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Archive 2016The 24-70mm f/2.8 GM MTF and Variance Tests
p.2 #1The 24-70mm f/2.8 GM MTF and Variance Tests
My 24-70 after my wall test looks outstanding for a zoom. Ill post those results Thursday and my 85 comes Friday. Roger thanks for your report
Apr 06, 2016 at 10:57 AM
p.2 #2The 24-70mm f/2.8 GM MTF and Variance Tests
RCicala wrote:
Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
ChrisChris, it can but there's simply a workload issue. Doing just the basic tests on the zoom took two full days. Stop downs would add another 3 or 4 days on multiple copies and both the machine and I have time constraints.
Roger
That's just testing a lens non-stop for an entire week!! I'm sure you don't have anything better to do.
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.
Schlotkins wrote
Thanks Roger!Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
Chris
Roger
That's just testing a lens non-stop for an entire week!! I'm sure you don't have anything better to do.
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.
Apr 06, 2016 at 11:04 AM
p.2 #3The 24-70mm f/2.8 GM MTF and Variance Tests
Fred Miranda wrote:
Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
ChrisChris, it can but there's simply a workload issue. Doing just the basic tests on the zoom took two full days. Stop downs would add another 3 or 4 days on multiple copies and both the machine and I have time constraints.
RogerThat's just testing a lens non-stop for an entire week!! I'm sure you don't have anything better to do.
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.
That's really not true. The aberrations present at f/2.8 are unknown; if there is 0 lateral color, 0 astigmatism and 0 petzval, the lens is diffraction limited at closed apertures but could look like this. If there is 0 spherical aberration, then the lens will look almost exactly like this at f/8 as well.
If you do nothing else and are extremely good at MTF testing quickly and accurately, and the distortion of the lens is well-behaved you can do the stop down set for a zoom lens at 3 focal lengths in about a day. Given the complications of a Sony lens, I would expect 2 days minimum. Add on, you know, running a huge rental company and 3-4 is not unrealistic.
Stop-down testing is extremely boring. A lens will end up getting done in early may when the intern arrives if I go down to introduce them to everything, simply because there are some special considerations for stopped-down testing I will need to go over with them. I spent weeks of my summer doing the FM landscape shooters a favor by doing most of the popular landscape lenses that existed then from full aperture to f/16, so this one is my choice
RCicala wrote
Schlotkins wrote
Thanks Roger!Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
Chris
Roger
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.
That's really not true. The aberrations present at f/2.8 are unknown; if there is 0 lateral color, 0 astigmatism and 0 petzval, the lens is diffraction limited at closed apertures but could look like this. If there is 0 spherical aberration, then the lens will look almost exactly like this at f/8 as well.
If you do nothing else and are extremely good at MTF testing quickly and accurately, and the distortion of the lens is well-behaved you can do the stop down set for a zoom lens at 3 focal lengths in about a day. Given the complications of a Sony lens, I would expect 2 days minimum. Add on, you know, running a huge rental company and 3-4 is not unrealistic.
Stop-down testing is extremely boring. A lens will end up getting done in early may when the intern arrives if I go down to introduce them to everything, simply because there are some special considerations for stopped-down testing I will need to go over with them. I spent weeks of my summer doing the FM landscape shooters a favor by doing most of the popular landscape lenses that existed then from full aperture to f/16, so this one is my choice
Apr 06, 2016 at 11:26 AM
p.2 #4The 24-70mm f/2.8 GM MTF and Variance Tests
Brandon Dube wrote:
Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
ChrisChris, it can but there's simply a workload issue. Doing just the basic tests on the zoom took two full days. Stop downs would add another 3 or 4 days on multiple copies and both the machine and I have time constraints.
RogerThat's just testing a lens non-stop for an entire week!! I'm sure you don't have anything better to do.
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.That's really not true. The aberrations present at f/2.8 are unknown; if there is 0 lateral color, 0 astigmatism and 0 petzval, the lens is diffraction limited at closed apertures but could look like this. If there is 0 spherical aberration, then the lens will look almost exactly like this at f/8 as well.
If you do nothing else and are extremely good at MTF testing quickly and accurately, and the distortion of the lens is well-behaved you can do the stop down set for a zoom lens at 3 focal lengths in about a day. Given the complications...Show more →
That extrapolation was based on my own tests at infinity.
https://www.fredmiranda.com/forum/topic/1422120
Fred Miranda wrote
RCicala wrote
Schlotkins wrote
Thanks Roger!Can your testing machine work stopped down? As a landscape guy, I'd love to see f/8 or f/11 comparisons,
Thanks again for your hard work.
Chris
Roger
I think we can safely extrapolate that the MTF graph will look way better for the corners at f/8.
If you do nothing else and are extremely good at MTF testing quickly and accurately, and the distortion of the lens is well-behaved you can do the stop down set for a zoom lens at 3 focal lengths in about a day. Given the complications...Show more →
That extrapolation was based on my own tests at infinity.
https://www.fredmiranda.com/forum/topic/1422120
Apr 06, 2016 at 03:20 PM
p.2 #5The 24-70mm f/2.8 GM MTF and Variance Tests
What about reliability and serviceability? The Canon is a workhorse pro lens with good reliability and is designed to be serviceable. Roger reported that other FE lenses have parts held together with glue (instead of hardware) and do not have internal hardware (everything is fixed in place) needed for adjustments. Waiting for his tear-down
Apr 06, 2016 at 08:38 PM
p.2 #6The 24-70mm f/2.8 GM MTF and Variance Tests
Roger, we all owe you a large pizza. Thanks for all you do.
Apr 07, 2016 at 09:28 AM
p.2 #7The 24-70mm f/2.8 GM MTF and Variance Tests
Okay so my earlier post was wrong, both the Canon and Nikon lenses were as expensive when they launched as this Sony.
On the other hand, neither of them were a third player trying to build market share and break into a well-set duopoly...
On the other hand, neither of them were a third player trying to build market share and break into a well-set duopoly...
Apr 07, 2016 at 09:01 PM