How can I set the aperture on my DSLR when it's attached to a telescope instead of a lens?





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I would like to use my Nikon D3100 for astrophotography. I have attached the camera to my telescope with a T-ring, after which the camera recognized the absence of the lens, which is perfectly normal. However, without the lens on, I am unable to adjust the aperture, which is extremely important for astrophotography. I can set the ISO, the shutter speed, and some other, minor things but not the Aperture.



I’m using the camera in manual mode.



Is setting the aperture without the lens even possible?










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    1















    I would like to use my Nikon D3100 for astrophotography. I have attached the camera to my telescope with a T-ring, after which the camera recognized the absence of the lens, which is perfectly normal. However, without the lens on, I am unable to adjust the aperture, which is extremely important for astrophotography. I can set the ISO, the shutter speed, and some other, minor things but not the Aperture.



    I’m using the camera in manual mode.



    Is setting the aperture without the lens even possible?










    share|improve this question









    New contributor




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























      1












      1








      1


      1






      I would like to use my Nikon D3100 for astrophotography. I have attached the camera to my telescope with a T-ring, after which the camera recognized the absence of the lens, which is perfectly normal. However, without the lens on, I am unable to adjust the aperture, which is extremely important for astrophotography. I can set the ISO, the shutter speed, and some other, minor things but not the Aperture.



      I’m using the camera in manual mode.



      Is setting the aperture without the lens even possible?










      share|improve this question









      New contributor




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












      I would like to use my Nikon D3100 for astrophotography. I have attached the camera to my telescope with a T-ring, after which the camera recognized the absence of the lens, which is perfectly normal. However, without the lens on, I am unable to adjust the aperture, which is extremely important for astrophotography. I can set the ISO, the shutter speed, and some other, minor things but not the Aperture.



      I’m using the camera in manual mode.



      Is setting the aperture without the lens even possible?







      dslr camera-settings astrophotography






      share|improve this question









      New contributor




      Gergely Kovacs 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




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      share|improve this question




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      edited 15 mins ago









      Michael C

      135k7154384




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      asked 4 hours ago









      Gergely KovacsGergely Kovacs

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      Check out our Code of Conduct.






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          3 Answers
          3






          active

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          5















          Is setting the aperture without the lens even possible?




          Considering that the aperture is a part of the lens, not the camera body, no, it is not possible.



          Telescopes do not typically have variable apertures — there's no need to stop down to limit incoming light (which is absolutely the opposite of what is wanted for star photography), and depth of field control is meaningless when all objects are no closer than the moon.



          The aperture of the telescope is the diameter of the front element. In ƒ-number terms, it is the ratio of the focal length of the telescope divided by the diameter of the front element. Be sure to use the same units (i.e., inches, or mm/cm/m).






          share|improve this answer


























          • I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

            – Hueco
            1 hour ago






          • 1





            @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

            – scottbb
            41 mins ago



















          3














          Check your telescope manual and find the telescope's aperture. Assuming no telescope eyepiece is utilized, the camera is said to be at the "prime focus" position. Find the scope's diameter. Find the scope's focal length. Divide focal length by diameter. The results of this math is the working f number of the system. Example: 1000mm focal length 4 inch diameter. Convert all units to millimeters. Inches to millimeters conversion is 25.4. Thus 1000 / (4 X 25.4) = 1000 / 101.6 = 9.8. Round to f/10. By the way, f/10 is typical of most systems.






          share|improve this answer































            -2














            WHAT aperture? A lens has focal length and aperture. The telescope is now the lens. As I understand telescopes, you pay money to get as LARGE an aperture as possible! Why is it important to adjust it?






            share|improve this answer
























              Your Answer








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              3 Answers
              3






              active

              oldest

              votes








              3 Answers
              3






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              5















              Is setting the aperture without the lens even possible?




              Considering that the aperture is a part of the lens, not the camera body, no, it is not possible.



              Telescopes do not typically have variable apertures — there's no need to stop down to limit incoming light (which is absolutely the opposite of what is wanted for star photography), and depth of field control is meaningless when all objects are no closer than the moon.



              The aperture of the telescope is the diameter of the front element. In ƒ-number terms, it is the ratio of the focal length of the telescope divided by the diameter of the front element. Be sure to use the same units (i.e., inches, or mm/cm/m).






              share|improve this answer


























              • I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

                – Hueco
                1 hour ago






              • 1





                @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

                – scottbb
                41 mins ago
















              5















              Is setting the aperture without the lens even possible?




              Considering that the aperture is a part of the lens, not the camera body, no, it is not possible.



              Telescopes do not typically have variable apertures — there's no need to stop down to limit incoming light (which is absolutely the opposite of what is wanted for star photography), and depth of field control is meaningless when all objects are no closer than the moon.



              The aperture of the telescope is the diameter of the front element. In ƒ-number terms, it is the ratio of the focal length of the telescope divided by the diameter of the front element. Be sure to use the same units (i.e., inches, or mm/cm/m).






              share|improve this answer


























              • I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

                – Hueco
                1 hour ago






              • 1





                @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

                – scottbb
                41 mins ago














              5












              5








              5








              Is setting the aperture without the lens even possible?




              Considering that the aperture is a part of the lens, not the camera body, no, it is not possible.



              Telescopes do not typically have variable apertures — there's no need to stop down to limit incoming light (which is absolutely the opposite of what is wanted for star photography), and depth of field control is meaningless when all objects are no closer than the moon.



              The aperture of the telescope is the diameter of the front element. In ƒ-number terms, it is the ratio of the focal length of the telescope divided by the diameter of the front element. Be sure to use the same units (i.e., inches, or mm/cm/m).






              share|improve this answer
















              Is setting the aperture without the lens even possible?




              Considering that the aperture is a part of the lens, not the camera body, no, it is not possible.



              Telescopes do not typically have variable apertures — there's no need to stop down to limit incoming light (which is absolutely the opposite of what is wanted for star photography), and depth of field control is meaningless when all objects are no closer than the moon.



              The aperture of the telescope is the diameter of the front element. In ƒ-number terms, it is the ratio of the focal length of the telescope divided by the diameter of the front element. Be sure to use the same units (i.e., inches, or mm/cm/m).







              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited 3 hours ago

























              answered 4 hours ago









              scottbbscottbb

              21k75896




              21k75896













              • I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

                – Hueco
                1 hour ago






              • 1





                @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

                – scottbb
                41 mins ago



















              • I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

                – Hueco
                1 hour ago






              • 1





                @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

                – scottbb
                41 mins ago

















              I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

              – Hueco
              1 hour ago





              I'm not sure about OP's camera - but I know some may refuse to shoot when no aperture is selected in certain modes. Do you know if this affects the D3100?

              – Hueco
              1 hour ago




              1




              1





              @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

              – scottbb
              41 mins ago





              @Hueco not sure precisely. It never occurred to me to use a t-mounted camera in anything other than manual mode. I had no problems shooting manual with a D90 mounted on a telescope, nor with my D800E on a scope.

              – scottbb
              41 mins ago













              3














              Check your telescope manual and find the telescope's aperture. Assuming no telescope eyepiece is utilized, the camera is said to be at the "prime focus" position. Find the scope's diameter. Find the scope's focal length. Divide focal length by diameter. The results of this math is the working f number of the system. Example: 1000mm focal length 4 inch diameter. Convert all units to millimeters. Inches to millimeters conversion is 25.4. Thus 1000 / (4 X 25.4) = 1000 / 101.6 = 9.8. Round to f/10. By the way, f/10 is typical of most systems.






              share|improve this answer




























                3














                Check your telescope manual and find the telescope's aperture. Assuming no telescope eyepiece is utilized, the camera is said to be at the "prime focus" position. Find the scope's diameter. Find the scope's focal length. Divide focal length by diameter. The results of this math is the working f number of the system. Example: 1000mm focal length 4 inch diameter. Convert all units to millimeters. Inches to millimeters conversion is 25.4. Thus 1000 / (4 X 25.4) = 1000 / 101.6 = 9.8. Round to f/10. By the way, f/10 is typical of most systems.






                share|improve this answer


























                  3












                  3








                  3







                  Check your telescope manual and find the telescope's aperture. Assuming no telescope eyepiece is utilized, the camera is said to be at the "prime focus" position. Find the scope's diameter. Find the scope's focal length. Divide focal length by diameter. The results of this math is the working f number of the system. Example: 1000mm focal length 4 inch diameter. Convert all units to millimeters. Inches to millimeters conversion is 25.4. Thus 1000 / (4 X 25.4) = 1000 / 101.6 = 9.8. Round to f/10. By the way, f/10 is typical of most systems.






                  share|improve this answer













                  Check your telescope manual and find the telescope's aperture. Assuming no telescope eyepiece is utilized, the camera is said to be at the "prime focus" position. Find the scope's diameter. Find the scope's focal length. Divide focal length by diameter. The results of this math is the working f number of the system. Example: 1000mm focal length 4 inch diameter. Convert all units to millimeters. Inches to millimeters conversion is 25.4. Thus 1000 / (4 X 25.4) = 1000 / 101.6 = 9.8. Round to f/10. By the way, f/10 is typical of most systems.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 2 hours ago









                  Alan MarcusAlan Marcus

                  26k23060




                  26k23060























                      -2














                      WHAT aperture? A lens has focal length and aperture. The telescope is now the lens. As I understand telescopes, you pay money to get as LARGE an aperture as possible! Why is it important to adjust it?






                      share|improve this answer




























                        -2














                        WHAT aperture? A lens has focal length and aperture. The telescope is now the lens. As I understand telescopes, you pay money to get as LARGE an aperture as possible! Why is it important to adjust it?






                        share|improve this answer


























                          -2












                          -2








                          -2







                          WHAT aperture? A lens has focal length and aperture. The telescope is now the lens. As I understand telescopes, you pay money to get as LARGE an aperture as possible! Why is it important to adjust it?






                          share|improve this answer













                          WHAT aperture? A lens has focal length and aperture. The telescope is now the lens. As I understand telescopes, you pay money to get as LARGE an aperture as possible! Why is it important to adjust it?







                          share|improve this answer












                          share|improve this answer



                          share|improve this answer










                          answered 3 hours ago









                          Laurence PayneLaurence Payne

                          1,36346




                          1,36346






















                              Gergely Kovacs is a new contributor. Be nice, and check out our Code of Conduct.










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