Objektivskolan - Ordlista - RF (Sigma)

Förkortningen betyder

RF = Rear Focus

Förklaring från Sigma

This lens is equipped with a system that moves the rear lens group for highspeed, silent focusing.

Conventional focusing has normallybeen performed by moving either all lens groups as a fixed unit or onlythe first lens group. AF cameras are now widely used, even for close-upphotography. Consequently, demand has arisen for a focusing system thatwill keep the length of the lens unchanged while showing little fluctuationof aberration. In response to this demand, SIGMA has developed a newinner focus system that moves two lens groups inside the telephoto andtelephoto MACRO lenses. This system has floating elements thatsubstantially improve the close-upcapability of the lens. The superwide angle lens having a large front-lens uses a rear focusing system tomove the rear-lens apparatus andenhance the floating effect, and the18-200mm F3.5-6.3 DC features aninner focusing system to move thesecondary lens group duringfocusing. This lens has a minimumfocusing distance of 45 cm / 17.7inch throughout entire zoom range.The rear focus system ensures high-speed focusing with the wide lens20mm F1.8 EX DG ASPHERICALRF.

Se exempel på berörda produkter

Sigma EX 20mm f/1,8 DG ASP RF

Se länkar

	sigmaphoto.com
	sigma-photo.co.jp

Objektiv för Canon
Nedan visas några populära alternativ (se alla)
	Canon EF 28mm f/1,8 USM
	Canon EF-S 18-200mm f/3,5-5,6 IS
	Canon EF-S 55-250mm f/4-5,6 IS
	Canon EF 800mm f/5,6 L IS USM

Objektiv för Nikon
Nedan visas några populära alternativ (se alla)
	Sigma EX 24mm f/1,8 DG ASP Macro
	Tokina AT-X DX 10-17mm f/3,5-4,5 Fisheye
	Sigma EX 50mm f/2,8 DG Macro
	Tokina AT-X Pro 12-24mm f/4 DX II

Objektivskolan
Våra artiklar utbildar dig (se alla)
Kameran kan påverka brännvidd
Att rengöra ett objektiv
Vilken betydelse har autofokusmotor?
Se bilder tagna med en viss brännvidd