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RE: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

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  • paul
    Hi Daniel, Close a Canon 350D not a 300D These 2 images were with the reducer: - http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/0.8-reducer/Cygnus-centr-ZS66-
    Message 1 of 9 , Sep 30, 2006
    • 0 Attachment
      Hi Daniel,

      Close a Canon 350D not a 300D

      These 2 images were with the reducer: -

      http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/0.8-reducer/Cygnus-centr-ZS66-
      Nik.jpg
      Or
      http://tinyurl.co.uk/hoga



      http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/0.8-reducer/Deneb-ZS66-0.8-red
      ucer.jpg
      Or
      http://tinyurl.co.uk/6ct5


      These were without a reducer: -
      M31
      http://www.madpc.net/WO/M31-26-09-06-Full.jpg

      M45
      http://www.madpc.net/WO/M45-26-09-06-Full.jpg

      M42 from Earlier in the year
      http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/M42-17-02-06-Full-Imge.jpg

      Regards,


      --
      Paul Gordon
      paul@...
      http://www.madpc.net


      > -----Original Message-----
      > From: William-Optics@yahoogroups.com
      > [mailto:William-Optics@yahoogroups.com] On Behalf Of The Ciobotas
      > Sent: 30 September 2006 04:31
      > To: William-Optics@yahoogroups.com
      > Subject: Re: [William-Optics] Field Curvature and the WO ZS66
      > SD Using DSLR's (EOS-350D)
      >
      > Very nice pics Paul, I think I recognize one of them. :-)
      >
      > Your unreduced images do indeed look pretty flat, although
      > they are reduced from the original size (you have a 300D, right?).
      >
      > What surprised me though is the amount of overcorrection
      > present with the reducer (also seems a bit off center imo, as
      > the distortion is not even left to right). Is this the
      > reducer just announced? I preordered one, it says it won't
      > be shipped till sometime in october. Or is that a different
      > reducer? If it's the same, I guess I'll wait and see how it
      > pans out with my setup. Is there maybe a recommended
      > distance or just use the t ring on it?
      >
      > John, I'm pretty sure you don't have a bad copy, your
      > results look exactly the same as mine. Unfortunately,
      > without a reducer you will indeed have to crop.
      >
      > I have tried two other alternatives, both which give better
      > results, although not perfect.
      >
      > First, use a meade/celestron 6.3 sct reducer. The scope
      > will become a 244mm fl f3.7 scope, and the reducer will show
      > a slight overcorrection from about 3/4 of the frame out.
      >
      > I wanted the old focal length back, so what I did was I used
      > the 6.3 reducer and added a 1.4x teleconverter to the camera,
      > effectively bringing the scope back to around 342mm.
      > Wonderfully flat field, but... two things.
      > One, due to all the extra glass, I lost about 1/3 stop of
      > exposure. Second, and this could be entirely due to the
      > inexpensive teleconverter, I got internal reflections,
      > resulting in stars flaring. It is entirely possible that a
      > better quality TC would alleviate flaring and light loss.
      >
      > Hope this helps,
      >
      > Daniel
      >
      >
      >
      >
      >
      > www.william-optics.com Yahoo!
      > Groups Links
      >
      >
      >
      >
      >
      >
      >
      >
      >
      >
    • Scott Walker
      Hi Paul Thanks for the images. Could you send me the full resolution jpg files of the images at a high quality factor (sdwalker@cox.net). I will make images
      Message 2 of 9 , Oct 2, 2006
      • 0 Attachment
        Hi Paul
         
        Thanks for the images. Could you send me the full resolution jpg files of the images at  a high quality factor (sdwalker@...). I will make images that show the center and corners at high resolution and post them. At the posted resolution it is hard to tell if the reducer is working well or not.
         
        Scott Walker
        ----- Original Message -----
        From: paul
        Sent: Saturday, September 30, 2006 1:16 AM
        Subject: RE: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

        Hi Daniel,

        Close a Canon 350D not a 300D

        These 2 images were with the reducer: -

        http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Cygnus-centr- ZS66-
        Nik.jpg
        Or
        http://tinyurl. co.uk/hoga

        http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Deneb-ZS66- 0.8-red
        ucer.jpg
        Or
        http://tinyurl. co.uk/6ct5

        These were without a reducer: -
        M31
        http://www.madpc. net/WO/M31- 26-09-06- Full.jpg

        M45
        http://www.madpc. net/WO/M45- 26-09-06- Full.jpg

        M42 from Earlier in the year
        http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/M42-17- 02-06-Full- Imge.jpg

        Regards,

        --
        Paul Gordon
        paul@...
        http://www.madpc. net


        > -----Original Message-----
        > From: William-Optics@ yahoogroups. com
        > [mailto:William-Optics@ yahoogroups. com] On Behalf Of The Ciobotas
        > Sent: 30 September 2006 04:31
        > To: William-Optics@ yahoogroups. com
        > Subject: Re: [William-Optics] Field Curvature and the WO ZS66
        > SD Using DSLR's (EOS-350D)
        >
        > Very nice pics Paul, I think I recognize one of them. :-)
        >
        > Your unreduced images do indeed look pretty flat, although
        > they are reduced from the original size (you have a 300D, right?).
        >
        > What surprised me though is the amount of overcorrection
        > present with the reducer (also seems a bit off center imo, as
        > the distortion is not even left to right). Is this the
        > reducer just announced? I preordered one, it says it won't
        > be shipped till sometime in october. Or is that a different
        > reducer? If it's the same, I guess I'll wait and see how it
        > pans out with my setup. Is there maybe a recommended
        > distance or just use the t ring on it?
        >
        > John, I'm pretty sure you don't have a bad copy, your
        > results look exactly the same as mine. Unfortunately,
        > without a reducer you will indeed have to crop.
        >
        > I have tried two other alternatives, both which give better
        > results, although not perfect.
        >
        > First, use a meade/celestron 6.3 sct reducer. The scope
        > will become a 244mm fl f3.7 scope, and the reducer will show
        > a slight overcorrection from about 3/4 of the frame out.
        >
        > I wanted the old focal length back, so what I did was I used
        > the 6.3 reducer and added a 1.4x teleconverter to the camera,
        > effectively bringing the scope back to around 342mm.
        > Wonderfully flat field, but... two things.
        > One, due to all the extra glass, I lost about 1/3 stop of
        > exposure. Second, and this could be entirely due to the
        > inexpensive teleconverter, I got internal reflections,
        > resulting in stars flaring. It is entirely possible that a
        > better quality TC would alleviate flaring and light loss.
        >
        > Hope this helps,
        >
        > Daniel
        >
        >
        >
        >
        >
        > www.william- optics.com Yahoo!
        > Groups Links
        >
        >
        >
        >
        >
        >
        >
        >
        >
        >

      • The Ciobotas
        Thanks Paul for the images. You might want to post crops of the middle and the corners from the full size images in the UK forum, there is an ongoing thread
        Message 3 of 9 , Oct 3, 2006
        • 0 Attachment
          Thanks Paul for the images. You might want to post crops of the middle and
          the corners from the full size images in the UK forum, there is an ongoing
          thread called coma and chromatic aberration in the equipment section there.
          Might give other folks an idea what to expect in terms of optical
          performance.

          Best regards,

          Daniel



          ----- Original Message -----
          From: "paul" <paul@...>
          To: <William-Optics@yahoogroups.com>
          Sent: Saturday, September 30, 2006 3:16 AM
          Subject: RE: [William-Optics] Field Curvature and the WO ZS66 SD Using
          DSLR's (EOS-350D)


          > Hi Daniel,
          >
          > Close a Canon 350D not a 300D
          >
          > These 2 images were with the reducer: -
          >
          > http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/0.8-reducer/Cygnus-centr-ZS66-
          > Nik.jpg
          > Or
          > http://tinyurl.co.uk/hoga
          >
          >
          >
          > http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/0.8-reducer/Deneb-ZS66-0.8-red
          > ucer.jpg
          > Or
          > http://tinyurl.co.uk/6ct5
          >
          >
          > These were without a reducer: -
          > M31
          > http://www.madpc.net/WO/M31-26-09-06-Full.jpg
          >
          > M45
          > http://www.madpc.net/WO/M45-26-09-06-Full.jpg
          >
          > M42 from Earlier in the year
          > http://www.madpc.net/EOS-350D/2006/WO-ZS66-SD/M42-17-02-06-Full-Imge.jpg
          >
          > Regards,
          >
          >
          > --
          > Paul Gordon
          > paul@...
          > http://www.madpc.net
          >
          >
          >> -----Original Message-----
          >> From: William-Optics@yahoogroups.com
          >> [mailto:William-Optics@yahoogroups.com] On Behalf Of The Ciobotas
          >> Sent: 30 September 2006 04:31
          >> To: William-Optics@yahoogroups.com
          >> Subject: Re: [William-Optics] Field Curvature and the WO ZS66
          >> SD Using DSLR's (EOS-350D)
          >>
          >> Very nice pics Paul, I think I recognize one of them. :-)
          >>
          >> Your unreduced images do indeed look pretty flat, although
          >> they are reduced from the original size (you have a 300D, right?).
          >>
          >> What surprised me though is the amount of overcorrection
          >> present with the reducer (also seems a bit off center imo, as
          >> the distortion is not even left to right). Is this the
          >> reducer just announced? I preordered one, it says it won't
          >> be shipped till sometime in october. Or is that a different
          >> reducer? If it's the same, I guess I'll wait and see how it
          >> pans out with my setup. Is there maybe a recommended
          >> distance or just use the t ring on it?
          >>
          >> John, I'm pretty sure you don't have a bad copy, your
          >> results look exactly the same as mine. Unfortunately,
          >> without a reducer you will indeed have to crop.
          >>
          >> I have tried two other alternatives, both which give better
          >> results, although not perfect.
          >>
          >> First, use a meade/celestron 6.3 sct reducer. The scope
          >> will become a 244mm fl f3.7 scope, and the reducer will show
          >> a slight overcorrection from about 3/4 of the frame out.
          >>
          >> I wanted the old focal length back, so what I did was I used
          >> the 6.3 reducer and added a 1.4x teleconverter to the camera,
          >> effectively bringing the scope back to around 342mm.
          >> Wonderfully flat field, but... two things.
          >> One, due to all the extra glass, I lost about 1/3 stop of
          >> exposure. Second, and this could be entirely due to the
          >> inexpensive teleconverter, I got internal reflections,
          >> resulting in stars flaring. It is entirely possible that a
          >> better quality TC would alleviate flaring and light loss.
          >>
          >> Hope this helps,
          >>
          >> Daniel
          >>
          >>
          >>
          >>
          >>
          >> www.william-optics.com Yahoo!
          >> Groups Links
          >>
          >>
          >>
          >>
          >>
          >>
          >>
          >>
          >>
          >>
          >
          >
          >
          >
          >
          >
          > www.william-optics.com
          > Yahoo! Groups Links
          >
          >
          >
          >
          >
          >
          >
          >
          >
          >
        • paul
          Hi Scott, I cannot find the original Raw :-( I think I have deleted them.. This image was just converted to .jpg and has not been touched up other than the
          Message 4 of 9 , Oct 12, 2006
          • 0 Attachment
            Hi Scott,
             
            I cannot find the original Raw :-( I think I have deleted them..
            This image was just converted to .jpg and has not been touched up other than the conversion.
             
             
            (Its just over 8Mb)
             
            Regards,
             

            --
            Paul Gordon
            paul@...
            http://www.madpc.net

             


            From: William-Optics@yahoogroups.com [mailto:William-Optics@yahoogroups.com] On Behalf Of Scott Walker
            Sent: 02 October 2006 18:30
            To: William-Optics@yahoogroups.com
            Subject: Re: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

            Hi Paul
             
            Thanks for the images. Could you send me the full resolution jpg files of the images at  a high quality factor (sdwalker@...). I will make images that show the center and corners at high resolution and post them. At the posted resolution it is hard to tell if the reducer is working well or not.
             
            Scott Walker
            ----- Original Message -----
            From: paul
            Sent: Saturday, September 30, 2006 1:16 AM
            Subject: RE: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

            Hi Daniel,

            Close a Canon 350D not a 300D

            These 2 images were with the reducer: -

            http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Cygnus-centr- ZS66-
            Nik.jpg
            Or
            http://tinyurl. co.uk/hoga

            http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Deneb-ZS66- 0.8-red
            ucer.jpg
            Or
            http://tinyurl. co.uk/6ct5

            These were without a reducer: -
            M31
            http://www.madpc. net/WO/M31- 26-09-06- Full.jpg

            M45
            http://www.madpc. net/WO/M45- 26-09-06- Full.jpg

            M42 from Earlier in the year
            http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/M42-17- 02-06-Full- Imge.jpg

            Regards,

            --
            Paul Gordon
            paul@...
            http://www.madpc. net


            > -----Original Message-----
            > From: William-Optics@ yahoogroups. com
            > [mailto:William-Optics@ yahoogroups. com] On Behalf Of The Ciobotas
            > Sent: 30 September 2006 04:31
            > To: William-Optics@ yahoogroups. com
            > Subject: Re: [William-Optics] Field Curvature and the WO ZS66
            > SD Using DSLR's (EOS-350D)
            >
            > Very nice pics Paul, I think I recognize one of them. :-)
            >
            > Your unreduced images do indeed look pretty flat, although
            > they are reduced from the original size (you have a 300D, right?).
            >
            > What surprised me though is the amount of overcorrection
            > present with the reducer (also seems a bit off center imo, as
            > the distortion is not even left to right). Is this the
            > reducer just announced? I preordered one, it says it won't
            > be shipped till sometime in october. Or is that a different
            > reducer? If it's the same, I guess I'll wait and see how it
            > pans out with my setup. Is there maybe a recommended
            > distance or just use the t ring on it?
            >
            > John, I'm pretty sure you don't have a bad copy, your
            > results look exactly the same as mine. Unfortunately,
            > without a reducer you will indeed have to crop.
            >
            > I have tried two other alternatives, both which give better
            > results, although not perfect.
            >
            > First, use a meade/celestron 6.3 sct reducer. The scope
            > will become a 244mm fl f3.7 scope, and the reducer will show
            > a slight overcorrection from about 3/4 of the frame out.
            >
            > I wanted the old focal length back, so what I did was I used
            > the 6.3 reducer and added a 1.4x teleconverter to the camera,
            > effectively bringing the scope back to around 342mm.
            > Wonderfully flat field, but... two things.
            > One, due to all the extra glass, I lost about 1/3 stop of
            > exposure. Second, and this could be entirely due to the
            > inexpensive teleconverter, I got internal reflections,
            > resulting in stars flaring. It is entirely possible that a
            > better quality TC would alleviate flaring and light loss.
            >
            > Hope this helps,
            >
            > Daniel
            >
            >
            >
            >
            >
            > www.william- optics.com Yahoo!
            > Groups Links
            >
            >
            >
            >
            >
            >
            >
            >
            >
            >

          • Scott Walker
            Thanks Paul I am assuming this is without the reducer. Could you also provide one with the reducer? It does not need to be the same object, just one with stars
            Message 5 of 9 , Oct 13, 2006
            • 0 Attachment
              Thanks Paul
               
              I am assuming this is without the reducer. Could you also provide one with the reducer? It does not need to be the same object, just one with stars all around. I did a quick look at the provided image. It looks like there is a slight tracking error that elongates stars in the vertical direction. Does that seem reasonable? The image is still very usable,but knowing that there is a slight tracking error makes enturprut the image a little easier.
               
              Thanks again
               
              Scott Walker
              ----- Original Message -----
              From: paul
              Sent: Wednesday, October 11, 2006 1:53 PM
              Subject: RE: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

              Hi Scott,
               
              I cannot find the original Raw :-( I think I have deleted them..
              This image was just converted to .jpg and has not been touched up other than the conversion.
               
               
              (Its just over 8Mb)
               
              Regards,
               

              --
              Paul Gordon
              paul@...
              http://www.madpc. net

               


              From: William-Optics@ yahoogroups. com [mailto:William- Optics@yahoogrou ps.com] On Behalf Of Scott Walker
              Sent: 02 October 2006 18:30
              To: William-Optics@ yahoogroups. com
              Subject: Re: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

              Hi Paul
               
              Thanks for the images. Could you send me the full resolution jpg files of the images at  a high quality factor (sdwalker@cox. net). I will make images that show the center and corners at high resolution and post them. At the posted resolution it is hard to tell if the reducer is working well or not.
               
              Scott Walker
              ----- Original Message -----
              From: paul
              Sent: Saturday, September 30, 2006 1:16 AM
              Subject: RE: [William-Optics] Field Curvature and the WO ZS66 SD Using DSLR's (EOS-350D)

              Hi Daniel,

              Close a Canon 350D not a 300D

              These 2 images were with the reducer: -

              http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Cygnus-centr- ZS66-
              Nik.jpg
              Or
              http://tinyurl. co.uk/hoga

              http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/0.8-reducer/ Deneb-ZS66- 0.8-red
              ucer.jpg
              Or
              http://tinyurl. co.uk/6ct5

              These were without a reducer: -
              M31
              http://www.madpc. net/WO/M31- 26-09-06- Full.jpg

              M45
              http://www.madpc. net/WO/M45- 26-09-06- Full.jpg

              M42 from Earlier in the year
              http://www.madpc. net/EOS-350D/ 2006/WO-ZS66- SD/M42-17- 02-06-Full- Imge.jpg

              Regards,

              --
              Paul Gordon
              paul@...
              http://www.madpc. net


              > -----Original Message-----
              > From: William-Optics@ yahoogroups. com
              > [mailto:William-Optics@ yahoogroups. com] On Behalf Of The Ciobotas
              > Sent: 30 September 2006 04:31
              > To: William-Optics@ yahoogroups. com
              > Subject: Re: [William-Optics] Field Curvature and the WO ZS66
              > SD Using DSLR's (EOS-350D)
              >
              > Very nice pics Paul, I think I recognize one of them. :-)
              >
              > Your unreduced images do indeed look pretty flat, although
              > they are reduced from the original size (you have a 300D, right?).
              >
              > What surprised me though is the amount of overcorrection
              > present with the reducer (also seems a bit off center imo, as
              > the distortion is not even left to right). Is this the
              > reducer just announced? I preordered one, it says it won't
              > be shipped till sometime in october. Or is that a different
              > reducer? If it's the same, I guess I'll wait and see how it
              > pans out with my setup. Is there maybe a recommended
              > distance or just use the t ring on it?
              >
              > John, I'm pretty sure you don't have a bad copy, your
              > results look exactly the same as mine. Unfortunately,
              > without a reducer you will indeed have to crop.
              >
              > I have tried two other alternatives, both which give better
              > results, although not perfect.
              >
              > First, use a meade/celestron 6.3 sct reducer. The scope
              > will become a 244mm fl f3.7 scope, and the reducer will show
              > a slight overcorrection from about 3/4 of the frame out.
              >
              > I wanted the old focal length back, so what I did was I used
              > the 6.3 reducer and added a 1.4x teleconverter to the camera,
              > effectively bringing the scope back to around 342mm.
              > Wonderfully flat field, but... two things.
              > One, due to all the extra glass, I lost about 1/3 stop of
              > exposure. Second, and this could be entirely due to the
              > inexpensive teleconverter, I got internal reflections,
              > resulting in stars flaring. It is entirely possible that a
              > better quality TC would alleviate flaring and light loss.
              >
              > Hope this helps,
              >
              > Daniel
              >
              >
              >
              >
              >
              > www.william- optics.com Yahoo!
              > Groups Links
              >
              >
              >
              >
              >
              >
              >
              >
              >
              >

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