Recommended portrait lenses for photography, for beginners I will recommend canon 50mm f/1.8 lens, for semi-pro and professional photographers 50mm f/1.4 and f/1.2L lens is highly recommended.
Traditionally, photographers have relied upon moderate telephotos for portraits, lenses such as the 85mm f/1.8 USM, the 85mm lenses allow you to back off a little bit from your subject, and still produce frame-filling shots while minimizing the amount of background distractions.
Zoom lenses such as 17-55mm f/2.8 is ideal for portrait and wedding photography for APS-C DSLRs (T3 / 1100D , T3i / 600D, 60D and 7D). Professional L-series Lenses such as 24-70mm and 70-200mm zooms, are versatile choices that allow you to back off and also tend to throw backgrounds out of focus, highly recommended for Full frame DSLRs like 5D series and 1Ds series.
Recommended Canon Prime Lens for Portrait Shooting
Canon 50mm f/1.8 II Lens
Lightweight and affordable portrait lens Canon 50mm F1.8 – one of the cheapest lenses available in the market today, the lens is sharp and shows minimal chromatic aberration and has relatively low distortion and f1.8 aperture is sufficiently large to achieve very blurred backgrounds. The 50mm 1.8 Lens is highly recommended for entry-level DSLR like T3 / 1100D and T3i / 600D. When you Mount this lens on a cropped sensor camera, such as 1100D and 600D it becomes equivalent to 80mm.
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Canon EF 50mm f/1.4 USM
Canon EF 50mm f/1.4 USM –  The 50mm F 1.4 lens is one step above the 50mm F 1.8 lens, The higher price and faster aperture gets you more better sharpness and bokeh is more soft and creamy compared to 50mm 1.8. The lens is highly recommended for cropped sensor bodies like T3, T3i, 7D and 60D
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Canon EF 50mm f/1.2 L USM
Canon EF 50mm f/1.2 L USM Lens is flagship 50mm prime lens from canon, The AF is very fast and at 1.2 aperture on this lens gives a quality to the bokeh that simply can’t be found anywhere else, cost approx $1,600, Recommended for Full frame camera like 5D series, 1Ds series & Crop sensor (APS-C) DSLR like 60D, 7D and 1D series.
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Canon EF 85mm f/1.8 USM
One more affordable Canon prime lens after 50mm f/1.8 lens, the Canon 85mm f/1.8 lens works very well with Full-Frame camera like 5D Mark II and 1Ds Mark III, If you use this lens on a crop sensor camera like T3, T3i, 60D or 7D it act as a longer lens (equivalent to 135mm on full frame)
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Canon EF 85mm f1.2L II USM
More better compared to Canon EF 85mm f/1.8 USM. The higher price and faster aperture gets you more better sharpness and bokeh is more soft and creamy compared to 85mm 1.8. Recommended for Full-Frame Camera like 5D Series and 1Ds Series.
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Recommended Canon Zoom Lens for Portrait Shooting
Canon EF-S 17-55mm f2.8 USM
First zoom lens for portrait and low-light work, The f2.8 aperture may not be as large as the primes listed above, but is still sufficient to deliver a nice blurred background. The Image Stabilization (IS) works very good, The Lens is highly recommended for event , wedding and concert shooting. The EF-S 17-55mm f2.8 USM fits only on APS-C DSLR like T3, T3i, 60D, 7D and 1D Series
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Canon EF 24-70mm f/2.8L USM
Canon EF 24-70mm f/2.8L USM -These lenses work very well for groups and full-body portraits. Canon EF 24-70mm standard zoom lens –it replaces the L-series 28-70mm f/2.8 lens with something even better. The AF is very fast and the lens is Sealed and gasketed against dust and moisture, highly recommended for Full frame camera like 5D, 5D mark II and 1Ds series. The Canon EF 24-70mm f/2.8L USM fits only on Full-Frame DSLR like 5D series and 1Ds Series.
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Canon EF 70-200mm f/2.8 L IS II USM Lens
Canon EF 70-200mm f/2.8 L IS II USM Lens – A Excellent performer at a very high price. It is sharp, versatile, fast focusing, and has excellent bokeh (background blur quality). The Image Stabilization works very well and you can use this lens indoor/lowlight shooting. The EF 70-200mm f/2.8L IS II USM features one fluorite and five UD elements for increased optical quality and reduced chromatic aberration. And as with all L-series lenses, the EF 70-200mm f/2.8L IS II USM is dust- and moisture-resistant and designed for use in the challenging environments typical of rigorous professional use. Highly Recommended for Full Frame camera like 5D Series and 1Ds Series.
With a crop sensor camera Canon EOS 7D, Canon EOS 60D , or Canon EOS Rebel T3i, this lens is effectively: 112mm – 280mm.
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