Founder Optics 42mm Low Profile T-Ring for Canon EOS M Mirrorless Cameras
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Important note:
- Canon "M" mirrorless cameras have an FFD (flange focal distance) of 18mm. To couple these with corrective telescope optics (such as flatteners or correctors) with a 55mm back focus requirement, your "M" T-ring should have an optical path length of 55 - 18 = 37mm.
- However, this adapter has a low profile design with an optical length of only 10mm (not 37mm). This allows you to insert additional M42-threaded accessories (such as OAGs or filter wheels/filter drawers) with a total optical path length of up to 27mm.
- You may need to insert additional M42x0.75 spacers (not included) in addition to other accessories between the corrective optics and this T-ring to get to 27mm so that your camera sensor can be placed at 55mm from the corrective optics' male thread to meet the 55mm back focus requirement.
- For example, to use this with ZWO's popular FD-M42-II filter drawer that has an optical length of 21mm, and ignoring the effect of filter thickness on lengthening the back focus requirement marginally, your imaging traing will be:
Corrective optic > T/T2 thread spacer (6mm optical length) > ZWO filter drawer (21mm optical length) > this T ring (10mm optical length) > Canon "M" camera (18mm FFD) so that 6+21+10+18 = 55mm.
Description:
- Founder Optics low profile T-Ring to convert your Canon mirrorless EOS-M camera's EF-M mount to a standard T/T2 42mm thread for attachment to various astronomy accessories such as prime focus adapters, corrective optics, guiders, etc.
- Fits Canon EOS SLR/DSLR mirrorless cameras with EF-M lens mounts
- M42 female thread on T-ring has a nominal diameter of 42mm and a thread pitch of 0.75mm
- Not for use with Canon EOS EF/EF-S or EOS-R mount cameras
- Not compatible with wide format 48mm or 54mm T-threaded accessories
- For use only with the smaller, more common standard 42mm T-threaded adapters and accessories which have a male M42x0.75 thread
- High-precision CNC-machined aluminum and black anodized
- Optical path length: 10mm
- Clear aperture: 40.60mm
- Weight: Xg / Xoz
Other Information
- Country of Manufacture: Taiwan
Important note:
- Canon "M" mirrorless cameras have an FFD (flange focal distance) of 18mm. To couple these with corrective telescope optics (such as flatteners or correctors) with a 55mm back focus requirement, your "M" T-ring should have an optical path length of 55 - 18 = 37mm.
- However, this adapter has a low profile design with an optical length of only 10mm (not 37mm). This allows you to insert additional M42-threaded accessories (such as OAGs or filter wheels/filter drawers) with a total optical path length of up to 27mm.
- You may need to insert additional M42x0.75 spacers (not included) in addition to other accessories between the corrective optics and this T-ring to get to 27mm so that your camera sensor can be placed at 55mm from the corrective optics' male thread to meet the 55mm back focus requirement.
- For example, to use this with ZWO's popular FD-M42-II filter drawer that has an optical length of 21mm, and ignoring the effect of filter thickness on lengthening the back focus requirement marginally, your imaging traing will be:
Corrective optic > T/T2 thread spacer (6mm optical length) > ZWO filter drawer (21mm optical length) > this T ring (10mm optical length) > Canon "M" camera (18mm FFD) so that 6+21+10+18 = 55mm.
Description:
- Founder Optics low profile T-Ring to convert your Canon mirrorless EOS-M camera's EF-M mount to a standard T/T2 42mm thread for attachment to various astronomy accessories such as prime focus adapters, corrective optics, guiders, etc.
- Fits Canon EOS SLR/DSLR mirrorless cameras with EF-M lens mounts
- M42 female thread on T-ring has a nominal diameter of 42mm and a thread pitch of 0.75mm
- Not for use with Canon EOS EF/EF-S or EOS-R mount cameras
- Not compatible with wide format 48mm or 54mm T-threaded accessories
- For use only with the smaller, more common standard 42mm T-threaded adapters and accessories which have a male M42x0.75 thread
- High-precision CNC-machined aluminum and black anodized
- Optical path length: 10mm
- Clear aperture: 40.60mm
- Weight: Xg / Xoz
Important note:
- Canon "M" mirrorless cameras have an FFD (flange focal distance) of 18mm. To couple these with corrective telescope optics (such as flatteners or correctors) with a 55mm back focus requirement, your "M" T-ring should have an optical path length of 55 - 18 = 37mm.
- However, this adapter has a low profile design with an optical length of only 10mm (not 37mm). This allows you to insert additional M42-threaded accessories (such as OAGs or filter wheels/filter drawers) with a total optical path length of up to 27mm.
- You may need to insert additional M42x0.75 spacers (not included) in addition to other accessories between the corrective optics and this T-ring to get to 27mm so that your camera sensor can be placed at 55mm from the corrective optics' male thread to meet the 55mm back focus requirement.
- For example, to use this with ZWO's popular FD-M42-II filter drawer that has an optical length of 21mm, and ignoring the effect of filter thickness on lengthening the back focus requirement marginally, your imaging traing will be:
Corrective optic > T/T2 thread spacer (6mm optical length) > ZWO filter drawer (21mm optical length) > this T ring (10mm optical length) > Canon "M" camera (18mm FFD) so that 6+21+10+18 = 55mm.
Description:
- Founder Optics low profile T-Ring to convert your Canon mirrorless EOS-M camera's EF-M mount to a standard T/T2 42mm thread for attachment to various astronomy accessories such as prime focus adapters, corrective optics, guiders, etc.
- Fits Canon EOS SLR/DSLR mirrorless cameras with EF-M lens mounts
- M42 female thread on T-ring has a nominal diameter of 42mm and a thread pitch of 0.75mm
- Not for use with Canon EOS EF/EF-S or EOS-R mount cameras
- Not compatible with wide format 48mm or 54mm T-threaded accessories
- For use only with the smaller, more common standard 42mm T-threaded adapters and accessories which have a male M42x0.75 thread
- High-precision CNC-machined aluminum and black anodized
- Optical path length: 10mm
- Clear aperture: 40.60mm
- Weight: Xg / Xoz
Other Information
- Country of Manufacture: Taiwan
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Founder Optics 42mm Low Profile T-Ring for Canon EOS M Mirrorless Cameras