Re: Digital camera again...

From: Etienne Garbaux ^lt;>
Date: 07/30/04-07:09:56 PM Z
Message-id: <p05210601bd3096fe54e5@[]>

Judy wrote:

> First, more, many more thanks to the list for help I would have been so
> much loster without -- and I'll add that one of the most valuable comments
> made here was about the depth of field being greater in digital than at
> the (supposedly) same f-stop in analog.

Just to be excruciating about it, so as not to confuse any newcomers --
it's not a matter of digital vs. analog, it's the size of the image sensor.
Lenses of equal _focal length_ have the same depth of field no matter what
size the film (or CCD/CMOS imager) is, but give different angular fields of
view -- an 80mm lens is "normal" on a medium format camera, telephoto on a
35mm camera, and wide angle on a large format camera, but the depths of
field are the same for all 3. For any given angle of view, the smaller
format uses a shorter lens and therefore has greater depth of field. The
G5 has a tiny sensor, so the "normal" lens has a very short focal length.
On the other hand, there's a reason 8x10 photographers use f/64 --
otherwise, they'd have no depth of field at all.

> One problem that everyone mentions when you say "digital camera" is the
> delay in shooting ("shutter lag"). But that's not happening -- maybe the
> G5 is quicker, or it's because I'm not doing moving targets: The actual
> picture-taking is so quick that folks tend to be surprised: "You mean you
> took it already?"

At the time it came out, the G3 (predecessor to the G5) was one of the
first non-SLR digicams to have a respectably fast shutter release.

> My first question is: I'm usually about two
> feet, maybe a tad more, from my subject... if I shoot at chest level,
> often the legs dwindle, a funny perspective effect. I figure that's NOT
> another effect of digital perspective, but just the way the 35 mm (or 28
> mm??) of the lens behaves.... I rarely saw anything like it in analog
> because I rarely shot that close and rarely with less than 50 mm.

As Loris noted, that is simply perspective. You can fix it in Photoshop if
you want. (I often find that a partial correction looks best.) In
essence, you stretch the picture into a trapezoid and then crop back to a
rectangle. Or, you could hold the camera at waist level and let your
subjects' feet and heads both dwindle compared to their giant bellies....

> (I can't zoom because in crowded streets it's nearly impossible to move
> further away... And there's no use heading for wide open spaces,,,,,, they
> have no pedestrians !)

Actually, there are any number of recreational paths and such that are
teeming with pedestrians and joggers. Most NYC parks fit the bill. I
don't know what's below 14th St. in Manhattan, but a short subway ride to
Brooklyn Heights will score you ... I forget what they call it ... the
Promenade? ... right up against the river (with lower Manhattan in full
view so you don't feel too anxious).

By the way, if you want to use larger apertures without blowing out the
highlights, lower the "film speed" and/or use the "ND Filter" setting in
the menu on the G5. Or, get the adapter that allows you to mount 58mm
accessories and use a real 58mm neutral density filter.

Best regards,

Received on Fri Jul 30 19:10:28 2004

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