- Canon EF 70-300mm lens
The EF 70-300mm lens is a telephoto zoom lens made by
Canon Inc. The lens has an EF mount to work with the EOS line of cameras.Two Canon EF telephoto
zoom lens es carry the 70-300mm designation. These are the EF 70-300mm f/4.5-5.6 DO IS USM and the EF 70-300mm f/4-5.6 IS USM. Both versions offer IS and USM and both have nearly the same maximumaperture of 4/4.5 to 5.6 over their entire focal range.EF 70-300mm f/4.5-5.6 DO IS USM
This lens makes use of Canon's Diffractive Optics rather than a traditional lens of wholly refractive design. This allows the lens to be more compact, albeit heavier and much more expensive than a lens of conventional design. The lens contains Image Stabilization and a ring USM, which allows full time manual focusing of the lens while using the camera in single shot mode. This lens offers good optical quality with the caveat that the diffractive element does not deal with strong incident light sources as well as conventional designs. [http://photozone.de/Reviews/Canon%20EOS%20Lens%20Tests/45-canon-eos-aps-c/201-canon-ef-70-300mm-f45-56-usm-is-lab-test-report--review]
EF 70-300mm f/4-5.6 IS USM
This lens is of a conventional design and was introduced recently in 2005, to offer an increase in performance from the earlier 75-300mm lenses in the Canon EF lens lineup. Like the 70-300mm f/4.5-5.6 DO it contains an image stabilizer, however for focusing it uses the lower quality micro-USM design, and therefore requires the focus motor to be disengaged before manual focusing. The optical performance of this lens is competitive to Canon's L series telephoto zoom lenses, such as the 70-200mm series of lenses. This is due to the fact that it features an ultra-low
dispersion glass element, something that is uncommon for a consumer grade lens, and is usually found only in Canon's L-series lenses. This lens is also very notable for having only a very slight decrease in performance at 300mm setting. A quality that is not common with other telephoto zooms, including the old 75-300mm lenses. [http://www.photozone.de/Reviews/Canon%20EOS%20Lens%20Tests/200-canon-ef-70-300mm-f4-56-usm-is-test-report--review]pecifications
External links
* [http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Image_Stabilization_Lenses/EF_70-300mm_f4-5.6_IS_USM/index.asp Canon UK product information for EF 70-300mm f4-5.6 IS USM]
* [http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Image_Stabilization_Lenses/EF_70-300mm_f_f4.5-5.6_DO_IS_USM/index.asp Canon UK product information for EF 70-300mm f/4.5-5.6 DO IS USM]
* [http://photonotes.org/cgi-bin/lens-lookup.pl?lens1=EF+70-300mm+f4-5.6+IS+USM&lens2=EF+70-300mm+f4.5-5.6+DO+IS+USM&lens3=*&lens4=*&lens5=* PhotoNotes.org detailed feature comparison between the two lens models]
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