[Leica] Depth of Field / Crop Factor was Doomed Leica MP 0.58X

[henningw at archiphoto.com (Henning Wulff)]

At 4:26 PM -0800 1/24/05, Feli wrote:
>On Jan 24, 2005, at 3:25 PM, Howard Cummer wrote:
>
>>Hi Guys,
>>The depth of field doesn't change - the lens mechanics remain the 
>>same - it is just the field of view which is cropped by the smaller 
>>area of the sensor. Henning Wulff may want to weigh in here as he 
>>sometimes does (hello Henning!)
>>Howard
>>(in Foggy Hong Kong this morning)
>>On Tuesday, Jan 25, 2005, at 03:41 Asia/Hong_Kong, 
>>lug-request@leica-users.org wrote:
>
>
>The way I understand it, it works like this:
>
>Lets say you have a x1.5 mag factor on your D70
>
>So a 50 shows the field of view of a 75, but you retain the DOF 
>characteristics of the 50
>
>Anyone?
>
>feli
>

Close.

The only additional factor is that the effective DOF is less than 
that of the 50 due to the additional enlargement needed for the same 
size print; this results in a smaller allowable circle of confusion 
at the image plane; thus slightly smaller DOF. Nothing like that of a 
75, but more like that of a 60.

Think of the DOF shrinking exponentially due to focal length 
increase, and linearly due to crop factor.

If you are really interested in shallow DOF from digital, wait until 
the Mamiya ZD is on the shelf at your local.

-- 
    *            Henning J. Wulff
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