Advise on Tilt

[jagsiva]

I was shooting the Narrows last weekend. It was a stunning location and used all of the limited skills I have - both photographic and physical

A lot of the scenes were challenging for both exposure and focus, so I bracketed for both.

Question I have is on use of tilt. I was using my RM3Di/32HR which allows for 5mm tilt/swing in either direction. In scenes like the one below, which is typical of the location, I was trying to get the foreground and back ground in focus. Foreground is just a few feet, and the background is in the 100's, and in other cases close to infinity.

With downward tilt, I was losing the focus at the top of the image (distant part of the image). I ended up bracketing for focus and will be stacking. However, is there a solution with tilt in this case?

On exposure, some of the scenes were 6-8 stops off, so I don't think there is any way around it than bracketing and blending.

Appreciate your thoughts.

 

[Bob]

That is a problem.
Looking at the image, you have essentially three planes that are orthogonal to one another that you would like to be sharp from near to far.
tilt alone on the floor will of course make the top of the image worse.
What you might have tried is to shoot three images, one with tilt and two with swing to get each of the three planes in focus and then to re-assemple them in post for a composite image.

It might be a bit simpler to use two un-tilted images in a focus stack to capture the canyon walls then one with tilt for the floor.
First blend together the focus stacked images and then add the floor to the composite.
There are times like this when I might be tempted to just shoot with some very small apertures and stack about 2-3 shots if necessary.
-bob

 

[Guy Mancuso]

Agree this is a tough one. I would like Bob mentioned take several focus stacks than use a program like Helicon focus which blend them very nicely. Tilt alone is tough because the sides would not fall into that plane

 

[jlm]

i wonder if a swing would have helped with the canyon walls, picking a vertical plane that falls between the walls and picks up the near rt wall and far end of the rt wall/edge of left wall? at the expense of the rocks in the foreground and no tilt at all

 

[Jamgolf]

I am just trying to learn from jagsiva's excellent illustration and question...

In this case, since an ultra-wide angle lens (32mm => 20mm in 135 terms) is being used, the inherent DOF would be high. Would a using max tilt (5 degrees for RM3di) @ f16 or f22 with focus point at a moderate distance say 6 feet not be the right thing to do - to get everything sharp?

 

[jagsiva]

It might be a bit simpler to use two un-tilted images in a focus stack to capture the canyon walls then one with tilt for the floor.
First blend together the focus stacked images and then add the floor to the composite.
There are times like this when I might be tempted to just shoot with some very small apertures and stack about 2-3 shots if necessary.
-bob

Thanks Bob. This is what I ended up doing. This is image is just at one focus point, but the final version will be stacked. My head was spinning after the long hike, standing in the middle of a cold river trying to figure this out.....with a small fortune sitting on a tripod in the water.

On f-stop, I always stayed at f9. The 80Mp back starts diffracting on the Rodie beyond this, and since I was not shooting LCC's at the time, I wanted to keep all of what I shot in my head!

 

[jagsiva]

I am just trying to learn from jagsiva's excellent illustration and question...

In this case, since an ultra-wide angle lens (32mm => 20mm in 135 terms) is being used, the inherent DOF would be high. Would a using max tilt (5 degrees for RM3di) @ f16 or f22 with focus point at a moderate distance say 6 feet not be the right thing to do - to get everything sharp?

Not really for a couple of reasons.

1. the 32mm lens still has a DoF of a 32mm lens, just the FoV is increased with a larger back.

2. The back is raised, so the foreground is almost at the base of the tripod, so very close. When the lens is tilted, the focus plane/cone drops from the vertical plane to a horizontal plane, so to top of the frame is de-focused.

 

[jagsiva]

Just a thought, perhaps I should have lugged the Monolith, I could have had up to 45degrees of tilt and swing at the sametime to work with....or wait, I don't think they allow mules in the narrows!

 

[jagsiva]

i wonder if a swing would have helped with the canyon walls, picking a vertical plane that falls between the walls and picks up the near rt wall and far end of the rt wall/edge of left wall? at the expense of the rocks int he foreground and any no tilt at all

This would likely be the best I would think, but again dependent on the width of of the subject at the near-distance. I fooled around with this, but did not get a workable DoF.

Another problem was practicing this prior to the trip, there aren't too many subject that lend themselves, short of a very long corridor.

 

[Shashin]

Not really for a couple of reasons.

1. the 32mm lens still has a DoF of a 32mm lens, just the FoV is increased with a larger back.

Format does change DoF. A 32mm will have different DoF depending on the format is used with or cropped to--the larger the format, the greater the DoF. Basically because the permissible circle of confusion changes with format.

 

[Shashin]

On f-stop, I always stayed at f9. The 80Mp back starts diffracting on the Rodie beyond this, and since I was not shooting LCC's at the time, I wanted to keep all of what I shot in my head!

I would shoot at f/16 easily with this. You can recover much of what is lost, which is not much, through unsharp masking. I also have no issue with using f/22 and on occasion f/32. The effects of diffraction are overstated.

 

[Shashin]

The walls make it so only stopping down or focus stacking practical.

 

[Bob]

Thanks Bob. This is what I ended up doing. This is image is just at one focus point, but the final version will be stacked. My head was spinning after the long hike, standing in the middle of a cold river trying to figure this out.....with a small fortune sitting on a tripod in the water.

On f-stop, I always stayed at f9. The 80Mp back starts diffracting on the Rodie beyond this, and since I was not shooting LCC's at the time, I wanted to keep all of what I shot in my head!

I have done some diffraction tests, and yes, it does begin to show, but nonetheless it is better than something way out of the DOF.
-bob

 

[jagsiva]

Format does change DoF. A 32mm will have different DoF depending on the format is used with or cropped to--the larger the format, the greater the DoF. Basically because the permissible circle of confusion changes with format.

I think we have had this discussion before. My understanding is CoC is largely determined by pixel pitch (hence the difference in CoC between an IQ260 and IQ280 with the IQ280 have a smaller CoC).

So if I am taking an image from the same location with two different backs with different formats, but the same pixel pitch, I don't see how the DoF would change. The framing, of course would be different.

For example, 32mm on IQ180 pixel pitch 5.2microns vs. 32mm on IQ250 pixel pitch 5.3mm. Scene taken from the same spot, I would think the DoF would be identical, except that the IQ250 with a crop factor of 1.3x will be cropped to the center.

 

[torger]

Back in the film days CoC was sort of well defined and was based on viewing conditions. Nowadays in the digital pixel peeping era we all have personal preferences of what the CoC should be, some say 2x pixel pitch, some say 1x Airy disc (I like that), and some stay with the traditional film definition.

In any case the scene you're shooting is not easy to make any gains with tilt, unless you choose to make a compromise. Perhaps it's more worth having sharp pebbles in the foreground than sharp on the upper part of the image, then you could gain by using some forward tilt.

 

[jagsiva]

Back in the film days CoC was sort of well defined and was based on viewing conditions. Nowadays in the digital pixel peeping era we all have personal preferences of what the CoC should be, some say 2x pixel pitch, some say 1x Airy disc (I like that), and some stay with the traditional film definition.

In any case the scene you're shooting is not easy to make any gains with tilt, unless you choose to make a compromise. Perhaps it's more worth having sharp pebbles in the foreground than sharp on the upper part of the image, then you could gain by using some forward tilt.

I agree. I think focus stacking is still the easiest given the shooting conditions. I just found it tedious since I had to bracket exposure as well for the rear wall. At least, I left LCC's for a later time

 

[Shashin]

Back in the film days CoC was sort of well defined and was based on viewing conditions. Nowadays in the digital pixel peeping era we all have personal preferences of what the CoC should be, some say 2x pixel pitch, some say 1x Airy disc (I like that), and some stay with the traditional film definition.

In any case the scene you're shooting is not easy to make any gains with tilt, unless you choose to make a compromise. Perhaps it's more worth having sharp pebbles in the foreground than sharp on the upper part of the image, then you could gain by using some forward tilt.

It is always based on the viewing condition. The very nature of DoF is how sharpness is perceived by the viewer. Even in the good old days of film, the CoC was defined differently. The effect does not change--take any image and redefine the CoC and the image will look the same. The CoC is just a variable to help you model perceived sharpness.

 

[Shashin]

I think we have had this discussion before. My understanding is CoC is largely determined by pixel pitch (hence the difference in CoC between an IQ260 and IQ280 with the IQ280 have a smaller CoC).

So if I am taking an image from the same location with two different backs with different formats, but the same pixel pitch, I don't see how the DoF would change. The framing, of course would be different.

For example, 32mm on IQ180 pixel pitch 5.2microns vs. 32mm on IQ250 pixel pitch 5.3mm. Scene taken from the same spot, I would think the DoF would be identical, except that the IQ250 with a crop factor of 1.3x will be cropped to the center.

DoF and CoC are defined by perceived sharpness. Since the pixels are unresolved by the viewer, a image taken by a larger format with the same focal length will have a greater DoF regardless of pixel pitch. Pixel pitch, just like granularity, has nothing to do with it.

 

[jagsiva]

DoF and CoC are defined by perceived sharpness. Since the pixels are unresolved by the viewer, a image taken by a larger format with the same focal length will have a greater DoF regardless of pixel pitch. Pixel pitch, just like granularity, has nothing to do with it.

Assuming you increase the SUBJECT DISTANCE to achieve the same framing. We are talking about same subject distance here, so DoF should be the same, not sure what I am missing.

If you look at the original question, it is implied that the camera to subject distance does not change.

 

[Shashin]

Assuming you increase the SUBJECT DISTANCE to achieve the same framing. We are talking about same subject distance here, so DoF should be the same, not sure what I am missing.

If you look at the original question, it is implied that the camera to subject distance does not change.

This would be from the same exact place. The larger format with the same focal length lens at the same subject distance would have greater DoF.