In article <g17dp2$hep$>,
lid writes
>Alfred Molon wrote:
>> In article <>, Kennedy McEwen
>>says...
>>
>>> In the old days (pre-1990), the tradeoff was made towards the
>>>accurate DoF representation. However, since AF became more common
>>>on SLRs, the tradeoff has shifted towards the brighter image,
>>>because the viewfinder is no longer used for focussing. As a
>>>consequence of the demand for brighter SLR viewfinders, DoF preview
>>>accuracy has reduced, to the point where it is very misleading these
>>>days in almost all SLRs, and pretty useless in many. The actual DoF
>>>is always much less than appears in the viewfinder with modern
>>>cameras - unless they have interchangeable focus screens and one is
>>>available that has been optimised for manual focus.
>> Thanks. So the only way to check depth of field accurately would be
>>to take one shot and examine it on the LCD screen (zooming into it)?
>
>Really? I never considered that even in the oldest of days an SLR
>screen DOF preview was for looking what was in focus ... it was for
>looking at what was really our of focus, to get the proper subject-
>background isolation.
I don't think it was ever called a "background isolation preview" button
by any manufacturer, and the reason is that it was meant to be for much
more than that! It was for assessing the depth of field - background
isolation being only an extreme limit of that. If all you are
interested in is a course decision of whether the background is isolated
then the DOF gauge on the lens barrel is good enough for that. Oh,
sorry, most of those have gone from modern AF lenses too.
>That still works fine on my Canon 30D.
>
It only gives you a rough idea, but always understates the level of
isolation, so if you are trying to do anything critical, it is virtually
useless.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)