Pentax smc Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR Specs & DoF

18–135 mm

Focal length

f/3.5–5.6

Maximum aperture

76°–12°

Diagonal angle of view (APS-C)

APS-C

Designed for

7.5×

Zoom ratio

Specifications#

Brand: Pentax
Model: smc Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR
Lens type: Superzoom
Focal length: 18–135 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 18 mm	At 49 mm	At 135 mm	Equiv. aperture (DoF)
APS-C	27 mm · 76°	74 mm · 32°	202 mm · 12°	f/5.2
APS-C (Canon)	29 mm · 73°	78 mm · 31°	216 mm · 11°	f/5.6
Micro Four Thirds	36 mm · 62°	98 mm · 25°	270 mm · 9°	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: 20 mm f/4 on aps-c.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
18 mm	f/3.5	43.4 cm	2.03 m	∞	∞	4.75 m	0.2%
18 mm	f/4	50.2 cm	2.48 m	∞	∞	4.16 m	0.2%
18 mm	f/8	1.22 m	45.6 m	∞	∞	2.09 m	0.1%
49 mm	f/3.5	5.4 cm	22.3 cm	1.44 m	6.17 m	35.1 m	1.5%
49 mm	f/4	6.2 cm	25.5 cm	1.66 m	7.25 m	30.7 m	1.3%
49 mm	f/8	12.4 cm	51.7 cm	3.60 m	22.4 m	15.4 m	0.7%
135 mm	f/3.5	0.6 cm	2.8 cm	18.3 cm	74.2 cm	266 m	11.9%
135 mm	f/4	0.7 cm	3.2 cm	20.9 cm	84.8 cm	233 m	10.4%
135 mm	f/8	1.5 cm	6.4 cm	41.8 cm	1.71 m	117 m	5.2%

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 18 mm	NPF at 18 mm, f/3.5
APS-C	1/200 s	19 s	13 s
APS-C (Canon)	1/200 s	17 s	13 s
Micro Four Thirds	1/250 s	14 s	12 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 smc Pentax-DA 18-250mm f/3.5-6.3 ED AL [IF] f/3.5–6.3
Sigma 18-200mm f/3.5-6.3 DC f/3.5–6.3
Sigma 18-200mm f/3.5-6.3 II DC OS HSM f/3.5–6.3
Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical (IF) f/3.5–6.3
Sigma 50-500mm f/4-6.3 EX DG HSM f/4–6.3
Sigma 50-500mm f/4.5-6.3 APO DG OS HSM f/4.5–6.3

Frequently asked questions#

Is the Pentax smc Pentax-DA 18-135mm f/3.5-5.6 ED AL IF 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 smc Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR equivalent to on APS-C?

Its focal length is already the real value for APS-C: 18–135 mm frames like 28–207 mm on full frame.

What is the Pentax smc Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR good for?

As a superzoom it suits travel photography with one lens from wide to telephoto.

Sources & licences#

Lensfun lens database — CC BY-SA 3.0