Sigma 20mm F1.8 EX DG RF is a Fixed aperture Auto Focus (AF)
Ultra-Wideangle Prime lens with 35mm FF max sensor coverage, and it is designed to be used with Pentax KAF mount cameras.
What type of photography is the Sigma 20mm F1.8 EX DG RF lens good for?
The type of photography that you are planning to use the Sigma 20mm F1.8 EX DG RF is an important decision factor. Here we have evaluated its suitability to various photography scenarios:
| Photography Type |
Suitability |
| Bird/Wildlife | Poor |
| Sports | Poor |
| Portrait | Fair |
| Travel | Average |
| Street | Excellent |
| Wedding | Fair |
| Walk Around | Average |
| Vlogging | Very Good |
| Landscape | Good |
Lenses in Pentax KAF Mount with Same Focal and Aperture Range
Reasons to Buy Sigma 20mm F1.8 EX DG Aspherical RF Lens
Here, we've included a summary of the advantages and disadvantages of the Sigma 20mm F1.8 EX DG Aspherical RF lens in a list form to help you determine whether it offers the features you need.
| Autofocus |
| Aperture Ring |
| Distance Scale |
| DoF(Depth of Field) Scale |
| Hood supplied |
| Full-time Manual Focusing |
| Fast Aperture |
| Covers Full-Frame Sensor |
| 9 Diaphragm Blades |
| Minimum focus distance of 0.2m / 7.9 inch |
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We couldn't find any significant Cons for Sigma 20mm F1.8 EX DG Aspherical RF
Lens Mount
Sigma 20mm F1.8 EX DG RF is compatible with cameras that have Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax KF, Pentax K-3 III and Pentax K-1 II.
Sigma 20mm F1.8 EX DG RF is also available in Canon EF , Nikon F (DX), Sony Alpha and Sigma SA mounts.
Size, Weight and Filter Thread
Size and weight is a very important decision factor when searching for your next lens. Sigma 20mm F1.8 EX DG RF has a maximum diameter of 89mm and total length of 90mm. It weighs 520g / 18.3 oz.
Sigma 20mm F1.8 EX DG RF has a filter thread of 82mm.
Focal Range
Sigma 20mm F1.8 EX DG RF has a fixed focal length of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 30mm.
Optical Image Stabilization
Sigma 20mm F1.8 EX DG RF doesn't have an optical image stabilization system so the only option to stabilize the image taken with this lens is to mount on a camera body with IBIS (sensor based In-body image stabilization).
Aperture
Sigma 20mm F1.8 EX DG RF has a max aperture of F1.8 and a minimum aperture of F22.0.
Optical Formula
Sigma 20mm F1.8 EX DG RF's optical formula consists of 13 elements in 11 groups . Special elements used in this design is 2 aspherical elements.
Lens Hood
Sigma 20mm F1.8 EX DG RF comes with a removable petal shaped lens hood which is handy to reduce lens flare and glare in your photos.
Body Colour
Sigma 20mm F1.8 EX DG RF is available in Black color.
Popular Comparisons of Sigma 20mm F1.8 EX DG RF
Here is the eight most popular comparisons of Sigma 20mm F1.8 EX DG RF amongst Camera Decision readers.
Top Alternatives of Sigma 20mm F1.8 EX DG RF Lens
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