LensAlign Long Ruler Add-On for MkII Focus Calibration System

This LensAlign specialty ruler is designed for fine tuning long lenses, 300mm and greater. It is best used with Tape's FocusTune software but you can do the fine tuning just with visible observations.Aligning really long lenses is far more difficult than for shorter focal length glass. The main problem is not the ruler itself, but rather the size of the centering and focusing targets that come standard with the LensAlign system. They're fine for up to about 300mm, but greater than that focal length causes you to be so far from the targets that both centering and focusing are difficult to achieve due to the very small size.The construction of the Long Ruler is top notch. Three sections snap together using magnetic connections to create the entire length of the ruler, which then fits perfectly into the LensAlign target hardware.Although not perfect, using the Long Ruler is still the best way to align a long lens, compared to all other methods available. That's why I'd still rate it with 5-stars.

This was needed for testing my new Nikon D800E which has had focusing problems thanks to Nikon's not releasing the problem S/N's.

Expensive for the actual material delivered, but well worth the price in terms of what it enables you to do for fine tuning the focus point of a large telephoto. I used it to calibrate my 200-500mm at 500mm. Turns out my lens/camera was back focusing - the chosen focus point being at the rear of the depth of field.

I have provided and extensive report on my experience using LensAlign MkII and the Long Ruler on my blog. I considered the issue for four consecutive postings. I suppose that I had difficulty distinguishing between lens resolving power and focus sharpness. I think that my takeaway was a more realistic understanding of the lenses I use.[...]

I was pleasantly surprised that this item was engineered to take up the weight of something so long and lightweight. I was honestly a bit concerned it would be floppy. The design is brilliantly executed with support beams and strong magnets. The structure snaps together quickly and easily. I'm really impressed, well done.

It works exactly as described. I would not recommend purchasing until after you have worked with the basic kit first... And found the need.