Tamron SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF) vs Pentax smc Pentax-DA 17-70mm f/4 AL [IF] SDM

Side-by-side comparison from our catalogue data. Better values are highlighted only where a clear difference exists.

Tamron

SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF)

Pentax

smc Pentax-DA 17-70mm f/4 AL [IF] SDM

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Verdict at a glance

Tamron SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF) is faster by 1 stop (f/2.8 vs f/4.0), letting in more light.
Pentax smc Pentax-DA 17-70mm f/4 AL [IF] SDM reaches further (70mm vs 50mm).

Specification comparison
Spec	SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF)	smc Pentax-DA 17-70mm f/4 AL [IF] SDM
Brand	Tamron	Pentax
Mount	Pentax K	Pentax K
Type	Zoom	Zoom
Focal length	17-50mm	17-70mm
Max aperture	f/2.8 (faster)	f/4.0
Released	n/a	2008
Format	aps-c	aps-c
Filter mm	67	67
Min focus m	0.27 (closer focusing)	0.28
Blades	n/a	7
Groups	n/a	12
Af motor	n/a	SDM
Elements	n/a	17
Weight g	n/a	485
Diameter mm	n/a	75.0
Max magnification	n/a	0.31

Tamron SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF)

A popular APS-C standard zoom with a constant f/2.8 aperture, much used on Pentax bodies with in-body stabilization. It has a 67mm filter thread and a minimum focus distance of 0.27 m.

Pros

Constant f/2.8
Compact 67mm filter size
Constant aperture with in-body stabilization support
Works with Pentax in-body stabilization

Cons

APS-C only
No weather sealing
Plastic build

Pentax smc Pentax-DA 17-70mm f/4 AL [IF] SDM

A versatile standard zoom for Pentax APS-C bodies with SDM focusing. It weighs about 485 g and takes 67mm filters.

Pros

Constant f/4
SDM autofocus
Wide 17-70mm range
Close focus 0.28 m

Cons

APS-C only
Not weather sealed
No stabilization

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