Pentax-K bajonet inexpensive zoom lenses test, quick OUTDOOR test

with the Pentax K-50 - 16MP DSLR, APS-C
Following my previous, very amatorial indoor test for these three zoom lenses, and the almost useless test for the Cosina Zoom, it is time to take a few shot at the city and see what real-world pictures look like.
As I said, results are not for granted.
These are the (cheap)lenses:
MORE CONSIDERATIONS
Some shots were intended to check about the bokeh, but it was late and I definitely consider them unsatisfactory (the distances between the in-focus and out-of-focus objects were not suitable).
By some practice with these lenses, though, I can state that the bokeh is not bad nor astounding for any of the three. At these focal lengths, indeed, bokeh is usually not much of a concern. Anyway, if you really want a final word on this, I'd say that the Takumar/Pentax is better, also because out-of-focus lights may display a bit of colour aberrations on the Tamron.
Anyway, what's more important, the Tamron suffers most from lateral CA while the Cosina really takes a punch in this outdoor test from the point of view of sharpness, I cannot exclude that it is due to poor focusing (the strong light prevented me from doing a good job with the Live View) and I only shot once per focal length/aperture combination, not twice as done indoor.




Cosina 80mm, f4.5 (Cosina), Takumar and Tamron 70 mm, f4
at the maximum aperture and minimal focal length, the Takumar does much better than the competion in the borders and is better in the center, too, though only slightly when compared to the Tamron.
Nice job for the old boy.


Cosina 80mm f4.5


Takumar 70mm f4


Tamron 70mm f4

Cosina 80mm, Takumar and Tamron at 70 mm, all at f5.6
same story at f5.6: the Takumar leads the pack, where the trailing zooms try to catch up. The Cosina improves visibly


Cosina 80mm f5.6


Takumar 70mm f5.6


Tamron 70mm f5.6

Cosina 80mm, Takumar and Tamron at 70 mm, all at f8
at f8, again, the Takumar wins -not hands down but for sure-, while the Cosina is still rather behind the center.


Cosina 80mm f5.6


Takumar 70mm f5.6


Tamron 70mm f5.6

135 mm, f4.5 (maybe the Cosina a bit more, I have no way to know)
at 135mm and full aperture, in the center, the Tamron does the best job.
At the borders, there is no clear winner. The Tamron is maybe lightly sharper but I can spot some lateral CA while the Takumar doesn't suffer any, so maybe the latter has the best IQ (image quality).
The Cosina does a good showing of itself but it is not very consistent; I already observed that it is not perfectly aligned.


Cosina 135mm


Takumar 135mm


Tamron 135mm

135 mm, f5.6
135mm clearly favours the Tamron, also at f5.6. The Cosina is improving at this aperture


Cosina 135mm


Takumar 135mm


Tamron 135mm

135 mm, f8
135mm, f8: no doubt, at 135mm the Tamron gets the prize because it beats the contenders again.
Notice how the Cosina, in spite of its age, wouldn't be that bad if it was more consistent.
The Takumar does fine, and it is in the center that the difference against the Tamron is pronounced


Cosina 135mm


Takumar 135mm


Tamron 135mm

200mm, f4.5 (Tamron only)
only the Tamron sports f4.5 at 200mm (so the camera says). Easy win!... but quality is not satisfactory


Tamron 200mm

200 mm, f5.6
agh! I was expecting something better from the Takumar here.
The Tamron slaps the other lenses though it manifests some lateral CA, but also the Takumar is displaying some.
The performance of the Takumar and the Cosina at the center is vary bad


Cosina 200mm


Takumar 200mm


Tamron 200mm

200 mm, f8
again and again, the Takumar and the Cosina improve but are not quite there...


Cosina 200mm


Takumar 200mm


Tamron 200mm

200 mm, f11
I took this shot by mistake. But let's see if the Takumar has still something to say going up to f11... well, actually it improves on all sides but the Tamron at f5.6 is still a bit better, not thanks to a better sharpness but to stronger contrast, instead


Takumar 200mm

only the Tamron sports the focal length of 300 mm, but I did not shoot outdoor with it at 300mm.
I already know that the image quality falls to the point where I don't usually would go.
Indeed, maybe once I'll try at smaller apertures to see if something good can be obtained at 300mm. Not today



CONCLUSION

Well... I'd like to have a definitive answer so that I can decide which lens to keep.
But let's first rule out the old Cosina. Though the "indoor test" was good and the outdoor shots are not too shabby, there are some focal lenghts were it is too bad and, last but not least, it would simply be insane to use a lens without auto-focus on a APS-C DSLR. Not one of this kind, at least. I'd only keep super-sharp primes without auto-focus, auto-focus is simply necessary with the current rigs. If you also take into consideration the Cosina that it starts from f4.5, not 4, the only good things about it are the compactenss (it is much shorter then the other two) and strudiness (metal is everywhere, the feeling is that of a compact tank).

As for the Tamron and the Takumar, I'm discomforted by the fact that the Takumar is better, somewhat much better, at 70mm (a focal length that I like most in the range), but is quite behind in the center when you go for bigger focal lengths. The fact that the Tamron borders are plagued by some colour aberrations or lateral CA (I hate colour issues, much more than pincushion and other optical aberrations) does not help much, it just maked me more uncapable of taking a final decision.

For the moment, I'll keep them both, but if I have to clear the shelves, I'll get rid of the Takumar (and maybe look for the Pentax-branded version, why not?).


Click here to go back to the first part of the test

::: Ubi's homepage ::: ::: me, on Facebook ::: ::: site index :::