[Leica] Leica lenses on Fuji X Pro 1 Vs Sony A7

[Peter Klein]

Good advice in this thread.  I've used the focusing method outlined in 
previous posts with Micro 4/3 cameras for years.  As others say, it's 
slow, but it works.

Here's a trick that might help when using fast lenses with focus shift 
on a mirrorless camera. If you are going to shoot stopped down, focus at 
f/2.8 instead of wide open. With sufficient magnification, at f/2.8 you 
can still see a point of best focus rather than a broad zone. And f/2.8 
displays most or all of the focus shift.

I've shot a test series at all stops on every RF lens I own. This tells 
me what to expect when I use it. It seems that for most fast f/1.2 - f/2 
lenses, the most drastic shift occurs between f/2 and 2.8.

The same principle works for rangefinder focusing, too.  Remember how 
Zeiss will optimize their recent 50/1.5 Sonnar for either wide-open or 
f/2.8?  Why?  Because if optimized for 2.8, the smaller stops fall 
pretty much into line. My non-FLE 35/1.4 Summilux ASPH also has focus 
shift. Wide open and at f/2, the rangefinder is accurate. At f/2.8-5.6, 
it focuses a little behind where the RF says. So I need to lean back 
slightly or focus a tiny bit closer. By f/8, DOF compensates, and I 
don't need to worry about it.

The above applies to shots where we only care that the subject is in 
focus, and not if the zone extends a little in front of or behind the 
subject.  If the exact placement of the focus zone is important, then 
use your focus magnifier mode and carefully focus at shooting aperture.

--Peter



On Thu, 26 Jan 2017 "Frank Filippone" <red735i at verizon.net>wrote:

 >...
 >...
 >...
 >I should mention that even with a Digi-Leica camera body, focus 
shifting is
 >an issue.  It is inherent in the specific lens design.  There is no camera
 >body based fix possible.  With a EVF,  you have the ability to correct
 >it....
 >Using more DOF ( smaller aperture) will help mask this error source.
 >Your other choice is to not use focus shifting lenses.....  or suffer
trying
 >to get really sharp focus on your subject by focusing initially at 
shooting
 >aperture, which will be frustrating, especially at F32 ( for example).
 >...
 >..
 >...

 >Frank Filippone

 >Red735i at verizon.net <Red735i at verizon.net>
==========================================================================================================================
A concern with f/32, or even f/16 on FF or smaller sensors is diffraction.
I posted a picture of a toy elephant head and a Brannock Device this month.
<
http://gallery.leica-users.org/v/Alan+Magayne-Roshak/Miscellaneous/20170108_MR_Mine_DSF3901.jpg.html
 >
When I was shooting it (on a 20 lb. tripod) I was trying to get everything
in focus, but I had to settle for f/11.  I could see a softening of detail
on the focused point as I stopped down past f/8, especially at f/16 and
f/32.  The frame at f/11 was the best compromise between sharpness and
D.o.F.  FYI, the lens was a 35mm f/3.5 Perspective Control Nikkor.

Ref: <http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/cirapp.html#c1>

-- 
Alan