Which 35mm 1.4 has the "flattest" focus field at close distance?

andreben wrote:

Hi everyone,

I need a 35mm 1.4 for my Nikon D800 (or alternatively 50mm 1.4 if advantages are obvious) for a scientific project. The main criteria, in additional to sharpness, are:

1. Focus field flatness

2. AF accuracy centre-frame

For this project, I will be taking pictures of low contrast objects at near distance, probably 0.3-0.5m. I need the "entire" frame to be captured in "perfect" focus left-right (top-down less important).

I've been eyeing the Sigma 35mm 1.4, but haven't been able to figure out much regarding the focus field on this lens. 35mm is the ideal focal lenght, but I can consider going to 50mm if the focus field is significantly improved.

All help appreciated!

Cheers,

Andreas

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