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 200mm f/2 L IS USM
	Sigma EX 180mm f/2,8 HSM OS DG Macro
	Sigma EX 10mm f/2,8 DC HSM Fisheye
	Sigma 18-125mm f/3,8-5,6 DC OS HSM

Objektiv för Nikon
Nedan visas några populära alternativ (se alla)
	Tokina AT-X Pro 35/2,8 DX Macro
	Tamron SP AF 17-50mm f/2,8 XR Di-II LD IF (motorized)
	Sigma EX 70mm f/2,8 DG Macro
	Sigma 18-125mm f/3,8-5,6 DC OS HSM

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