If Diffraction is bad at f22, why does the 24 shift
have a stop at f22 considering that it is also an f3.5
and in my totally unscientific tests I have found no
difference between f16 and f22 on that lens; neither
did Gary Reese (Yes I know these lenses have little in
common other than their f-stop and wide angle nature
I'm asking a stupid question but still...)
Also how do you use filters with this thing? The 49mm
filters I have exibit obvious vignetting in the
viewfinder. I have a set of 55mm filters for the 50/2
and 90/2 macro lenses so would it be wise to invest in
a step up ring? Is 55mm wide wnough to get rid of the
vignetting? I'd rather not get into slim filters.
Mark Lloyd
--- "John A. Lind" <jlind@xxxxxxxxxxxx> wrote:
> At 02:40 3/7/02, Mark Lloyd wrote:
> Aperture diffraction limiting is the reason.
> Resolving power would plummet
> at f/22. Lens design cannot fix this; it's a
> relationship between focal
> length, absolute aperture diameter required for f/22
> at that focal length
> (f-number is focal length divided by effective
> absolute aperture diameter)
> and the wavelength of visible light.
>
> [snipped out some "rambling" :-) ]
>
> Yes, a super-wide is more difficult to control, it's
> not a lens for
> everything, and you won't likely use it as much as
> other focal
> lengths. However, it can create some magnificent
> perspectives if the
> subject material supports the super-wide view. I
> wouldn't think of giving
> up my 18/3.5 even though I use other lengths much
> more often. When I want
> the super-wide perspective, my next step up, a 24mm,
> doesn't have what I'm
> looking for. It takes a while to learn how to
> envision what it will do
> because it is so different from the human eye's
> perspective. Keep using it
> and experimenting with it; give it a chance to grow
> on you, and for you to
> grow with it. Don't forget to think about vertical
> as well as horizontal
> composition with it.
>
> Start saving for the 24mm and be patient. Don't
> worry, there's plenty of
> them around!
>
> -- John
__________________________________________________
Do You Yahoo!?
Try FREE Yahoo! Mail - the world's greatest free email!
http://mail.yahoo.com/
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|