SVBONY SV109 M42 (T2) Variable Extension Tube (24–35 mm)

Product Overview

The SVBONY SV109 M42 (item F9180A) is a variable-length T2 extension tube with M42×0.75 male and female threads. It adjusts from 24 mm to 35 mm, giving you continuous control of the spacing behind a reducer or field flattener, or of focus position in a camera or eyepiece train. The body is all-metal with an anodized aluminium finish.

Who It's For

This is a good match if your imaging train is M42/T2-threaded and you need to hit a corrector's backfocus precisely, or you want an adjustable spacer for focus and framing.

Key Features & Design

• Adjustable 24–35 mm: continuous spacing without stacking fixed rings.
• M42×0.75 (T2) male and female threads: connects cameras, eyepiece adapters and other T2 accessories.
• All-metal, anodized aluminium: for long-term durability.

Recommended Uses

• Backfocus tuning behind M42 reducers and field flatteners.
• Focus adjustment for astrophotography or visual trains.

Compatibility and Accessory Notes

• Threads: M42×0.75 (T2) male and female.
• Spacing: add 24–35 mm to your camera's flange distance and any filter holder to reach your corrector's backfocus. Send us your setup and we will work the figure out with you.

Good to Know Before You Order

• Mechanical spacer only: no glass.
• Minimum length 24 mm: shorter gaps need fixed M42 spacers.
• Weight: SVBONY does not publish a weight for this item.

Frequently Asked Questions

Is it difficult to set up?

No. Thread it between your corrector and camera, adjust the length to your target spacing, and lock it.

What is the adjustment range?

24 mm to 35 mm.

Is there an M48 version?

Yes, SVBONY makes the SV109 in an M48 version as a separate product.

Bottom Line

In short: an all-metal M42×0.75 (T2) extension tube that adjusts from 24 to 35 mm for precise backfocus and focus spacing.