Beginner Why is 50mm so important?

cmcm789

cmcm789

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I have seen it quoted frequently about the importance of 50mm as it is equivalent as to how we see the world with the naked eye. But would we really notice a difference or would an image be less pleasing to us if it were shot at 30mm or 70mm?

Also out of curiosity, if 50mm is the ideal focal length, then why is 85mm or 100mm recommended as a good focal length for portraits, and not 50mm?
 
If you are looking the same view as the eye sees then I think its more closer to 35mm on full frame.
I like 50mm and have 4 versions of nikon for various film cameras but the 35 mm is also a fantastic lens
 
Try it and find out..

With a 50mm eq. lens you'll generally find hat when you lift the camera to your eye the scene in the viewfinder is pretty close to the view your eye saw. With a 30mm eq. you might find yourself taking a coupleof stepsforward,and with a 70mm eq. a couple of steps backwards to try and frame the shot the way you saw it.

Longer focal lengths are recommended for portraits because the telephoto compression effect is flattering, as is the effect of putting some distance between the camera and the subject. Shorter focal lengths mean you're closer to the subject and this can be unflattering,for example it tends to make the nose more prominent. The Phoglographer blog has a number of useful tips that include a lot of portrait tips that may help explain this better.
 
As @Alastair says very true, with a longer lens also a larger DOF has a bit more depth to it so I can shoot my 105mm at F2.5 and get someons head all in focus, its all good.
the great thing about the 50mm range is loads of lenses dead cheep especially if you look at old maunal and AF lenses.
 
I remember asking this question many moons ago of some wise old photographer, his reply was that they are cheap to make ...

As for the same field of view as the human eye (when used on a FF camera) - I beg to differ. A little experiment makes the point, focus your eyes on a point in front of you. Without moving your eyes allow the peripheral vision to register, i.e. what you can see "out of the corner of your eye" as the saying goes, then put the camera to your eye with a 50mm or equivalent lens on, focussed on the same point and see what is at the edges of the frame - if you have typical eyesight the field of view of the 50mm will be significantly less. Or perhaps I take things too literally sometimes ;)
 
I have the 35mm lens, and a sigma 50mm f1.4

I personally prefer the 50mm over the 35mm but they're both decent lenses in my opinion
 
Mr Bump said:
As @Alastair says very true, with a longer lens also a larger DOF has a bit more depth to it so I can shoot my 105mm at F2.5 and get someons head all in focus, its all good.
the great thing about the 50mm range is loads of lenses dead cheep especially if you look at old maunal and AF lenses.
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A longer lens has less depth of field for a given aperture, that's another advantage that helps seperate a portrait subject from the background.
 
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There is no ideal focal length, it depends on use.

50mm on full frame is said to be a 'normal' length which means it is CLOSE to the diagonal size of the frame - a real 'normal lens' would be more like 42mm but what's 8mm between frames?

When you are making a lens that is 'normal' to the film size they don't need to be very complex, therefore they are cheap AND good AND they offer a natural perspective.
 
cmcm789 said:
I have seen it quoted frequently about the importance of 50mm as it is equivalent as to how we see the world with the naked eye. But would we really notice a difference or would an image be less pleasing to us if it were shot at 30mm or 70mm?

Also out of curiosity, if 50mm is the ideal focal length, then why is 85mm or 100mm recommended as a good focal length for portraits, and not 50mm?
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A 50mm lens is not 'important' as such. There are a lot of them around because in the days when 99% of the cameras in use were 35mm film (full-frame in digital terms) it was the 'standard' focal length - when the focal length is approximately equal to the diagonal length of the frame. On larger medium format film, 75-80mm is regarded as standard, and on the smaller format of APS-C digital today, something around 30mm is the standard focal length.

The field of view with a standard lens is roughly about 40-45 degrees side to side and this is generally quite versatile in walkabout photography. A kit zoom or standard zoom will always include the standard focal length, and a bit more either side. In no way does a standard lens relate to the field of view of the human eye, but it does tend to give quite natural-looking perspective in a lot of situations.

And longer focal length lenses do not inherently give less depth of field. If the subject is framed the same, then depth of field is the same for a given aperture. There are some other significant changes, relating to perspective and the greater distance that longer lenses tend to be used at, but reduced depth of field is not one of them.
 
I spotted a photo of apartment blocks in Honk Kong in the latest (Sept) edition of Digital photo where the photographer had used a Canon 5D iii and 24-105. He said he had chosen a focal length of 50mm to give a field of view similar to that seen by the human eye.
 
cmcm789 said:
I spotted a photo of apartment blocks in Honk Kong in the latest (Sept) edition of Digital photo where the photographer had used a Canon 5D iii and 24-105. He said he had chosen a focal length of 50mm to give a field of view similar to that seen by the human eye.
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It isn't so much field of view, it's about perspective.

At wide angle you get lots of perspective distortion, at telephoto you get perspective flattening. 50mm (or thereabouts) is a nice in between that generates a perspective that is similar to how we perceive the world.

edit: to add, as Kipax says, all this talk of 50mm is relative to 35mm/Full Frame and is different if you have a crop sensor for which you want a 30 or 35mm lens for the same field of view.
 
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cmcm789 said:
I have seen it quoted frequently about the importance of 50mm as it is equivalent as to how we see the world with the naked eye.
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I have never seen this once..ever... also wouldn't the camera make a difference.. on a 1.7 crop or full frame giving different views....

To summarize.... Poppycock!

:)
 
50mm is simply a good 'normal' lens. Perspective is more or less the same as the human eye perceives it, I.E. not exaggerated or foreshortened as wide angles and teles do respectively. It won't give you the same field of view as what you see, and on digital probably won't give you the same magnification, though on a decent FF viewfinder it won't be far wrong. Prior to AF ccameras, viewfinders were much better and generally 50mm did deliver magnification close to how you'd see it with the naked eye, making it a naturally very easy focal length to work with.
 
I'd say it's because it's fixed focal length, fast glass and cheap. This makes it a good lens to start off with... fewer variables to muck around with yet a capability to do very shallow DOF (along with the usual f/11 etc. shots with the whole scene in focus).

I learnt my photography with a 50mm (on a crop camera) and found it very helpful... but others might want to use a cheap kit zoom lens instead to give more flexibility. Horses for courses, to be honest.

Whatever the choice, I wouldn't recommend starting off with a top-of-the-range piece of glass though, because unless you have money to burn, cheaper glass will be perfectly adequate for 99% of the tasks us beginners need. Another positive for a good (but cheap) fast prime: as your photography develops, it'll be far, far longer before you outgrow that particular lens. Compare that with, perhaps, a cheap zoom: you might find you want* a faster / fixed aperture / sharper lens before too long.

* want and need are obviously two quite different fellows!
 
PaulButler said:
I remember asking this question many moons ago of some wise old photographer, his reply was that they are cheap to make ...

As for the same field of view as the human eye (when used on a FF camera) - I beg to differ. A little experiment makes the point, focus your eyes on a point in front of you. Without moving your eyes allow the peripheral vision to register, i.e. what you can see "out of the corner of your eye" as the saying goes, then put the camera to your eye with a 50mm or equivalent lens on, focussed on the same point and see what is at the edges of the frame - if you have typical eyesight the field of view of the 50mm will be significantly less. Or perhaps I take things too literally sometimes ;)
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Absolutely. See the repository of all knowledge... Wiki... :D...

http://en.wikipedia.org/wiki/Human_eye#Field_of_view

Even an individual eye has a FoV wider than a 50mm lens and once you add the two together (if you're lucky enough to have two) you also have a very powerful processor stitching the two images together :D

To me, as others have said, the attraction of 50mm (FF, 25mm MFT etc...) is that the perspective looks pretty natural.
 
As a former forensic photographer (investigator) with over 20 years experience. The 50mm ( in 35mm DSLR / SLR context) is vital to recording a crime scene accurately. For this example, consider a Fatal Road Traffic Collision. To record the scene you would photograph the road ahead from the drivers position in the road and use a tripod to get the positioning and height correct. This would include the total viewpoint, the bend, any signage etc etc. The 50mm will record this as the eye(s) see it - or as near as damn it. In any case this has been accepted by the courts as a true and accurate record. Imagine then taking the same scene with a 10mm, 24mm or even a 100mm lens. ? - the perspective is entirely different. Imagine how misleading this could be in Court. That is one reason why this lens is so important - it's perspective and viewpoint is as close to the human eye as possible.

The lens is no good in a tiny living room where a wide angle lens is used. However, that can and should be explained in a Court as and when required. Forensic Photographers have a duty to the Court to produce accurate photographs. The 50mm is the Forensic Photographers lens of choice whenever possible for this reason in many Police Forces ( but not all )
 
A camera's standard lens is usually given as being the same as the diagonal measurement of the film or sensor format.

5" x 4" film is about 160mm diagonally - 150mm is the standard lens.
6cm x 6cm film is about 79mm diagonally - 80mm is the standard lens.
135 film though measures 43mm diagonally so a 50mm lens is a little longer than standard.


Steve.
 
In addition, in the late 60s, 70s, 80s and early 90s the lens you purchased with the camera was the 50mm 'standard' - 'standard purchase SLR + 50mm. 'kit lenses' didn't exist as such then, although zoom lenses did. These were big heavy things, not very fast, the quality was inferior to today's zoom lenses and very expensive.
 
50mm is essentially how we see the world. However, due to the differences in magnification (ie 1.6 vs FF) it will actually come out larger on other cameras.

frame_sensor.png


One of the reasons that you use a 50mm is to get used to zooming with your feet as opposed to using the lens.

8wp8OjKleCo

Not sure if that picture showed up but it shows the difference in focal length. Getting close and shooting wide is a lot better in some situations. It gives you more background and everything.

the 50mm also limits you on where you're able to shoot from. different angles, and the like.

Hope this helps some/
 
Soulex summed it up. Having a lens with a restricted angle of view teaches you more about composition and your positioning. Lately it has been a delight using my primes on my Pentax 35mm and DSLR and the M645
 
Glad to see so many people rebutting the commonly held belief that 50mm lens = the human eye.

Ive always considered this hogwash, (you've only got to open your eyes to see this!)

Eyes have a field of view of nearly 180 degrees (roughly equivalent to a 12mm lens?), but only approx a 2 degree angle of view of high acuity (approx equivalent of a 1000mm lens)

Also, perspective is affected by where you stand and you relation to the subject, not the lens. Stand in the same place, centre the camera on the same object with a 12mm lens and a 200mm lens and the perspective willl be the same.

PS you cant zoom with your feet, that will change your perspective!
 
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Zooming with your feet is an expression is all :/

I know a few videographers and photographers that are afraid to get close
 
I only ever use prime lenses. 35mm for an APS-C sensor in a DSLR feels about right. 50mm for a 35mm film SLR/ full frame DSLR feels about right. 80mm for a medium format 6 x 6 feels about right.

Anything shorter feels wide angle. Anything longer feels telephoto. The human eye/brain may have a wider field of view, but actually eyes are very poor cameras - the brain has to photoshop the mess and convince us that it works. It scans that wide angle, but we only really see and focus (and think about) on a relatively smaller area. The rest of the scanned view is there, to catch that charging lion, in "the corner of my eye".
 
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35mm on FF works for me as a walkaround, street photography, architecture, landscapes and environmental portraits.

I'll have that in a small body soon, so no need to lump around my DSLR :)
 
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one other thing tobear in mind (though not directly relevant to the question in the OP) is that the 50mm f18 is the cheapest available f1.8 lens (particularly for canon) , so a lot of people who usually shoot with zooms have this as their only prime for that reason
 
"Normal" comes down to the camera recording an ~45* FOV on the sensor. The image is then being printed/displayed at a size so that when viewed from a corresponding distance it occupies ~45* of your FOV (larger print/display sizes are supposed to have correspondingly longer viewing distances). This is because the average human's primary FOV is ~ 45* (the area easily focused on).

Crop factor must be considered. "Normal" is ~30mm for APS, 50mm for FF, and 80mm for MF. This also corresponds to the FL being ~equivalent to the diagonal measurement of the sensor/film (I happen to think they figured this out after-the-fact).

I don't own a 50mm... I couldn't care less about "normal."
 
Soulex? said:
That cheapness comes with disadvantages, like the aperture blades
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and the fact that the whole thing is basically held together will selotape and goodwill ( I was lucky and got a mk1 off ebay)
 
Rapscallion said:
Glad to see so many people rebutting the commonly held belief that 50mm lens = the human eye.

Ive always considered this hogwash, (you've only got to open your eyes to see this!)

Eyes have a field of view of nearly 180 degrees (roughly equivalent to a 12mm lens?), but only approx a 2 degree angle of view of high acuity (approx equivalent of a 1000mm lens)

Also, perspective is affected by where you stand and you relation to the subject, not the lens. Stand in the same place, centre the camera on the same object with a 12mm lens and a 200mm lens and the perspective willl be the same.

PS you cant zoom with your feet, that will change your perspective!
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Please read post 17.
 
Blank_Canvas said:
Please read post 17.
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Nick, I can understand why the courts would want some standards in photographic evidence supplied. But it is a falsehood that 50mm is the same as perspective of the human eye, perspective is governed by where you are in relation to the subjects, not the lens.
 
Rapscallion said:
Nick, I can understand why the courts would want some standards in photographic evidence supplied. But it is a falsehood that 50mm is the same as perspective of the human eye, perspective is governed by where you are in relation to the subjects, not the lens.
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Perspective is only one aspect of this topic. It's how the eye:brain perceives the world that's more important to the conversation.

There's a good discussion at www.cambridgeincolour.com/tutorials/cameras-vs-human-eye.htm
 
It's as close as damn it to the human eye. Stand in the same place with a 24mm a 100mm lens the perspective will change. The 24 mm will give a wide perspective. The 100mm will compress the perspective - both completely unsuitable for the example I articulated above.that is why the 50mm is so important to accurately record
 
I am talking about recording a 3 dimensional image on to a two dimensional format to demonstrate the right, height, with and depth or as near as possible.
 
Blank_Canvas said:
It's as close as damn it to the human eye. Stand in the same place with a 24mm a 100mm lens the perspective will change. The 24 mm will give a wide perspective. The 100mm will compress the perspective - both completely unsuitable for the example I articulated above.that is why the 50mm is so important to accurately record
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But that's not true, and is the point Alastair is making. If you stand in the same place, perspective is the same regardless of the lens. It's only when you move back with a longer lens, or closer with a wide-angle to frame the subject the same, that perspective changes.

The only thing you can say about a 50mm lens on full-frame is that it 'tends' to give normal looking perspective, because 'generally' it is used from the same viewpoint that we 'normally' use. And vague thought that is, there is certainly some truth in it.

As for field of view of the human eyes, there are various ways of measuring that and none of them relate to the 40 degrees-ish seen with a 50mm lens. Our total peripheral vision is close to 180 degrees, or maybe 60 degrees is an area we commonly scan with our eyes without moving our heads, down to 2 degrees of critical sharpness when reading text like this. Or you can look at zones of good colour or best brightness sensitivity, but trying to relate our scanning, moving, stereo view of the world to any single focal length doesn't work.
 
That was my point entirely, to a create a normal perspective (as possible) you would use a 50mm lens. Fully aware of all the other factors.
 
Blank_Canvas said:
It's as close as damn it to the human eye. Stand in the same place with a 24mm a 100mm lens the perspective will change. The 24 mm will give a wide perspective. The 100mm will compress the perspective - both completely unsuitable for the example I articulated above.that is why the 50mm is so important to accurately record
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Nick - perspective has nothing to do with the lens and everything to do with the distance to the subject.

Perhaps take tow test picture, standing in the same spot - one with a moderately wide lens and another with a short tele. The perspective and proportional sizes of the objects in the frame will be identical.
 
I've made my point. Just out of interest if you wanted to record a scene with a normal perspective as possible (in 35mm context) what focal length would you use ?
 
Blank_Canvas said:
I've made my point. Just out of interest if you wanted to record a scene with a normal perspective as possible (in 35mm context) what focal length would you use ?
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You've made your point, but with a factually wrong statement along the way.

For 'normal perspective' you would use something in the 35-50mm range, as per Cartier-Bresson really, though note that he also worked at 'normal' shooting distances, as if he was just walking by a scene (which mostly, he was) so the image looks like a slice of normal life.
 
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