Pentax HD 28-105mm f/3.5-5.6 D FA IF ED DC WR Full-Frame Autofocus Lens for K-Mount, Black {62}

Pentax's full-frame kit zoom built for the field

The 28-105mm f/3.5-5.6 ED DC WR covers the range most photographers actually use day to day, from wide environmental shots at 28mm to a compressed 105mm for portraits and detail work. ED glass elements keep lateral chromatic aberration in check across that range, and the HD multi-layer coating cuts flare and ghosting in scenes with strong backlight. Super Protect coating adds a surface-level defense against smudging and scratching. Internal focusing means the front element stays fixed during AF, which matters when you're using a polarizer on the 62mm filter thread.

Weather resistant construction makes this a practical choice for shooting outdoors without babying your kit. The DC autofocus motor drives focus quietly and without the bulk of a larger coreless motor design. On a full-frame K-mount body like the K-1 II, this lens covers everything from architecture and street to casual portraiture without a bag change. For Pentax shooters who want one lens that handles most of what a working day demands, this one earns its place on the camera.

Who It's For

Travel photographers shooting with a K-mount full-frame body will appreciate covering 28-105mm in a single, weather-resistant package than swapping glass on location. Documentary and street shooters benefit from the internal focusing design, which keeps the lens profile consistent and polarizer alignment intact. Portrait photographers working in mixed or outdoor light will use the 105mm end for natural compression on faces. Landscape shooters heading into unpredictable weather can rely on the WR construction alongside a sealed K-1 body for a fully protected system.

Key Features

• 28-105mm focal range covers wide to medium telephoto on full-frame K-mount
• Variable f/3.5-5.6 aperture keeps size compact without sacrificing early-zoom speed
• ED glass elements suppress lateral chromatic aberration across the zoom range
• Internal focusing locks front element so polarizers stay put
• HD multi-layer coating cuts flare and ghosting in backlit scenes
• Weather Resistant construction for field work without coddling
• DC autofocus motor operates quietly with fixed-length design
• 62mm filter thread integrates with standard filter systems

FAQ

What's the filter thread size on this lens?

62mm. That matters if you're already invested in circular polarizers or ND filters for other glass.

Does the front element rotate during autofocus?

No. Internal focusing keeps the front element fixed, so polarizers stay oriented without needing adjustment as you focus.

Is this lens weather sealed?

It has WR (Weather Resistant) construction, meaning it can handle field conditions without being as heavily sealed as professional telephotos. You're not getting the rubber gaskets of a pro build, but it won't fail in light rain or dusty environments.

What autofocus motor does it use?

A DC (direct-current) motor, which is quiet and compact compared to older coreless designs. It's fast enough for general shooting but not designed for tracking fast action.

Will this work on full-frame K-mount bodies?

Yes. It's designated for full-frame DSLRs like the K-1 II and will cover the entire frame without vignetting at any focal length.

How does the variable aperture affect exposure as you zoom?

At 28mm you get f/3.5, but at 105mm the maximum aperture drops to f/5.6. That's the trade-off for keeping the lens compact. In low light at the long end, you'll either need to raise ISO or accept slower shutter speeds.

What's the difference between the HD multi-layer coating and Super Protect coating?

HD coating is optical, reducing flare and ghosting. Super Protect is a surface treatment that resists smudging and scratching. Both are factory-applied to this lens.