p.1 #1 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
Was trying some close-in, shots of ornaments on the tree and for some I was using LV 10x zoom AF and yet shot after shot was a mess with the AF seeming off despite looking perfect in LV. It was dark so LV had lens at f/2.8 but my shots were maybe f/4-f/5. I held in the DOF button to focus at actually shooting aperture and noticed that the focus placement suddenly jumped to a different spot. Focusing with DOF button held down, the final shots had focus where it was intended. It actually made a tremendous real world difference.
p.1 #2 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
One thing was not clear, you were using Live View 10X then you had to be manual focusing at f2.8? Then when you shot (from Live view) at a smaller aperture (4-5.6) there was focus shift? So you are not talking about AF using LV Quick or LV Live? AF using LV Quick is affected by micro adjust setting while LV Live is not. LV Live simply optimizes sensor contrast in the magnify area.
You checked this by using LV at f2.8, mf followed by use of DOF button the stop down. Are you sure it was not just greater DOF where you has the view on magnify?
This behavior happened at which zoom position, and at very close distances? Does it behave this way at all zoom positions at MFD? Does it also happen with normal AF & LV Live AF?
Mike K
p.1 #4 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
Mike K wrote:
One thing was not clear, you were using Live View 10X then you had to be manual focusing at f2.8? Then when you shot (from Live view) at a smaller aperture (4-5.6) there was focus shift? So you are not talking about AF using LV Quick or LV Live? AF using LV Quick is affected by micro adjust setting while LV Live is not. LV Live simply optimizes sensor contrast in the magnify area.
You checked this by using LV at f2.8, mf followed by use of DOF button the stop down. Are you sure it was not just greater DOF where you has the view on magnify?
This behavior happened at which zoom position, and at very close distances? Does it behave this way at all zoom positions at MFD? Does it also happen with normal AF & LV Live AF?
Mike K ...Show more →
I was shooting quite close, relatively close to MFD. I haven't tried anything like this at longer distances. I forget the exact zoom positions, I think more middle to long end, although I did mess around with some close, wide shots too. Haven't tested it out much. It was just something I noticed.
It was nothing to do with getting more DOF. I'd focus on, say, an eye (and this was a static scenario, camera fixed on tripod) with LV at f/2.8 and DOF would be dead centered around the eye and it would look sharp. Hit the remote shutter release. Inspect results. Blurry, OOF.
Then I tried hitting DOF button while focusing and as soon as I'd hit it I'd see the focus plane shift. If I focused it on the eye at f/2.8, as soon as I hit DOF button, despite more DOF, the eye would go OOF. If I then re-focused while holding it down, centered about the eye then the final shot would maintain focus on the eye.
p.1 #6 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
The workaround would be refocusing (in LV) whenever changing apertures. However,that would be a problem for you because f/2.8 made the screen brighter in your dark environment. I wish Canon would add more tools for critical focusing in live view...
p.1 #7 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
Fred Miranda wrote:
The workaround would be refocusing (in LV) whenever changing apertures. However,that would be a problem for you because f/2.8 made the screen brighter in your dark environment. I wish Canon would add more tools for critical focusing in live view...
As it turned out focusing in LV under actual aperture shot was good enough, I could still see where the focus was even through all the noise in this case.
p.1 #8 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
skibum5 wrote:
As it turned out focusing in LV under actual aperture shot was good enough, I could still see where the focus was even through all the noise in this case.
I would think so. When setting your lens aperture and focusing in LV, what you see is what you get.
p.1 #9 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
skibum5 wrote:
Was trying some close-in, shots of ornaments on the tree and for some I was using LV 10x zoom AF and yet shot after shot was a mess with the AF seeming off despite looking perfect in LV. It was dark so LV had lens at f/2.8 but my shots were maybe f/4-f/5. I held in the DOF button to focus at actually shooting aperture and noticed that the focus placement suddenly jumped to a different spot. Focusing with DOF button held down, the final shots had focus where it was intended. It actually made a tremendous real world difference.
yah, any focal plane that flip its wings while stopping down will do that to you...so does most fast lenses. Its focal plane shifts regardless subject distance...distance dof might fool our eyes but the effects is always there.
p.1 #10 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
Fred Miranda wrote:
I would think so. When setting your lens aperture and focusing in LV, what you see is what you get.
Unless the low light handler gets triggered (as in this case, whichis how I came across this all), then it uses f/2.8 for LV no matter what the aperture is set to, so you need to hold down DOF preview button or change something in the LV menu settings when dealing with a scenario where focus shifts can occur.
p.1 #11 · 24-70 II near MFD focus shift f/2.8 vs stopped down?
My 24-70 II also has a small bit of focus shift when I stop it down. It is good visible at f/9 or smaller and on a close focus distance. The focus plane shifts to the back, but the focus point itself stays in focus. I would expect a 1/3 and 2/3 ratio in focus in front and back of the focus area, but it's more 1/5 and 4/5.
I will do some tests with the dof preview button.
Btw In daily shooting it's not really a big issue, but it is visible in forces test environments.
