Tamron 28-75mm f/2.8 XR Di Pentax-k vs Sigma 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

differences

Reasons to consider the Tamron 28-75mm f/2.8 XR Di Pentax-k

Has a consant aperture

Yes

Constant aperture lenses offer the same aperture at all focal lengths

Significantly narrower aperture

f/32

f/22

At its narrowest, the 28-75mm f/2.8 XR Di Pentax-k goes 1.1 f-stops narrower

Wider aperture

f/2.8

f/3.5

At its widest, the 28-75mm f/2.8 XR Di Pentax-k captures slightly more light, 0.6 f-stops

Learn more about
the Tamron 28-75mm f/2.8 XR Di Pentax-k

Reasons to consider the Sigma 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Much more zoom

13.9x

2.7x

More than 5x more zoom, giving you more flexibility for photos

Has a silent focus motor

Sigma HSM

None

Focuses quickly and silently

Image stabilization

Sigma OS

None

Helps eliminate blur caused by small camera movements

Significantly better telephoto

250 mm

75 mm

Around 3.5x more reach, less perspective distortion

Slightly more magnification

1:3.4 (0.3x)

1:3.9 (0.3x)

Take macro shots with subjects more than 10% larger in your photo

Learn more about
the Sigma 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

similarities

Compared to lenses

Common Strengths

Common Weaknesses

LensHero is not aware of any interesting strengths shared by these two products.

	Both are zoom lenses
	Typically not as sharp as prime lenses

Compared to portrait lenses

Common Strengths	Common Weaknesses
LensHero is not aware of any interesting strengths shared by these two products.	LensHero is not aware of any interesting weaknesses shared by these two products.

competitors

Sigma 28-300mm f/3.5-6.3 DG Macro Pentax-k

Wildlife lens

$299

Has a narrower aperture

Compare the 28-300mm f/3.5-6.3 DG Macro Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the 28-300mm f/3.5-6.3 DG Macro Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Pentax SMC DA 18-135mm f/3.5-5.6 ED AL DC WR

Travel lens

$497

Has a higher max f/stop

Has a narrower aperture

Compare the SMC DA 18-135mm f/3.5-5.6 ED AL DC WR vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the SMC DA 18-135mm f/3.5-5.6 ED AL DC WR vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Sigma 17-70mm f/2.8-4 DC Macro OS HSM Pentax-k

Wide angle lens

$449

Compare the 17-70mm f/2.8-4 DC Macro OS HSM Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the 17-70mm f/2.8-4 DC Macro OS HSM Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Sigma 18-125mm f/3.8-5.6 DC OS HSM Pentax-k

Travel lens

$339

Has a narrower aperture

Has a lower max f/stop

Compare the 18-125mm f/3.8-5.6 DC OS HSM Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the 18-125mm f/3.8-5.6 DC OS HSM Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Sigma 18-200mm f/3.5-6.3 DC OS

Wildlife lens

$369

Has a narrower aperture

Compare the 18-200mm f/3.5-6.3 DC OS vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the 18-200mm f/3.5-6.3 DC OS vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Lensbaby Composer Special Effects Fisheye Pentax-k

Fisheye lens

$179

Is a fisheye lens

Compare the Composer Special Effects Fisheye Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the Composer Special Effects Fisheye Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Pentax SMC DA 17-70mm f/4 AL SDM

Wide angle lens

$597

Has a narrower aperture

Compare the SMC DA 17-70mm f/4 AL SDM vs the 28-75mm f/2.8 XR Di Pentax-k

Compare the SMC DA 17-70mm f/4 AL SDM vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Tamron 90mm f/2.8 SP Di Macro Nikon-f

Macro lens

$499

Much more magnification

Is a prime lens

Worse wide angle

Less zoom

Compare the 90mm f/2.8 SP Di Macro Nikon-f vs the 28-75mm f/2.8 XR Di Pentax-k

Sigma 24-70mm f/2.8 IF EX DG HSM Pentax-k

Portrait lens

$899

Has a silent focus motor

Significantly wider aperture

Slightly less magnification

Compare the 24-70mm f/2.8 IF EX DG HSM Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Sigma 24-70mm f/2.8 EX DG Macro DF Pentax-k

Portrait lens

$569

Slightly longer

Slightly heavier

Compare the 24-70mm f/2.8 EX DG Macro DF Pentax-k vs the 28-75mm f/2.8 XR Di Pentax-k

Fujifilm 35mm f/1.4 XF R

Low light lens

Is a prime lens

Significantly wider aperture

Less zoom

Less magnification

Compare the 35mm f/1.4 XF R vs the 28-75mm f/2.8 XR Di Pentax-k

Pentax SMC DA 16-45mm f/4 ED AL

Wide angle lens

$600

Slightly better wide angle

Slightly lighter

Significantly wider aperture

Narrower aperture

Compare the SMC DA 16-45mm f/4 ED AL vs the 28-75mm f/2.8 XR Di Pentax-k

Tamron 70-300mm f/4-5.6 Di LD Macro Pentax-k

Macro lens

$165

More magnification

Better telephoto

Much less zoom

Doesn't have a silent focus motor

Compare the 70-300mm f/4-5.6 Di LD Macro Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Pentax SMC DA 50-200mm f/4-5.6 ED WR

Wildlife lens

$197

Slightly lighter

Slightly cheaper

Much less zoom

Doesn't have a silent focus motor

Compare the SMC DA 50-200mm f/4-5.6 ED WR vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

Tamron 28-300mm f/3.5-6.3 XR Di Pentax-k

Wildlife lens

$390

Better telephoto

Slightly more magnification

Doesn't have a silent focus motor

No image stabilization

Compare the 28-300mm f/3.5-6.3 XR Di Pentax-k vs the 18-250mm f/3.5-6.3 DC OS HSM Pentax-k

discussion Which do you think is better?

Speech is free, but discussion at LensHero is moderated! Please discuss your opinion of these lenses here, and discuss feedback for LensHero at our support community.

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Tamron
28-75mm f/2.8 XR Di Pentax-k
vs
Sigma
18-250mm f/3.5-6.3 DC OS HSM Pentax-k

differences

Reasons to consider the Tamron 28-75mm f/2.8 XR Di Pentax-k

Reasons to consider the Sigma 18-250mm f/3.5-6.3 DC OS HSM Pentax-k