Portrait Session - equipment

For my planned session in the studio I will be using Canon 5D MK2 but I have not yet decided on a lens.

I have available 24-70mm and a 50mm macro and have used both to take portraits in the field.  I also have available, through the college, a 50mm prime lens which I am assured will do the job.  However, after reading various magazine articles and books most seem to recommend 85mm.

HERE IS WHAT CANON SAY ABOUT THEIR 85MM F1.8 USM LENS

A short telephoto focal length, combined with a large maximum aperture and fast autofocus speed, make the EF 85mm f/1.8 USM an ideal optic for any photographer shooting portraiture.

Features

Fast f/1.8 aperture Short/medium telephoto lens USM focus motor with full-time manual focus 85cm closest focusing distance 58mm filter size Super Spectra coatings reduce ghosting and flare

A very popular short telephoto lens with portrait photographers.

A practical and portability telephoto lens The EF 85mm f/1.8 USM produces images that are sharp and clear at all apertures. A virtually circular aperture diaphragm gives out-of-focus regions a softer, more even feel, and lets in-focus subjects stand out against a blurred background. The lens features a non-rotating front element during focusing, enabling specialist filters (such as polarisers and graduates) to be used. Large f/1.8 aperture A large maximum aperture of f/1.8 lets photographers shoot hand-held in difficult, low-light conditions, as well as restrict depth-of-field for creative effects. Compressed perspective in portraiture The short telephoto focal length of the lens slightly compresses perspective, reducing the size of prominent facial features for a flattering result. Ultrasonic focusing A ring-type ultrasonic motor drives autofocus extremely quickly, and in near silence. Excellent holding torque ensures the point of focus is reached accurately, without overshooting. Furthermore, full-time manual override is available, making it possible to adjust focus without leaving AF mode. Super Spectra coating Super Spectra coatings ensure accurate colour balance and enhance contrast. They also reduce flare and ghosting – a common problem caused by light bouncing off a camera's sensor. Integration with E-TTL II flash metering The lens passes distance information back to a compatible EOS camera's E-TTL II flash system to ensure optimal flash metering."

AND ITS SIMILARLY PRICED 50MM F1.4 USM With its fast maximum aperture and rapid focusing system, the compact, high performance EF 50mm f/1.4 USM standard lens can be relied on for superb performance in any field of photography. Features Fast f/1.4 aperture Standard 46° angle of view USM focus motor with full-time manual focus override 45cm closest focusing distance Aspherical lens element 58mm filter size The ultimate mixture of versatility and image quality. Versatile, compact standard-lens design Gaussian optics, combined with two high-refraction lens elements allow photographers working in all fields to capture crisp, clean images, even wide open at f/1.4. The lens is ideal for photographing landscapes and travel scenes as well as portraits and reportage. Ultrasonic focusing A ultrasonic motor drives autofocus extremely quickly, and in near silence. Excellent holding torque ensures the point of focus is reached accurately, without overshooting. Furthermore, full-time manual override is available, making it possible to adjust focus without leaving AF mode. Smooth background blur A virtually circular aperture diaphragm gives out of focus regions a softer, more uniform feel. Sharp foreground objects stand out against a smooth blurred background. Super Spectra coating Super Spectra coatings ensure accurate colour balance and enhance contrast. They also reduce flare and ghosting – a common problem caused by light bouncing off a camera's sensor. They would seem to recommend the 50mm more as a general purpose lens whereas the 85mm is specifically recommended for portraiture.