Sigma's better 150-600 lens on the 5DS R:
http://www.photozone.de/canon_eos_ff/977-sigma150600f563sports?start=1
Recall that last week they ran the same test on the Tamron 150-600:
http://www.photozone.de/canon_eos_ff/976-tamron150600f563vc?start=1
An interesting disclaimer is made before resolution is reported:
"Some may be surprised by the relatively moderate performance figures below. Please note that two effects are coming together here. First of all - the "common" peak performance on the EOS 5Ds R, out test camera, is reached around f/4. The Tamron lens is slower than that thus diffraction effects are already decreasing the resolution potential at all aperture settings. On top of that comes the fact that we are talking about a super tele lens here. Remember that this is a chart-based MTF system and the longer the focal length, the longer the distance between camera and chart. Beyond 300mm air diffusion is starting to have an impact and as you can conclude, it's correspondingly more pronounced the more you zoom out. Please keep that in mind here."
(I either missed this completely last week with the Tamron review or it was added after the fact. I'm aware MTF testing needs to be modified with longer lenses, but for those who know this better than I, is this an appropriate statement?)
At any rate, comparing the two lenses just from a resolution perspective:
150mm @ f/5 --> Sigma clearly better
150mm @ f/8 --> Tamron largely closes the gap as you'd expect
600mm --> Sigma better, stopping the Tamron down doesn't close the gap.
- A
http://www.photozone.de/canon_eos_ff/977-sigma150600f563sports?start=1
Recall that last week they ran the same test on the Tamron 150-600:
http://www.photozone.de/canon_eos_ff/976-tamron150600f563vc?start=1
An interesting disclaimer is made before resolution is reported:
"Some may be surprised by the relatively moderate performance figures below. Please note that two effects are coming together here. First of all - the "common" peak performance on the EOS 5Ds R, out test camera, is reached around f/4. The Tamron lens is slower than that thus diffraction effects are already decreasing the resolution potential at all aperture settings. On top of that comes the fact that we are talking about a super tele lens here. Remember that this is a chart-based MTF system and the longer the focal length, the longer the distance between camera and chart. Beyond 300mm air diffusion is starting to have an impact and as you can conclude, it's correspondingly more pronounced the more you zoom out. Please keep that in mind here."
(I either missed this completely last week with the Tamron review or it was added after the fact. I'm aware MTF testing needs to be modified with longer lenses, but for those who know this better than I, is this an appropriate statement?)
At any rate, comparing the two lenses just from a resolution perspective:
150mm @ f/5 --> Sigma clearly better
150mm @ f/8 --> Tamron largely closes the gap as you'd expect
600mm --> Sigma better, stopping the Tamron down doesn't close the gap.
- A
