This is a boxed set of three unbranded Japanese extension tubes with M42 screw mount, with rear pin coupling for auto-stopdown on cameras that support it. Tubes lengths are 11mm, 18mm and 30mm giving the following possible lengths, singly or combined: 11mm, 18mm, 29mm (11+18), 30mm, 41mm (11+30), 48mm (11+30), and 59mm (all tubes).

Condition of the tubes is good throughout, with no damage apart from minor scuffs and working well. I'm supplying them with a vinyl storage pouch, not original.

I tested operation on a Praktica body, and took test pictures using a Canon Eos 40D with M42 adapter set to 800 ASA - the test pictures were taken on a cloudy afternoon using a 58mm Helios lens set to F8 and show a 50p coin, width 27mm, taken without a tube, with each of the tubes individually then all three combined.
No tube (about 18") 1/500th
11mm (approx  0.2x) 1/400th
18mm (approx 0.33x) 1/200th
30mm (approx 0.5x) 1/125th
59mm (approx 1x) 1/60th

Light loss is common to all extension tubes - basically, you're magnifying part of the image and the rest of the light entering the lens is lost, which means that the higher the magnification, the smaller the proportion of the light entering the lens that reaches the film or sensor. Shutter speed must be reduced, or the aperture opened, to compensate. Since depth of field is greater when a lens is stopped down the usual preference is reduction in shutter speed. Please note that tubes usually work best with prime standard or moderate telephoto lenses, and give poorer results with zooms (unless specifically designed for it) and wide angle lenses.

There's an online magnification calculator here if exact magnification is needed:

https://thingsupclose.com/tools/extension-tube-magnification-calculator/

As usual I'm starting low and with no reserve. See my other listings for more photographic items. If you buy multiple auction items from me please request a combined postage invoice, I'll do my best to get it down to the lowest possible price. I do not make any profit on postage. Prices changed at the end of March.

International buyers: The postage price shown is based on an estimate of packed weight, around 200g. Please note that eBay will add VAT or sales tax to the final price in Europe and some other countries.