[falconeye]

German photo magazine "Fotohits 04/2009" tested and compared:

• Pentax smc DA 55-300 F4-5.8
• Sigma 70-300 F4-5.6 DG APO Macro
• Tamron 70-300 F4-5.6 Di LD Macro

And the winner is ... Pentax.

Measurements:
- Resolution 300mm f/5.6 [Lp/PH] Pentax/Sigma/Tamron: 2447 / 2156 / 1785
- Resolution 100mm f/8.0 [Lp/PH] Pentax/Sigma/Tamron: 2941 / 2905 / 2937

Chromatic abberations Pentax/Sigma/Tamron: Fair / Good / Poor.


Comment:

"The Pentax was by far superior in the tele range, out-performing its test competition as well as bridge cameras or mega/super zooms. Contrast was excellent. Somewhat lesser resolution towards the image borders, more like its competitors there."

Only negative remark was the absence of an 1:2 macro option for Pentax (1:3.6).

[k100d]

seeing as it is more than double the price on the used market, it's not a surprise
the lens performed well when i had it, photozone seems to indicate that the resolution isn't that spectacular, however, the overall impression of photos is sharp.

[falconeye]

photozone seems to indicate that the resolution isn't that spectacular

Of course not. It's not a prime nor a 100-300 f/4 ... It's still a budget zoom.

Nevertheless, it sort of seems to be better than other budget zooms like DA 50-200 or super zooms.

[kenyee]

- Resolution 300mm f/5.6 [Lp/PH] Pentax/Sigma/Tamron: 2447 / 2156 / 1785

That's well done by the 55-300. Most zooms aren't good at their extremes and have to be either backed off or stopped down (e.g., the Tamron is a lot sharper at 280mm than 300mm, so I tend to swing it 300mm and back off a hair when I need it that long).

[aweir]

I also tested the lenses. the file names indicate the lens and focal length.

The purple fringing is much stronger on the Tamron.

Order of images:

Pentax 300mm f/5.6
Tamron 300mm f/5.6

Pentax 300mm f/5.6
Tamron 300mm f/5.6

[aweir]

Pentax 300 f/5.6
Tamron 300 f/5.6

the purple fringing almost eliminated when the photos were resized but are still visible in 100% cropped examples when viewed at actual pixels.

[NorthPentax]

Only negative remark was the absence of an 1:2 macro option for Pentax (1:3.6).

No thanks. But I would like a focus limiter like many macro lenses have. Limit from 10m mark to the ∞ mark, perfect for wildlife photog.

[boom]

German photo magazine "Fotohits 04/2009" tested and compared:

• Pentax smc DA 55-300 F4-5.8
• Sigma 70-300 F4-5.6 DG APO Macro
• Tamron 70-300 F4-5.6 Di LD Macro

And the winner is ... Pentax.

Measurements:
- Resolution 300mm f/5.6 [Lp/PH] Pentax/Sigma/Tamron: 2447 / 2156 / 1785
- Resolution 100mm f/8.0 [Lp/PH] Pentax/Sigma/Tamron: 2941 / 2905 / 2937

Chromatic abberations Pentax/Sigma/Tamron: Fair / Good / Poor.


Comment:

"The Pentax was by far superior in the tele range, out-performing its test competition as well as bridge cameras or mega/super zooms. Contrast was excellent. Somewhat lesser resolution towards the image borders, more like its competitors there."

Only negative remark was the absence of an 1:2 macro option for Pentax (1:3.6).

Does this mean the Sigma APO is sharper than the Tamron wide open at the tele?

[falconeye]

Does this mean the Sigma APO is sharper than the Tamron wide open at the tele?

Yes (in the center at least)
Together with the heavier CA, I think they considered Sigma a better buy than Tamron. And Pentax the winner.

[Alfisti]

Yes (in the center at least)
Together with the heavier CA, I think they considered Sigma a better buy than Tamron. And Pentax the winner.

Which is odd because virtually any other comparison we have seen shows the Tamron clearly a good chunck sharper than the sigma past 200mm.

[falconeye]

Which is odd because virtually any other comparison we have seen shows the Tamron clearly a good chunck sharper than the sigma past 200mm.

They can have made a mistake in their test. But this is what they printed.

On the other hand ...

... at 300mm ...

photozone shows the Sigma (in Canon mount) with aperture-constant (read rather good) center resolution (and very poor at borders).

and shows Tamron (in Pentax mount) with slightly more loss at 5.6 (but better at borders).


Stranger even:
Photozone gives the Tamron a better center resolution at 300/5.6 than the Pentax!

So, I really don't know. Those tests ... However, Photozone concedes that they may have had a bad copy of the Pentax. And maybe, Fotohits had a bad copy of the Tamron ...

[res3567]

They can have made a mistake in their test. But this is what they printed.

On the other hand ...

... at 300mm ...

photozone shows the Sigma (in Canon mount) with aperture-constant (read rather good) center resolution (and very poor at borders).

and shows Tamron (in Pentax mount) with slightly more loss at 5.6 (but better at borders).


Stranger even:
Photozone gives the Tamron a better center resolution at 300/5.6 than the Pentax!

So, I really don't know. Those tests ... However, Photozone concedes that they may have had a bad copy of the Pentax. And maybe, Fotohits had a bad copy of the Tamron ...

Went to a Wolf camera that is closing a bought a Quantaray LD 70-300 f/4-5.6. It also has a macro switch that gives it a 1:2 in the 180-300 focal range.

I paid $74 for it.

Is it the same lens as the one you tested and did I score a bargain ?

The clerk said it was a rebadged Sigma.

[pacerr]

An' I still wanna see a comparison of the Tamron 70-300 LD Di and the 75-300LD.

H2

[Prognathous]

I tested the Tamron vs. the Sigma, and the former is much sharper at 300/5.6 and better at other aperture values too. Here's the test shot (long end, wide open):



And here are 100% crops (from the areas marked in blue above):

Center:


Right side:


Lower left corner:


The Tamron shows more CA, but is overall much better in my opinion.

Prog.

[falconeye]

The Tamron shows more CA, but is overall much better in my opinion.

This may very well be the case.
I don't want to defend the Fotohits magazine. They can be as wrong as anybody else.
They print sample crops from center, middle and border, at 100mm f/8 and 300mm f/5.6, of all three lenses. They say that manual focussing yielded better results than AF.
At the center at 300mm f/5.6, the Pentax looks sharpest and the Tamron looks worst with visible color aberrations even in the center. Which is consistent with what they wrote (FotoHits 04/2009 p.76-79 FOTO HITS Magazin für Fotografie und Bildbearbeitung).

On the other hand, the color aberrations of the Tamron look even worse in the center than the middle. So, their copy from Tamron may have been decentered.


As for your test ...
Are you sure the Sigma was focussed properly? I applied a "revert blur from defocus" filter and it worked so well that it let's me think that the blur was from defocus, indeed. Cf. attachment, right half corrected.