Wow, now that is interesting. F/1.4 shows the nikon sharper out to the edges. Look at the magazines on the left. Sigma has more contrast. The sigma is WEAK at 2.8 and doesn't catch up until f/8. Interesting....I wonder if there is focus shift to account for in that Sigma?
Yeah, i don't know what happened with the Sigma at f/2.8.... I re-took it thinking it was a fluke and it ended up with the same result so i just posted it
i will do more shooting with the Sigma at f/2.8 to see if that's the case
Regardless... i'm pretty confident this proves the Nikon being sharper
I'm going to take this test with a grain of salt. There have been much better examples of the sigma from both camps then these. Shoot for a couple weeks what you normally would shoot and evaluate the outcome based on those results.
Bruce Sawle wrote:
I'm going to take this test with a grain of salt. There have been much better examples of the sigma from both camps then these. Shoot for a couple weeks what you normally would shoot and evaluate the outcome based on those results.
+1
I already sold the 85D and will hand it off on Saturday. I will keep the Sigma and will shot as normal and then evaluate. Did you get your copy yet?
It's at UPS I will pick it up tomorrow. For whatever reason 47 street photo would not deliver to my door. I will chime in tomorrow afternoon on my initial thoughts.
Did you ever shoot a focus test chart with the Sigma? That sort of behavior in the sharpness test could be a result of a small degree of misfocus. www.focustestchart.com
It could also be focus shift upon stopping down, much like the Canon 50mm f/1.2L suffers from.
I find it very odd that the lower left corner of the crop at f/1.4 from the Sigma is so blurry on a mostly planar test, that tells me something is amiss. Have you ran a test to make sure you don't have a decentered element and your sample is equally sharp across the frame? (think brick wall or garage door photo)?
Jammy, I did the focus test on both lenses and the Sigma looked fine from the tests. The Nikon looked off, but I manually focused and got the sweet spot for the tests and then just adjusted aperture from there.
Since I will be keeping the Sigma, I will have to evalulate it much more. Good point, and i'll have to run some tests (brick wall). I hope my copy doesn't suffer from focus shift, and if that's the case, then i'll probably send it in for an exchange and hope i get a better copy
JR Magat wrote:
Jammy, I did the focus test on both lenses and the Sigma looked fine from the tests. The Nikon looked off, but I manually focused and got the sweet spot for the tests and then just adjusted aperture from there.
Since I will be keeping the Sigma, I will have to evalulate it much more. Good point, and i'll have to run some tests (brick wall). I hope my copy doesn't suffer from focus shift, and if that's the case, then i'll probably send it in for an exchange and hope i get a better copy
This may be the issue I remember reading somewhere that you need to refocus once you change the aperature on some lenses.
Bruce Sawle wrote:
This may be the issue I remember reading somewhere that you need to refocus once you change the aperature on some lenses.
That would be a huge strike against the Sigma if there is focus shift issues with the lens....especially if you are purchasing this lens for faster focus than the Nikon D version. Focus shift will be in the design...not in some lenses and not in others. I don't think I have heard of any other Sigma lenses with focus shift issues.
I noticed the same thing as Jammy. Focus is more blurred in the corner at 2.8 than 1.4. That doesn't make any sense whatsoever. I think a more defined test in focus is in order. Manually focusing with liveview in between each aperture change will confirm focus shift.
Bruce Sawle wrote:
This may be the issue I remember reading somewhere that you need to refocus once you change the aperature on some lenses.
Well, i only did this with the Nikon. With the Sigma, I had it set to auto-focus and refocused for each shot. I'll try to get more shots with the Sigma to see if this test was a fluke; which I hope it was!
oh I haven't done any tests with a tripod through an aperture range yet....I'm not seeing any focus issues though...I'll put it through some paces this weekend. (It's a full resize to 1000 wide@72, not a crop)
James Burden wrote:
oh I haven't done any tests with a tripod through an aperture range yet....I'm not seeing any focus issues though...I'll put it through some paces this weekend. (It's a full resize to 1000 wide@72, not a crop)
i'll have to put my copy through the paces as well to get a better feel for it. i'll be interested to see how yours and Bruce's copies turn out!
