Red wavelengths for everyday photography

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
1
down vote

favorite












I've done a lot of research regarding filters as I'm about to do a modification on my DSLR for astrophotography. I've settled on removing the existing IR filter and replacing it with one the will still allow H-alpha (656 nm) and S-II (672 nm) plus the visible spectrum below that.
My question is..if the eye can see red to approximately 700nm (before it reaches near-IR), why do most stock IR filters cut off below 650 nm ?










share|improve this question







New contributor




77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.























    up vote
    1
    down vote

    favorite












    I've done a lot of research regarding filters as I'm about to do a modification on my DSLR for astrophotography. I've settled on removing the existing IR filter and replacing it with one the will still allow H-alpha (656 nm) and S-II (672 nm) plus the visible spectrum below that.
    My question is..if the eye can see red to approximately 700nm (before it reaches near-IR), why do most stock IR filters cut off below 650 nm ?










    share|improve this question







    New contributor




    77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.





















      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      I've done a lot of research regarding filters as I'm about to do a modification on my DSLR for astrophotography. I've settled on removing the existing IR filter and replacing it with one the will still allow H-alpha (656 nm) and S-II (672 nm) plus the visible spectrum below that.
      My question is..if the eye can see red to approximately 700nm (before it reaches near-IR), why do most stock IR filters cut off below 650 nm ?










      share|improve this question







      New contributor




      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      I've done a lot of research regarding filters as I'm about to do a modification on my DSLR for astrophotography. I've settled on removing the existing IR filter and replacing it with one the will still allow H-alpha (656 nm) and S-II (672 nm) plus the visible spectrum below that.
      My question is..if the eye can see red to approximately 700nm (before it reaches near-IR), why do most stock IR filters cut off below 650 nm ?







      infrared-conversion






      share|improve this question







      New contributor




      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      share|improve this question







      New contributor




      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      share|improve this question




      share|improve this question






      New contributor




      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      asked 5 hours ago









      77pro

      62




      62




      New contributor




      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.





      New contributor





      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






      77pro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.




















          2 Answers
          2






          active

          oldest

          votes

















          up vote
          2
          down vote













          With few exceptions, data for infrared filters are not published for the region from 700 to 900nm. This is because most infrared filters are offshoots of the Wratten gelatin filters recipe. These were made by dissolving dye in gelatin and then floating the liquid gelatin on the surface of water. The gelatin was then allowed to gel and then lifted from underneath via a wire frame. The dried gelatin filter was then over-coated with lacquer. Often these gelatin filters were sandwiched between two sheets of optically flat glass.



          Anyway, infrared radiation is strongly absorbed by matter. Most gelatin filters begin to absorb infrared beginning at about 2000nm and fully absorb at about 3000nm. Most glass infrared filters fare worse. The typical absorption curve is generally published for the region 750nm to 3000nm



          To pass the frequencies you need, the filter would likely need to be made of quartz. I think none are available at affordable prices. Perhaps you can find such a filter under “specialized filters for science”. I don’t think you will find them in the general photographic community.






          share|improve this answer



























            up vote
            1
            down vote













            Camera imaging sensors are much more sensitive to longer wavelengths than human vision. The normalized response of the "red" sensitive cone cells drops off rapidly above 640nm. A camera without ir filters will be much more sensitive to red light that contains material percentages of photons with longer wavelengths. Cameras often have such filters built-in just to prevent overly strong response to flames and red hot embers. Add-on IR filters are most useful for cameras that have weak or no IR filtering.



            However, these filters are a problem when trying to capture longer wavelengths in astro-photography and replacing these with filters that pass specifically desired, longer wavelengths allows better capture of this light.






            share|improve this answer






















              Your Answer








              StackExchange.ready(function()
              var channelOptions =
              tags: "".split(" "),
              id: "61"
              ;
              initTagRenderer("".split(" "), "".split(" "), channelOptions);

              StackExchange.using("externalEditor", function()
              // Have to fire editor after snippets, if snippets enabled
              if (StackExchange.settings.snippets.snippetsEnabled)
              StackExchange.using("snippets", function()
              createEditor();
              );

              else
              createEditor();

              );

              function createEditor()
              StackExchange.prepareEditor(
              heartbeatType: 'answer',
              convertImagesToLinks: false,
              noModals: true,
              showLowRepImageUploadWarning: true,
              reputationToPostImages: null,
              bindNavPrevention: true,
              postfix: "",
              imageUploader:
              brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
              contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
              allowUrls: true
              ,
              noCode: true, onDemand: true,
              discardSelector: ".discard-answer"
              ,immediatelyShowMarkdownHelp:true
              );



              );






              77pro is a new contributor. Be nice, and check out our Code of Conduct.









               

              draft saved


              draft discarded


















              StackExchange.ready(
              function ()
              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphoto.stackexchange.com%2fquestions%2f102621%2fred-wavelengths-for-everyday-photography%23new-answer', 'question_page');

              );

              Post as a guest






























              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes








              up vote
              2
              down vote













              With few exceptions, data for infrared filters are not published for the region from 700 to 900nm. This is because most infrared filters are offshoots of the Wratten gelatin filters recipe. These were made by dissolving dye in gelatin and then floating the liquid gelatin on the surface of water. The gelatin was then allowed to gel and then lifted from underneath via a wire frame. The dried gelatin filter was then over-coated with lacquer. Often these gelatin filters were sandwiched between two sheets of optically flat glass.



              Anyway, infrared radiation is strongly absorbed by matter. Most gelatin filters begin to absorb infrared beginning at about 2000nm and fully absorb at about 3000nm. Most glass infrared filters fare worse. The typical absorption curve is generally published for the region 750nm to 3000nm



              To pass the frequencies you need, the filter would likely need to be made of quartz. I think none are available at affordable prices. Perhaps you can find such a filter under “specialized filters for science”. I don’t think you will find them in the general photographic community.






              share|improve this answer
























                up vote
                2
                down vote













                With few exceptions, data for infrared filters are not published for the region from 700 to 900nm. This is because most infrared filters are offshoots of the Wratten gelatin filters recipe. These were made by dissolving dye in gelatin and then floating the liquid gelatin on the surface of water. The gelatin was then allowed to gel and then lifted from underneath via a wire frame. The dried gelatin filter was then over-coated with lacquer. Often these gelatin filters were sandwiched between two sheets of optically flat glass.



                Anyway, infrared radiation is strongly absorbed by matter. Most gelatin filters begin to absorb infrared beginning at about 2000nm and fully absorb at about 3000nm. Most glass infrared filters fare worse. The typical absorption curve is generally published for the region 750nm to 3000nm



                To pass the frequencies you need, the filter would likely need to be made of quartz. I think none are available at affordable prices. Perhaps you can find such a filter under “specialized filters for science”. I don’t think you will find them in the general photographic community.






                share|improve this answer






















                  up vote
                  2
                  down vote










                  up vote
                  2
                  down vote









                  With few exceptions, data for infrared filters are not published for the region from 700 to 900nm. This is because most infrared filters are offshoots of the Wratten gelatin filters recipe. These were made by dissolving dye in gelatin and then floating the liquid gelatin on the surface of water. The gelatin was then allowed to gel and then lifted from underneath via a wire frame. The dried gelatin filter was then over-coated with lacquer. Often these gelatin filters were sandwiched between two sheets of optically flat glass.



                  Anyway, infrared radiation is strongly absorbed by matter. Most gelatin filters begin to absorb infrared beginning at about 2000nm and fully absorb at about 3000nm. Most glass infrared filters fare worse. The typical absorption curve is generally published for the region 750nm to 3000nm



                  To pass the frequencies you need, the filter would likely need to be made of quartz. I think none are available at affordable prices. Perhaps you can find such a filter under “specialized filters for science”. I don’t think you will find them in the general photographic community.






                  share|improve this answer












                  With few exceptions, data for infrared filters are not published for the region from 700 to 900nm. This is because most infrared filters are offshoots of the Wratten gelatin filters recipe. These were made by dissolving dye in gelatin and then floating the liquid gelatin on the surface of water. The gelatin was then allowed to gel and then lifted from underneath via a wire frame. The dried gelatin filter was then over-coated with lacquer. Often these gelatin filters were sandwiched between two sheets of optically flat glass.



                  Anyway, infrared radiation is strongly absorbed by matter. Most gelatin filters begin to absorb infrared beginning at about 2000nm and fully absorb at about 3000nm. Most glass infrared filters fare worse. The typical absorption curve is generally published for the region 750nm to 3000nm



                  To pass the frequencies you need, the filter would likely need to be made of quartz. I think none are available at affordable prices. Perhaps you can find such a filter under “specialized filters for science”. I don’t think you will find them in the general photographic community.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 4 hours ago









                  Alan Marcus

                  24k12758




                  24k12758






















                      up vote
                      1
                      down vote













                      Camera imaging sensors are much more sensitive to longer wavelengths than human vision. The normalized response of the "red" sensitive cone cells drops off rapidly above 640nm. A camera without ir filters will be much more sensitive to red light that contains material percentages of photons with longer wavelengths. Cameras often have such filters built-in just to prevent overly strong response to flames and red hot embers. Add-on IR filters are most useful for cameras that have weak or no IR filtering.



                      However, these filters are a problem when trying to capture longer wavelengths in astro-photography and replacing these with filters that pass specifically desired, longer wavelengths allows better capture of this light.






                      share|improve this answer


























                        up vote
                        1
                        down vote













                        Camera imaging sensors are much more sensitive to longer wavelengths than human vision. The normalized response of the "red" sensitive cone cells drops off rapidly above 640nm. A camera without ir filters will be much more sensitive to red light that contains material percentages of photons with longer wavelengths. Cameras often have such filters built-in just to prevent overly strong response to flames and red hot embers. Add-on IR filters are most useful for cameras that have weak or no IR filtering.



                        However, these filters are a problem when trying to capture longer wavelengths in astro-photography and replacing these with filters that pass specifically desired, longer wavelengths allows better capture of this light.






                        share|improve this answer
























                          up vote
                          1
                          down vote










                          up vote
                          1
                          down vote









                          Camera imaging sensors are much more sensitive to longer wavelengths than human vision. The normalized response of the "red" sensitive cone cells drops off rapidly above 640nm. A camera without ir filters will be much more sensitive to red light that contains material percentages of photons with longer wavelengths. Cameras often have such filters built-in just to prevent overly strong response to flames and red hot embers. Add-on IR filters are most useful for cameras that have weak or no IR filtering.



                          However, these filters are a problem when trying to capture longer wavelengths in astro-photography and replacing these with filters that pass specifically desired, longer wavelengths allows better capture of this light.






                          share|improve this answer














                          Camera imaging sensors are much more sensitive to longer wavelengths than human vision. The normalized response of the "red" sensitive cone cells drops off rapidly above 640nm. A camera without ir filters will be much more sensitive to red light that contains material percentages of photons with longer wavelengths. Cameras often have such filters built-in just to prevent overly strong response to flames and red hot embers. Add-on IR filters are most useful for cameras that have weak or no IR filtering.



                          However, these filters are a problem when trying to capture longer wavelengths in astro-photography and replacing these with filters that pass specifically desired, longer wavelengths allows better capture of this light.







                          share|improve this answer














                          share|improve this answer



                          share|improve this answer








                          edited 3 hours ago

























                          answered 3 hours ago









                          doug

                          57727




                          57727




















                              77pro is a new contributor. Be nice, and check out our Code of Conduct.









                               

                              draft saved


                              draft discarded


















                              77pro is a new contributor. Be nice, and check out our Code of Conduct.












                              77pro is a new contributor. Be nice, and check out our Code of Conduct.











                              77pro is a new contributor. Be nice, and check out our Code of Conduct.













                               


                              draft saved


                              draft discarded














                              StackExchange.ready(
                              function ()
                              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphoto.stackexchange.com%2fquestions%2f102621%2fred-wavelengths-for-everyday-photography%23new-answer', 'question_page');

                              );

                              Post as a guest













































































                              Popular posts from this blog

                              How to check contact read email or not when send email to Individual?

                              Displaying single band from multi-band raster using QGIS

                              How many registers does an x86_64 CPU actually have?