How do you take "studio" portraits outside a studio?
If you are looking to do out door portraits, a flash can be used as fill or as a main light, it is easier to use a bracket for off camera flash. There are also studio mains that can work out doors with battery packs.
Small flash units can be slaved like studio mains; some are even self slaved (expensive).
Outdoors, my preference is for reflectors ratrher than flash; the results are more subtle.
The lens you use is dependent upon the distance to the subject, either the 105 or the 150 would work. If you are talking head shots. Full body and groups can be done with a 50mm or wider, when neccessary.
The use of selective focus to buzz out the background is a function of the distance to subject and the selected aperture and focal length. The longer the focal length and the greater the distance, the wider the aperture must be to blurr the background.
Rangefinder or ttl viewing may be a matter of preference.
Why would you consider a macro lens for portraits?

Ronk,

>>Why would you consider a macro lens for portraits?<<

For much of the 30 some years I worked in Hollywood a significant part of my bread and butter photography was what you refer to as portraits, but what we called 'headshots', close-up photographs of people for publicity purposes, and occasionally magazine covers and inside editorial pieces. The two lenses I most valued for this kind of photography were a Canon 100mm f/2.8 macro and a 120mm f/4 macro for the Rollei 6008. Macro lens optical design is optimized for closer focus distances than general purpose lenses. Several of my colleagues who shot Hasselblad used the same 120mm f/4 macro and it had the reputation for being just about the sharpest lens available for 6x6cm cameras. So, it was also used a lot for small product studio illustration work.

1. Medium format 6x4.5 SLR or RF (you'll love the enlargements!) USED prices are low. Good choice of film.
You might even find a 6x7 RF.
2. 75/80 lens and 150 lens (no macros)
3. LIGHT METER!!
4. TRIPOD!! Just accept this especially if you are working alone. Using a tripod you can frame your subject and adjust items around your subject without having to reframe them. It also helps to keep the camera off the ground.
5. Diffusion filters, women don't like to see their facial
imperfections; enlarged pores, crows feet, etc. Study the old Hollywood portrait masters.
6. Sunpak or Vivitar flash with difusion/color panel set.
Portraits always look better if there is a catch light in the eyes, they don't look dead. The color panel can be used to simulate effects like sunrise or sunset, an overcast day anytime. If you are workig alone a small light stand is also a plus. The tripod and light stand sounds like a lot of burden but there are some good light weight units available and they will make a difference in the finished product.
7. Remote shutter release, either cable or electronic.

You can use 35mm, I do, but medium format just has the edge
you can't get with the 35mm. I'm now giving digital a whirl. I've been doing portraits since 1981, photography since mid sixties, always for cost no more. I got started doing friends and family, then formal executive type, a few pro country western singers, hooter girls (that was rough), a few pro footballs players, or course senior portraits, bridal portraits (no weddings to much legal hassel, to say nothing about the mothers and their nerves) it kept my hobby going and it was all word of mouth and by keeping the person satisfied. May you have as much fun as I did and that I'm going to have.

Did not consider that aspect of macro lenses; thanks David.

Ronk, Thank-you for your answers. I saw an advertisement from Canon in two of this months photography magazines for macro for portraits. But it was for a digital camera. Steve

David, Thank-you for your information. I hope to be able to use it in the future. Respectfully, Steve

Thank-you Warren, That was very interesting and helpful. Respectfully, Steve