Archived posting to the Leica Users Group, 1999/07/08

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] Noctilux VS 75mm Now DOF
From: (David Morton)
Date: Thu, 8 Jul 1999 16:52 +0100 (BST)

Robert Rose writes:

> Also, there is a really nice portable version for the Palm at:
> called Focus+

Oh thanks *very* much for posting that, it took about 10 seconds to decide 
to register it, much easier than my clunky spreadsheet.
> These programs confirm that Jim is correct.  The reason the Summilux 
> has "less" DOF than the Noctilux at the same subject distance is 
> because it has a smaller field of view.  They will give identical DOF 
> at equivalent f/stops only if you move in with the Noctilux to frame 
> the identical image.

I don't think anyone was claiming anything different, were they?

What I said was "Perhaps it's worth pointing out that - for the same 
subject distance - the 75mm used at f1.4 has a significantly *shallower* 
DoF than the 50mm used at f1."

Notice that I specifically said the *SAME* subject distance.

I then said "If you come closer with the 50mm to frame tighter - say to 
2/3 distance - then the situation reverses" (I was referring to the 50mm 
used at f1 and the 75mm used at 1.4). So there's never been any 

David Morton