Entry level zoom lense sharper than a prime?


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Nov 13, 2005
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#1
Hello guys, ive recently upgraded from a sony alpha100 to a canon 40d + sigma 30mm f/1.4 prime lense, as i realised i usually shoot under low light conditions. However i was pretty surprised to know that an entry level kit lense (18-55mm f/3.5-5.6) is sharper than my prime at f/3.5. (centre,border & extreme border sharpness!), of cos stopping down the prime to f/3.5 too. Arent prime lenses supposed to be sharper stopped down? so if the kit lense is really sharper at f/3.5 onwards, are we paying top dollar only for the bokeh effect and lower light capability?

http://www.photozone.de/canon-eos/181-canon-ef-s-18-55mm-f35-56-is-test-report--review?start=1

http://www.photozone.de/canon-eos/298-sigma-af-30mm-f14-ex-hsm-dc-test-report--review?start=1

I was comparing the resolution of both lenses using the MTF graphs.

Looking to be enlighten thanks !
 

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android17

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Sep 27, 2009
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Maybe u got a bad copy of the sigma prime? If u read about it, sigma isn't renowned for their qc, there tends to be a few very bad copies among their lenses.
 

ZerocoolAstra

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Mar 13, 2008
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#3
Hello guys, ive recently upgraded from a sony alpha100 to a canon 40d + sigma 30mm f/1.4 prime lense, as i realised i usually shoot under low light conditions. However i was pretty surprised to know that an entry level kit lense (18-55mm f/3.5-5.6) is sharper than my prime at f/3.5. (centre,border & extreme border sharpness!), of cos stopping down the prime to f/3.5 too. Arent prime lenses supposed to be sharper stopped down? so if the kit lense is really sharper at f/3.5 onwards, are we paying top dollar only for the bokeh effect and lower light capability?

http://www.photozone.de/canon-eos/181-canon-ef-s-18-55mm-f35-56-is-test-report--review?start=1

http://www.photozone.de/canon-eos/298-sigma-af-30mm-f14-ex-hsm-dc-test-report--review?start=1

I was comparing the resolution of both lenses using the MTF graphs.

Looking to be enlighten thanks !

Hmmm based on the MTF values as you referred, it does look like the kit lens beats the sigma prime in sharpness.

I'm not sure what the values are but my Nikkor 50mm f/1.8 (cheap lens) is perceptibly sharper @ f/2.8 than my kit lens is at 50mm and max aperture.
I generally do believe that prime lenses are way sharper than their zoom counterparts, especially the kit lens variety :)
 

jaRv1s

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Jun 5, 2009
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#4
sorry to say that... that's quite the norm for sigma prime lenses... insanely sharp center but the corners never catch up even at f8... it's a bokeh customized lens i would say...
 

Nov 13, 2005
485
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#5
sorry to say that... that's quite the norm for sigma prime lenses... insanely sharp center but the corners never catch up even at f8... it's a bokeh customized lens i would say...
Understand that the sigma is razor sharp centre but resolution drops drastically at borders, however ive also looked at canon's famous 35L f/1.4 prime lense, looking at the MTF values with respect to the kit lense, it seems the kit lense is also slightly sharper than the 35L at
f/5.6 ! :eek:

Its like a $300 lense vs a premium $2100..... so my question is still why do people say that
prime's give better IQ and sharpness ? Are they refering to bokeh, vignetting, etc ?

http://www.photozone.de/canon-eos/336-canon-ef-35mm-f14-test-report--review?start=1

Hmmm.... :think:
 

frankchn

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Dec 8, 2008
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Here is a comparison of 18-55IS at 35mm f/4.5 on 50D vs the 35mm f/1.4L at f/4.0 on 1Ds3 - http://www.the-digital-picture.com/...meraComp=453&SampleComp=0&FLIComp=0&APIComp=4

The 35L is still sharper than the 18-55L with better chromatic aberration control as well. I must say that the kit lens is sharper than people give it credit for though =p
 

jaRv1s

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Jun 5, 2009
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#7
i have to say that i regret selling off my kit lens during my innocent days of my DSLR journey... almost all dudes say kit lens not sharp etc etc... but after buying a few and sold off one... i must conclude that kit lens are sharp... just slower... depends on what you shoot, you might not really need those pro lenses...
 

Nov 13, 2005
485
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#8
Now i'am starting to figure if my $750 prime lense purchase was worth it ! It seems that after much research based solely on MTF values... the kit lense is technically sharper than some other canon L zoom lenses... i hope i do not get flamed by saying this.. but my conclusion was based by looking at lab test graphs... so wat gives? :think:

frankchn, thanks for the link to the comparision between the kit lense & 35L, however i noticed that the 35L is on a 1ds3... and the kit lense on a 50d... that isnt really a fair test now huh? pardon my noobness... :embrass:
 

Rashkae

Senior Member
Nov 28, 2005
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#9
so if the kit lense is really sharper at f/3.5 onwards, are we paying top dollar only for the bokeh effect and lower light capability?
1. There is no such thing as "bokeh effect". And no such thing as "Lense". It's just lens, no "e".

2. If you are shooting both lenses at 30mm, and both lenses are at f/3.5 or f/4 (whatever it may be, so long as they are at the same aperture) then the out-of-focus background blur will be very very similar. The bokeh itself may be different though, the Sigma may have better bokeh.

3. Just because it's a prime lens doesn't mean it will be sharper; it may *usually* mean it's sharper, but the main benefit is the larger aperture for a much thinner depth of field and faster shutter speeds at larger apertures.
 

Rashkae

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Nov 28, 2005
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#10
Now i'am starting to figure if my $750 prime lense purchase was worth it ! It seems that after much research based solely on MTF values... the kit lense is technically sharper than some other canon L zoom lenses... i hope i do not get flamed by saying this.. but my conclusion was based by looking at lab test graphs... so wat gives? :think:

frankchn, thanks for the link to the comparision between the kit lense & 35L, however i noticed that the 35L is on a 1ds3... and the kit lense on a 50d... that isnt really a fair test now huh? pardon my noobness... :embrass:

simple. You were pixel-peeping and basing on pure numbers instead of experience and subjective, hands-on use. A lens is far more than just MTF values.

Also, you've not considered the benefits of having a full-frame lens vs. a cropped-sensor lens for long-term upgradeability.
 

aspenx

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Aug 10, 2008
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#11
simple. You were pixel-peeping and basing on pure numbers instead of experience and subjective, hands-on use. A lens is far more than just MTF values.
:thumbsup:

TS should consider the Nikkor 28mm f/2.8 AiS (with adaptor of course) if he is so concerned about all-around sharpness.

My 35mm lens is far from perfected, but being able to use it at f/1.4 and the special way it "draws" is something that a kit lens can not accomplish.
 

giantcanopy

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Feb 11, 2007
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#12
I generally do believe that prime lenses are way sharper than their zoom counterparts
But having said that, some of Nikon's old formula primes are probably in need of revising, the stellar 14-24mm is sharper than the older AFD 14mm prime at the 14mm end..

ryan
 

ZerocoolAstra

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Mar 13, 2008
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#13
But having said that, some of Nikon's old formula primes are probably in need of revising, the stellar 14-24mm is sharper than the older AFD 14mm prime at the 14mm end..

ryan
Hahaha Ok I'll have to admit that my conclusion (prime sharper than zoom) does not apply to all lenses.
I was thinking more along the lines of 35 f/2 vs 18-55 kit, or 50 f/1.8 vs 18-55 or 18-135 kit.

I would guess that a 35 f/2 vs a 24-70 f/2.8 (for example), both at 35mm and same aperture, the real-world sharpness difference is indistinguishable.
 

Rashkae

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Nov 28, 2005
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#14
I would guess that a 35 f/2 vs a 24-70 f/2.8 (for example), both at 35mm and same aperture, the real-world sharpness difference is indistinguishable.
Yup. At f/5.6, it's 2135/1988 (centre/edge) for the 35, and 2174/1928 for the 24-70G. You'd not be able to tell the difference.
 

M

maxtheevil

Guest
#15
hi there, usually, the prime lens is sharper than the zoom lens.

and from what i have seen, a manual lens gives sharper images than a autofocus lens.

the less complicated the construction, it sharper the images.

that seems to be the axiom.
 

ZerocoolAstra

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Mar 13, 2008
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#16
hi there, usually, the prime lens is sharper than the zoom lens.

and from what i have seen, a manual lens gives sharper images than a autofocus lens.

the less complicated the construction, it sharper the images.

that seems to be the axiom.
though it does not apply to ALL lenses, as 'giantcanopy' has just mentioned ;)
 

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