Using the 17mm TS-E, how much DOF advantage with max tilt?

I figured this is the place to find the most users of T/S lenses, and I know EJ will be able to answer my question if no one else can! 

Simply put, for landscapes with a foreground object within a few inches of the lens I need to enter into the zone of diffraction inducing apertures, so I've begun focus stacking two shots at f8 to get maximum resolution. My question is if focus stacking is still needed when using maximum tilt in the same situation? Does f8 provide enough DOF along with tilting the plane forward to get everything sharp in one shot, or is that only possible with a technical camera with more tilt range? 

Affording the 17mm TS-E is currently not realistic for me anyway, but I am curious to know what I'm missing out on. Focus stacking using live view and zooming around takes me out of the moment quite a bit and is pretty fussy, but maybe it will become quicker with more practice. Also, Magic Lantern has a focus stacking feature which seems to do absolutely nothing on my camera and wide lens, but I'll do more experimenting with that to try to get it to work. 

Here's a photo where I think I was at f16 and 22mm and still didn't quite have the foreground in focus, so it's soft from diffraction as well as limited DOF, so it was the photo that made me get serious about achieving maximum pixel sharpness.

For this photo you would not need to stack with a 17 TSE and you might be able to shoot as open as f/5.6. What a TSE lens does when tilted is that it tilts the plane of focus from vertical down into a plane. In this case if tilted properly you would have the plane going from the area right in front to the mountain peaks. And then you only need to stop down to capture things that aren't in that plane - the midground rocks and the sky but at 17mm that would be in within the DOF in that plane, maybe even with the lens wide open. If you use your camera in Live iew you can zoom in and cruise around the image to make sure that everything is in focus at your aperture.

You may want to Google Scheimpflug Prinicple to gain a greater understanding of how this all works.

Thanks for the info EJ! I definitely didn't realize the tilt range went far enough to be able to shoot even wide open for a scene like that, so now I know I NEED this lens, as well as the 24mm TS-E. Hmm should I sell my car or live in a tent? Tough decisions.

It may not go down that flat but at 17mm, you have so much inherent DOF to begin with that it likely wouldn't matter. When you read up on Sheipflug you will see that the plane of focus lays down a lot more than the angle of the front element might lead you to think.

I am not an expert, but I do use tilt & shift lenses. This scene is especially well suited to a T&S lens. Often, something in the foreground (close) rises to a high vertical level in the frame. This causes the "high" foreground to be out of focus since, the scene does not have a planar (diagonal) point of focus. In this case, you must stop down, or use focus stacking to achieve sharp focus across the frame.

T&S is great, but it has its limits.

The focus plane in a T&S lens is still a plane--it's just not parallel to the sensor anymore.  You control the angle of that plane with the amount of tilt, but anything not on the plane won't be in perfect focus.  However, an image like the one you've shown should be very good, as nothing is particularly far off a tilted plane, and a 17 mm lens has pretty huge DOF anyway.

But here's an example showing that you can some interesting effects, depending on where the plane of focus is placed:  http://www.naturescapes.net/forums/viewtopic.php?f=4&t=173420

-Paul