. . .One thing that did bother me a bit was the field curvature. I tend to place the subject in the center, focus, and then recompose. However, whenever I do this with the 40mm at f1.2 the subject is not as crisp as it was when I focused. So I had to focus with the subject in place, which sadly adds some tediousness (I use focus magnification). What do you people do about this? Hope my copy's curvature is not more pronounced than usual :|
I'll do some tests the following days to look at curvature and sharpness. For curvature, I'll shoot the same subject focused in center vs focused in center and recomposed vs focused directly in final composition.
While I haven't acquired the currently elusive Nokton 40/1.2 yet and don't have a feel for the degree of field curvature it possesses, be careful talking about field curvature.
If a lens had a technically flat field, it would still exhibit the behavior you describe. To illustrate my point, imagine a "T"-square, one with a 3 or 4 foot vertical rod and a 3 or 4 foot top rod at 90 degrees. Hold it out at arms length and touch a wall where the top rod is flat against the wall. When you try to rotate and have the end of the top rod touch the wall you will have to take a step back. This is what you describe, re-framing from center changes the focus point distance from sensor and that focus point will not be optimally in focus because it has moved away from sensor.
If you really want to focus and recompose, and have that focus point in focus, you will have to find a lens that actually has field curvature in the shape of an open umbrella held at arms length. The in focus field wraps around like the umbrella and your subject will be in focus.
Good point, I should try the ground trick next time. Peaking kind of disappointed me when I first got my a7II, so I'm mostly using the evf moire trick with focus magnification.
Speaking of focus magnification, before the nokton, my previous all arounder was a canon FD 35 f2.8, and I was kind of tired to keep pressing the focus magnification custom button on almost each shot that involved fine grained focusing. The auto magnification that I get with the nokton makes the flow much nicer, save for the field curvature problem. When I want to quickly turn it off, I noticed that pressing the magnification button once disables auto magnification, while at the same time does not magnify anything (just brings up the magnification crosshair).
One feature that I wish my a7II had: if there is a face in the frame, then put the auto magnification crop on that face. That would solve many of my focusing issues with the nokton's curvature (since I can take my time with off center non inanimate objects).
imagesfromobjects wrote:
You can use peaking on "low" and just look where the center of the peak line is on the ground where your subject is standing, "tuning" back and forth, you'll see the line move. You can actually do the same thing with peaking off, there's a ripple where things are in focus- just use the ground (or similar stationary objects with contrasty edges) to pre-focus and fire away. I've learned to become friends with burst mode, too.
Very good point. I guess this is my first ultra fast lens, and up until now the focus plane shift during recomposition was not that evident. I'll have to find some other trick to make sure off-center eyes are in focus. Right now I just move the magnification crop but that's slow.
Regarding the curvature, I remember someone suggesting it's actually the way you described it
JimBuchanan wrote:
While I haven't acquired the currently elusive Nokton 40/1.2 yet and don't have a feel for the degree of field curvature it possesses, be careful talking about field curvature.
If a lens had a technically flat field, it would still exhibit the behavior you describe. To illustrate my point, imagine a "T"-square, one with a 3 or 4 foot vertical rod and a 3 or 4 foot top rod at 90 degrees. Hold it out at arms length and touch a wall where the top rod is flat against the wall. When you try to rotate and have the end of the top rod touch the wall you will have to take a step back. This is what you describe, re-framing from center changes the focus point distance from sensor and that focus point will not be optimally in focus because it has moved away from sensor.
If you really want to focus and recompose, and have that focus point in focus, you will have to find a lens that actually has field curvature in the shape of an open umbrella held at arms length. The in focus field wraps around like the umbrella and your subject will be in focus....Show more →
Apr 07, 2018 at 10:26 PM
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This is beyond torture. I ordered my 40/1.2 from Adorama over a month ago. They remain closed and I'm sentenced to watching endless new posts :-) I remain hopeful that mine will arrive before June. Grrrr
RobertHolloway wrote:
This is beyond torture. I ordered my 40/1.2 from Adorama over a month ago. They remain closed and I'm sentenced to watching endless new posts :-) I remain hopeful that mine will arrive before June. Grrrr
For your sake - I hope some of the supply trickled down to Adorama. It was mentioned in this post that they get their supply from the likes of Photo Village. Both Photo Village and Camera Quest are out of stock again.
I'm having a blast with mine - a learning curve for me as I don't shoot very much MF and I've never shot MF at these apertures before. It's very rewarding when I can land a good sharp shot.
Regarding the 0.95 - interesting, they don't seem afraid to really cluster their lenses. 35/1.2 (M), 35/1.4, 35/1.7 (M), 40/1.4 (M), 40/1.2 (FE), 50/1.2 (M), 50/1.1 (M), 50/1.5 (M), etc.
I can't imagine that a 0.95 would be outside of the 35-50 range, so where does it fit in there? Maybe they're replacing the 50/1.1 with a 50/.95 in both mounts? hmm.
edit: they don't have an FE 50mm yet, so that seems to be the likely target. They are keeping the FE-mount lenses relatively spread out so far.
Taylor Sherman wrote:
Regarding the 0.95 - interesting, they don't seem afraid to really cluster their lenses. 35/1.2 (M), 35/1.4, 35/1.7 (M), 40/1.4 (M), 40/1.2 (FE), 50/1.2 (M), 50/1.1 (M), 50/1.5 (M), etc.
I can't imagine that a 0.95 would be outside of the 35-50 range, so where does it fit in there? Maybe they're replacing the 50/1.1 with a 50/.95 in both mounts? hmm.
Perhaps it's not full frame but I hope it is. Is there a link to the article?
