Question about focal length and portraits

ronlane · Jan 17, 2013

I am working to improve my portrait photos and have been playing with lighting and focal length, when I realized that I didn't understand much at all.

My question is this. Popular focal lengths for portrait are 50mm and 85mm and with a 70-200mm. Most of the people I hear about using these have a full framed camera. So having a crop sensor and say a 24-135mm, would it be best to put it at 50mm which gives you about an 80mm equivalent or use a 35mm to get approximately a 50mm equivalent or just use 85mm for a 100+mm equivalent?

Am I over thinking this. What do you do?

jwbryson1 · Jan 17, 2013

I had the same question so thanks for posting this...

KmH · Jan 17, 2013

It boils down to how much room you have. Using longer focal lengths you have to be further away from the subject to keep the subject in the frame.

A 50 mm lens on a crop camera is, still a 50 mm lens when it's mounted on a full frame camera.
At the same camera distance the difference is that the FF camera captures more of the scene than the crop camera does. technically the difference is the point-of-view.

My favorite portrait lens was a 200 mm f/2 prime lens.
It didn't matter to me if it was mounted on a crop frame camera, or a full frame camera.

The reason I used 200 mm was because it had a narrower point-of-view that included less of the background, and it magnified background elements making them seem even blurrier than if I had been closer and using less focal length.

For just a head shot, you don't have to be all that much further away when using a longer focal length. For a full body shot the distance difference gets much larger.

cgipson1 · Jan 17, 2013

What Keith said is dead on! The only thing I have to say... is that when you are very close to your subject, a wide angle lens can cause barrel distortion... whether it is on a crop body or a full frame. I would recommend trying to stay at 50mm or above for portraiture... longer focal lengths are more flattering than shorter focal lengths!

jwbryson1 · Jan 17, 2013

cgipson1 said:
I would recommend trying to stay at 50mm or above for portraiture... longer focal lengths are more flattering than shorter focal lengths!

But wouldn't shooting a portrait photo with my D90 and 35mm 1.8 be "equivalent" to shooting with a 50mm lens? If I shoot with my 50mm lens and crop sensor camera, I'm shooting at a 75mm point of view...

KmH · Jan 17, 2013

jwbryson1 said:
cgipson1 said:

I would recommend trying to stay at 50mm or above for portraiture... longer focal lengths are more flattering than shorter focal lengths!

Click to expand...

But wouldn't shooting a portrait photo with my D90 and 35mm 1.8 be "equivalent" to shooting with a 50mm lens?

It's "equivalent" only if the 50 mm lens is mounted on a full frame camera.

The 35 mm lens on a crop camera still delivers it's 35 mm lens characteristics, like distorting body parts.

ronlane · Jan 17, 2013

Thank you Keith and Charlie. I see the agrument for just shoot it at the focal length (50 or 85 or 200) and not worry about the crop sensor. What will be the change would be how far you have to stand away from the subject.

Charlie you say longer is more flattering. That would be why I liked the 85mm shots that I have been taking more then the 50mm ones.

TCampbell · Jan 17, 2013

On a "full frame" camera (24mm x 36mm sensor), 85mm or above is considered ideal for portraiture. A 50mm lens provides a "normal" angle of view, but that modest telephoto length provides a more flattering look and is preferred whenever possible.

On a "medium format" camera (so now we're talking about much larger sensors), 120mm is considered the "portrait" lens and 80mm is considered a "normal" angle of view.

On an APS-C DSLR (the vast majority of DSLRs), 30mm to 35mm is considered a "normal" angle of view, but 50mm or above is ideal for portraits.

Can you use other focal lengths? Sure. But the slightly longer focal lengths are preferred to guarantee no barrel distortion and also to provide DoF compression (which increases background blur).

ronlane · Jan 17, 2013

Thanks Tim. So I am okay shooting 50mm or 85mm to my preference and room availability and will be good.

Derrel · Jan 17, 2013

http://www.tek-lado.com/wp-content/uploads/strip-600x341.jpg

I wish this were still available FULL-sized, but now that Stephen Eastwood has been promoted to a Canon Explorer of Light, his website has been allowed to become "suspended", which looks soooo classless.

This site has been suspended

In the original full-sized image, Eastwood photographed a woman with lenses ranging from, I believe it was 17 or 19mm on the wide end, to 350mm on the long end, while moving the camera and lens farther and farther and farther back, to keep the SAME, exact head height of the woman in all of the final pictures. What you saw was ever-more background width showing up as the focal lengths got into the very short range, as well as distorted size relationships between her nose, and her ears.

MiFleur · Jan 17, 2013

cgipson1 said:
What Keith said is dead on! The only thing I have to say... is that when you are very close to your subject, a wide angle lens can cause barrel distortion... whether it is on a crop body or a full frame. I would recommend trying to stay at 50mm or above for portraiture... longer focal lengths are more flattering than shorter focal lengths!

I had a vague feeling of that but it was not so clear, thanks for this explanation!

paigew · Jan 17, 2013

I have a crop sensor and a 50mm. I shoot primarily portraits and 'lifestyle' images. For me it is all about room, are you shooting indoors? Because I often times feel very limited (space wise) with my 50 and have rented a 30 and LOVED it. Another thing to consider is WHO you are shooting. If you are shooting kids you may not want a 200 because you will have to be very far away from them.

cgipson1 · Jan 17, 2013

A 30mm??? And you can shoot a heavy person, and make them look even heavier!

paigew · Jan 17, 2013

cgipson1 said:
A 30mm??? And you can shoot a heavy person, and make them look even heavier!

yeah there would def be distortion, but...that is why I said it matters who you shoot too

ronlane · Jan 17, 2013

paigew said:
I have a crop sensor and a 50mm. I shoot primarily portraits and 'lifestyle' images. For me it is all about room, are you shooting indoors? Because I often times feel very limited (space wise) with my 50 and have rented a 30 and LOVED it. Another thing to consider is WHO you are shooting. If you are shooting kids you may not want a 200 because you will have to be very far away from them.

Having room at 50mm hasn't been an issue at this time. I am shooting indoors and right now I am shooting both kids and adults. (Mostly self, as I'm the only one patient enough to sit there while I learn.) I am currently using a 24-135mm but have a 55-200mm (both kit lenses). I feel that the 24-135 is a better lens and produces better photos than the 55-200.

When you post, are you cropping the image or just leaving it full size? What would be considered best? At the 50mm length, I feel that I need to crop them to fill the frame and meet the ROF.