liupublic wrote in post #14215244
Forgot to compare against Canon 24-70L II MTF charts.
Tamron 24-70 VC looks very similar to 24-70L II. Tamron is just about 0-10% worse at 30 Lp/mm everywhere at both 24mm and 70mm.
So it's fairly promising just looking at MTF.
Putting aside that you really can't compare MTF's between different companies since they don't use the same methodology for testing, here is my analysis of the various Canon MTF charts against the Tamron. This was done by assigning actual number values to the results at each given mm measurement from center (0, 5, 10, 15, 20, 21) on the MTF charts and comparing those numbers to the other charts mathematically. I then averaged the overall difference. (Keep in mind there is some margin of error here since I am estimating numbers by eyeballing small charts that I have zoomed in on. The general results should hold true though).
All comparisons are Wide Open f/2.8 only since Tamron doesn't provide F/8 information like Canon does. Radial results only...
Tamron 24-70VC vs Canon 24-70 L at 24mm = Tamron ~9% better across the frame.
The Tamron has better contrast (10mm LP/mm) results from corner to corner. It is slightly better in the center, about the same from 5-15mm out, and then increasingly better until it dominates entirely at the corners (~0.34 points higher, on a 1 point scale!)
The Tamron has WAY better resolution (30mm LP/mm) results in the center (0.21 points higher on a 1 point scale), with the Canon slowly catching up until it surpasses at around 17mm out, but then at the corners the Tamron beats the Canon again.
Tamron 24-70VC vs Canon 24-70 L at 70mm = Tamron is ~8% better.
Tamron is better at both contrast and resolution in the center by a significant margin (0.08-0.1 contrast, 0.1-0.3 resolution)Both start falling off in relative terms around 14mm and by 20mm the Tamron is lagging behind by a tiny bit. However, the Tamron catches back up and surpasses in the extreme corners.
Tamron 24-70VC vs Canon 24-70 L II at 24mm = Canon is ~7% better.
The Tamron is essentially equal at the center of the frame, but both contrast and resolution begin to fall behind at about 12mm, and by 20mm the difference becomes fairly significant, especially resolution.
Tamron 24-70VC vs Canon 24-70 L II at 70mm = Canon is ~11% better.
The Tamron is about equal dead center, but stars falling off immediately. Contrast holds up well until about 12mm, but resolution is in the doghouse by about 7mm out from center. The Tamron does regain a little past 15mm, but that is in relative terms, it is still well behind the Canon the whole time.
Overall results? The Tamron should fall almost dead in the middle between the two Canon lenses on FF, and is actually very close to the Canon L II on Crop, especially at 24mm.
(Just for fun I did a valid comparison as well, Canon to Canon.. The L II wins by ~16% at 24mm and ~19% at 70mm. At 24mm a LOT of the gain is the corners. I assume because with this new lens they have probably resolved the field curvature issue.)
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