How to change aperture on Canon EOS 450D

[ThomasF1234]

Hi all i have a canon eos 450d and tonight I was trying to take some photos of the moon whilst using a T-Ring and attaching my camera to my telescope however I could figure out how change the aperture settings as it said F00 and would not let me move it. I’ve found I can only change the aperture when a lens is connected to the telescope. Is there any way to change the aperture when the camera is attached to the telescope via a T-Ring? 

[Shimrod]

1 minute ago, ThomasF1234 said:

Hi all i have a canon eos 450d and tonight I was trying to take some photos of the moon whilst using a T-Ring and attaching my camera to my telescope however I could figure out how change the aperture settings as it said F00 and would not let me move it. I’ve found I can only change the aperture when a lens is connected to the telescope. Is there any way to change the aperture when the camera is attached to the telescope via a T-Ring? 

The aperture when attached to a telescope is fixed to  that of the telescope (or telescope and reducer). The aperture in a lens is changed by a diaphragm within the lens which increases or decreases the amount of light coming into the lens - this mechanism does not exist in the telescope. You can change the shutter speed only when attached to a telescope.

[JoshHopk]

Hi Thomas, 

Your Canon DSLR will use the aperture of the telescope, which is fixed, whereas a lens is able to alter its aperture.

Edited April 27, 2020 by JoshHopk
Typo

[ThomasF1234]

5 minutes ago, Shimrod said:

The aperture when attached to a telescope is fixed to  that of the telescope (or telescope and reducer). The aperture in a lens is changed by a diaphragm within the lens which increases or decreases the amount of light coming into the lens - this mechanism does not exist in the telescope. You can change the shutter speed only when attached to a telescope.

Ah ok thank you

[ThomasF1234]

4 minutes ago, JoshHopk said:

Hi Thomas, 

Your Canon DSLR will use the aperture of the telescope, which is fixed, whereas a lens is able to alter its aperture.

Thank you makes sense