Julian Loke wrote:
> I went shopping, and ... came home with a Canon EF 20-35mm f/3.5-4.5 zoom
>
> Common negative points
> 1) 5 bladed diaphragm. Pentagonal bokeh, ugghh...
In practice I don't think this is a problem. Personally, when using this lens
I'm trying to keep the background in focus, not throw it out of focus.
> 2) Hood not included
You would have paid for it one way or the other. :-)
> 3) Hey, I thought there were 20 million EF lenses ever made.
> So, how come there are so few used EF 20 and EF 20-35's?
People who own them like them? I know I like my 20-35--one of two non-"L" EF
lenses I have. Yes, under test conditions there is perimeter distortion and all
that, but in everyday use you probably won't notice; similarly, in everyday use
it is plenty sharp. Also, it doesn't vignette at 20mm even with a standard (i.e.
thick) B+W filter attached.
> The zooming aspect became relatively important, especially for
> travelling in Europe with two young children.
Yes; IMO a fixed 20mm lens comes very close to being a specialized lens--the
20-35 zoom is far more versatile.
> Does this mean that "infinite DOF" scenics need to be composed so
> that "everything" lies between 0.5m to infinity?
Yes. However, it is ok to let the far distance go somewhat soft--this is how we
see the world anyway: when our eyes are focused on a close object, distant
objects are not in sharp focus. In a photograph, because it is a flat object,
our eyes can focus on the foreground and background at the same time. But
because the objects in the distance are both "far away" and small on the film, a
little softness there will probably not matter--indeed, this is how DOF works
anyway, since there is only one plane of true focus in any photograph--our brain
makes certain adjustments. In a sense, DOF is a "psycho-optical" phenomenon
similar to the way we see snow (for example) as "white" even when the existing
light makes it in actuality orange or blue. We see it as white because we know
snow is white; similarly, if the background in your photo is sufficiently sharp
we perceive it as sharp although in actuality it is not really in focus. The
most important thing with a wide-angle (as a general rule) is that the
foreground be in focus, since that's where the viewer's eye will go first and
any lack of sharpness there will be immediately apparent and distracting. This
is part of the reason why a wide-angle photo generally needs a strong foreground
subject to be effective.
> Does this mean that focussing closer blur distant objects?
Yes. You can compensate for this somewhat by "eyeballing" depth of field. With
your lens reasonably stopped down--say f/8 or f/11--the plane of focus will
occur roughly 1/3 of the way into the region of apparent focus. So, if you focus
on those rocks in the foreground, apparent focus will extend some distance in
front of the rocks (and twice as far behind). If the rocks happen to be the
closest objects that need to be in focus, you can focus on a point a bit behind
them in order to increase the sharpness of the background without losing
apparent sharpness for the rocks. This is easier to do than to explain, and with
a bit of practice it can become rather automatic. When shooting landscapes, I
rarely focus on the main subject, but rather pick a point that will give me the
region of apparent focus that I want, and then reframe the photo as necessary
(BTW, this is one reason I almost always use a single, manually-selected focus
point). Don't get too worked up over this--the perceived depth of field you can
achieve in a photo depends not only on the capability of your lens but also on
the resolving power of your film, the sharpness of the enlarging lens (if we're
talking about prints), and the resolving power of the print paper. The paper, or
course, is the weakest link here, and beyond a certain point the background just
isn't going to look any sharper, no matter where in the field of view you've
focused. So concentrate on keeping the foreground sharp (and interesting).
> Another reason for choosing the zoom is the ability to crop the
> unwanted detail out of the picture. Details like my shoes, tripod
> legs, camera bag, power lines, sun, etc :-)
Lol! A remote release is good for this.
> The filter situation bothered me more. A good solution would be to
> have drop-in rear filters, like the EF 17-35 L.
I'm not convinced that gelatin filters are an advantage. :-)
> Another method is
> to forego filters altogether and buy a rangefinder with a Zeiss
> 16mm Hologon or 21mm Biogon or even a Voigtländer 12mm or 15mm
> Heliar. Those solutions are not in my current budget :-)
Those Bessa Rs have been flying out of my local camera shop! (Seriously.)
> In order to use my existing 72mm filters, I could either buy the
> EF 20mm or search for a used discontinued (non USM) EF 20-35 L in
> good condition. (KEH has some battered ones on their website).
For the extra cost of one of those battered L lenses, wouldn't it be just as
well to bite the bullet for a couple 77mm filters? I know that monetary
considerations affect most of us (including myself), but should filter size be a
determining factor when choosing a lens, if you're serious about your
photography? In any case, you will have noticed that the front element of the
20-35/3.5~4.5 seems pretty vulnerable, even with the hood attached. All you
really need is a skylight and a polarizer--not cheap I know if you get good
ones, but IMO worth it in the long run. And if you ever decide to spring for a
28-70L, they'll fit that too!
> However, since I also have Cokin P filters (83 to 85mm in size), I was
> equally happy to use the Cokin CPOL and Grad NDs. There are many reports
> of vignetting with Cokin P and super-wide angle lenses in the archives.
Also, neither of these are true neutral filters--both are gray, and add a color
cast to your photos. In any case, Cokin has introduced a new "pro" line of
holders and filters that are larger than the "P" series, but at a significantly
higher cost--possibly not much less than the HiTech stuff. For what it's worth,
I have a Cokin "P" holder and a couple graduated ND filters, but I've never used
them on the 20-35--they work fine on the 28-70L though!
> Would it help to just hold the filters by hand in front of the lens?
More trouble than it's worth?
fcc
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