another focusing challenge

[h2oman]

When focusing the attached image I initially thought I'd apply some front tilt to put the focal plane on the surface of the water. After tearing my hair out for a bit I finally realized that the portion of the water in front of me actually needed to be focused as if it were farther away, since the distance light travelled from the reflected trees that I wanted in focus was much farther than the light that came from the ice. Is that reasoning correct?

I then tilted the other way to try to bring both the ice and the trees into focus, but then the leaves and gunk on the surface of the water was out of focus. Should I have just forgotten about tilts and stopped down farther? (I was trying to get everything in focus.) Tell me what you think.

[Doremus Scudder]

You are on the right track Waterman... A reflected image appears the same distance away from the reflecting surface as the original object is. In this case you have a horizontal reflecting surface with a vertical reflection, making matters worse. Notice that the nearest and the farthest objects (the near water surface and the treetops) occupy roughly the same place in the image. That means you need DoF to cover that part and that any movements you use will be superfluous since everything else in the scene is at an intermediate distance. The best you can do is focus near/far, split the difference then find the optimum f-stop.

Best,

Doremus Scudder

BTW, nice shot! where in your area did you take it? I'm a part-time Oregonian myself and lived in K-Falls for a while years ago (headquarters in the States is Redmond, OR for me now).

[Chuck P.]

My rationale for focusing, please correct if wrong:

If there were no reflections in this subject, then it seems focusing would be very simple with front tilt or even a combination of front and back tilt when geometry is not a concern.

Becasue it's a flat planar subject of the water/ice, it seems the primary focus plane is well defined already as there's no need to decide where it shoud be---it's the flat surface before you. Therefore, sharp focus could be gotten at a wide aperture.

But with the verticle reflections in the surface of the water, suddenly there is an element of height to consider and now it becomes a matter of also having to use enough DoF to bring the water/ice surface and the vertical reflections of the trees in sharp focus.

BTW, also a very nice shot.

Chuck

[Lachlan 717]

Perhaps think of it as being like shooting through a window. The frame of the window
equates to the edge of the puddle. The detail outside the window is the same as the reflection of the trees.

If you consider it this way, you will easily understand that this can only be a DoF issue, not a movement issue.

I would think that a small aperture and hyperfocal distance would solve this.

Lachlan.

[pocketfulladoubles]

The trees in the reflection are a virtual image of the real trees. Basically, they are the same distance away as the real trees but flipped upside-down as if they were growing out of the ground downward, so just treat them like that. You may not need to focus on the water specifically. In fact, if you play around with long-ish exposures, you may get better reflections, and the water will be smoothed out anyway - time to play around.

[Lachlan 717]

The trees in the reflection are a virtual image of the real trees. Basically, they are the same distance away as the real trees but flipped upside-down as if they were growing out of the ground downward, so just treat them like that. You may not need to focus on the water specifically. In fact, if you play around with long-ish exposures, you may get better reflections, and the water will be smoothed out anyway - time to play around.

You still need enough DoF to bring the edges of the puddle AND the trees into focus.

You can use all the long exposures that your heart desires; however, the shot will look weird if the edges of the puddles aren't in focus.

Lachlan.