1. Focal Length:
* 35mm:
* Pros: Wider field of view, good for environmental portraits (showing the subject in their surroundings), storytelling.
* Cons: Can distort facial features if you get too close, not ideal for extreme close-ups.
* Best For: Street portraits, lifestyle portraits, group portraits, when you want to capture the environment around the subject.
* 50mm:
* Pros: Versatile, relatively inexpensive (especially the "nifty fifty" f/1.8), produces a natural perspective similar to human vision.
* Cons: Might need to move around to get the framing you want, not as much background separation as longer lenses.
* Best For: Head and shoulder portraits, full-body portraits (in a smaller space), general purpose portraits. A great starting point for portrait photography.
* 85mm:
* Pros: Classic portrait lens, good balance of perspective and background separation, compresses features slightly for a flattering look, creates a pleasant bokeh (blurred background).
* Cons: Requires more distance between you and the subject, can be limiting in small spaces.
* Best For: Headshots, half-body portraits, focusing on the subject and blurring the background. Considered the sweet spot for many portrait photographers.
* 100-135mm:
* Pros: Excellent background separation, flattering perspective, allows for comfortable working distance, great for isolating the subject.
* Cons: Can be expensive, requires even more distance, may need a tripod for sharper images at longer focal lengths.
* Best For: Headshots, close-ups, particularly flattering for minimizing perceived imperfections, creating a soft and dreamy look.
* 70-200mm Zoom (and similar ranges):
* Pros: Versatile, can cover a range of focal lengths suitable for portraits (from environmental to close-ups), good for shooting in dynamic environments.
* Cons: Often larger and heavier than prime lenses, can be more expensive, image quality might be slightly less sharp than a dedicated prime.
* Best For: Event photography, shooting in unpredictable situations, capturing a variety of shots without changing lenses.
2. Aperture (f-stop):
* Wider Apertures (f/1.2, f/1.4, f/1.8, f/2.8):
* Pros: Shallower depth of field (more background blur), better low-light performance, creates a more dramatic and isolating effect.
* Cons: More expensive, more difficult to nail focus (especially at wider apertures), image quality can sometimes be softer at the widest apertures.
* Use Case: Headshots with very blurred backgrounds, portraits in low light.
* Narrower Apertures (f/4, f/5.6, f/8):
* Pros: Deeper depth of field (more of the image in focus), easier to nail focus, less expensive, can capture more environmental detail.
* Cons: Less background blur, requires more light (or higher ISO), can make the subject appear less isolated.
* Use Case: Environmental portraits, group portraits, when you want to show more of the background in focus.
3. Sensor Size (Full Frame vs. Crop Sensor):
* Full Frame:
* The focal length on the lens is the "true" focal length. An 85mm lens acts like an 85mm lens.
* Better low-light performance.
* Shallower depth of field at the same aperture as a crop sensor camera.
* Crop Sensor (APS-C, Micro Four Thirds):
* Focal length is effectively *multiplied* by a crop factor (usually 1.5x or 1.6x for APS-C). So, a 50mm lens on an APS-C camera acts more like a 75mm or 80mm lens. This means you get a tighter field of view.
* The crop factor can be helpful for portraits because it effectively gives you a longer focal length at a lower cost.
* Consider this crop factor when choosing your focal length. A 35mm lens on a crop sensor will feel more like a 50mm, while a 50mm will feel like an 85mm.
4. Other Considerations:
* Budget: Lens prices vary dramatically. Start with an affordable option and upgrade later as your skills and needs grow.
* Autofocus: Fast and accurate autofocus is important, especially for portraits with shallow depth of field. Consider lenses with advanced autofocus systems.
* Image Stabilization (IS/VR): Helpful for shooting handheld, especially at longer focal lengths or in low light.
* Build Quality: A well-built lens will be more durable and last longer.
* Lens Coatings: Look for lenses with multi-layer coatings to reduce flare and ghosting.
* Sharpness: While sharpness is important, it's not the only factor. A lens with pleasing bokeh and good color rendition can be more desirable than an overly sharp lens.
* Personal Style: Experiment with different lenses to find what works best for *your* creative vision.
Recommendations based on common scenarios:
* Beginner on a Budget (Crop Sensor Camera): 50mm f/1.8 (acts like an 85mm on crop sensor - great for headshots)
* Beginner on a Budget (Full Frame Camera): 50mm f/1.8
* Classic Portrait Look (Any Camera): 85mm f/1.8 or f/1.4
* Versatile Zoom (Any Camera): 70-200mm f/2.8 (expensive but very versatile)
* Environmental Portraits: 35mm f/1.4 or f/1.8
How to Choose:
1. Determine your budget.
2. Consider your shooting style. Do you prefer close-ups or environmental portraits?
3. Think about your subject matter. Individuals, couples, groups?
4. Read reviews and compare lenses. DPReview, Photography Life, and Lensrentals.com are good resources.
5. Rent lenses before you buy. This is the best way to try out different focal lengths and apertures to see what you like.
6. Practice and experiment. The more you shoot, the better you'll understand what works best for your style.
Ultimately, the best portrait lens is the one that helps you create the images you envision. Don't be afraid to experiment and find what works best for you!