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p.1 #20 · Best microcontrast at 50mm | |
http://www.pebbleplace.com/Personal/Contax_db.html
Pebbleplace has links to zeiss (c/y) lens data pdf's that include mtf charts ... you can compare the mtf characteristics of their different lenses i.e. 50 1.7 vs. 50 1.4, etc.
For instance, I shoot on a 1D MKII, so with a crop factor of 1.25x my dimensions are:
1D MK II Width Height Diagonal
Sensor Size 28.70 19.10 34.47
From center 14.35 9.55 17.24
Accordingly, I like to see at what distance from center the lens mtf tangential & sagittal lines start to separate. For me, those lenses that hold tight for at least 10mm suggests that I'll get very good results. Your shooting style & sensor size may vary your interpretation.
For my uses ... the 50mm 1.7 holds tight out to 20mm (trailing a bit @ 15mm). It is a tiny bit lower MTF than the 1.4 which starts to separate around 10mm. For me, the tradeoff of keeping the tangential & sagittal tight longer, vs. a small difference in in MTF resolution suggests a better performance to my style.
Also, I'm not inclined to shoot razor thin DOF or low light, so the 1.4 doesn't mean much to me, 1.7 is fine. I'm shooting with the 35-70 Macro right now, so I don't have the 50mm 1.7 ... but that is the direction I'll be headed when I feel the need. It's character is close to the same as the 35-70 @ 50mm, albeit a little better resolution ... but just a little.
For comparison ... check out the 21mm ... it has smoking hot high mtf and it holds tight ... no wonder it is a $2K lens ... in my dreams, but it shows me what I should be striving for ... also the 100mm Planar & the 85mm Planar show simliar patterns (albeit not quite as high MTF). Given the 100mm & 21mm are lenses that speak for themselves ... I like the fact that the 1.7 looks more like they do than the 1.4 (on paper)
The MTF's are usually shown for both wide open (specific to that lens) and at 5.6 for a benchmark comparison. Zoom lenses usually show 3 ranges (wide, middle, long). It is really nice info to know ... props to PebblePlace.
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