Focus stacking

Hi there! Please excuse my ignorance...I'm a bit embarrassed to even ask this question...I have heard a lot about focus stacking, this great technique for achieving super sharp images with everything in focus. I understand the basic concept, but I don't understand how to change focus points without moving the camera. I don't have a focus rail, but I've heard you don't really need one. I would be using this technique for landscape shots, not macro, so I wouldn't need a lot of bracketed images. I simply don't know how to switch focal points and focus on a new plane without moving the camera. I have a Nikon d700. Any help would be greatly appreciated!

Natalie

The simple answer is to use manual focusing, not auto focus. I haven't done much with focus stacking, but the times I have used it for landscapes that is how I accomplished it. No rail, just a tripod locked down tight, and manual focus. Good luck.

I've found this technique very succesful Natalie, thanks to guidance from Mark Metternich. As Rob says, secure the camera to the tripod. I hang my camera bag from a home-made hook on the centre post as well, to prevent the possibility of any movement. Turn autofocus off. I start by focusing on the object closest to the camera, then move the focusing ring towards infinity - to the left on Canons - about half a centimetre at a time. I make every exposure at f8 or whatever the lens's sharpest aperture happens to be. I don't even look through the viewfinder. When the focusing ring hits infinity, I'm done.

I load the images into Photoshop from Bridge (Tools/Photoshop/Load files into Photohop layers). I don't know what everyone else is doing but I then activate each layer (click on it), then go to Edit/Auto align layers/Auto blend layers. This procedure is actually very simple. On a fast computer it should take about 20 seconds and
gives me an accurate blend if the camera hasn't moved.

This is great stuff. Thank you so much. I had a feeling it was as simple as that, but I wasn't sure if I was missing something. Thanks again!

I'd add just one bit of additional advice. You have to be sure as you focus deeper and deeper into the scene that the foreground objects don't become so blurry that the blur zone obscures the sharp image of the distant landscape. The problem is most pronounced with telephotos, but of course that's when you most want to use focus-stacking. I saw this problem most clearly when shooting some cow parsnip in an aspen grove this summer with a 70-200mm lens. The foreground flowers became so blurry and effectively enlarged in the shots focused on the most distant trees that the blur obscured some of the distant trunks. As a result, there was no image which contained a sharp representation of that portion of the distant trunks that was immediately adjacent to the flowers. Those trunks were blurry in the shot focused on the foreground, of course, and that portion of the trunks next to the flowers was blurry in the shot focused on the trunks because the camera couldn't "see" those trunks behind the blurry flowers. When Photoshop was done blending the images, I had an odd out-of-focus "halo" around all of the sharp flowers. In other situations, however, this technique can work well.

I have successfully used AF for this too. If your focusing screen has movable focal points from back to front (top to bottom on your screen), you can use them. You will just be limited to the number of points on the screen. Manual obviously gives you more control of fovus points.

I would recommend focusing using live view and the zoom review feature. You can get precise focus, make sure, there is no lens movement or "shaking" of the live view image, and the mirror is locked up to minimize camera vibration. Then move the zoom portion to various parts of the image, manually focus, take a shot, move on to the next plane of focus. Great for low light situations, though it may eat up more battery power than just turning the manual focus dial.