geezer7 Loc: Michigan

I apologize if this topic has been covered in other posts. I have often seen comments stating that since the 50mm lens has an equivalent field of view (FOV) to a 75mm lens on a full-frame (FF) Nikon camera it would be a good lens to use on an APS-C camera for portraits. What bothers me is that 50mm lenses on FF cameras are said to produce unflattering features on faces and therefore 80+mm lenses are a better choice for portraits. Since we know that using a 50mm lens on an APS-C camera does not change the focal length to 75mm why wouldn't the unflattering features occur on the APS-C camera. The only difference that I can see is the possibility that the APS-C camera is further away than a FF camera for the same coverage on the sensor. I would be interested in hearing informed opinions on this topic!
Thanks for your time and comments.

BebuLamar

What you said is really perspective and not the lens focal length. Generally to make a portrait one would want to position the camera a good distance from the subject. Often about 6ft to get the flattening effect. (I said often but some do use longer distance). At 6ft the 80mm lens or so would frame about a half length portrait and so is the 50mm lens on an APS-C camera. In fact one can stand at a distance from the subject to get the right flattening effect using say a 20mm lens. However doing so the subject is too small in the frame so if you crop then it give you the same effect as using the longer lens.
It's the distance from camera to subject that give you the flattening or unflattening effect and not the lens focal length.

Apaflo Loc: Anchorage, Alaska

You nailed it right there! Focal length does not actually change the perspective. Only relative distance affects perspective.

You can position the camera at a distance that gives you the desired perspective and the use any focal length you want. With shorter focal lengths cropping will be necessary to get the right framing, but the perspective will stay the same.

Note that many portrait photographers actually prefer the working distance that a 135mm, or even greater, gives them. That works well where the setup is always the same, but a picture taken with a 50mm lens and then cropped to size has exactly the same perspective! (One reason for high megapixel sensors. You can grab such a shot even if the lens you have is not the "right" focal length.)

Joe Blow

A 50mm lens on a 35mm sensor (or 35mm negative) was considered the equivalent of a normal eye. Any lens with a higher focal length was considered telephoto and less was wide angle. In the early days of photography and changeable lenses, a focal length of 80-100mm was an accepted good range as it created a comfortable distance from the subject. Photographers could set up their equipment and get consistent results. (As they all used different medium and large format cameras, they would have used an equivalent size lens)

With todays wide range of cameras and lenses, you can use almost any lens to get a decent portrait. But, what makes a good portrait has changed a lot from the days of Karsh. We don't sit the subject in a full second, very large aperture, angled head shot pose with a dark back ground. We allow much more leeway in our approach to position, background, and amount of body. We use backgrounds as an element and light as a bonus. Motion and facial expressions are allowed.

If you want to recreate a Karsh era portrait then ya, go for that 80-120mm lens on your APC-C with the dark background and side lighting. My experience is to just keep a comfortable distance from the subject and let them be them. That requires talking to them and using a mild telephoto (~70-200) with larger (f3.5 - 5.6) aperture. (I dislike working at extreme apertures)

geezer7 Loc: Michigan

Thank you everyone for responding. The consensus is that distance is the main determinant in whether features are distorted. That makes sense to me.

BebuLamar

And because of that distance you pick the focal length that let you frame your subject accordingly. If the lens forces you to come closer or back away further then you change the perspective.

bobmcculloch Loc: NYC, NY

Perspective, you are not as close.

Lyle Johnson Loc: central Florida

Great discussion

PHRubin Loc: Nashville TN USA

Yes to many above, you would be further away to get the same framing (composure) with a 50 on a APS-C frame than a FF, hence composing and getting the perspective of a 75mm.

pendennis

For the correct perspective, you need a short telephoto, regardless the format. Generally, anything from around 85mm, to around 120mm will work. You're after image compression and not perspective, as others have mentioned. After 120mm, you get a bit too much compression, especially for head and shoulders portraits. A 50mm will work well for waist-length.

SharpShooter Loc: NorCal

Geezer, there's only one catch to any of the "ideal" portrait lenses, they are all pretty long! No 50 is not long but when most are talking portraits(headshots), so they're talking studio and in a studio to get a full length shot you have to get maybe 20-30 feet back, a luxury most people don't have.
So have fun with that 50 but always be ready to break out a zoom or a short lens for those time where you simply don't have the distance. Happy shooting!!!
SS

Apaflo Loc: Anchorage, Alaska

There is no such thing as telephoto compression.

There is only perspective, which is a function of relative distance. Changing focal length has no direct effect, but it allows a change in distance which affects perspective.

CaptainC Loc: Colorado, south of Denver

Yep. One of the hardest things to get some folks to understand. A focal length change does not change perspective.

Dennis833 Loc: Australia

I recently shot a series of commercial portraits using a 50mm lens on an aps-c camera. I shot them as horizontals and cropped the images square to give the same effect as shooting with an 85mm on FF. I agree with pendennis 80-120mm on FF is ideal.

sirlensalot Loc: Arizona

50mm works nicely on my APS-C. 85 works better on either FF or crop sensor.