Canon patents 70-135mm f/2 full frame zoom

Canon has filed a patent application for a 70-135mm f/2 zoom lens designed for full frame cameras. The internal-zoom design, with a fixed front group, appears to be a direct response to the Sony FE 50-150mm f/2 GM lens released last year.

Reported by Canon Rumors as application JP 2026-144169, the numerical optical example runs from 72.10mm to 136.89mm at an aperture of f/2.05. The patent states the optical length from the front lens surface to the sensor would be 211mm, placing it in a similar physical class as the competing Sony lens. The same patent filing also includes examples for a 200-400mm f/4 and a 180-600mm f/6.3 lens.

A Lens for Portrait Focal Lengths

A 70-135mm f/2 zoom would cover the classic portrait focal lengths of 85mm, 105mm, and 135mm. This offers a full stop of additional light over standard 70-200mm f/2.8 lenses. Sony has been marketing this concept since it launched its 50-150mm f/2 GM in April 2025.

The physics of such a design is challenging but not impossible. The entrance pupil diameter required for a 135mm f/2 lens is 67.5mm. For comparison, a 70-200mm f/2.8 lens needs a 71.4mm entrance pupil at 200mm. The greater difficulty lies in the optical design behind the front element. Maintaining an f/2 aperture at the wide end demands large rear lens groups and a significant amount of glass, which contributes to substantial weight.

The Race for f/2 Zooms

Canon initiated the modern push for fast full frame zooms with its RF 28-70mm f/2L USM in 2018. That lens weighed 1,430 grams and used 95mm filters. Sony responded six years later with its own FE 28-70mm f/2 GM in November 2024, weighing 918 grams and priced at $2,899.99. Sony then extended the concept to telephoto ranges with its 50-150mm f/2 GM, an internal zoom weighing 1,340 grams, using 95mm filters, measuring 200mm in length, and costing $3,899. This new patent is the first indication that Canon intends to develop a competing f/2 telephoto zoom.

Fast telephoto zooms have a history on smaller sensor systems. Olympus built the Zuiko Digital ED 35-100mm f/2 for the Four Thirds system in 2005. Sigma later produced a 50-100mm f/1.8 Art zoom for APS-C cameras in 2016.

The Practical Advantage of One Stop

The primary benefit of an f/2 lens over an f/2.8 is one full stop of light. At a telephoto focal length like 135mm, this has tangible effects. For a subject 3 meters away, a 135mm lens at f/2 yields approximately 6 centimeters of depth of field, compared to about 8 centimeters at f/2.8. This creates visibly greater background separation. The extra light also allows photographers to halve their ISO setting under identical lighting conditions.

For wedding and portrait photographers who often carry both an 85mm f/1.4 and a 135mm f/1.8 prime lens to achieve this look, a single zoom covering both ranges at f/2 holds significant appeal. Sony's sales of its 50-150mm f/2 lens have demonstrated a market exists for such a product.

Patent Versus Product

It is key to note that patents are not product announcements. Canon files many optical patents that never become commercially available lenses. For instance, a 24mm f/0.7 design from a previous filing has not materialized. Canon Rumors notes that Canon has one more announcement day scheduled before the end of 2026, with new lenses expected. Two f/2 zoom designs have now appeared in recent patent filings.

If a 70-135mm f/2 lens does launch, it will likely be positioned against Sony's model. The key comparable figures from the source are as follows:

Canon's rumored lens would need to compete with these specifications, particularly Sony's $3,899 price tag and 1,340-gram weight for the telephoto zoom.