[Klaus]

+1 for including both Center and Near-center (off-center?) along with Corners....and dropping extreme corners.  

 

Always found the Extreme Corners mostly useless data but also misleading...as has been discussed periodically in these forums.  Extreme corners seems to be a legacy of testing FF coverage lenses on low-res APS-C sensors and trying to force data to find some minor differences among lens-sensor combos that all performed similarly.  Consequently, Extreme corner data is over-weighted at PZ.  

 

I've never had a photo where I ever needed any performance out of the extreme corner.  It's such a small area of the photo, but given far too much importance by PZ.  I always ignore the results from it.  

 

Meanwhile, there is no data from the truly important golden-ratio / rule-of-thirds parts of the frame.

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Center / Off-Center / Corners provide much more useful spread of data across the frame.  Also avoids the perception of such extreme drop-off that you are currently getting with high-res sensors for Center / Corner / Extreme Corners.

 

Thanks for considering my input.

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Funnily I consider the center to be pretty useless (when was the last time when a lens was really bad or just good in the center?) but I'm loving my corners. ;-)

We are all different I guess.

 

@ Brightcolors - yes, this last mm of sensor space is a bit of an issue because this is where everything amplifies. We have to have some space there though.

[dave9t5]

The corners are not that extreme, in PZ tests... Case in point, the EF 35mm f2. Its real (extreme) corners are very soft, very sudden. But the PZ corners are just outside of that, showing relatively good results.

 

I too find not testing the center a bit odd.

 

Ah, I should've clarified that I meant of only testing at 3 positions for time reasons, then those 3 seem more useful.  But I have no problem with more than 3 positions.

 

No doubt there are some lenses with soft extreme corners.  But I'm pretty sure that I've no photos where there was anything of interest in the extreme corner.  

[dave9t5]

Funnily I consider the center to be pretty useless (when was the last time when a lens was really bad or just good in the center?) but I'm loving my corners. ;-)

We are all different I guess.

 

@ Brightcolors - yes, this last mm of sensor space is a bit of an issue because this is where everything amplifies. We have to have some space there though.

 

I can't recall the lat time I had a photo with a subject in the extreme corner.

 


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Most of the subjects in my photos usually closer to being on or within the orange circle.  The green circle is important for some images.  The blue circle is 99% useless...most of it is not even within the frame.  

 

PZ tests do not include data for the useful orange zone and give great importance to the blue zone.


 

[popo]

Would it be fair to say, if time and resources were practically unlimited, it would be possible to test at multiple various distances from the centre? Basically you could end up with something like an MTF chart. I recognise that time and resources are usually not unlimited...

[Brightcolours]

I can't recall the lat time I had a photo with a subject in the extreme corner.

 

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Most of the subjects in my photos usually closer to being on or within the orange circle.  The green circle is important for some images.  The blue circle is 99% useless...most of it is not even within the frame.  

 

PZ tests do not include data for the useful orange zone and give great importance to the blue zone.

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In landscape/cityscape shots with not a singular subject in the center, blurry extreme corners can be noticed at times. Not something too unusual, for 35mm. For some more than for others.

[Klaus]

Would it be fair to say, if time and resources were practically unlimited, it would be possible to test at multiple various distances from the centre? Basically you could end up with something like an MTF chart. I recognise that time and resources are usually not unlimited...

 

That is the point ...

[Klaus]

I can't recall the lat time I had a photo with a subject in the extreme corner.

 

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Most of the subjects in my photos usually closer to being on or within the orange circle.  The green circle is important for some images.  The blue circle is 99% useless...most of it is not even within the frame.  

 

PZ tests do not include data for the useful orange zone and give great importance to the blue zone.

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In the current version of the chart the "near center" point would be close to your orange zone.

 

However, again, we have different priorities.

I love my ultra-wides and in this case, the foreground is emphasized. And my attention is then usually drawn to the border zone.

I also enjoy "harmony" in my images - that is sharpness across the image field.

 

Honestly speaking - if just the orange zone is important to you, then 80% of the lenses should be fine really.

[youpii]

I'd rather have center/mid-frame/border and forget about extreme.