[Klaus]

I am still not impressed by this lens.

[url="http://www.opticallimits.com/pentax/736-pentax43f19k5"]http://www.opticallimits.com/pentax/736-pentax43f19k5[/url]



The difference towards the MTFs in the initial review is somewhat puzzling.



Klaus

[moving_comfort]

[quote name='Klaus' timestamp='1337448525' post='18334']

I am still not impressed by this lens.

[url="http://www.opticallimits.com/pentax/736-pentax43f19k5"]http://www.opticallimits.com/pentax/736-pentax43f19k5[/url]



The difference towards the MTFs in the initial review is somewhat puzzling.



Klaus

[/quote]





Klaus, how do you account for the MTF numbers being *lower* on the edge on the 16MP sensor than they were on the 10MP sensor? (Sample variation?) On a related note, where was the copy you tested manufactured?



Thanks!

[Klaus]

[quote name='moving_comfort' timestamp='1337523067' post='18352']

Klaus, how do you account for the MTF numbers being *lower* on the edge on the 16MP sensor than they were on the 10MP sensor? (Sample variation?) On a related note, where was the copy you tested manufactured?



Thanks!

[/quote]



I do not know for sure. The 16mp sensor of the K5 is not much different than the 10mp sensor of the K10D.

The AA filter characteristic is very different though. The K10D AA filter has no vertical filtering at all so the border performance figures can be different if the sagittally or tangentially is emphasized.

The center resolution characteristic may be different due to the different RAW profile of the cameras although I am surprised about the difference.

[Guest]

[quote name='Klaus' timestamp='1337448525' post='18334']

I am still not impressed by this lens.

[url="http://www.opticallimits.com/pentax/736-pentax43f19k5"]http://www.opticallimits.com/pentax/736-pentax43f19k5[/url]



The difference towards the MTFs in the initial review is somewhat puzzling.



Klaus

[/quote]



it's unreal - for example

at K10D - f2.8 corner - 1993 LW/PH

at K-5 - f2.8 corner - 1743 LW/PH



The same situation at f4-5.6.



10 MP is always lower than 16 MP. The maximum resolution of system - camera+lens+soft of higher MP couldn't be lower <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />

Any lens of any system will show higher resolution at 16 MP camera than at 10 MP.



FA43 coudn't be worse at 16 MP than at 10 MP. In the worst case the resolution could be almost the same in test. But not lower.



1993 LW/PH is very good resolution at 10 MP, the drop of 250 LW/PH at 16 MP camera indicates that Klaus has no good sample of lens.

I have K200D and K-5, my FA43 is sharper at K-5 at all apertures. The center and corners. It's fact.

[Guest]

[quote name='Klaus' timestamp='1337526324' post='18353']

I do not know for sure. The 16mp sensor of the K5 is not much different than the 10mp sensor of the K10D.

The AA filter characteristic is very different though. The K10D AA filter has no vertical filtering at all so the border performance figures can be different if the sagittally or tangentially is emphasized.

The center resolution characteristic may be different due to the different RAW profile of the cameras although I am surprised about the difference.

[/quote]

AA filter characteristic which may explain at least part of the results.

AA filter could affect only at sharpness and WHOLE resolution of system, which 2750 LW/PH for K-5. AA filter has no any affect at the drop of resolution of lens at 16 MP vs 10 MP. Klaus, it's strange to hear such explanation from you.



I have K200D with weak AA filter (more than 4 year) and K-5 (1 year). I don't see than K-5 has much thicker AA filter.

Thicker, but just a bit. I use C1 Pro.



As for strange corner result of FA43 at K-5 - it seems to me - it's lens variation - you got strange sample with good center and bad corners. Pay attention - FA43 is soft at center at f1.9 at K10D, but MUCH better at K-5 - I see the same at my cameras.

As for corners - I'm puzzled. FA43 is one of the sharpest lens at my K200D and the same at K-5.

[Klaus]

[quote name='ogl69' timestamp='1337532114' post='18355']

AA filter characteristic which may explain at least part of the results.

AA filter could affect only at sharpness and WHOLE resolution of system, which 2750 LW/PH for K-5. AA filter has no any affect at the drop of resolution of lens at 16 MP vs 10 MP. Klaus, it's strange to hear such explanation from you.

[/quote]



Maybe I have a better insight then ?







We measure the MTFs at quadrant transitions - at the borders / corners the edges of the quadrants are slightly aligned to the sagittally and tangentially resolution respectively (not on purpose). If a lens suffers from astigmatism these resolution types will differ.

On a symmetrical AA filter the measured results are just averaged whereas an asymmetrical one favors one resolution type at the quadrants - not much, of course, but there is a certain tendency.

[Guest]

OK...But how can you explain that lens lost 200-250 LW/PH at the borders at sensor with 16 MP? It's 16 MP sensor of K-5 with max. resolution 2750 LW/PH vs 2350 LW/PH. Let's allow that your sample has bad corners and AA filter affects at corner resolution of FA43....

BUT....if the resolution was 1993 LW/PH at 10 MP, it couldn't be 1743 LW/PH at 16 MP camera.

250 LW/PH drop at the system with 400 LW/PH higher max. resolution. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/blink.gif' class='bbc_emoticon' alt=':blink:' />





All lenses retested at K-5 have better resolution than at K10D. And it's no surprise. Even FA31/1.8 if we say about film era optical design.

Except for FA43's corners. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/huh.gif' class='bbc_emoticon' alt='' />

[Klaus]

As mentioned I have no complete explanation at this stage.

[Class A]

[quote name='Klaus' timestamp='1337526324' post='18353']

The center resolution characteristic may be different due to the different RAW profile of the cameras although I am surprised about the difference.

[/quote]

In what sense are you suggesting that a RAW profile may influence resolution?

[Klaus]

[quote name='Class A' timestamp='1337555748' post='18362']

In what sense are you suggesting that a RAW profile may influence resolution?

[/quote]



Sharpening could have a different impact due to the different AA characteristic.