Focusing in Digital Era

[SteveF]

Very interesting article - thanks for putting it together.

One other thing I've noticed with the Helicon software for a shot which needs to give a wide range of focus is that I can use whatever f/stop is a len's best and worry less about what f/stop will give me the DOF needed.

In the article the Canon 90-TSE was used at f/11. I don't know if f/8 or f/5.6 on this lens is sharper, but if one of them were you can use it, take the set of shots and still get the required DOF.

It seems a little odd doing a landscape at f/4 or f/5.6 (the two apertures which are sharpest in my testing on my CZ 21), but it gives the Helicon the best images to start with.

[kit]

"One other thing I've noticed with the Helicon software for a shot which needs to give a wide range of focus is that I can use whatever f/stop is a len's best and worry less about what f/stop will give me the DOF needed."

This statement is the crux of the matter, now how do I find, calculate or whatever
what a len's best f/stop is ?  The lens manual does not give that info.

Kit

[wood]

Hello,

I did many pictures with Helicon.
Set  AV and f/6.3, for ex., and start shot(about 10 to 20 shots) since the closest option until the infinity of your lens. Use the Helicon and you have the total DOF.  

Wood

[SteveF]

This statement is the crux of the matter, now how do I find, calculate or whatever
what a len's best f/stop is ?  The lens manual does not give that info.

Kit
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Some lenses have accuate MTF charts, but really you just need to test your lens yourself to see where its sweet spot is.