[Rockhounds] achieving depth of field w digicam?

[Axel Emmermann]

Hi Bryan,

Thanks for the input, it's very interesting and, frankly, I learned a thing
or two just gancing at it. ;-)))

However, I did a quick test and got this result
Aperture                       16
Sensor Width                   22.2 mm (Canon 400D)  
Subject Width                  4 mm  
Circle Of Confusion            0.0178 
Optical Magnification          5.55 X
Depth Of Field                 0.12085045045045044 mm

Well, I know for a fact that this is wrong... I do macro a lot and 3 and 4
mm imagewidth is target size for me.
When I shoot objects at the above settings I get an DOF of just under 1 mm
as this photo proves:
http://flickr.com/photos/22753159@N04/2223234472/in/set-72157603704255629/
This is at least 5 times more (estimated) than predicted by the formula.
True, I use bellows and reversed lenses... That may affect matters perhaps?

Axel


> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com 
> [mailto:rockhounds-bounces at lists.drizzle.com] Namens J Bryan Kramer
> Verzonden: donderdag 17 april 2008 1:57
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem 
> collectors
> Onderwerp: Re: [Rockhounds] achieving depth of field w digicam?
> 
> Whoops URL:
> 
> <http://www.robertseber.com/calculators/MacroDOFCalculator.html>
> 
> On Wed, Apr 16, 2008 at 8:56 PM, J Bryan Kramer <codeburner at gmail.com>
> wrote:
> 
> > Here is a macro DOF calculator, use 22.5 as the sensor width for a 
> > Canon crop frame camera like yours. At f/45 on a 30 mm 
> object the most 
> > DOF you could get is 5mm and you would suffer loss of 
> resolution at that f/stop.
> > You'd need very bright lights too. At a more reasonable 
> f/16 you drop 
> > back to 1.7mm DOF.
> >
> > BK
> >
> >
> > On Wed, Apr 16, 2008 at 7:59 PM, Kreigh Tomaszewski < 
> > Kreigh at tomaszewski.net> wrote:
> >
> > > Tim,
> > >
> > > The classic trick might work. More light and a higher f 
> stop to get 
> > > more depth of field.
> > >
> > > Kreigh
> > >
> > >
> > >
> > > Tim Jokela Jr. wrote:
> > > >
> > > > This one goes out to the digital photography gurus out there.
> > > >
> > > > I was talking to a buddy last night about macrophotography of 
> > > > small
> > > fossils,
> > > > 1-3cm stuff, and how capturing any depth of field 
> continues to be 
> > > > the
> > > major
> > > > challenge. He suggested three ways of doing it: buy the $25,000 
> > > > camera system made to do the job, take the picture 3 
> meters away 
> > > > from the
> > > specimen
> > > > and blow up the image, or take multiple shots, focusing on 
> > > > different
> > > areas,
> > > > and stitch them together with Helicon, Combine-Z, or 
> the expensive 
> > > > new version of PhotoShop.
> > > >
> > > > All are basically horrible options.
> > > >
> > > > So, is there anything new and interesting in the world 
> of digital 
> > > > photography that's giving depth of field to 
> macrophotography in a
> > > simple,
> > > > affordable manner? (My weapon of choice atm is a Canon Digital 
> > > > Rebel
> > > with a
> > > > 50mm macro lens.)
> > > >
> > > > Many thanks for any info!
> > > >
> > > > Tim Jokela Jr., tjokela at execulink.com
> > > > Business: http://www.element51.com
> > > > Pleasure: http://www.ontariominerals.com
> > > >
> > > > --
> > > > _______________________________________________
> > > > Rockhounds at drizzle Mailing List
> > > > Subscription Services:
> > > > http://lists.drizzle.com/mailman/listinfo/rockhounds
> > > > List Home Page, with a link to the List Usage Policy:
> > > > http://www.eclecticlapidary.com/Rockhounds/index.html
> > >
> > > --
> > > _______________________________________________
> > > Rockhounds at drizzle Mailing List
> > > Subscription Services:
> > > http://lists.drizzle.com/mailman/listinfo/rockhounds
> > > List Home Page, with a link to the List Usage Policy:
> > > http://www.eclecticlapidary.com/Rockhounds/index.html
> > >
> >
> >
> >
> > --
> > "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
> >
> 
> 
> 
> --
> "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
> 
> 
> --- StripMime Report -- processed MIME parts ---
> multipart/alternative
>   text/plain (text body -- kept)
>   text/html
> ---
> -- 
> _______________________________________________
> Rockhounds at drizzle Mailing List
> Subscription Services:
> http://lists.drizzle.com/mailman/listinfo/rockhounds
> List Home Page, with a link to the List Usage Policy:
> http://www.eclecticlapidary.com/Rockhounds/index.html
>