Pentax HD Pentax-D FA 28-105mm f/3.5-5.6 ED DC WR Specs & DoF

28–105 mm

Focal length

f/3.5–5.6

Maximum aperture

53°–15°

Diagonal angle of view (APS-C)

APS-C

Designed for

3.8×

Zoom ratio

Specifications#

Brand: Pentax
Model: HD Pentax-D FA 28-105mm f/3.5-5.6 ED DC WR
Lens type: Standard zoom
Focal length: 28–105 mm
Maximum aperture: f/3.5–5.6
Image circle: APS-C (23.5×15.6 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	At 54 mm	At 105 mm	Equiv. aperture (DoF)
APS-C	42 mm · 53°	81 mm · 29°	158 mm · 15°	f/5.2
APS-C (Canon)	45 mm · 51°	86 mm · 28°	168 mm · 15°	f/5.6
Micro Four Thirds	56 mm · 42°	108 mm · 23°	210 mm · 12°	f/7.0

Depth of field & background blur#

Computed on its native APS-C format (CoC 20 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/4 on aps-c.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
28 mm	f/3.5	17.1 cm	71.0 cm	5.35 m	72.0 m	11.5 m	0.5%
28 mm	f/4	19.6 cm	81.9 cm	6.58 m	2.0 km	10.0 m	0.4%
28 mm	f/8	40.3 cm	1.86 m	643 m	∞	5.04 m	0.2%
54 mm	f/3.5	4.4 cm	18.3 cm	1.18 m	4.94 m	42.7 m	1.8%
54 mm	f/4	5.1 cm	20.9 cm	1.35 m	5.75 m	37.3 m	1.6%
54 mm	f/8	10.2 cm	42.2 cm	2.85 m	14.9 m	18.7 m	0.8%
105 mm	f/3.5	1.1 cm	4.7 cm	30.4 cm	1.23 m	161 m	7.1%
105 mm	f/4	1.3 cm	5.4 cm	34.8 cm	1.41 m	141 m	6.2%
105 mm	f/8	2.5 cm	10.8 cm	69.8 cm	2.87 m	70.6 m	3.1%

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/3.5
APS-C	1/160 s	12 s	9 s
APS-C (Canon)	1/160 s	11 s	8 s
Micro Four Thirds	1/200 s	9 s	8 s

Compatible cameras#

Bodies in our database with a native Pentax K mount. Full-frame bodies switch to an APS-C crop with this lens.

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 F 28-80mm f/3.5-4.5 f/3.5–4.5
Pentax smc Pentax-FA 28-70mm f/4 AL f/4
Sigma 28-70mm f/2.8 EX DG f/2.8
Tamron SP AF 28-105mm f/2.8 LD Aspherical IF f/2.8
Tokina 28-70mm f/2.8 AT-X Pro SV f/2.8
Tokina AF 28-80mm f/2.8 AT-X 280 Pro f/2.8
Pentax HD Pentax-D FA 24-70mm f/2.8 ED SDM WR f/2.8
Sigma 24-60mm f/2.8 EX DG f/2.8
Sigma 24-70mm f/2.8 IF EX DG HSM f/2.8
Pentax smc Pentax-F 35-80mm f/4-5.6 f/4–5.6
Pentax smc Pentax-F ZOOM 35-70mm f/3.5-4.5 f/3.5–4.5
Pentax HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR f/2.8–4

Frequently asked questions#

Is the Pentax HD Pentax-D FA 28-105mm f/3.5-5.6 ED DC WR full frame?

No — it is designed for APS-C sensors. On a full-frame body it vignettes or triggers crop mode.

What is the Pentax HD Pentax-D FA 28-105mm f/3.5-5.6 ED DC WR equivalent to on APS-C?

Its focal length is already the real value for APS-C: 28–105 mm frames like 43–161 mm on full frame.

What is the Pentax HD Pentax-D FA 28-105mm f/3.5-5.6 ED DC WR good for?

As a standard zoom it suits everyday shooting, travel, events and walkaround use.

Sources & licences#

Lensfun lens database — CC BY-SA 3.0