I have them all in color too but the ones in B&W lost a lot with the color versions. Trust me I never shoot her in straight B&W except for my B&W photography class.
I prefer number 4. In the BW shoots you have some shadows very distracting. In number 4 light is it beutuful and, if i could do, my only change will be format from horizontal to vertical.
She has a character face, too, byetco. I like the window of her eyes in no. 1. The light is a little harsh, perhaps, on the skin of hand, but the moment is more intimately sincere than 2. through 4.
#2 is my favorite. Light is a bit harsh, but otherwise an attractive pose and perspective. Also, the background is simple and does not detract.
I love B&W, so I like what you did. It is really a lovely shot.
#3 is okay too, but the wind is taking her hair too much.
#2 and #3 really show the thing I am least pleased with in my F717. The max. shutter speed of 1/1000th is a terrible hindrance in bright light with wide apertures. Using F2.4 at 1/1000th at full zoom (as I'm sure that's what #3 was shot at) leads to overexposure in bright sun. For outdoor portraits I'd try a neutral density filter to knock down the highlights so you can expose properly at the largest apertures. It's a pain to mess with filters, and they degrade image quality somewhat, but it's a good tradeoff.
I'd try exploring the option of using different colour channels, and perhaps chucking the red channel for overexposed skin, as it'll be the most overexposed band in this situation. This is a very good reason to always shoot in colour, even if the intentions are in black and white.
A pretty model! I like the first couple of shots the most I think, but they are all good. A couple of technical things I've been told, though I'm far from a good portrait photographer:
The light is pretty harsh in these, appart from the last one. They all look pretty good though - if you have to do it in full sun, perhaps you could try just before sunset when the light is a lot softer ?
Also try to get some light into her eye sockets, either from a reflector, a small amount of fill flash or have her look towards the sunlight (as long as it is late evening and not going to make her squint, or a cloudy day) You can notice in number 4 that the eye sockets are quite dark.
I think having her looking upwards towards you will help flatter her more too as well as bringing a touch more light in. It is hard to shoot up towards someone and make them look their best.
