Shooting on 50mm


dougs

New Member
Jun 7, 2010
261
0
0
#1
Just curious and seeking some views here. If I shoot at 50mm at F4 using a 50mm Prime (F1.8) compared to shooting at 50mm at F4 using a kit lens (18-105mm), is there any difference?
 

#2
Just curious and seeking some views here. If I shoot at 50mm at F4 using a 50mm Prime (F1.8) compared to shooting at 50mm at F4 using a kit lens (18-105mm), is there any difference?
In short yes, but nothing very much vast in difference. Primes have lesser distortion, have reason to believe it should prove a tad sharper than the kit lens.. but no cause to jump straight to primes just for that.

Zooms have all the versatility u need.
 

avsquare

Senior Member
Jan 26, 2012
3,306
0
0
#3
depends on what you are looking at I guess. if talking about angle of view it's the same at 50mm.

but when compare about image quality, it may be different. Zoom lens tends to have more distortion like barrel/pincushion distortion.
 

yrh0413

New Member
Oct 21, 2004
1,793
0
0
Singapore
www.danielyee.net
#4
in terms of FOV they will be exactly the same. However due to the fact that a prime lens is optimized only for its designated focal length you can expect it to perform much better than your 18-105 at the same aperture as the 18-105.

By the way if you are talking about the Nikon 18-105 VR, your max aperture @ 50mm is f/5. If you compare a 50mm stopped down to f/5 against your 18-105 wide open at f/5 the former definitely has an edge in image quality.
 

Octarine

Moderator
Staff member
Jan 3, 2008
12,491
26
48
Pasir Ris
#5
While technically there is no difference (same focal length, same aperture) several non-measurable aspects are different. Sharpness has been mentioned as well as distortion. But you should also to simple test shots of close objects and have a look at the rendering of out of focus area (blurring, also named 'bokeh'). You will see a difference there.
Another aspect: using a prime lens you need to focus more on your composition and (if required) do your zooming via feet. Many people (not excluding myself) have reported a better thought process about composition which results in better pictures.
 

dougs

New Member
Jun 7, 2010
261
0
0
#6
Why would there be a diff in IQ? Due to the lens make? Thanks for all the insights thus far. Really enlightening.
 

tecnica

Senior Member
Dec 26, 2004
3,660
10
0
#7
Why would there be a diff in IQ? Due to the lens make? Thanks for all the insights thus far. Really enlightening.
i not sure about the nikon lenses as i am from the canon camp but let's just use the USM(ultrasonic motor)as an example.

18-55 vs 50L, the former is fitted with a micro-motor while the latter has USM. ring-USM is very damped, unlike the micro-motor which may over/under commit when focusing. being accurate(USM) in focus will translate to a sharper subject and therefore better image quality. the same applies to exotic lens elements and delicate lens coatings which helps in increasing IQ.
 

avsquare

Senior Member
Jan 26, 2012
3,306
0
0
#8
Why would there be a diff in IQ? Due to the lens make? Thanks for all the insights thus far. Really enlightening.
i not sure about the nikon lenses as i am from the canon camp but let's just use the USM(ultrasonic motor)as an example.

18-55 vs 50L, the former is fitted with a micro-motor while the latter has USM. ring-USM is very damped, unlike the micro-motor which may over/under commit when focusing. being accurate(USM) in focus will translate to a sharper subject and therefore better image quality. the same applies to exotic lens elements and delicate lens coatings which helps in increasing IQ.
And not sure how true or how applicable this is - your 50mm prime should have less lens element than your zoom. Light defracts as they pass through a medium, for example, a lens. Distortions and things like chromatic aberration occurs. The more lens the light pass through, the more derogation it suffers.
 

Jun 7, 2011
939
3
0
#9
And not sure how true or how applicable this is - your 50mm prime should have less lens element than your zoom. Light defracts as they pass through a medium, for example, a lens. Distortions and things like chromatic aberration occurs. The more lens the light pass through, the more derogation it suffers.
True.. in short, more lens element = reduced picture quality.

Usually primes has fewer lens element compared to zoom lenses. In-lens anti-shake system also add more lens element.

But please also note that, nowadays modern zooms are reasonably good. Like technoglitz87 said, not a reason to jump straight into primes.
 

ed9119

Moderator
Staff member
Mar 11, 2002
11,013
37
48
56
Singapore
www.walkeast.com
#10
Why would there be a diff in IQ? Due to the lens make? Thanks for all the insights thus far. Really enlightening.
Essentially , the difference in the image quality (or more accurately, the RESOLUTION or resolving power) is due to the difference in the number of lens elements in a prime vs a zoom .... and of course other lens technologies at play

a ZOOM lens has additional lens elements grouped in various formations and known as an afocal zoom system that allows the actual "zooming" to take place

a PRIME lens is a lens with a few lens elements grouped to form a dedicated fixed focal length

so technically, light travelling through more groups of elements (as in a zoom) will result in images not as resolved as simple prime lenses which uses less lens elements... all other things being equal

light also falls off more going through more lens elements therefore also resulting in zoom lenses with higher f-stops .... which is why even the better zoom lenses are maximum only f2.8 and most others usually begin at f3.5 .... with a drop to f5.6 at the long end of the zoom range

.... which is also why you seldom see a 'slow' prime lens beyond f2.8 (including older ones)

please correct me if i am wrong .... been too many years since I last took my photography club exams
 

Last edited:

ed9119

Moderator
Staff member
Mar 11, 2002
11,013
37
48
56
Singapore
www.walkeast.com
#11
just as an example ...... a Canon 50mm prime has between 6 to 9 elements in different grouping configurations depending what you're talking about (a 1.8, 1.4, 1.2, 1.0)

a Canon 24-70 f2.8L FOR EXAMPLE .... has 18 elements
a Canon 18-85 f3.5 - 5.6 has 17 elements
even a Canon kit lens 18-55 has about 11 elements

of course its more complicated than these very simple examples but that should be the why and how about primes vs zooms
 

yrh0413

New Member
Oct 21, 2004
1,793
0
0
Singapore
www.danielyee.net
#15
Why would there be a diff in IQ? Due to the lens make? Thanks for all the insights thus far. Really enlightening.
Photography is an art, don't get caught in technical terminologies. What matters most is to make full use of your tools to create the photography you want. Take more photographs, try different tools and eventually you will find out the answers all by yourself.
 

ed9119

Moderator
Staff member
Mar 11, 2002
11,013
37
48
56
Singapore
www.walkeast.com
#16
Photography is an art, don't get caught in technical terminologies. What matters most is to make full use of your tools to create the photography you want. Take more photographs, try different tools and eventually you will find out the answers all by yourself.
true true :thumbsup::thumbsup::thumbsup:
artists and musicians also needs to know their tools as well
 

dougs

New Member
Jun 7, 2010
261
0
0
#17
just as an example ...... a Canon 50mm prime has between 6 to 9 elements in different grouping configurations depending what you're talking about (a 1.8, 1.4, 1.2, 1.0)

a Canon 24-70 f2.8L FOR EXAMPLE .... has 18 elements
a Canon 18-85 f3.5 - 5.6 has 17 elements
even a Canon kit lens 18-55 has about 11 elements

of course its more complicated than these very simple examples but that should be the why and how about primes vs zooms
thanks for taking time to explain in detail. Really interesting. :)
 

kfchrispy

New Member
Jun 29, 2009
77
0
0
#18
Dear ducky, since u have both prime and zoom, shoot both at same aperture and upload to monitor and see lor, not much point so technical and all about number of elements, distortion, bokeh and stuff. People can list down 101 differences between pime and zoom but in the end, the most important thing is whether you like what you see on the screen lah. Cheers
 

one eye jack

Senior Member
Jun 11, 2011
804
10
18
#19
thanks for taking time to explain in detail. Really interesting. :)
Hi, Apart from the number of lens elements there are other factors that determine the image quality and formost is construction of the
lens mechanisms such as the barrel and helicoid ring from which the individual lens elements working as a group is shifted for focusing and
zooming,in other words mechanical precision.The accurate dimensions and tolerances which these individual mechanical pieces which are
assembled together to form a lens so to speak.So it's not only optical but mechanical precision that come to bear on this topic.

As you can imagine for a fixed focal length lens the variable is the focusing part and the rest is fixed physically.Compared to a zoom,focusing
and zooming are variable so you have more tendencies for dimensional error such as backlash or play in dimensional tolerances.I'm sure you
remember in physics laboratory class in school where you are asked to physically determine or plot the position of the image of a simple bi-convex
lens.so there is an element of spatial accuracy involved. Then you have the lens part where using different types of glass gives diferent optical
properties.Terms like crown and flint glass are commonly encounted.Very interesting indeed.
 

Top Bottom