[stevebrot]

I will add my piece, for no reason other than I always do on this discussion topic. Here are a few bullet points:

• Portrait photography is all about perspective*
• Perspective is driven by camera position (in strictest terms the position of the front lens element).
  
  The look you get is based on where you stand.
  
  This is true both for you with camera and you without camera.
• Portrait photography is not about focal length (not usually, see below regarding working distance)
• Focal length determines field of view (FOV)
• FOV determines framing for a particular perspective (where you stand)
• A shorter focal length allows you to stand closer and still frame the subject
• Standing closer produces certain side-effects such as lending increased prominence to the parts of the subject closest to the lens front element. This is true regardless of focal length and is NOT distortion. Repeat the last sentence for emphasis.
• A longer focal length allows you to stand further away and still frame the subject. Standing further away produces certain side-effects such as reducing foreground prominence.
• Standing close can freak out the subject and throw undesired shadows
• Standing far requires greater working distance and may be difficult if space is at a premium.
• You do not need a longer focal length to stand further away. The same framing can be accomplished with a crop (not advised).
• You do not need a shorter focal length to stand closer. The same framing can be accomplished using a stitch (also not advised).

Note that at no point above is a particular focal length range listed. Also note that depth of field (DOF) is not discussed. So, what about DOF? Narrow DOF is good, right? I dunno, what do you want? Having control over DOF is generally a good thing. How you use that control is a matter of personal taste and artistic vision. Here are more bullet points:

• DOF is not absolute. It is sort of a mushy concept driven by the notion of acceptable lack of blur at a given viewing distance.
• DOF is driven by the aperture size and image magnification
• DOF is not driven by focal length or image format, at least not directly
• It is enough to say that for a given magnification, a wider aperture will result in less DOF than a narrower aperture
• For a given magnification and absolute aperture, DOF is the same regardless of focal length**
• DOF control falls to two considerations:
  1. Deep enough for adequate subject near/far sharpness
  2. Shallow enough to isolate subject from background
• In practice, for a given framing:
  • Longer focal length + wider aperture ==> easier subject isolation
  • Shorter focal length + narrow aperture ==> easier subject near/far sharpness
  Choose your poison.

OK, are we ready for focal lengths?

Conventions for 35mm film and FF digital sensor:

• As short as 40mm for full body and upper torso
• As short as 50mm or 55mm for head/shoulders
• Range of 70mm to 135mm being the classic focal lengths

On 35mm film, I shoot my M 50/1.7, FA 77/1.8 Limited (optional: Jupiter-9 85/2), and Vivitar 135/2.8.

Conventions for APS-C:

• As short as 28mm for full body and upper torso
• As short as 35mm or 40mm for head/shoulders
• Range of 50mm to 90mm being the classic focal lengths

On APS-C, I shoot my FA 35/2, DA 50/1.8, and FA 77/1.8 Limited (optional: Jupiter-9 85/2). I have used my Sigma 17-70/2.8-4 (C), but it feels clumsy.


Steve

* Other stuff too, but for lenses the desired perspective, framing, and DOF are the points of practice.

** This is counter-intuitive, but true. What must be appreciated is that magnification is affected by both focal length and image format.

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Last edited by stevebrot; 08-20-2015 at 04:30 PM.

[KDAFA]

I've got four portrait lenses I really adore:

Pentax FA43 1.9 Limited
Pentax FA77 1.8 Limited
Pentax DA* 50-135 2.8
Tamron 28-75 2.8

Other than the Tamron, I have the same lenses - they're excellent.

The 43 and 77 in particular yield portraits with that special "FA Ltd" rendering - superb.

[condor27596]

Steve is right. But note ( what I noted two years ago ) every thread every poster always mentions using the fa 77 for portraits.

[Edgar_in_Indy]

I second this. If you are up to the challenge you can one some with broken SDM and convert it to screw drive and save a lot of $$
I am sure there might be a few around

Don't forget about the Sigma 50-150mm f/2.8. Heck of a good lens, and you don't need to lose sleep over the SDM.

I've also gotten excellent portraits from the Tamron 28-75mm f/2.8. Extremely flexible focal range that allows you to capture everything from small groups to head shots.

[biz-engineer]

Conventions for 35mm film and FF digital sensor: As short as 40mm for full body and upper torso As short as 50mm or 55mm for head/shoulders Range of 70mm to 135mm being the classic focal lengths On 35mm film, I shoot my M 50/1.7, FA 77/1.8 Limited (optional: Jupiter-9 85/2), and Vivitar 135/2.8.

It looks like the classic portrait lenses of the 24x36 film era where the 85mm and 135mm, so that would be 58mm and 90mm ? But we don't have those, do we ?

[malinku]

the times I go out and do portrait shoots. I always bring my Jupiter-9 and super tak 105mm f2.8. I really like how these two lenses render a scene. Since they are m42 lenses they fit on nearly all my 35mm cameras.

when those lenses are too long I take out a 55mm f1.8 (super tak or k-mount depending on camera) or super tak 35mm f3.5. Both are really good lenses and cheap.

[Cee Cee]

It looks like the classic portrait lenses of the 24x36 film era where the 85mm and 135mm, so that would be 58mm and 90mm ? But we don't have those, do we ?

the Tamron 90m 2.8 macro & Tokina ATXpro 28-70 f2.8 (which covers 58m) the two I prefer in my collection, but I also like my A501.7, Tak135/3.5, Viv, S1 70-210 etc. etc. You will get as many different answers as there are photographers.
I read some were that a study concluded that pictures taken from about 10ft away gave the appearance of most natural perspective to the majority of people, if you go with that, then the lens FL selection becomes easy, the FL that gives you the shot you are after (head, head& shoulders, full length etc). But focal length is only one part of the equation.

[Rondec]

My favorite portrait lenses are the FA 77 limited, DA *55 and DA *50-135. The DA *55 is probably my favorite APS-C portrait lens. The FA 77 is nice too, but it is a little long for a lot of situations.

DA *50-135



FA 77



DA *55

[LeRolls]

Anyone who has taken a look at my photostream on Flickr knows that I favor the 77 for my portraits. Fantastic lens IMO.

[lukulele]

As Steve said earlier, it's where you're standing, your perspective, and objectives. Even a manual A/400 can do a portrait. I'll second the absolutely quiet Sigma EX II 50-150 and (with enough light) the F35-70, a $50-75 jewel.

[pericombobulation]

I'm glad Stevebrot made his points so well because now I don't feel so strange in making an unconventional recommendation - the DA 35mm f/2.4. It is really cheap, and surprisingly wonderful for portraits, especially in close quarters and/or indoors. It is an incredibly versatile lens and very sharp, especially for the price. Or, if you can handle manual focus, check out the 50mm A f/1.7. Another of my favorite lenses and also quite affordable.

Really though, I'm no pro portrait shooter, but in my humble experience I'd recommend worrying less about exactly which lens to buy and instead worrying about how you are going to light your subjects. Soft box? Strobes? Natural? Etc. etc. Lenses are important, but proper lighting makes all the difference in portraits.

[ChristianRock]

Since my budget is tight, my options are the DA 35 2.4 and the F 50 1.7 (before that it was my M 50 1.7).

If I had more money available for this, it would be the FA 31 (environmental portraits), the DA*55 and the FA 77 - which I think are the 3 best lenses in the whole Pentax lineup, not just for portraits.

[pericombobulation]

Both great options. You'll be very happy with either one.

One thing to think about is what else you're going to be doing with the lens once your portrait gig is over. What I'm getting at is that (in my opinion, at least), 35mm is a more useful focal length on APS-C than 50mm for general walkabout, vacation, family photos, etc.. 50 just feels too tight sometimes, especially for landscapes. Even for family group portraits, I'd prefer the 35mm 2.4.

[stevebrot]

It looks like the classic portrait lenses of the 24x36 film era where the 85mm and 135mm, so that would be 58mm and 90mm ? But we don't have those, do we ?

Over the years, Pentax made several lenses intended for 35mm format portraiture. Those include lenses at 77mm, 85mm, 100mm, and 105mm focal lengths. 135mm was a common option for amateurs due to price point. Current DA-series offerings at 50mm, 55mm, and 70mm should do nicely as APS-C equivalents. If the options are broadened to include all compatible glass, the choices are quite broad.* If one simply must have lens with 28.6° FOV**, there are several currently available zooms.


Steve

* Both 58mm and 90mm are available in K-mount at f/2.8 and faster

** The FOV of an 85mm lens on 35mm FF

[Bunch]

It seems the answer is any quality lens besides a ultra wide angle is usable for portraits depending on your circumstances or environment. The DA 35 to the DA*300 and everything in between have all been mentioned here. A good lens and a good photographer can make things happen.