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06-27-2013, 09:28 AM   #1
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Quick and dirty test SMC-M 40mm vs XS 40mm - judge for yourself

Ok, I once had this test done for myself and finally decided to keep them both. I like both of these lenses and to me both are useful and unique. However while discussing which 40mm for K-01 is the best choice in this thread :

The test I posted there wasn't done up to standards - so I decided to do another one - this time I picked proper subject.

The test was done on tripod with remote so no in camera SR or camera shake.
The subject wasn't prone to the wind either so no subject motion.
The images taken with K-01.

The images supplied are 100% crops for sharpness test and slightly scaled down for bokeh - which is blurred anyway so so worries about loose of details.

Please judge for yourself and let me know what you think.

NOTE: While judging the images - right click on 100% crop images and select 'View image' - on firefox - this will load it to separate window or tab - where should be available in full size which is about 1500 x 1500 pix. Only this way you can see all the details properly - otherwise the image can be scaled down by the browser.

My own opinion is subjective and can be wrong but I think that both lenses performs similarly well - altough I can see that XS has slightly better micro contrast - especially visible at 2.8 - but I still think that in parts where both lenses are sharp on the pictures below - especially at 2.8 I can see some more detail on SMC-M than XS40mm.

Also from the crops below should be clear now that XS 40mm is slightly wider than SMC-M - although the difference is very little - it is good to know.

SMC-M 40mm f/2.8 sharpness

XS 40mm f/2.8 sharpness

Here are results for f4.8 - both lenses gets phenomenal for me :
SMC-M 40mm f4.0 sharpness

XS-40mm f4.0 sharpness

Below you can see how both lenses perform in term of bokeh. My observation is that XS gives slightly smother bokeh at all apertures - but that might be my or my copy only or I simple can be wrong. Judge for yourself from the images below

SMC-M f2.8 bokeh test

XS 40mm f2.8 bokeh test

SMC-M 40mm f4.0 bokeh test

XS 40mm f4.0 bokeh test

Now I hope for a discussion - which lens you think is better ?
Were you surprised by the results ?
Have you done similar tests in the past with different results ?
Could you compare one or both lenses with Limited lenses ?

- manntax

06-27-2013, 09:41 AM   #2
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The XS is the same lens (optically) as the 40mm limited. One big difference between the modern lenses and the old one is flare/ghosting resistance, though the modern lenses should be significantly sharper in the corners as well.

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06-27-2013, 10:00 AM   #3
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My XS40mm shows more CA/fringing than my DA 40mm. The In-Depth test on this site seems to have found a similar difference:
"Chromatic aberrations were comparable to the DA 35mm, though it displayed nothing near the control of the DA 40mm Limited—differences in coating, perhaps?"

I suspect they've used a cheaper element in the XS40 design.

Last edited by audiobomber; 06-27-2013 at 10:16 AM.
06-27-2013, 10:09 AM   #4

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The formal tests by SLRgear also found CAs on the XS to be twice as large,
typically 4/100 of a percent of frame height versus 2/100,
comparing with those on the DA 40 Limited.

Pentax Lens: Primes -!


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