First results with Pentax SMC K 135mm f2.5

Started Jul 23, 2013 | Discussions thread
kitsios_spyros
Senior MemberPosts: 1,288
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Re: First results with Pentax SMC K 135mm f2.5
In reply to Kerusker, Jul 26, 2013

Kerusker wrote:

Thanks for the info. I've re-read your post section in that thread.

Maybe you're interested in reading a comparison of 135 lenses:

http://forum.digitalfotonetz.de/userpix/3484_Vergleichstest_135mm.pdf

It's in German but images and tables can be evaluated easily and there are translation tools.

If I remember correctly the difference between the SMC 135 and SMC 135mm is visable in the color aberrations (seen on images like the ones with 'Halogen lamp'. When I bought mine (the 135mm) I also tried the other one (135) - if I remember correctly.

I also owned the Auto Revuenon but I've sold it later on.

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][.Kerusker
we don't see that we don't see (eye's blind spot)

Well, that is a very usefull test. Many thanks!

The F version seems the best and actually I was looking for one but the prices were pretty high. Regarding the K SMC version, this test is not far appart from other reviews. In this test it looses points due to its size/weight/not retracted hood, sharpness is improved if stopped down from ~f4 and has this lovely bokeg that attracted me so much. For me this was the most important reason in selecting it. Some tests/owners report better sharpness wide open, which looked very promising also, but mine possibly behaves closer to the sample of this review. But I need more tests to conclude.

Below I attach the photos of the aperture blades. It seems to me that the problem is almost non existant at f16, minimal at f22 but at f32 one specific blade always closes a little more than the others. It is always the same blade. I tried Miles Greens suggestion but it did not work with this issue. Sometimes this problematic blade is closer to the ideal possition (like at f11 setting0 but usually there is some stretching of the octagone shape. I will probably never use it at f32 due to diffraction but I don't know if this problem starts presenting at wider apertures too after some usage of the lens. Or if it is fixable.

You can also see the shape of octagone's angles at around f4 that I was talking about.

Any thoughts?

Kind Regards,

Spyros

The lens

f2.5

f4. This shape is similar at the f3.5 / f4 / f4.5 positions

f5.6

f8

f11

f16

f22

f32 at its best - less problematic form

f32 again

f32 at its typical form

f32 at its worst- most problematic form

f32 at its typical form again

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