a special scientific test in 2002. He examined three six megapixel cameras with high-quality lenses designed for analogue models and a five megapixel camera with a lens optimised for digital photography. The aim was to investigate the capabilities of digital cameras and compare 'analogue' lenses (designed for 35mm systems) with those optimised for digital capture.
The result was, that the camera with fewer pixels but using a lens system optimised for digital photography was more effective than the higher-resolution models with lenses made for analogue cameras.
http://www.popphoto.com/article.asp?print_page=y§ion_id=2&article_id=849&page_number=1&preview=
This extra reach is a real plus, but what about other possible side-effects, such as lower corner resolution, contrast, and brightness, that some manufacturers claim you get when older lenses are used on digital SLRs? Are these real problems or a marketing ploy?
According to Olympus and several other manufacturers, resolution and light falloff around the edges of an image are caused by the extreme angles of light from a non-aspheric lens striking the smaller image sensor found on a typical digital SLR (see our test of the Olympus E-1 (http://www.popphoto.com/article.asp?section_id=2&article_id=742), November 2003). This is particularly noticeable at wide apertures on wide-angle lenses. Image contrast is also lowered by increased lens flare, which is caused by two things: First, light bouncing off the internal components and sides of a lens adds unwanted light to shadow areas. Second, light striking the protective glass filters on the front of a CCD or CMOS sensor reflects back to the rear lens elements and is mirrored back to the image sensor, again adding light where it doesn’t belong. On film SLRs, a coating on the back of the film minimized this part of the flare problem, so few lenses were designed with anti-reflective coatings on the rear elements. Newer digital lenses include more aspherical lens elements to straighten out the light path and more anti-reflective coatings on rear elements.
http://www.photoxels.com/tutorial_focal_length.html
Digital Lenses
Digital camera manufacturers are now working on lenses that are made specially for digital cameras ['Digital' lens is really an unfortunate misnomer]. Film can be properly exposed with light incident on it at any angle. An image sensor, on the other hand, consists of a matrix of light-gathering photosites set in "wells" and pretty much requires that light be incident on it at right-angle. This means that lenses made for 35mm film cameras may not be always adequate to the job.
http://www.shutterbug.net/test_reports/1204zuiko/index1.html
Unlike lenses originally designed for film photography, all Zuiko Digital lenses are engineered to produce optimal image quality with the “Four Thirds” CCD with its three-dimensional surface structure. According to an Olympus rep, the digital optimization starts with higher resolving power, “to get the most out of the imaging element.” The lenses also benefit from improved polishing technology, low dispersion or aspherical elements, and superior coatings to suppress internal flare caused by the highly reflective sensor. In addition, each barrel lens includes an Olympus exclusive, called “smart lens design.” A built-in CPU and special firmware enables the lens to transfer data to the camera, allowing for correction of aberration and darkening at the corners of the frame. (For vignetting correction, the camera’s Shading Compensation feature must be enabled; this is also unique to Olympus.) Any distortion can be easily corrected later using the Olympus Viewer software.
Short focal length lenses, such as the 11-22mm zoom, particularly benefit from the new design that causes all light rays to strike the CCD sensor at a near perpendicular angle. In older wide angle lenses, light entering near the edges strikes the sensor plane at increasingly oblique angles. That’s not a problem when shooting film, but in digital photography it can produce softness and darkening at the periphery of the frame
Thanks for the replys