Great example of prime vs. zoom sharpness

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Ron Parr

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As some of you have noticed, Dave over at the imaging resource goofed and posted a resolution chart with taken with a 28-70L instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper) than a good prime. Still others have claimed that all lenses are equally sharp when stopped down. I don't agree with either of these statements and I don't think they're supported by the tests: mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last time I posted this, I was told by some that I had a bad copy of the 28-70L. IMO, the softness in my 28-70L seems comparable to others that I've seen.

http://www.pbase.com/parr/2870lvs50mm18

I really enjoy my 28-70L, but I've never seen an example where the 28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
and very true

The 28-70 is probably the sharpest zoom I've ever had, but the primes are still better.

I do all my landscapes with primes.
 
As some of you have noticed, Dave over at the imaging resource
goofed and posted a resolution chart with taken with a 28-70L
instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper)
than a good prime. Still others have claimed that all lenses are
equally sharp when stopped down. I don't agree with either of
these statements and I don't think they're supported by the tests:
mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last
time I posted this, I was told by some that I had a bad copy of the
28-70L. IMO, the softness in my 28-70L seems comparable to others
that I've seen.

http://www.pbase.com/parr/2870lvs50mm18
They don't appear to be focused at the same point since the dof of one seems deeper. Sharpen them in PS and look at them side by side. The bush in one is in focus but in the other not....
I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
--
http://www.pbase.com/blokey
 
Not to be too much of a devil's advocate, but I actually prefer the slightly brighter and redder bricks of the 28-70 L shot.

Jim
As some of you have noticed, Dave over at the imaging resource
goofed and posted a resolution chart with taken with a 28-70L
instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper)
than a good prime. Still others have claimed that all lenses are
equally sharp when stopped down. I don't agree with either of
these statements and I don't think they're supported by the tests:
mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last
time I posted this, I was told by some that I had a bad copy of the
28-70L. IMO, the softness in my 28-70L seems comparable to others
that I've seen.

http://www.pbase.com/parr/2870lvs50mm18

I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
Hi
And Thank You very much for Your excellent test.

I just ordered 10D and 100mm macro, ring flash and 24-70mm L, so I'm very pleased !
  • Ari -
As some of you have noticed, Dave over at the imaging resource
goofed and posted a resolution chart with taken with a 28-70L
instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper)
than a good prime. Still others have claimed that all lenses are
equally sharp when stopped down. I don't agree with either of
these statements and I don't think they're supported by the tests:
mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last
time I posted this, I was told by some that I had a bad copy of the
28-70L. IMO, the softness in my 28-70L seems comparable to others
that I've seen.

http://www.pbase.com/parr/2870lvs50mm18

I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
Not to be too much of a devil's advocate, but I actually prefer the
slightly brighter and redder bricks of the 28-70 L shot.
The exposure is slightly different. I noticed that too.

--

I just want to take really spectacular pictures of my vacations, pets, family, projects, and drunk friends.
 
I seem to remember those same pictures when I bought my D30!

Neil
As some of you have noticed, Dave over at the imaging resource
goofed and posted a resolution chart with taken with a 28-70L
instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper)
than a good prime. Still others have claimed that all lenses are
equally sharp when stopped down. I don't agree with either of
these statements and I don't think they're supported by the tests:
mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last
time I posted this, I was told by some that I had a bad copy of the
28-70L. IMO, the softness in my 28-70L seems comparable to others
that I've seen.

http://www.pbase.com/parr/2870lvs50mm18

I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
Here's a comparison of my 28-70L with my 50mm f/1.8 at F8.
I noticed that you are comparing the two lenses at f8. Almost every lens performance excellent at f8. It would be interesting if you would extend your comparsion and compare the performance at difference apertures. In particular, I would be interested in whether the L zoom performs "more consistently" (i.e. less of a difference between f2.8, f5.6 and f8, let's say).

Thank you for taking the time doing the comparison; illustrations like that are very valuable, in my opinion.

Andi

--
http://www.andreassteiner.net/photography
 
There should be some sort of rhyme to finish that phrase with...

...a prime in time saves nine?
...a zoom in the hand is better than a prime in the bush?

Those don't really make any sense... Oh well.

--

I just want to take really spectacular pictures of my vacations, pets, family, projects, and drunk friends.
 
Cool... you can see that the prime is a tiny bit sharper (at least to me, maybe other will see it more pronounced) in the leaves.

So I have a question. I've done a search on wide angle and landscape photography and I notice everyone keeps mention zooms like the Sigma 15-30mm and the Canon 17-40L... why doesn't anybody just have say a Canon 20mm prime for landscapes? Is the lack of a zoom that restrictive (more so than having a 50mm prime?).

I was wondering if you could put a third photo of your "ordinary" 24-85mm zoom with these just to give a perspective of the difference in sharpness between consumer vs L glass.

Thanks.
--Arvin
As some of you have noticed, Dave over at the imaging resource
goofed and posted a resolution chart with taken with a 28-70L
instead of 100mm fixed focal length lens. He now has both posted:

http://www.imaging-resource.com/PRODS/E10D/E10DPICS.HTM

Some people claim that the 28-70L is as sharp (or even sharper)
than a good prime. Still others have claimed that all lenses are
equally sharp when stopped down. I don't agree with either of
these statements and I don't think they're supported by the tests:
mine, photodo's, and now Dave's.

Here's a comparison of my 28-70L with my 50mm f/1.8 at F8. Last
time I posted this, I was told by some that I had a bad copy of the
28-70L. IMO, the softness in my 28-70L seems comparable to others
that I've seen.

http://www.pbase.com/parr/2870lvs50mm18

I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
Cool... you can see that the prime is a tiny bit sharper (at least
to me, maybe other will see it more pronounced) in the leaves.
The leaves look like they are out of focus. The DOF should be the same for the same focal length and aperture, but there appear to be differences.

--

I just want to take really spectacular pictures of my vacations, pets, family, projects, and drunk friends.
 
I don't know why people always say the 28-70L is sharp as prime, in my test the 28-70 has significant vignette at 28mm wide open, it is not sharp at 50mm at the centre part, overall it is not particular sharp. I've test mine which was bought just one week and then sent to Canon service, they can't fixed it and promised to exchange one or refund. I then tested two others from my friend and they showed same characteristics of softness, finally I chosed refund, I still keep the EF70-200mm f2.8L USM which is much better in sharpness.

The colour of 20-70L is bias to warm and saturate side, for shooting people it's a good choice.

You may test your own easily, just shoot a full page newpaper using tripod and shutter release, no need to use test chart is you just want to examine visual sharpness.
 
For a lens that is less sharp, DOF may appear to drop off faster.

I tried to redo the tests last summer with the camera at an angle with respect to the house as a way of determining if my 28-70L was backfocusing. Unfortunately, the test was flawed in several ways:
  • I used the 28-70L at 48mm instead of 50mm.
  • There were mixed clouds and the lighting was changing dramatcially between shots.
  • I was trying to get the camera to focus on the railing, but this was not a realiable target. The same lens sometimes focused at different depths.
I was hesitant to upload the shots because I think they will do little other than confuse the issue. I'll say that they do somewhat support the hypothesis of a backfocusing 28-70L, but I'd be very hesitant to draw conclusions from such a bad test. Here's an example at f/8:

http://www.pbase.com/parr/flawedlenstest

When we have a sunny weeked, I'll try things again with my D60.

I'm digging through my archives to see if I have any other examples.

Finally, I did many of my tests at different apertures, so I could upload some if people are really interested.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
So I have a question. I've done a search on wide angle and
landscape photography and I notice everyone keeps mention zooms
like the Sigma 15-30mm and the Canon 17-40L... why doesn't anybody
just have say a Canon 20mm prime for landscapes? Is the lack of a
zoom that restrictive (more so than having a 50mm prime?).
Some do.

At wide focal lengths, a change in a few mm is a pretty big change (percentage wise) in things, so a lens like a 15-30, 16-35, 17-35, or 17-40 can be very versatile b/c it really covers a dramatic range of views. Still, these ultra-wide angle zooms can be pretty soft.
I was wondering if you could put a third photo of your "ordinary"
24-85mm zoom with these just to give a perspective of the
difference in sharpness between consumer vs L glass.
I've posted some from a somewhat flawed test below. I hope to do a better test at some point. I'm also digging to see if I have any better examples.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
i got similar results on a zoom vs prime test
film several years back. i did several shots
around the city and got the wet prints back
on 4x6. at times it took me up to 10 minutes
to decide which was better but i was able to pick
out the prime in every scene.
 
Ron,

The zoom vs prime argument goes on and on. But I have run similar tests using a 16-35L and I found it unacceptably soft at anything outside f5.6-f11. Therefore, it went back. These wide zooms are great all-round lenses, but (I'm preaching to the choir) if you are serious about sharpness...go with primes.

For landscapes I use the Canon 20mm 2.8.
So I have a question. I've done a search on wide angle and
landscape photography and I notice everyone keeps mention zooms
like the Sigma 15-30mm and the Canon 17-40L... why doesn't anybody
just have say a Canon 20mm prime for landscapes? Is the lack of a
zoom that restrictive (more so than having a 50mm prime?).
Some do.

At wide focal lengths, a change in a few mm is a pretty big change
(percentage wise) in things, so a lens like a 15-30, 16-35, 17-35,
or 17-40 can be very versatile b/c it really covers a dramatic
range of views. Still, these ultra-wide angle zooms can be pretty
soft.
I was wondering if you could put a third photo of your "ordinary"
24-85mm zoom with these just to give a perspective of the
difference in sharpness between consumer vs L glass.
I've posted some from a somewhat flawed test below. I hope to do a
better test at some point. I'm also digging to see if I have any
better examples.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
--
Home page - http://home.attbi.com/~lozoyad
 
Ron,

The zoom vs prime argument goes on and on. But I have run similar
tests using a 16-35L and I found it unacceptably soft at anything
outside f5.6-f11. Therefore, it went back. These wide zooms are
great all-round lenses, but (I'm preaching to the choir) if you are
serious about sharpness...go with primes.

For landscapes I use the Canon 20mm 2.8.
Actually, I'm not advocating one or the other. Both involve tradeoffs.

I don't want to start another prime vs. zoom fight. I'm just trying to improve the understanding of the tradeoffs.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/
 
I really enjoy my 28-70L, but I've never seen an example where the
28-70L rivals a good prime.
And it is unlikely that you never will.

I think the differences between primes and zooms in terms of optical quality is generally underestimated and overlooked. It is diffucult not to believe that more people would not select prime lenses if they were aware of how superior primes are.

I do not deny that some extremely expensive zooms may be approaching the quality of a prime of similar quality, even though I doubt it.

Conclusion: Those who care about quality will be far better off by choosing primes instead of zooms, and we should encourage them to do so.

Thank you for sharing your knowledge with us, Ron.

Per Inge Oestmoen, Norway
http://www.coldsiberia.org/
 

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