Visualizing Field Tilt and Field Curvature with MTF Mapper

Started Dec 10, 2016 | Discussions thread
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craig66 Senior Member • Posts: 1,474
Visualizing Field Tilt and Field Curvature with MTF Mapper
9

As per the title. These are animated GIFs that cannot be posted on DPR, so just use the external links.

The GIFs are produced from a series of MTF50 surface plots made from a stacked series of test images of an MTF Mapper grid chart. Chart is A0 size and average camera distance is about 2m. Test images are shot with about 9.2 mm camera movement between each for a total depth of stack of around 280mm.

"focus" is initially behind the chart and the stack is made by moving the camera in increments away from the chart.

Here are results from three lenses that behave very differently.

1. Kind of "normal" behavior. Sony DT 16-50 f2.8 SSM

https://s27.postimg.org/hyqcavd1v/animation.gif

2. Considerable field curvature. Sony DT 30mm f2.8 macro. And it's a macro lens! In fairness it might be better at close focusing distance - or it might not.

https://s24.postimg.org/4vvjdhbz9/surface_plot.gif

3. Just wow! Surfs up and it's choppy too! Sony DT 35mm f1.8.

https://s23.postimg.org/xj50twpbv/surface_plot.gif

I will shoot some real world shots with #3 later today and post them to see how such an "interesting" lens fares in real use.

Comments?

 craig66's gear list:craig66's gear list
Sony a77 II Sony DT 55-300mm F4.5-5.6 SAM Tamron SP AF 200-500mm F/5-6.3 Di LD (IF) Sigma 150mm F2.8 EX DG OS Macro HSM Sigma 500mm F4.5 EX DG HSM +10 more
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