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Using A Focal Reducer with Crop Lenses | An Option Worth Exploring

By Justin Heyes on March 23rd 2015

A focal reducer is a little piece of magic between two lens mounts. When I had my Fuji X-E1, I used Lens Turbo exclusively with K-Mount glass (it was a travesty that I never got use the Fujinon XF 16-55 f/2.8 on it; it just had to suffice with the vintage Takumars I had). The focal reducer took the vintage lenses and gave me almost full frame coverage, with increased sharpness, and an extra stop of light. That combination provided some of my favorite shots to date.

[REWIND:Fujifilm 16-55mm F2.8 R LM WR For Wedding Photography | Just Take My Money Already]


Since I needed more from my camera and I ended up selling the X-E1 and Lens Turbo and replaced it with a Nikon D3300. In my desire to have that bokeh-rific look that the focal reducer gave me, I found an option to mount a Nikon lens to the EOS-M. Here are some sample shots of the Nikon DX 18-55mm (the only lens I had at the time) mounted to my EOS-M.

eos-m-focal-reducer-nikon-crop-lens-example_headlight eos-m-focal-reducer-nikon-crop-lens-example_pipes eos-m-focal-reducer-nikon-crop-lens-example_barn-door eos-m-focal-reducer-nikon-crop-lens-example_-0004

Kit lenses typically get a bad rep; complaints range from the plastic bodies, flimsy lens mounts, and poor optics (probably the biggest complaint is that aperture range just doesn’t give enough bokeh). Photographers crave shallow depth of field and use that to justify buying bigger and better lenses. With the focal reducer, I can turn my kit lens into an equivalent 20-63mm f/2.4-4 lens without spending a ton of money.


Since crop lenses (DX or EF-S) usually produce an image circle slightly larger than the sensor size, using a focal reducer with a crop lens can still help you obtain that extra stop of light with only slight vignetting at certain focal lengths (for that full frame look without a full frame lens).

Focal reducers do not give you a 1:1 ratio like the Sony A7 II‘s full frame, it’s more like a 1:0.72 ratio. This results in a slightly longer than full frame look. APS-C users will have almost full frame coverage with a crop factor of 1.08 (or 1.152 for Canon). Micro 4/3 users, on the other hand, will have slightly larger than APS-C coverage at 1.44x crop due to their original 2x crop factor. This short teleconverter aspect of focal reducers can make mounting crop lenses to mirrorless cameras usable.


Nikon DX 18-55mm at 18mm


Nikon DX 18-55mm at 24mm


Nikon DX 18-55mm at 35mm

Since purchasing the focal reducer, I have used the Nikon glass more with the the EOS-M than the original camera I bought it for. I love the crazy shallow depth of field that the 18-55mm provides and the increased sharpness and speed of the kit lens has made it a main contender in my work.


eos-m-focal-reducer-nikon-crop-lens_on camera

If you are interested, you can find a focal reducer for your mirrorless camera here. Have any questions about the set-up or comments? Please leave them below.

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Justin Heyes wants to live in a world where we have near misses and absolute hits; great love and small disasters. Starting his career as a gaffer, he has done work for QVC and The Rachel Ray Show, but quickly fell in love with photography. When he’s not building arcade machines, you can find him at local flea markets or attending car shows.

Explore his photographic endeavors here.

Website: Justin Heyes
Instagram: @jheyesphoto

Q&A Discussions

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  1. Joseph Prusa

    Good info.

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  2. Derek Schwartz

    I’ve been using vintage Nikon AI lenses on my Canon DSLR and my EOS-M – it would be really interesting see what the 55mm 1.2 lens could produce in terms of bokeh with the focal reducer…

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  3. Bogdan Roman

    I wonder if this would work on an ultra-wide lens mounted on a FF camera to make it even wider

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    • J. Dennis Thomas

      No. The adapter reduces the image circle to fit a smaller sensor, but keep the same angle of view. Fitting an adapter on a FF camera would result in a severely vignetted image. It would look like a circular fisheye with a black circle around the edges of the frame.

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    • J. Dennis Thomas

      As far as kit lenses go, the Nikon 18-55 lenses have always had a high IQ quality. I always used mine for a walk-around lens over the 17-55 f/2.8 when I wasn’t on a job. It’s definitely an underrated lens especially considering the price point.

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  4. Dave Haynie

    The focal reducer’s a great idea. But without electronic diaphragm control, it’s fairly annoying to adapt Canon lenses to anything. That’s the main reason to buy the spendy Metabones adapters, aside from the focal reducer part, of course. Not much of a problem for other lens families — I still use a few OM-System Zuikos on both my Canons and my OM-Ds via adapters, and they’re dandy. I might consider a cheaper focal reducer for that on the OM-Ds… extra light is always a welcome thing on a m43 camera.

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  5. Graham Curran

    Great idea.

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  6. Gregory Davidson

    I like how you combined a Nikon lense with a Canon body.

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  7. Hannu Siika-aho

    Focal reducer with APS-C lenses—interesting.

    I have heard that the v. II Mitakon Lens Turbo adapters are optically quite much better than the first gen. ones. Some say it’s as good (at least in the center) as Metabones’s Speedbooster that costs four times more!

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