Nikonreflex.com fotoblog

Now the fun part. You forget everything you ever learned about hyper focal distance and other hyper or hypo things.
You make a picture using the optimal aperture for the lens sharpness in the corners, starting at the point closest to the camera. Don't be afraid to use f/8 (for the corners) and stick to one aperture for all exposures. (Forget the BS you read everywhere about diffraction, thanks to the way RAW data are processed diffraction becomes visible later then people tell you. If your lens is perfect at f/2.8 or f/4 (e.g. a 200/2 or 300/2.8) you don't have to close the aperture further, but you will have a lot more work. Mostly f/5.6-f/8 gives you more than enough sharpness and in case there is slightly less contrast than you would have in the centre at f/4 or so, you can cure that with a slight curve. Remember: we are using digital, not film and forget the stupid 50% MTF-tests everybody uses!
You use Live View to focus, so you can choose any place in the image, even at the bottom of the image or in the corners.
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How do you make a picture like this?

First you download Helicon Focus, Zerene Stacker or if you have Photoshop you just try to work with that software first. (I mentioned the software packages in order of tested output quality and ease of use when focus stacking.)
Then you do some research on where and when you can make the pictures, pack your camera and a tripod.
You tell your girlfiend or wife or whatever that it might take some time to make the pictures, but that this is a once in a lifetime experience that however requires the co-driver or whatever to bring a huge novel along (À la recherche du temps perdu comes to my mind.).
You hop on a plane or train, or drive there.
Then you drive with a (eventually rented) car, motorbike (or bike, but that takes a lot more time) in the beginning of July on the Route Lavende. If you find a photogenic place, you try to make a picture. Mostly you'll have to come back at a later moment when the sun stands lower or even the next morning - all provided the sun shines.