Middle zone soft with my 360mm nikkor.

[Jim K. Decker]

I'm using a Nikkor 360mm tele design on my 4X5 Toyo field. I keep getting the middle zone soft when using the lens. Far and near are sharp, middle is soft. What am I doing wrong?

[Steve Hamley]

Are you using movements, like a back tilt or front tilt?

Steve

[Moe_4073]

Is it just this particular lens that does this or do you have the same problem with other focal lengths as well?

[David A. Goldfarb]

I don't think it's a lens fault, but just the normal issue of trying to use tilt to improve focus when you have two surfaces that are more or less perpendicular. Of course with a longer lens, DOF will be smaller, so the problem will be more pronounced. In such situations it is often better not to tilt and just stop down, as one would with a fixed camera.

[Scott Walton]

Take the elements off the shutter to see if you have a finger print or something on the elements.

[Doug Meek]

Hi Jim.

I can't be sure without seeing the scene you're shooting, but it sounds like your using tilt to bring a near and far object into focus, such as a foreground valley with mountains in the back. The far end of the valley or bottom of the mountains is probably what's soft and can only be made sharper by stopping down to increase dof. I could be way off base, but it sounds like a likely scenario.

[Brian Ellis]

If you're using forward tilt there's probably things in the middle ground that are sticking up above the plane of focus. That kind of thing can be brought into apparent focus only by stopping down the aperture after tilting to adjust the plane of focus to bring the near and far into focus. If you aren't using any movements and/or there isn't anything in the middle ground that could be sticking up above the plane of focus then I would think there's an equipment defect somewhere, presumably with the lens if this problem exists only with this lens.