50mm or 50mm

[Bubby]

Hey guys, bit of a noob question here which I'm sure a few of you can easily answer.

I was browsing in the "for sale" section & I have seen a few people selling (for example) 50mm len's. (are these for portraits?)

Anyway...

What is the difference in say "a dedicated" 50mm lens and selecting "50mm" on a 18-105mm lens?

 

[Bendihossan]

A 50mm prime lens will have a faster aperture and have better quality glass because it's aimed at that specific focal length where as in a zoom the image quality in the glass will be aimed at providing a good average across the range. Hope that helps

Oh and yes, they are used for portraits and anything else that you need a shallow depth of field for

 

[mastertrinity]

a fixed 50mm is a prime lens, these are meant to be much better quality due to its simple construction. most people (especially APS-C users) will use the 50mm as a portrait lens due to the huge F1.8 aperture making for a beatiful defocused effect and also brilliant for low light photography.

if i was you i would google "why buy a 50mm" and there will be hundreds of articles on the subject that will explain it easily.

 

[Bubby]

Excellent! Very helpful indeed guys. I'm assuming you would always stand roughly a certain distance away from the subject when shooting portraits?

 

[smooth]

Excellent! Very helpful indeed guys. I'm assuming you would always stand roughly a certain distance away from the subject when shooting portraits?

Beauty of the 50 or any prime is that it encourages you to think a lot about composition; what you what included in the framing of the shot. Filling frame more = stand closer!

I love primes

 

[Slimbert]

Prime everytime! Just taken a quick snap to show the effect of shooting at wide apertures:

Taken with a wide open Canon 50mm f1.4.....try getting that depth of field with an 18-105mm!!

 

[Richard King]

A 50mm prime lens will have a faster aperture and have better quality glass because it's aimed at that specific focal length where as in a zoom the image quality in the glass will be aimed at providing a good average across the range. Hope that helps

Oh and yes, they are used for portraits and anything else that you need a shallow depth of field for

Uh?

A prime lens has the potential for better optics.

Better optics will normally be achieved because the design is simpler, and without the comprimises the additional optics a zoom lens needs

The overall range of apetures may be better, but that is not given

A wide open lens is not better optically than a stopped down lens

If we are measuring optical quality, we are looking at:

- resolving power
- off axis abberations
- abberations induced by difraction
- abebrations/quirks caused by reflections

The smaller the apeture, the greater the abberations induced by difraction are

The larger the apeture, the greater the off axis abberations such as TCA will be

This is why there is often a sweet spot in terms of resoloution at about f8 on most lenses

On top of that, the image quality will be very dependant on the materials and sequence of materials used for all of the lens elements, the efacacy of all the anti reflection coatings, the quality of the lens surfacing, and the cleverness of the lens design and the design of each curve on each of the lens elements

It is easier, cheaper and simpler to design and make a prime lens, and the optics are fairly simple. However we are not in 1968, when calculations for lens combinations took years. With the advent of computer modeling (they can model the optical performance before making anything), and CNC lens machining, designers can make both great zooms and prime lenses. the gap in quality is not as wide as it used to be

 

[Richard King]

Prime everytime! Just taken a quick snap to show the effect of shooting at wide apertures:

Taken with a wide open Canon 50mm f1.4.....try getting that depth of field with an 18-105mm!!

You are assuming a shalow DOF is quality, and it isnt, it is just a characteristic of having a wide open apeture

 

[Slimbert]

You are assuming a shalow DOF is quality, and it isnt, it is just a characteristic of having a wide open apeture

Didn't say it had anything to do with quality so stop putting words in my mouth :nono:, I said effect!

 

[Richard King]

Beauty of the 50 or any prime is that it encourages you to think a lot about composition; what you what included in the framing of the shot. Filling frame more = stand closer!

I love primes

While I agree, the beauty of a zoom is flexibility and if you are rooted to the spot out of necesity, and you have to shoot things all over the place, then a prime is a nightmare. Horses for courses

 

[Arkady]

It used to be the case that a prime lens was 'better' quality at any given focal length than a zoom covering the same focal legths, but this is no longer true...

The only real reason to own a prime nowadays (aside from cost issues), is for the extra 'speed' the wider apertures allow, the effect those wider apertures give in your images and maybe lightness and portability.
Generally-speaking, primes in the 50-135mm range offer a more pleasing background 'bokeh' over zooms, hence their popularity for portraiture...

I have a 50mm f/1.4 and an 85mm f/1.4 and at equivalent apertures, they are no sharper than my 25-70mm f/2.8 and 70-200 f/2.8 set at 50mm and 85mm respectively...(guaged by Pixel-Peep examination).

I own them purely for the effects that the extra wide apertures allow.

 

[Bubby]

It used to be the case that a prime lens was 'better' quality at any given focal length than a zoom covering the same focal legths, but this is no longer true...

The only real reason to own a prime nowadays (aside from cost issues), is for the extra 'speed' the wider apertures allow, the effect those wider apertures give in your images and maybe lightness and portability.
Generally-speaking, primes in the 50-135mm range offer a more pleasing background 'bokeh' over zooms, hence their popularity for portraiture...

I have a 50mm f/1.4 and an 85mm f/1.4 and at equivalent apertures, they are no sharper than my 25-70mm f/2.8 and 70-200 f/2.8 set at 50mm and 85mm respectively...(guaged by Pixel-Peep examination).

I own them purely for the effects that the extra wide apertures allow.

Am I being a PITA by asking you have you any comaprision photographs?

Thanks for everyones help, has helped a great lot.

 

[Arkady]

Am I being a PITA by asking you have you any comaprision photographs?

Thanks for everyones help, has helped a great lot.

You're not... but - I honestly can't be bothered to take the photos again, edit and crop them again, upload them to Flickr again and link them to here again...

Maybe later this afternoon after lunch...but the sun is out and i want to polish the car in the sunshine...

 

[HoppyUK]

Spot on from Arkady.

Modern zooms are at least as good as similar focal length primes. Some are better. If that wasn't true, nobody would use zooms.

But generally the aperture limit for zooms is f/2.8 max, and even those are very expensive, whereas primes easily go down to f/1.8, f/1.4 and even f/1.2. Good for low light, great for mega-shallow depth of field.

 

[Slimbert]

I sure I've seen some older manual lenses that went to f1 or maybe even f0.9..........or maybe I just dreamt it! :shrug:

The DOF must have been razor thin!!

 

[HoppyUK]

I sure I've seen some older manual lenses that went to f1 or maybe even f0.9..........or maybe I just dreamt it! :shrug:

The DOF must have been razor thin!!

There were quite a few old lenses lenses that went to f/1.0 and even to f/0.7. They were all huge, horrible, unsharp, fuzzy, flarey things.

Not that it stops them being highly prized collectors items.

 

[Bubby]

You're not... but - I honestly can't be bothered to take the photos again, edit and crop them again, upload them to Flickr again and link them to here again...

Maybe later this afternoon after lunch...but the sun is out and i want to polish the car in the sunshine...

No problem - I fully understand

 

[Donki]

Is a reason the 50mm is so popular is because its pretty much the same focal length as the human eye (different on a crop obviously), therefore making picures with it seem more familiar/appealing. Learned something about that in my course but could be talking a lot of brown, or could be just a lot of lecturer theory.

 

[HoppyUK]

No problem - I fully understand

And all they would show is... no difference.

 

[benhaha85]

Is a reason the 50mm is so popular is because its pretty much the same focal length as the human eye (different on a crop obviously), therefore making picures with it seem more familiar/appealing. Learned something about that in my course but could be talking a lot of brown, or could be just a lot of lecturer theory.

I think you're right, but that's not taking crop factor into account. 50mm on full frame or 35mm on crop iirc.

 

[Bubby]

And all they would show is... no difference.

What are the effects Arkady talks about? (Ill assume you are washing your car Arkady )

"I own them purely for the effects that the extra wide apertures allow".

 

[Arkady]

Is a reason the 50mm is so popular is because its pretty much the same focal length as the human eye (different on a crop obviously), therefore making picures with it seem more familiar/appealing. Learned something about that in my course but could be talking a lot of brown, or could be just a lot of lecturer theory.

Probably more to do with the fact that it's the simplest in terms of optical-design and therefore the cheapest to manufacture.
The human eye's angle-of-view (mine at any rate) is more like 32mm, making a 35mm prime my 'standard' lens...
If you take into account peripheral vision and the eye's tendency to 'scan' subjects, it makes even more sense to go slightly wider than 50mm for standard.
Someone did make a fast-ish 45mm lens once, but I forget who (maybe Olympus?) and it's no longer around...

Also, 35mm primes are typically 30% to 50% more expensive for each stop slower than an equivalent 50mm though...
If you want to match apertures, then sometimes they're almost 200% more expensive.

The 35mm f/2 is generally found to be the best of the bunch optically-speaking - a good used Nikkor MF will set you back £100-£150 - a new Nikkor AF-D over £250 (while the faster f/1.8 is only £166 - that tells you everything you need to know about it's optical capabilities...).

 

[Arkady]

What are the effects Arkady talks about? (Ill assume you are washing your car Arkady )

"I own them purely for the effects that the extra wide apertures allow".

Shallow DOF and a creamy out-of-focus background (bokeh) like this: taken as a test-shot on my 85mm f/1.4 wide-open...
(someone has parked in my parking-space so the hose won't reach...pffft...)

 

[HoppyUK]

Is a reason the 50mm is so popular is because its pretty much the same focal length as the human eye (different on a crop obviously), therefore making picures with it seem more familiar/appealing. Learned something about that in my course but could be talking a lot of brown, or could be just a lot of lecturer theory.

Often quoted, almost always misquoted

Focal length of the human eye is around 22mm. Field of view of the human eye is over 180 degrees. Angle of view of a 50mm lens on a full frame camera is 46 degrees.

However, when you look through a lens of around 50-60mm the image appears around life size (depends on the camera) so when you put the camera to your eye it appears as if you are recording a section of the scene as you're seeing it. As a result, the perspective generally looks about 'right'. It usually looks 'natural'.

Also, about 40-70 degrees is the angle of view of the most active area of the eye - the area of highest awareness, the area you scan with your eyes before turning your head, that kind of thing. Even though you can actually see far more in total, while the actual area you're focusing on is tiny - like just this typed word you're looking at now, and maybe a couple either side.

So, while the 'same as your eye' bit is literally untrue, there is some truth in it. Cartier-Bresson famously used a 50mm lens on his (full frame) Leica for those wonderful street images of Paris for this reason. Which is a great excuse to link one of my favourites - just like he saw it walking past http://1.bp.blogspot.com/_0AZZvuenG...U/kNmGTGxGDVo/s1600/henri_cartier-bresson.jpg

 

[Donki]

Shallow DOF and a creamy out-of-focus background (bokeh) like this: taken as a test-shot on my 85mm f/1.4 wide-open...
(someone has parked in my parking-space so the hose won't reach...pffft...)

Rob,

I seen that image on here when you posted it before/or on you flickr and its a cracker really pops out at you, that 3Dy effect. Love it.

 

[Clonetrooper]

I did some comparisons this morning with my 17-55 2.8 and 50mm 1.8 both at 50mm at various apertures indoors, on a tripod taking a picture of a textured cushion to see which was sharper at 100%. I was surprised and slightly dissapointed in the 17-55 in comparison to the cheap prime

 

[Donki]

Often quoted, almost always misquoted

Focal length of the human eye is around 22mm. Field of view of the human eye is over 180 degrees. Angle of view of a 50mm lens on a full frame camera is 46 degrees.

However, when you look through a lens of around 50-60mm the image appears around life size (depends on the camera) so when you put the camera to your eye it appears as if you are recording a section of the scene as you're seeing it. As a result, the perspective generally looks about 'right'. It usually looks 'natural'.

Also, about 40-70 degrees is the angle of view of the most active area of the eye - the area of highest awareness, the area you scan with your eyes before turning your head, that kind of thing. Even though you can actually see far more in total, while the actual area you're focusing on is tiny - like just this typed word you're looking at now, and maybe a couple either side.

So, while the 'same as your eye' bit is literally untrue, there is some truth in it. Cartier-Bresson famously used a 50mm lens on his (full frame) Leica for those wonderful street images of Paris for this reason. Which is a great excuse to link one of my favourites - just like he saw it walking past http://1.bp.blogspot.com/_0AZZvuenG...U/kNmGTGxGDVo/s1600/henri_cartier-bresson.jpg

So I was only half wrong, it was Cartier-Bresson that we were looking at as a case study, like you I found his street images class, ended up doing my final review on him.

 

[intotherainbow]

I did some comparisons this morning with my 17-55 2.8 and 50mm 1.8 both at 50mm at various apertures indoors, on a tripod taking a picture of a textured cushion to see which was sharper at 100%. I was surprised and slightly dissapointed in the 17-55 in comparison to the cheap prime

i would be surprised to hear that

 

[Arkady]

However this one (had to search to find one sans overt boobage) was taken on the 24-70 at 70mm @ f/3.2 - you can see there's not that much difference in the background and certainly none sharpness-wise...but it does lack the 'pop' of the one taken on the 85mm...

Processing was more or less the same in both instances.
This was taken on a D3x, the previous one on a D3...

 

[Arkady]

I did some comparisons this morning with my 17-55 2.8 and 50mm 1.8 both at 50mm at various apertures indoors, on a tripod taking a picture of a textured cushion to see which was sharper at 100%. I was surprised and slightly dissapointed in the 17-55 in comparison to the cheap prime

The Nikkor 17-55 f/2.8 DX was also a bit rubbish - I hated it as well when I was issued one to go with my D2x kit and ended up using my personally-owned 17-35mm f/2.8 instead...

 

[HoppyUK]

I did some comparisons this morning with my 17-55 2.8 and 50mm 1.8 both at 50mm at various apertures indoors, on a tripod taking a picture of a textured cushion to see which was sharper at 100%. I was surprised and slightly dissapointed in the 17-55 in comparison to the cheap prime

That was probably because you were very close. 17-55 2.8 is sharper at normal distances - check Canon's MTF graphs on the links.

50mm f/1.8
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=152&modelid=7306

17-55mm 2.8
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=149&modelid=12955

Many lenses, particularly zooms with low f/numbers, are not at their best at minimum focusing distance. The 17-55 2.8 is known for it. Try it on something a bit further away and all will become clear

 

[Clonetrooper]

That was probably because you were very close. 17-55 2.8 is sharper at normal distances - check Canon's MTF graphs on the links.

50mm f/1.8
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=152&modelid=7306

17-55mm 2.8
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=149&modelid=12955

Many lenses, particularly zooms with low f/numbers, are not at their best at minimum focusing distance. The 17-55 2.8 is known for it. Try it on something a bit further away and all will become clear

56 inches from lens to item is that what you would call too close?

 

[HoppyUK]

56 inches from lens to item is that what you would call too close?

No it isn't Under 30in maybe. What was your shutter speed (tripod or not)? Try it in good light, high shutter speed, no higher than f/8, more distance.

I'm not suggesting the zoom will be dramatically better, even if it should be if you're pixel peeping fine detail. But it certainly shouldn't be worse.

 

[Clonetrooper]

Here's my examples. Naturally I know this is OTT pixel peeping but I did it to work out which lens I'd use indoors most often.

Original to show distance before 100%



2.8 on the 17-55 point of focus is the lower l/h star.



2.8 on the 50mm



f5 on the 17-55



f5 on the 50mm

 

[trencheel303]

the 17-55 has more contrast and better colour but - looks like - more CA.

 

[Clonetrooper]

I'm not happy with it tbh for the money I paid, that a cheap lens gives me a sharper image Not sure what to do.

 

[Arkady]

Test shots from 50mm f/1.4; 24-70mm f/2.8; 85mm f/1.4 and 70-200 f/2.8

The usual 'lens-cap in bright sunlight' shot will show a recognisable object in it's worst light - the silver paint on the logo will show any CA on the lens.

Taken on a D3.
All lenses are fitted with UV filters.
All shot at the same aperture/shutter speeds on manual.
All shot RAW (compressed) edited in ACR with only the camera pre-sets applied.
All have the same level of sharpening applied.


50mm aov

50mm f/1.4

24-70mm f/2.8

85mm aov

85mm f/1.4

70-200 f/2.8

 

[HoppyUK]

Here's my examples. Naturally I know this is OTT pixel peeping but I did it to work out which lens I'd use indoors most often.

<snip>

That's not right at all. I don't think we need to see any more. Your 17-55 2.8 needs calibrating. It's easily done, I'm guessing with the front focusing group at the front which sits on a rotating cam. But you need a laser collimator to do it.

Try Canon, I've always found them very helpful and their interpretation of the warranty period can be quite liberal. But if you've got to pay, these folks are much cheaper and pretty good http://www.advancedcameraservices.co.uk/ They'll give it a complete overhaul, clean, calibrate everything and six months warranty for £60 (that's what they charged me).

 

[Clonetrooper]

That's not right at all. I don't think we need to see any more. Your 17-55 2.8 needs calibrating. It's easily done, I'm guessing with the front focusing group at the front which sits on a rotating cam. But you need a laser collimator to do it.

Try Canon, I've always found them very helpful and their interpretation of the warranty period can be quite liberal. But if you've got to pay, these folks are much cheaper and pretty good http://www.advancedcameraservices.co.uk/ They'll give it a complete overhaul, clean, calibrate everything and six months warranty for £60 (that's what they charged me).

Ok I feel bad because I bought it off these forums last week off a very decent member. I've pm'd him but I have to admit from the shots I have taken I was dissapointed with the sharpness.

 

[HoppyUK]

Test shots from 50mm f/1.4; 24-70mm f/2.8; 85mm f/1.4 and 70-200 f/2.8

The usual 'lens-cap in bright sunlight' shot will show a recognisable object in it's worst light - the silver paint on the logo will show any CA on the lens.

Taken on a D3.
All lenses are fitted with UV filters.
All shot at the same aperture/shutter speeds on manual.
All shot RAW (compressed) edited in ACR with only the camera pre-sets applied.
All have the same level of sharpening applied.

<snip>

What are we looking for Rob? What f/number? Check the corners at low f/number.

You'll be hard pressed to see any significant difference in sharpness with any lens in the centre, pretty much at any f/number. That's why I'm sure there's something wrong with DJ's lens - that's a good and conclusive set of direct comparison pictures he posted. Maybe it took a bash in the post or summat. Fixable though