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Archive 2014 · Is Field Curvature Subject to Sample Variation?

  
 
Dr88man
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p.1 #1 · p.1 #1 · Is Field Curvature Subject to Sample Variation?


Does the amount of field curvature vary from sample variation or is it "fixed" or intrinsic to a particular design of a lens type? For example if I have 3 samples of the 24-70/2.8G, can they differ in the amount of field curvature?

I ask the question because both my new 14-24/2.8 and 24-70/2.8G lenses have considerable field curvature which make them unsharp at the corners. I'm a new Canon convert, and it was never a big issue when I was using Canon because the lenses I was using had flatter field of curvature.

My set up is D810, 14-24/2.8, 24-70/2.8G, 70-200/4 VR. I shoot only landscapes and aerials.

Thanks!



Dec 09, 2014 at 11:50 PM
EB-1
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p.1 #2 · p.1 #2 · Is Field Curvature Subject to Sample Variation?


Not so much. If there is such variation that the curvature is substantially different in a sample then typically there would be other undesirable optical artifacts. However, I have no knowledge of the characteristics of those particular lenses.

EBH



Dec 10, 2014 at 01:27 AM
hans98ko
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p.1 #3 · p.1 #3 · Is Field Curvature Subject to Sample Variation?


Dr88man wrote:
Does the amount of field curvature vary from sample variation or is it "fixed" or intrinsic to a particular design of a lens type? For example if I have 3 samples of the 24-70/2.8G, can they differ in the amount of field curvature?


Field curvature is supposed to be fixed to a particular design. For example if you set both your 14-24mm f/2.8G and your 24-70mm f/2.8G at 24mm f/2.8 or at it's maximum aperture, they will have very different field curvature due to their intrinsic design.
But field curvature can also vary from sample to sample due to it's tolerance during manufacturing and also during assembly, as with de-centering of elements. For example if you have 2 identical 24-70mm f/2.8G, they can have slightly different field curvature (must add extremely slight that is not visible to our naked eyes) due to stack errors or even uneven field curvature due to de-centering of elements which is very visible to our eyes.

Hope this helps to clear up your understanding of field curvature.



Dec 10, 2014 at 01:38 AM
akul
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p.1 #4 · p.1 #4 · Is Field Curvature Subject to Sample Variation?


Check out Roger Cicala's blog from Lensrental.com. He recently started mapping field curvature of actual lenses using his Olaf optical bench.

https://www.lensrentals.com/blog/2016/09/fun-with-field-of-focus-part-1/

Very informative.

Luka



Nov 23, 2016 at 03:45 PM





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