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Author Topic: Lens quality - what matters?  (Read 2829 times)

The View

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Lens quality - what matters?
« on: May 29, 2007, 09:32:07 pm »

A lens to be sharp, give excellent color reproduction in all its nuances it doesn't have to be a fast lens, or does it?

But it looks like as if many manufacturers build their top lenses as fast lenses.

I want to spend money on a really good lens, but it doesn't have necessarily be fast (and, that comes with being fast - big and heavy).

So there should be lenses, that are excellent, but not super expensive and super heavy, as they do not strive for maximum speed.

Or are there?

I am particularly interested in Nikon and Pentax lenses.

Thank you.
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Lisa Nikodym

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Lens quality - what matters?
« Reply #1 on: May 30, 2007, 01:14:24 pm »

Bjorn Rorslett's web site has excellent reviews of many Nikon lenses, where he discusses their relative merits:

http://www.naturfotograf.com/index2.html

(It's there somewhere - you need to search the web site.)

Lisa
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Ray

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Lens quality - what matters?
« Reply #2 on: May 30, 2007, 09:44:17 pm »

Quote
But it looks like as if many manufacturers build their top lenses as fast lenses.

I want to spend money on a really good lens, but it doesn't have necessarily be fast (and, that comes with being fast - big and heavy).

So there should be lenses, that are excellent, but not super expensive and super heavy, as they do not strive for maximum speed.

Or are there?
[a href=\"index.php?act=findpost&pid=120171\"][{POST_SNAPBACK}][/a]

That's a good point. To some extent we do have such options with Canon lenses. Don't know about Pentax and Nikon though. For example we have the choice of the 70-200 f2.8 zoom or the 70-200 f4 zoom. Both lenses are about equally excellent, but the latter is significantly cheaper and lighter.

We have the choice of the 50/1.4 and 50/1.8, the latter being cheaper and lighter but both lenses probably just as sharp when stopped down to f5.6 and lower. My copy of the 50/1.8 appears very slightly sharper than my copy of the 50/1.4, probably due to QC variation.

We've also got the choice of the 85/1.2 and 85/1.8, the latter being cheaper and lighter but both probably about equally good at f8.

I think it would be true to say that most (at least reasonably good) lenses would be equal at f11, or as close as matters.

The problem of designing a lens purely for lightness, low cost and good performance at relatively narrow apertures is that such a lens would tend to be specialised. It wouldn't be useful for applications where a shallow DoF is sought, or for low light situations. Such a lens would therefore probably not sell well and that would add to its cost and defeat the purpose.
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The View

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Lens quality - what matters?
« Reply #3 on: May 31, 2007, 05:15:28 am »

Thanks, Ray

For headshots you often go to f/5.6 or f/4 for depth of field control.

How much quality loss would there be in zoom and primes?

As I don't need a zoom for headshots, how would I know what prime to choose?

Every manufacturer has a great number of lenses out there, and the speed of a lens isn't necessarily and indicator of its quality.

So how would you go about buying such a lens? (Especially when you don't know the manufacturer - Pentax, in my case).

I got the recommendation for a Pentax lens test site.
Overview:  http://www.bdimitrov.de/kmp/

resolution test: http://www.bdimitrov.de/kmp/

I wonder of how much use such tests are.

Photographing test charts under controlled conditions and working out in the field are two completely different things.
« Last Edit: May 31, 2007, 05:16:03 am by The View »
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Ray

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Lens quality - what matters?
« Reply #4 on: May 31, 2007, 06:26:35 am »

Quote
Thanks, Ray

For headshots you often go to f/5.6 or f/4 for depth of field control.

How much quality loss would there be in zoom and primes?

As I don't need a zoom for headshots, how would I know what prime to choose?

Every manufacturer has a great number of lenses out there, and the speed of a lens isn't necessarily and indicator of its quality.

So how would you go about buying such a lens? (Especially when you don't know the manufacturer - Pentax, in my case).

I got the recommendation for a Pentax lens test site.
Overview:  http://www.bdimitrov.de/kmp/

resolution test: http://www.bdimitrov.de/kmp/

I wonder of how much use such tests are.

Photographing test charts under controlled conditions and working out in the field are two completely different things.
[{POST_SNAPBACK}][/a]

There's quite a bit of resolution variation amongst lenses of the same model, so if you want to be sure you are getting a good copy you really have to test it yourself before committing yourself to its purchase, either in the store before buying or later, on the understanding you can return it for any reason.

In addition to this quality control variation there will always be some variation in the methodology of different lens testers, so I guess all you can do is buy a lens on reputation from viewing a number of reports on the net. Have you tried Photozone at [a href=\"http://www.photozone.de/8Reviews/#nikon]http://www.photozone.de/8Reviews/#nikon[/url] ?
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