DOF Cheating

Discussion in 'Digital Photography' started by Chris W, Nov 5, 2007.

  1. Chris W

    Chris W Guest

    As I am sure most everyone here knows, with macro photography, sometimes
    it is just impossible to get the depth of field you want. What I was
    wondering is, if you are using a tripod on a stationary subject, could
    you take several images with the focus at various points and some how
    merge them to get a greater DOF? My first guess is it won't work or it
    will take far more work that it is worth, but I thought I would ask.


    --
    Chris W
    KE5GIX

    "Protect your digital freedom and privacy, eliminate DRM,
    learn more at http://www.defectivebydesign.org/what_is_drm"

    Ham Radio Repeater Database.
    http://hrrdb.com
     
    Chris W, Nov 5, 2007
    #1
    1. Advertising

  2. Chris W

    Pat Guest

    On Nov 5, 11:13 am, Chris W <> wrote:
    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could
    > you take several images with the focus at various points and some how
    > merge them to get a greater DOF? My first guess is it won't work or it
    > will take far more work that it is worth, but I thought I would ask.
    >
    > --
    > Chris W
    > KE5GIX
    >
    > "Protect your digital freedom and privacy, eliminate DRM,
    > learn more athttp://www.defectivebydesign.org/what_is_drm"
    >
    > Ham Radio Repeater Database.http://hrrdb.com


    There's software that does that. You take the pictures by changing
    nothing but the focus point. The software then determines what's in
    focus and what isn't and puts the image together to give you the best
    focus.

    There was an article on it in Rangefinder a year or so ago.

    The other option is to do it by hand. Just stack the images to give
    perfect registration. Then cut out the areas that aren't sharp on
    each of the images and what you have left is a sharp image. Because
    they are stacked, registered images then there shouldn't be much/any
    difficulty blending the places where the images come together.
     
    Pat, Nov 5, 2007
    #2
    1. Advertising

  3. Chris W

    C J Campbell Guest

    On 2007-11-05 08:13:38 -0800, Chris W <> said:

    > As I am sure most everyone here knows, with macro photography,
    > sometimes it is just impossible to get the depth of field you want.
    > What I was wondering is, if you are using a tripod on a stationary
    > subject, could you take several images with the focus at various points
    > and some how merge them to get a greater DOF? My first guess is it
    > won't work or it will take far more work that it is worth, but I
    > thought I would ask.


    Sure, you can do that. There are a few issues to be aware of. For one
    thing, changing focus distance with a macro lens will probably make
    small changes in image size. People used to adjust for this by moving
    the camera slightly, but it is easier to correct in post-processing
    software.

    The basic technique is to take two or three shots at different focus
    distances to get the depth of field you want, import them as layers,
    and erase the out of focus parts you do not want. It takes a little
    practice. Some software automates the whole process.
    --
    Waddling Eagle
    World Famous Flight Instructor
     
    C J Campbell, Nov 5, 2007
    #3
  4. Chris W

    HEMI-Powered Guest

    Chris W added these comments in the current discussion du jour
    ....

    > As I am sure most everyone here knows, with macro photography,
    > sometimes it is just impossible to get the depth of field you
    > want. What I was wondering is, if you are using a tripod on a
    > stationary subject, could you take several images with the
    > focus at various points and some how merge them to get a
    > greater DOF? My first guess is it won't work or it will take
    > far more work that it is worth, but I thought I would ask.
    >

    Gee, I never thought of that approach. I suppose it could work if
    your tripod setup were sturdy enough so as to prevent even the
    minutest movement, else you'd likely get slightly overlapping
    images which might be tough to deal with.

    What are you trying to take photos of and at what distance?

    --
    HP, aka Jerry
     
    HEMI-Powered, Nov 5, 2007
    #4
  5. Chris W

    HEMI-Powered Guest

    Pat added these comments in the current discussion du jour ...

    > On Nov 5, 11:13 am, Chris W <> wrote:
    >> As I am sure most everyone here knows, with macro
    >> photography, sometimes it is just impossible to get the depth
    >> of field you want. What I was wondering is, if you are using
    >> a tripod on a stationary subject, could you take several
    >> images with the focus at various points and some how merge
    >> them to get a greater DOF? My first guess is it won't work
    >> or it will take far more work that it is worth, but I thought
    >> I would ask.
    >>
    >> "Protect your digital freedom and privacy, eliminate DRM,
    >> learn more athttp://www.defectivebydesign.org/what_is_drm"
    >>
    >> Ham Radio Repeater Database.http://hrrdb.com

    >
    > There's software that does that. You take the pictures by
    > changing nothing but the focus point. The software then
    > determines what's in focus and what isn't and puts the image
    > together to give you the best focus.
    >
    > There was an article on it in Rangefinder a year or so ago.
    >
    > The other option is to do it by hand. Just stack the images
    > to give perfect registration. Then cut out the areas that
    > aren't sharp on each of the images and what you have left is a
    > sharp image. Because they are stacked, registered images then
    > there shouldn't be much/any difficulty blending the places
    > where the images come together.
    >

    I jsut replied to the OP that I had never thought of this
    technique, but getting perfect what you're calling
    "registration" would seem to be pretty tough as minor rotations
    or shifts or even distortions might occur if the tripod or copy
    stand set-up weren't rock solid. But then, I've never tried
    anything like this, so I don't know what problems might arise.
    Interesting thought, though.

    --
    HP, aka Jerry
     
    HEMI-Powered, Nov 5, 2007
    #5
  6. Chris W

    Pat Guest

    On Nov 5, 11:58 am, "HEMI-Powered" <> wrote:
    > Pat added these comments in the current discussion du jour ...
    >
    >
    >
    > > On Nov 5, 11:13 am, Chris W <> wrote:
    > >> As I am sure most everyone here knows, with macro
    > >> photography, sometimes it is just impossible to get the depth
    > >> of field you want. What I was wondering is, if you are using
    > >> a tripod on a stationary subject, could you take several
    > >> images with the focus at various points and some how merge
    > >> them to get a greater DOF? My first guess is it won't work
    > >> or it will take far more work that it is worth, but I thought
    > >> I would ask.

    >
    > >> "Protect your digital freedom and privacy, eliminate DRM,
    > >> learn more athttp://www.defectivebydesign.org/what_is_drm"

    >
    > >> Ham Radio Repeater Database.http://hrrdb.com

    >
    > > There's software that does that. You take the pictures by
    > > changing nothing but the focus point. The software then
    > > determines what's in focus and what isn't and puts the image
    > > together to give you the best focus.

    >
    > > There was an article on it in Rangefinder a year or so ago.

    >
    > > The other option is to do it by hand. Just stack the images
    > > to give perfect registration. Then cut out the areas that
    > > aren't sharp on each of the images and what you have left is a
    > > sharp image. Because they are stacked, registered images then
    > > there shouldn't be much/any difficulty blending the places
    > > where the images come together.

    >
    > I jsut replied to the OP that I had never thought of this
    > technique, but getting perfect what you're calling
    > "registration" would seem to be pretty tough as minor rotations
    > or shifts or even distortions might occur if the tripod or copy
    > stand set-up weren't rock solid. But then, I've never tried
    > anything like this, so I don't know what problems might arise.
    > Interesting thought, though.
    >
    > --
    > HP, aka Jerry


    It is the same problem faced by astronomers. If they need a 3 minute
    exposure, they will often take 6, 30 second exposures so that the
    starts don't move.
     
    Pat, Nov 5, 2007
    #6
  7. Chris W

    Pat Guest

    On Nov 5, 11:56 am, "HEMI-Powered" <> wrote:
    > Chris W added these comments in the current discussion du jour
    > ...
    >
    > > As I am sure most everyone here knows, with macro photography,
    > > sometimes it is just impossible to get the depth of field you
    > > want. What I was wondering is, if you are using a tripod on a
    > > stationary subject, could you take several images with the
    > > focus at various points and some how merge them to get a
    > > greater DOF? My first guess is it won't work or it will take
    > > far more work that it is worth, but I thought I would ask.

    >
    > Gee, I never thought of that approach. I suppose it could work if
    > your tripod setup were sturdy enough so as to prevent even the
    > minutest movement, else you'd likely get slightly overlapping
    > images which might be tough to deal with.
    >
    > What are you trying to take photos of and at what distance?
    >
    > --
    > HP, aka Jerry


    I don't know what the OP is doing, but the "typical" application would
    be someone shooting pool. You need the pool table (right in front of
    you) in focus, the balls, the stick, and the shooter -- so you need an
    incredible depth of field.
     
    Pat, Nov 5, 2007
    #7
  8. Chris W

    nospam Guest

    In article <ZiHXi.2568$>, Chris W
    <> wrote:

    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could
    > you take several images with the focus at various points and some how
    > merge them to get a greater DOF? My first guess is it won't work or it
    > will take far more work that it is worth, but I thought I would ask.


    it works well.

    <http://www.heliconsoft.com/heliconfocus.html>
     
    nospam, Nov 5, 2007
    #8
  9. Chris W

    HEMI-Powered Guest

    Pat added these comments in the current discussion du jour ...

    >> > As I am sure most everyone here knows, with macro
    >> > photography, sometimes it is just impossible to get the
    >> > depth of field you want. What I was wondering is, if you
    >> > are using a tripod on a stationary subject, could you take
    >> > several images with the focus at various points and some
    >> > how merge them to get a greater DOF? My first guess is it
    >> > won't work or it will take far more work that it is worth,
    >> > but I thought I would ask.

    >>
    >> Gee, I never thought of that approach. I suppose it could
    >> work if your tripod setup were sturdy enough so as to prevent
    >> even the minutest movement, else you'd likely get slightly
    >> overlapping images which might be tough to deal with.
    >>
    >> What are you trying to take photos of and at what distance?
    >>

    > I don't know what the OP is doing, but the "typical"
    > application would be someone shooting pool. You need the pool
    > table (right in front of you) in focus, the balls, the stick,
    > and the shooter -- so you need an incredible depth of field.
    >

    I haven't personally done any macro work since my Nikon FTN days
    with the 55mm Macro Nikkor and a copy stand, so yeah, I know of
    whence this is about, but not in the digital realm. But, one
    piece of good news is the reduced sensor size which, if I
    understand the principles correctly, allows one to use in the
    case of a Canon a lens with a 1.6X shorter focal length, which
    would allow all that much more DOF no matter what the focused
    distance and aperture may be. My work in the film days was more
    flat stock like a coin collections, stamps, and the like, rather
    than something truly 3-D that needs the "incredible DOF" you so
    correctly point out.

    --
    HP, aka Jerry
     
    HEMI-Powered, Nov 5, 2007
    #9
  10. Chris W

    HEMI-Powered Guest

    Pat added these comments in the current discussion du jour ...

    >> I jsut replied to the OP that I had never thought of this
    >> technique, but getting perfect what you're calling
    >> "registration" would seem to be pretty tough as minor
    >> rotations or shifts or even distortions might occur if the
    >> tripod or copy stand set-up weren't rock solid. But then,
    >> I've never tried anything like this, so I don't know what
    >> problems might arise. Interesting thought, though.
    >>

    > It is the same problem faced by astronomers. If they need a 3
    > minute exposure, they will often take 6, 30 second exposures
    > so that the starts don't move.
    >

    I didn't know that, either, but in celestial photography, isn't the
    big thing to keep the telescope "registered" according to the
    rotation of the earth whilst a 6, 30, or 180 second exposure takes
    place, or in extreme cases, when it is an hour? I do know that
    telescopes have had machinery that was mechanical at one time and
    now computer-controlled that take care of that sort of thing. But,
    in any case, I learned something new today - never gave a single
    thought to multiple exposures to "simulate" or "cheat" DOF. Novel
    approach.

    --
    HP, aka Jerry
     
    HEMI-Powered, Nov 5, 2007
    #10
  11. On Mon, 05 Nov 2007 16:58:21 GMT, "HEMI-Powered" <> wrote:

    >Pat added these comments in the current discussion du jour ...
    >
    >> On Nov 5, 11:13 am, Chris W <> wrote:
    >>> As I am sure most everyone here knows, with macro
    >>> photography, sometimes it is just impossible to get the depth
    >>> of field you want. What I was wondering is, if you are using
    >>> a tripod on a stationary subject, could you take several
    >>> images with the focus at various points and some how merge
    >>> them to get a greater DOF? My first guess is it won't work
    >>> or it will take far more work that it is worth, but I thought
    >>> I would ask.
    >>>
    >>> "Protect your digital freedom and privacy, eliminate DRM,
    >>> learn more athttp://www.defectivebydesign.org/what_is_drm"
    >>>
    >>> Ham Radio Repeater Database.http://hrrdb.com

    >>
    >> There's software that does that. You take the pictures by
    >> changing nothing but the focus point. The software then
    >> determines what's in focus and what isn't and puts the image
    >> together to give you the best focus.
    >>
    >> There was an article on it in Rangefinder a year or so ago.
    >>
    >> The other option is to do it by hand. Just stack the images
    >> to give perfect registration. Then cut out the areas that
    >> aren't sharp on each of the images and what you have left is a
    >> sharp image. Because they are stacked, registered images then
    >> there shouldn't be much/any difficulty blending the places
    >> where the images come together.
    >>

    >I jsut replied to the OP that I had never thought of this
    >technique, but getting perfect what you're calling
    >"registration" would seem to be pretty tough as minor rotations
    >or shifts or even distortions might occur if the tripod or copy
    >stand set-up weren't rock solid. But then, I've never tried
    >anything like this, so I don't know what problems might arise.
    >Interesting thought, though.


    Here's a fun CHDK script for CHDK capable Canon P&S cameras.

    http://chdk.wikia.com/wiki/UBASIC/Scripts:_yet_another_DOF_stacker

    You set the nearest focus of your subject. Run the script. While it's running
    you set the furthest focus (or vice versa, start out setting the far focus and
    then the near). The script mathematically divvies up the subject into the right
    number of focal planes you need, ensuring each one is just enough to include the
    DOF that's in focus according to the f/stop that your camera is using.

    All done automatically for you. Then just use CombineZM (freeware) or Helicon
    Focus to combine them into a seamlessly in-focus subject. Of any depth you
    desire for any macro to life-size subjects that you require.

    Doesn't get any simpler nor faster than that.


    Disclaimer: This free software and method is not available on any other cameras,
    not even for $12,000 DSLRs. In fact it's impossible to port to DSLR's due to
    their limited OVF-only last-century viewfinder systems. Don't hope that it will
    be available for your DSLR one day, it won't be done.
     
    Albert Trestin, Nov 5, 2007
    #11
  12. Chris W

    Marty Fremen Guest

    Chris W <> wrote:

    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could
    > you take several images with the focus at various points and some how
    > merge them to get a greater DOF?


    One problem at macro distances is that (unless perhaps the lens has
    internal focussing) when you change focus you are changing both the lens-
    sensor and lens-subject distance, this will result in a different
    magnification & perspective of the subject making it harder to align the
    images. Best approach if you have the equipment is to use a bellows setup
    and keeping the lens stationary, focus by racking the camera body back and
    forward. That way the perspective stays the same and change in
    magnification due to refocussing should be less too.
     
    Marty Fremen, Nov 5, 2007
    #12
  13. Chris W

    Ali Guest

    I keep suggesting that Canon should provide aperture bracketing on their
    bodies. However, it falls on deaf ears. For a camera manufacturer it would
    be so easy to do and is nothing more than a software change, so no hardware
    is needed.



    "Chris W" <> wrote in message
    news:ZiHXi.2568$...
    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could you
    > take several images with the focus at various points and some how merge
    > them to get a greater DOF? My first guess is it won't work or it will
    > take far more work that it is worth, but I thought I would ask.
    >
    >
    > --
    > Chris W
    > KE5GIX
    >
    > "Protect your digital freedom and privacy, eliminate DRM,
    > learn more at http://www.defectivebydesign.org/what_is_drm"
    >
    > Ham Radio Repeater Database.
    > http://hrrdb.com
     
    Ali, Nov 5, 2007
    #13
  14. In article <ZiHXi.2568$>, says...
    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could
    > you take several images with the focus at various points and some how
    > merge them to get a greater DOF? My first guess is it won't work or it
    > will take far more work that it is worth, but I thought I would ask.
    >

    Some chaps at work do precisely that.. But it's with a $2M electron
    microscope !

    T.
     
    Tony Gartshore, Nov 5, 2007
    #14
  15. There is software just for this. It's called Helicon Focus.
    http://www.heliconsoft.com/heliconfocus.html
    Dose the job quite well and will adjust to some extent the images to the
    same size to compensate for the changing image size as you focus. I use
    both ways, by changing the focus and with a focusing rail. The results are
    somewhat better with the focusing rail but good both ways. I think its
    worth the money for what it does.

    John Passaneau
     
    John Passaneau, Nov 5, 2007
    #15
  16. Chris W

    eclyma Guest

    Had a gentleman at one of the GSCCC conventions who did this. He called it
    stacking and said he might take 40 exposures and more to get the shots he
    displayed. He combined with ZM Combine that earlier reply mentioned. Sorry I
    can't find his name or webpage.
    ernie
     
    eclyma, Nov 5, 2007
    #16
  17. Chris W

    bugbear Guest

    Albert Trestin wrote:
    >
    > All done automatically for you. Then just use CombineZM (freeware) or Helicon
    > Focus to combine them into a seamlessly in-focus subject. Of any depth you
    > desire for any macro to life-size subjects that you require.
    >
    > Doesn't get any simpler nor faster than that.
    >
    >
    > Disclaimer: This free software and method is not available on any other cameras,
    > not even for $12,000 DSLRs. In fact it's impossible to port to DSLR's due to
    > their limited OVF-only last-century viewfinder systems. Don't hope that it will
    > be available for your DSLR one day, it won't be done.
    >


    The idea, of course, is not new:

    http://www.graficaobscura.com/depth/index.html

    I suspect Hugin or registax might be helpful if your tripod
    isn't killer rigid.

    Finally, for this approach to work perfectly,
    your focusing should leave the lens in a fixed position,
    and move the film (sensor) plane to focus, otherwise
    the magnification of the lens will change as you change
    focus. I think only field/view/monorail camera can (in fact) do this ;-)

    BugBear
     
    bugbear, Nov 6, 2007
    #17
  18. Chris W

    bugbear Guest

    Ali wrote:
    > I keep suggesting that Canon should provide aperture bracketing on their
    > bodies. However, it falls on deaf ears. For a camera manufacturer it
    > would be so easy to do and is nothing more than a software change, so no
    > hardware is needed.


    That doesn't help (this issue)

    BugBear
     
    bugbear, Nov 6, 2007
    #18
  19. Chris W

    Charles Guest

    On Mon, 05 Nov 2007 18:17:34 GMT, "HEMI-Powered" <> wrote:

    >Pat added these comments in the current discussion du jour ...
    >
    >>> I jsut replied to the OP that I had never thought of this
    >>> technique, but getting perfect what you're calling
    >>> "registration" would seem to be pretty tough as minor
    >>> rotations or shifts or even distortions might occur if the
    >>> tripod or copy stand set-up weren't rock solid. But then,
    >>> I've never tried anything like this, so I don't know what
    >>> problems might arise. Interesting thought, though.
    >>>

    >> It is the same problem faced by astronomers. If they need a 3
    >> minute exposure, they will often take 6, 30 second exposures
    >> so that the starts don't move.
    >>

    >I didn't know that, either, but in celestial photography, isn't the
    >big thing to keep the telescope "registered" according to the
    >rotation of the earth whilst a 6, 30, or 180 second exposure takes
    >place, or in extreme cases, when it is an hour? I do know that
    >telescopes have had machinery that was mechanical at one time and
    >now computer-controlled that take care of that sort of thing. But,
    >in any case, I learned something new today - never gave a single
    >thought to multiple exposures to "simulate" or "cheat" DOF. Novel
    >approach.



    Browse for a while in alt.binaries.pictures.astro. I'm impressed with
    the changes in processing that are being done. what you describe was
    accurate some years ago, and probably still is for the large
    telescopes. The multiple image stacking is bringing advances to users
    of smaller telescopes.
     
    Charles, Nov 6, 2007
    #19
  20. On Nov 5, 4:13 pm, Chris W <> wrote:
    > As I am sure most everyone here knows, with macro photography, sometimes
    > it is just impossible to get the depth of field you want. What I was
    > wondering is, if you are using a tripod on a stationary subject, could
    > you take several images with the focus at various points and some how
    > merge them to get a greater DOF? My first guess is it won't work or it
    > will take far more work that it is worth, but I thought I would ask.
    >
    > --
    > Chris W
    > KE5GIX
    >
    > "Protect your digital freedom and privacy, eliminate DRM,
    > learn more athttp://www.defectivebydesign.org/what_is_drm"
    >
    > Ham Radio Repeater Database.http://hrrdb.com


    Auto-Montage software is widely used by microscopists, particularly
    for entomology, and also corrects for minor movements between frames.
    Demo versions at...
    http://www.syncroscopy.com/syncroscopy/automontageshort.asp
     
    Al, Cambridge, UK, Nov 7, 2007
    #20
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. JM

    Cheating?

    JM, Feb 22, 2005, in forum: Microsoft Certification
    Replies:
    2
    Views:
    699
  2. Rob Cimarolli

    Cheating

    Rob Cimarolli, Mar 18, 2005, in forum: Microsoft Certification
    Replies:
    4
    Views:
    1,197
    Guest
    Mar 21, 2005
  3. =?Utf-8?B?U2ltYXMgSy4=?=

    cheating

    =?Utf-8?B?U2ltYXMgSy4=?=, Dec 16, 2005, in forum: MCSE
    Replies:
    136
    Views:
    3,957
  4. =?Utf-8?B?ZmVsaXBlY3B2?=

    Is using TestKing to study cheating?

    =?Utf-8?B?ZmVsaXBlY3B2?=, Jan 4, 2006, in forum: MCSE
    Replies:
    84
    Views:
    10,560
    Consultant
    Jan 6, 2006
  5. Justin Weinberg

    The next generation and cheating

    Justin Weinberg, Feb 6, 2006, in forum: MCSD
    Replies:
    21
    Views:
    3,029
Loading...

Share This Page