Irix 11mm F4 is a Fixed aperture Manual Focus (MF)
Ultra-Wideangle Prime lens with 35mm FF max sensor coverage, and it is designed to be used with
KAF3 Mount cameras.
What type of photography is the Irix 11mm F4 lens good for?
The choice of photography type for which you intend to use the Irix 11mm F4 is a crucial decision factor. Below, we have assessed its suitability for various photography scenarios:
Reasons to Buy the Irix 11mm F4 Lens
Here we've included a summary of the advantages and disadvantages of the Irix 11mm F4 lens in a list form to assist you in determining whether it offers the features you need.
Weather-sealed |
Aperture Ring |
Distance Scale |
DoF(Depth of Field) Scale |
Hood supplied |
Full-time Manual Focusing |
Covers Full-Frame Sensor |
9 Diaphragm Blades for Smooth Bokeh |
Extreme Wide-angle capability |
Minimum focus distance of 0.28m / 11.0 inch |
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No Autofocus |
Not so fast for a short Prime Lens |
Lens Mount
Irix 11mm F4 is compatible with cameras that have a Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with the Pentax KAF3 lenses are Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III.
Irix 11mm F4 is also available in Canon EF and Nikon F (FX) mounts.
Size, Weight and Filter Thread
The size and weight are crucial factors to consider when searching for your next lens. Irix 11mm F4 has a maximum diameter of 103mm and total length of 118mm. It weighs 790g / 27.9 oz.
Below, you'll find a scaled side-by-side image comparing the sizes of the Irix 11mm F4 and the Venus 17mm F4 Zero-D GFX, offering a better understanding of their dimensions in real life. Check the detailed comparison of these two lenses here.
Focal Range
Irix 11mm F4 has a fixed focal length of 11mm.
Weather Sealings
The Irix 11mm F4 is a weather-sealed lens, which provides extra protection to prevent water and dust get inside the lens and camera body under light rain, snow and wind. In order to have effective protection, you have to pair the Irix 11mm F4 with a weather-sealed camera body such as the Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III.
Optical Image Stabilization
Irix 11mm F4 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).
Maximum Magnification Ratio
Irix 11mm F4 has a Max Magnification Ratio of 0.07x and has a minimum focusing distance of 0.28m. 0.07x means that the max magnification ratio is very low and not suitable even for modest close-up shots.
Below are the 2 Ultra-Wideangle Prime type Pentax KAF mount lens alternatives with highest max magnification ratios:
Aperture
Irix 11mm F4 has a max aperture of F4 and a minimum aperture of F22.
Optical Formula
Irix 11mm F4's optical formula consists of 16 elements in 10 groups . Following special elements are used in this design:
- 3 aspherical
- 4 HRI
- 2 ED elements
- Neutrino coating
Lens Hood
Irix 11mm F4 comes with a removable lens hood which is handy to reduce lens flare and glare in your photos.
Popular Comparisons of Irix 11mm F4
Here are the eight most popular comparisons of the Irix 11mm F4 amongst Camera Decision readers.
Top Alternatives of Irix 11mm F4 Lens
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