Pentax smc Pentax-DA* 50-135mm f/2.8 ED IF SDM Specs & DoF

50–135 mm

Focal length

f/2.8

Maximum aperture

32°–12°

Diagonal angle of view (APS-C)

APS-C

Designed for

2.7×

Zoom ratio

Specifications#

Brand: Pentax
Model: smc Pentax-DA* 50-135mm f/2.8 ED IF SDM
Lens type: Telephoto zoom
Focal length: 50–135 mm
Maximum aperture: f/2.8
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 50 mm	At 82 mm	At 135 mm	Equiv. aperture (DoF)
APS-C	75 mm · 32°	123 mm · 20°	202 mm · 12°	f/4.2
APS-C (Canon)	80 mm · 30°	131 mm · 19°	216 mm · 11°	f/4.5
Micro Four Thirds	100 mm · 24°	164 mm · 15°	270 mm · 9°	f/5.6

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: 50 mm f/2.8 on aps-c.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
50 mm	f/2.8	4.2 cm	17.1 cm	1.10 m	4.58 m	45.7 m	1.9%
50 mm	f/4	6.0 cm	24.5 cm	1.59 m	6.90 m	32.0 m	1.4%
50 mm	f/8	11.9 cm	49.6 cm	3.43 m	20.3 m	16.0 m	0.7%
82 mm	f/2.8	1.5 cm	6.2 cm	40.1 cm	1.63 m	123 m	5.3%
82 mm	f/4	2.1 cm	8.9 cm	57.4 cm	2.34 m	86.0 m	3.7%
82 mm	f/8	4.3 cm	17.9 cm	1.16 m	4.88 m	43.1 m	1.9%
135 mm	f/2.8	0.5 cm	2.2 cm	14.6 cm	59.3 cm	333 m	14.9%
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 50 mm	NPF at 50 mm, f/2.8
APS-C	1/200 s	7 s	4 s
APS-C (Canon)	1/200 s	6 s	4 s
Micro Four Thirds	1/250 s	5 s	4 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 50-200mm f/4-5.6 DA ED f/4–5.6
Pentax smc Pentax-DA L 50-200mm f/4-5.6 ED WR f/4–5.6
Sigma 50-150mm f/2.8 APO EX DC HSM II f/2.8
Sigma 50-150mm f/2.8 APO EX DC OS HSM f/2.8
Pentax HD Pentax-DA 55-300mm f/4-5.8 ED WR f/4–5.8
Pentax HD Pentax-DA 55-300mm f/4.5-6.3 ED PLM WR RE f/4.5–6.3
Pentax smc Pentax-DA 55-300mm f/4-5.8 ED f/4–5.8
Pentax smc Pentax-DA L 55-300mm f/4-5.8 ED f/4–5.8
Sigma 55-200mm f/4-5.6 DC f/4–5.6
Pentax smc Pentax DA* 60-250mm f/4 IF SDM f/4
Pentax HD Pentax-D FA* 70-200mm f/2.8 ED DC AW f/2.8
Sigma 70-200mm f/2.8 EX DG HSM f/2.8

Frequently asked questions#

Is the Pentax smc Pentax-DA* 50-135mm f/2.8 ED IF SDM 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* 50-135mm f/2.8 ED IF SDM equivalent to on APS-C?

Its focal length is already the real value for APS-C: 50–135 mm frames like 77–207 mm on full frame.

What is the Pentax smc Pentax-DA* 50-135mm f/2.8 ED IF SDM good for?

As a telephoto zoom it suits sport, wildlife, events and compressed landscapes.

Sources & licences#

Lensfun lens database — CC BY-SA 3.0