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I've read several times that a 50mm lens will make features like noses noticeably stand out compared to an 85mm lens. However, I'm never sure if the post/article is describing results on a full frame or crop sensor. I know that the longer the focal length, the more the compression to features....because the crop sensor gives a 50mm the effect of a longer focal length, how noticeable is the facial distortion on say, a Canon 550D? I'm considering a prime for portrait work and I'm 'at the crossroads' like all of you who came before me.

I will generally be using the lens for wedding portraits on the beach (and they generally want to get married around sunset, so formal portraits come as I'm losing light — hence wanting a tack sharp f1.8 or below), so it would be handy to have a lens that can take more than just a head/shoulder shot.

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    Blog to the rescue, check this (this was on a crop sensor) out. And having done much with a 50mm and 85mm - 85mm all the way, but its really just an opinion. – rfusca Jul 16 '12 at 14:31
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    I've been trying to find a way to phrase this exact question. Thanks for doing it far more succintly than I could have. – seanmc Jul 16 '12 at 22:15
  • Quick'n'dirty answer - Neither will distort much at all on an APS-C sensor. The choice is up to personal preferences. If you are shooting such low light though, the bit larger aperture provided by a f/1.4 or f/1.2 over f/1.8 might actually be beneficial. – dpollitt Jul 17 '12 at 1:00
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    As a note related to @dpollitt's answer, while you may get an acceptable exposure at f/1.2 or f/1.4, you may find yourself tossing away a lot of properly exposed shots because the depth of field was too shallow and your AF chose the wrong feature to focus on. Example: if shooting at f/1.2 and AF chooses the tip of the nose, the eyes will be out of focus. For me, that can ruin a shot. The standard answer of "focus manually" would seem just right until you consider the fact that people actually move. It's a tough nut to crack, that wide-open aperture one. – Steve Ross Jul 17 '12 at 20:07

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I think Eric's answer is what I have been trying to justify to myself. I'm going to try to explain it, and I hope I get it right (I know people will correct me if I'm wrong!).

That is, it is the distance that determines the compression/disortion, not the focal length. However to get the same framing on a crop-sensor vs. a full-frame sensor, you'd need to change the distance if using the same lens on each camera.

In other words, a 57mm focal length on a 1.5x crop sensor, should provide the same perspective and framing as an 85mm focal length on a full-frame sensor if shot from the same distance.

Now, it seems that 85mm-105mm is most recommended for portraits (full-frame), so a 50mm on a crop-sensor might be too wide (you'd have to get in tighter and introduce more distortion). I think this is why you'll see people using a 70mm (like a 70-200mm) for portaits on a crop-sensor (yielding an effective 105mm on full-frame).

  • Great point about having to move in closer to get the shot on a 50mm and introducing distortion. I definitely want to get a prime, though, so I think I'll play around with my zoom lens as another poster suggested at 50 and at 85 and see which I like best. – huzzah Jul 17 '12 at 14:00
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I've read several times that a 50mm lens will make features like noses noticeably stand out compared to an 85mm lens

What you read was likely referring to full frame or equivalent focal lengths of 50 and 85mm.

In any case a 50mm lens on an APS-C sensor will allow you to take well framed portraits at a distance which doesn't cause any undesirable perspective effects on noses etc. I have shot a great many three quarters shots with a 50mm lens on APS-C.

Whether you chose 50 or 85 is a matter of preference, how you prefer to work and how much space you have. Personally I like to go longer (as it tends to give you more subject separation from the background) but it can be a pain when you don't have room!

  • I like the idea of separation from the background...honestly, the majority of portrait work I'd be doing would be beach wedding portraits, so what's behind me isn't generally an issue. I suppose, though, that the 50mm would be handier for more than the usual head/shoulders shot, since it's wider. – huzzah Jul 16 '12 at 15:28
  • I agree it is just preference. I have both, and prefer the 50mm on an APS-C. – dpollitt Jul 17 '12 at 0:58
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I'd suggest you take one of your existing zoom lenses (or borrow one) and set it on 50mm, shoot for a while, then set it on 85mm and shoot for awhile. Think about how well the focal length suits your shooting style. Then... look at the images and see whether you find the 85mm shots more appealing than the 50mm ones.

I shoot with an 85mm f1.2 and a couple of things: You almost never need that fast a lens and the cost may not be worth the number of shots made at that aperture. The depth of field at 1.2 is not sufficient to shoot pictures of people unless you are looking for a specific selective focus effect. One thing (and I'm using a full-frame DSLR) about shooting with the 85mm is that I find myself backing into things sometimes to get enough space to work. That's why I recommend you try the focal length in your intended shooting environment. If I'm feeling cramped with an 85mm, I imagine you would feel more cramped using a crop sensor in the same circumstances.

  • That is an excellent suggestion. I think because I'm on a crop sensor the answer is going to be fairly subjective and full of opinions here....just gonna have to find which I like best. – huzzah Jul 17 '12 at 14:01
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    This is my go to recommendation when "what focal length is best" kit lenses are a great cheap way to get a feel for the photographers style! – AthomSfere Jul 8 '17 at 16:24
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The focal length doesn't affect distortion or compression as you're describing. Only distance to subject can change that.

What focal length and sensor size affect is the magnification of the subject from a given distance. If you have a lens at least as wide as 50mm, you can determine for yourself what you want. What do you want your working distance to be? Take sample photos from that, as well as other distances. Find the distance you find most flattering. Determine the crop that you need to apply to make the subject as large in the frame as you want. From that, you'll be able to determine the best focal length for your working distance and your tastes.

Eric

  • Good points. I am finding the answer here is generally a consensus on "they're both good, stick with the one you like the best".... – huzzah Jul 17 '12 at 14:02
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A 50mm on a cropped sensor behaves exactly like an 85mm on a full frame. The answer to your question is a subjective one as others have mentioned; it's a personal choice. I shoot both 50 & 85 but for serious portraiture and commercial work, I always use my 85.. . the silky bokeh and wafer thin field of focus work to my advantage with regard to expressive, emotive portraits & fashion work. I use the Sigma 85mm EX DG HSM on a Pentax K3. I would consider using a 50mm for more serious work but I'd only have faith in a model with a larger diameter to get results I'd be happy with....

enter image description here

above image taken with my Pentax 50mm auto prime 1.7

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above image taken with my Sigma 1.4 EX DG 85mm

All that said, if you shoot fully on manual and know how to get the best out of your kit you'll do ok with either focal length.

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    +1, although I wouldn't quite say "exactly" — it's more mostly. – mattdm May 6 '15 at 14:15
  • I agree with mattdm. It behaves differently since the rendering of the out of focus elements won't match exactly, plus the fact that you have to take the crop factor into account when calculating the DOF and FOV. – Hugo May 26 '15 at 11:07
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You are correct that a 50mm lens on a cropped sensor camera will be more suited to close-up photography than on a full frame sensor. The smaller sensor size means that you don't need to get as close to the subject to fill the frame, meaning there is not the same distortion of the nose in particular.

Having said that, the answer really depends on your personal style; if you can get your hands one one of each types of lens (e.g. rented, or in a camera shop) and try them out on a willing subject (you could take a friend with you to the shop :D ) you'd get a better idea of which lens works best with your style.

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For headshots, 85mm will perform much better than 50mm. If you shoot family portraits, then 50mm might be a better option.

Apart from the focal length, you might want to look into the out of focus control or number of diaphragm blades as they determine the quality of the bokeh.

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I got the Canon 85mm "sharp as a tack". First time I used it, the house was bearly big enough to back up far enough. For a small family grouping, not a single close-up, it's too long.

Look at this Depth of Field calculator which is actually a full angle-of-view and distance planner. See what the lens might be good for in terms of how much room you have.

You might also see some side-by-side example of the perspective of a face shot with each length. Use your existing zooms; you're looking at the perspective not the sharpness. Amazing that some people don't even perceive that a wide angle (way up close) looks wonky. I'm always telling family members to stand farther back, don't zoom back. Point is, many people might not notice any difference as long as it's over 45mm or so. That's how a face looks when talking to someone in front of you.

For a picture viewed from farther away (that is, larger than life sized print!) It may seem odd to mix cues; it should look like a (big) face seen farther away. The normal perspective one might look more intamite, though. Context of the resulting print matters.

Note that a "nifty fifty" for Canon is cheap and has very good quality. There are a couple variations and versions you can read about. I have an original from 1987, first month of production. So you might look at the the many x cost difference, too. Get an original on eBay and then later see if you want a pricy 85.

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A 50mm lens on a crop sensor camera, acts pretty much the same as a 50mm lens on a full frame camera that you cropped in photoshop. There is some separation differences, but they are more noticeable on long focal length lenses. Distortion is a factor of lens to subject distance, so is less noticeable on the crop sensor that the full frame with the same lens.

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Yes a 50mm on an APS-C will have almost the same facial distortion as a 85mm on a full frame (as a 75mm to be exact).

So yes, get a 50mm f/1.4 lens for your APS-C body and you will be set to go.

However personally I prefer the 90-135mm range on APS-C for head shoots (135-200mm FF equivalency), but a 50mm will do the job.

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50mm on a crop sensor has the same field of view like 75mm on FF. But that is all. All other like DOF and Bokeh are not the same like a 75mm lens. 50mm are always 50mm and you can't say thats 50mm on crop is the same like 75 (85) on FF. The difference is clearly visible. For a full portrait you need round about 50% more working distance on crop and this changes the DOF. If you want a least nearly the same field of view you need to have a 1 f-stop faster lens on crop camera.

Of course you can take portraits with 50mm on both DX and FX. Distortion is a matter of distance. Mostly you won't take close-ups with that length.

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The Depth of Field calculator is a great tool to work with - been playing with that the past hour, thank you, @JDługosz! The ultimate answer is to shoot, compare and shoot more. Borrowlenses will let you check out the 60 or 80mm lens. Grab a kid or a neighbor, or a mannequin and shoot at every possible setting. Write down (or just use the EXIF) the settings and see what you like from each lens. Identify which lens provides the look you need, then shop the refurb sales to save a dollar or two.

It's all about experience - the more frames you shoot, knowing what you shot the frame at, will build a body of knowledge and habits to get the best portraits!

  • Unfortunately, depth of field calculator doesn't tell you the background bokeh, see my answer for a link to a video that explains why DoF calculators are flawed. – juhist Apr 9 at 15:21
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In theory, depth of field only depends on the f-stop (and sensor size), if you fill the entire frame with the subject (longer focal lengths having longer subject distance). Focal length doesn't affect depth of field, assuming the subject distance is varied accordingly.

In practice, though, the amount of background bokeh tremendously varies based on the focal length, see this video for example (starts at 8min 0sec). Depth of field calculators don't tell you this!

If you have 50mm f/1.8 and 85mm f/1.8, thus, the preference would be the 85mm f/1.8, because of the beautiful background bokeh.

However, 50mm f/1.8 has an aperture opening of 27.8mm, whereas 85mm f/1.8 has an aperture opening of 47.2mm. Thus, these lenses are not equivalent: the 85mm f/1.8 costs more than the 50mm f/1.8. To compare somewhat equivalent lenses, you could compare 50mm f/1.4 and 85mm f/1.8, and then the question of background bokeh isn't that easy to answer anymore.

So, all it boils down is this:

  • How much working distance is available? 85mm on a crop sensor requires long distance.
  • Are you comparing 50mm f/1.8 with 85mm f/1.8, or 50mm f/1.4 with 85mm f/1.8?

Both 50mm and 85mm on a crop sensor camera can be used for portraits if you understand their different properties.

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50mm on cropped do not work like 85mm on full.

Field of view may be somewhat alike, but bokeh and background separation are much more different.

85mm bokeh and separation is %70 better on a 85mm.

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    I voted this down since I think the answer is unnecessarily rude. Also the answer is very vague, confusing and incorrect. The answer could be saved by reworking it entirely. Until then it has my -1 vote. – Hugo May 26 '15 at 11:04
  • It's similar to a 75mm on FF, but pretty close to 85mm although not exactly the same. Bokeh and separation is a lens property not a focal length or field of view property, hence it's depends on the lens in question. – Goat Dec 11 '16 at 21:58
  • Please keep it civil. Insulting the knowledge of other posters is not necessary to say that you believe their answers are wrong. I have modified the answer accordingly. – AJ Henderson Jul 8 '17 at 16:03

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