Pentax smc Pentax-F 28mm f/2.8 Specs & DoF

28 mm

Focal length

f/2.8

Maximum aperture

75°

Diagonal angle of view (Full frame)

Full frame

Designed for

Specifications#

Brand: Pentax
Model: smc Pentax-F 28mm f/2.8
Lens type: Wide-angle prime
Focal length: 28 mm
Maximum aperture: f/2.8
Image circle: Full frame (36×24 mm)
Mount(s): Pentax K
Projection: Rectilinear
Lensfun correction profile: Yes — distortion/vignetting/TCA

Equivalent focal length on different cameras#

Field of view and depth-of-field equivalence when this lens is used on bodies with different sensor sizes (natively or via an adapter).

Camera format	At 28 mm	Equiv. aperture (DoF)
Full frame	28 mm · 75°	f/2.8
APS-C	42 mm · 53°	f/4.2
APS-C (Canon)	45 mm · 51°	f/4.5
Micro Four Thirds	56 mm · 42°	f/5.6

Depth of field & background blur#

Computed on its native Full frame format (CoC 30 µm). “Blur @2 m” is the size of an out-of-focus point at infinity, as a percentage of frame width, with the subject at 2 m — a simple bokeh index. Full table: 28 mm f/2.8 on full frame.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
28 mm	f/2.8	21.1 cm	88.5 cm	7.44 m	∞	9.36 m	0.4%
28 mm	f/4	30.4 cm	1.33 m	18.1 m	∞	6.56 m	0.3%
28 mm	f/8	65.3 cm	3.80 m	∞	∞	3.29 m	0.1%

Handheld & night-sky limits#

NPF assumes typical 20–24 MP sensors (≈6 µm pixels on full frame, ≈3.9 µm on APS-C, ≈3.3 µm on Micro Four Thirds).

Body	Min. handheld shutter (longest focal)	500 rule at 28 mm	NPF at 28 mm, f/2.8
Full frame	1/30 s	18 s	10 s
APS-C	1/40 s	12 s	8 s
APS-C (Canon)	1/50 s	11 s	7 s
Micro Four Thirds	1/60 s	9 s	7 s

Compatible cameras#

Bodies in our database with a native Pentax K mount.

Adapt it to other systems#

Sony E-mount Canon RF Nikon Z Fujifilm X-mount Micro Four Thirds L-Mount Canon EF-M Fujifilm G-mount Hasselblad XCD Nikon 1 (CX)Pentax Q Samsung NX Canon EF Nikon F

Similar lenses#

Pentax smc Pentax-A 28mm 1:2.8 f/2.8
Pentax smc Pentax-FA 28mm f/2.8 AL f/2.8
Pentax smc Pentax-M 28mm 1:3.5 f/3.5
Pentax smc Pentax-M 28mm f/2.8 f/2.8
Sigma 28mm f/1.8 EX DG f/1.8
Pentax smc Pentax K 30mm f/2.8 f/2.8
Pentax smc Pentax-FA 31mm f/1.8 AL Limited f/1.8
Zeiss Distagon T* 25mm f/2.8 ZF.2 f/2.8
Samyang 24mm f/1.4 ED AS IF UMC f/1.4
Samyang T-S 24mm f/3.5 ED AS UMC f/3.5
Sigma 24mm f/2.8 Super Wide II f/2.8
Pentax HD Pentax-DA 21mm f/3.2 ED AL Limited f/3.2

Frequently asked questions#

Is the Pentax smc Pentax-F 28mm f/2.8 full frame?

Yes — it covers the full 36 × 24 mm frame.

What is the Pentax smc Pentax-F 28mm f/2.8 equivalent to on APS-C?

On a 1.5× APS-C body it frames like 42 mm, and like 45 mm on Canon APS-C.

What is the Pentax smc Pentax-F 28mm f/2.8 good for?

As a wide-angle prime it suits street, environmental portraits, landscapes and astro.

Sources & licences#

Lensfun lens database — CC BY-SA 3.0