6. 42 mm Extension Tubes & Spacer Rings

42 mm Extension Tube - 10 mm Length - SFE-M42-010

  This is a 42 mm extension tube that adds 10 mm of length. The outside diameter is 1.8". The male thread is just under 3 mm long and the female thread is about 8.4 mm deep. 

42 mm Extension Tube - 20 mm Length - SFE-M42-020

  This is a 42 mm extension tube that adds 20 mm of length. The outside diameter is 1.8". The male thread is just under 3 mm long and the female thread is about 18.5 mm deep. 

42 mm Extension Tube - 30 mm Length - SFE-M42-030

  This is a 42 mm extension tube that adds 30 mm of length. The outside diameter is 1.8". The male thread is just over 3 mm long and the female thread is about 27.6 mm deep. 

42 mm Extension Tube - 5 mm Long - SFE-M42-005

This is a 42mm extension tube that adds 5mm in total length. The outside diameter is 2.0". The male thread is 5mm long and the female thread is 4.5mm deep. IMPORTANT: Most 42mm male threads are longer than the female thread in this extension...

42 mm Female to 48 mm Male Adapter - SFA-M48F42

This adapts the M42 X .75 T thread to the over-sized M48 X .75 T thread. It adds about .9 mm to the M42 male thread length and measures 3.85mm in total length.

42 mm Spacer Ring - 1 mm Length - SFE-M42-001

  This is a precision, CNC machined 42 mm ID spacer ring that is 1 mm thick. It provides 1 mm of additional space between the field flattener and the imaging camera. 

42 mm Variable Extension Tube - 8 - 12 mm Length - SFE-M42-V

  This is an adjustable 42 mm extension tube that adds 8-12 mm of length. Thread is the standard 1.8" filter thread size of M42 X .75. The depth of the male thread is 8.3 mm and there is a thin (1.72 mm) threaded locking ring on this thread to...

48 mm Female to 42 mm Male Adapter - SFA-F48M42-008

  This adapts the over-sized M48 X .75 T thread (same as 2” filter thread) to the standard M42 X .75 T thread. It adds about 8 mm to the spacing, so it is not recommended for use with a DSLR camera and our SFF3 flattener. However, when...

SFE-M42-0.50 -- 42 mm Spacer Ring - 1/2 mm Thick

  Description:  This is a precision, CNC machined 42 mm ID spacer ring that is 0.5mm thick. It provides 0.5mm of additional space between the field flattener and imaging camera.