[Rockhounds] achieving depth of field w digicam?

Fri Apr 18 09:08:25 PDT 2008

There is also a new tilt-shift attachment called a "Lensbaby",)--that uses
your lens (I think) -- it has a bellows, and you can actually take a picture
around a 90 degree corner with it.

Margaret

-----Original Message-----
From: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of J Bryan Kramer
Sent: Thursday, April 17, 2008 2:45 PM
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
Subject: Re: [Rockhounds] achieving depth of field w digicam?

Actually there are lenses like that, their exisitence would probably not be
known outside of the photography community:

<
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=15
6&modelid=7322
>

Tilt and Shift lenses. Much used by architectural photographers to fix the
converging line problem. They aren't much use for macro photography tho with
a minimum focus distance of 40cm. Canon makes 3 T&S lenses.

BK

> There are no such lenses but there are bellows that can be tilted and
> turned
> at both sides obtaining similar result. They are used for mainly technical
> purposes wher DOF is important and some art photography.
> Why are they used instead of stacking software? RIGHT, the photographer
> STILL reserves the right for himself to choose were his photo is in or out
> focus. There are plenty of examples on the internet.
>
>
http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/24004-my-self-
>
made-tilt-shift-bellows.html<http://www.pentaxforums.com/forums/pentax-slr-l
ens-discussion/24004-my-self-made-tilt-shift-bellows.html>
> Look at the flower on this page:
> http://www.outdoorphotographer.com/content/2007/july/macro.shtml
> Not stacked, just tilted lens. The flower is sharp as it should and the
> rest
> is beautifully out of focus.
> I rest my case.
>
> > 4.    The depth of focus of our eyes is far better than that
> > of a camera.
>
> No, it's not nearly as good as a good technical camera can achieve.
>
>
> > This means that a photo (not stacked) does
> > show in fact even less than your eyes would see directly. In
> > fact the depth of focus of human eyes is perhaps not "far
> > better", but the brains combine the images of both eyes... in
> > fact what we see is a "stack" of two images... a photo shows
> > only one image instead of a combination of two.
>
> I don't agree (but you knew that) ;-)))
> You don't SEE more with both eyes!
> Your brain actually fills in the gaps just like the "unshap mask" filter
> does in photoshop. You think you see more but you may in fact see things
> that only appear to be there. That is how we actually recognize faces. We
> look at mouth, eyes and nose and the brain fills in the rest in a few
> thousands of a second. But sometimes the brain fails and we mistake people
> for someone else.
>
> > 5.    Any photographer would have no objection to a
> > photographic panoramic view. Again, this is an example of
> > something that we would not be able to see with our eyes.
>
> We see about 180 degrees or so. Try that with a fish-eye lens and look at
> the ridiculous amount of distortion. You seriously underestimate our eyes,
> Rik.
>
> > 6.    The purpose of a photo has, IMHO, always some
> > didactical purpose, and therefore, the more detailed information
> > one can show clearly in one photo, the better. Even if that
> > necessitates the use of stacking software. On the condition,
> > however, that nothing is shown that wasn't there in reality.
> > Then it would become fake.
>
> Photography means "painting with light", creating a facsimile of reality.
> Reality is dicontinous. It is like a string of pearls where each pearl is
> a
> moment in time. You scan the depth of the object you perceive in limited
> time frames (about 1/30 of a second per frame).
> A photo HAS to be a pearl. What you see at ONE monent in time. Only then
> can
> it be a true representation of the world that we see. You can't focus on
> every distance at once so any close-up photo that is in focus all over has
> to be a fake
>
> > 7.    Perhaps the most important of my arguments is that a
> > stacked composition of photos shows nothing that was not
> > really present, therefore for me nothing is wrong with such
> > type of imaging.
>
> You confuse a photo with a movie. There you can zoom in without violating
> reality.
>
> > And I admit that there is, as always, some sort of a gray
> > zone : what about the correction of a wrongly tuned color
> > temperature ?
>
> Why would you do that when you used the right camera setting and the right
> lighting?
>
> >What about enhancing sharpness,
>
> That you can't do. There are PS-filters that EMULATE the effect by merging
> pixels and adjusting this and that... Ultimately you CREATE (and I have
> demonstrated that on several occasions) artefacts that are not there.
> Lines
> and grooves that are simply create by your software suddenly appear and
> your
> photo seems so much richer in detail...that wasn't there in reality.
> Enough
> licht to subdue noise and take the time to focus.... Those are the tricks
> that make a photo sharp.
>
>
> >contrast etc ?
>
> RE-Why would you do that when you used the right camera setting and the
> right lighting?
>
> > What about the use of a "soft focus" lens, that reduces
> > sharpness artificially ? Those things are done digitally, but
> > were done as well in the dark room in the last century.
> > Also in analogous photography many techniques produce images
> > that are not exactly as the naked eye would see.
>
> Art, Rik... Art... Art has no foothold in reality unless and only so far
> sa
> the artist deems in appropriate.
>
> > On the other hand I want to emphasize on the fact that I
> > don't even have any stacking software, and so far I did never
> > use it. Since the time I have a decent digital camera I did
> > not have the time to do much about photography of minerals.
> > So I am not defending "my technique".
> > I hope to get to mineral photography as soon as I will retire
> > (that is 1 July 2010).
>
> We rejoice in the prospect ;-)))
> I'm sure you'll have our full attention.
>
> > And of course, this is just my opinion and interpretation of
> > things, not the absolute truth. I think that this discussion
> > is fruitful as such, and everyone has to distill his own
> > conclusions from it.
>
> NOW we agree (roflmao).
> It was fun refuting you... This seems to be an never-ending story...
>
> Cheers my friend
> Axel
>
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-- 
"Photography, as we all know, is not real at all. It is an illusion of
reality with which we create our own private world."
Arnold Newman

J Bryan Kramer
North Florida, USA
photos at:
http://pbase.com/photoburner

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