Sony kit lens as mediocre as Canon's?

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RichA - 04 Aug 2006 18:01 GMT

It doesn't look like it, but one test of it I saw shows it to be pretty
mediocre.
For a camera with 10 megapixels, the user would be well-advised to get
something
better. Maybe the Zeiss alternative is out for it?

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David Kilpatrick - 04 Aug 2006 19:41 GMT

> It doesn't look like it, but one test of it I saw shows it to be pretty
> mediocre.
> For a camera with 10 megapixels, the user would be well-advised to get
> something
> better. Maybe the Zeiss alternative is out for it?

It's much improved mechanicallty (smoothness, firmness) over the KM
version, but still essentially a cheap Chinese kit optic. At 18mm, it's
about as good as any kit lens gets. At 70mm it's fairly soft. I now have
two of them, one KM one Sony. Earlier in the week I was at a business
meeting and was suddenly asked to shoot two or three still lifes, four
book and video covers, and a PR shot live in an office. I had no flash,
and was not intending to do any photography, just a KM 7D with the
18-70mm slung in the car with with. The 18-70mm did fine, perfectly. The
book cover shots needed a tiny barrel distortion correction in ACR. The
PR shot was amazingly crisp and what should have been rubbish lighting
actually made a very attractive final shot. I would be hard put to have
found any other lens in my kit which could have done better.

But I don't have a 16-80mm Zeiss yet :-)

David

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bmoag - 05 Aug 2006 00:16 GMT

"cover shots needed a tiny barrel distortion correction"

We live in a different photographic world now. A predictable level of
barrel distortion is not a deal killer for a lens because of sophisticated
image processing programs. Most dSLR lenses in the 11-20mm range, regardless
of their overall zoom range, have significant linear distortion that would
be hard to accept for in a film and wet print world but can be reasonably
corrected with some simple image processing in the brave new digital world.
Does that mean lens quality is declining or overall photographic options are
increasing?

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Stacey - 05 Aug 2006 09:11 GMT

> but can be
> reasonably corrected with some simple image processing in the brave new
> digital world.

But doing this causes a loss of image quality and sharpness so it still is a
problem.

Signature

Stacey

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Andrew Haley - 08 Aug 2006 11:05 GMT

>> [barrel distortion] can be reasonably corrected with some simple
>> image processing in the brave new digital world.

> But doing this causes a loss of image quality and sharpness so it
> still is a problem.

Well, that depends. You have to do raw conversion anyway, so you can
do the distortion correction at the same time, at high resolution.
Will this lose quality over not doing any geometric correction at all?
A little, but will it be visible?

In the end it's all about cost and weight. Is it cheaper to make a
sharp zoom lens with some barrel distortion than one without? And is
the resulting digitally corrected lens quality better value for money
(and weight) than one without any digital correction?

I suspect that if you have, say, $500 to spend on a lens, you're going
to get better quality by a combination of lens design and digital
correction than the best lens design can possibly do in its own.

Andrew.

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J. Clarke - 08 Aug 2006 13:03 GMT

>>> [barrel distortion] can be reasonably corrected with some simple
>>> image processing in the brave new digital world.
[quoted text clipped - 6 lines]
> Will this lose quality over not doing any geometric correction at all?
> A little, but will it be visible?

Will the distortion be visible?

> In the end it's all about cost and weight. Is it cheaper to make a
> sharp zoom lens with some barrel distortion than one without? And is
[quoted text clipped - 4 lines]
> to get better quality by a combination of lens design and digital
> correction than the best lens design can possibly do in its own.

I can't see where digital correction is going to improve noticeably on the
less than 0.01 percent distortion of the $259 50mm Sigma macro.

Further, most zooms have a sweet spot with very low distortion, the trick is
finding it and using it if low distortion is needed for a particular shot.

> Andrew.

Signature

--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

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Andrew Haley - 08 Aug 2006 17:40 GMT

>>>> [barrel distortion] can be reasonably corrected with some simple
>>>> image processing in the brave new digital world.
[quoted text clipped - 6 lines]
>> Will this lose quality over not doing any geometric correction at all?
>> A little, but will it be visible?

> Will the distortion be visible?

Yes.

>> In the end it's all about cost and weight. Is it cheaper to make a
>> sharp zoom lens with some barrel distortion than one without? And
>> is the resulting digitally corrected lens quality better value for
>> money (and weight) than one without any digital correction?

>> I suspect that if you have, say, $500 to spend on a lens, you're
>> going to get better quality by a combination of lens design and
>> digital correction than the best lens design can possibly do in its
>> own.

> I can't see where digital correction is going to improve noticeably
> on the less than 0.01 percent distortion of the $259 50mm Sigma
> macro.

I think there has been a loss of context here. We're talking about
midrange zoom lenses, as the subject line suggests.

> Further, most zooms have a sweet spot with very low distortion, the
> trick is finding it and using it if low distortion is needed for a
> particular shot.

As long as that's the focal length you need.

Andrew.

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J. Clarke - 09 Aug 2006 03:24 GMT

>>>>> [barrel distortion] can be reasonably corrected with some simple
>>>>> image processing in the brave new digital world.
[quoted text clipped - 10 lines]
>
> Yes.

.005 % distortion will be visible? You're sure about that?

Your problem is that you're assuming that every lens has a huge amount of
distortion at every focal length but is so incredibly sharp that any
imaginable loss of sharpness will be acceptable. It ain't so on either
count.

>>> In the end it's all about cost and weight. Is it cheaper to make a
>>> sharp zoom lens with some barrel distortion than one without? And
[quoted text clipped - 20 lines]
>
> Andrew.

Signature

--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

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Andrew Haley - 11 Aug 2006 18:56 GMT

>>>>>> [barrel distortion] can be reasonably corrected with some simple
>>>>>> image processing in the brave new digital world.
[quoted text clipped - 10 lines]
>>
>> Yes.

> .005 % distortion will be visible? You're sure about that?

We aren't talking about fixed focal length macro lenses.

> Your problem is that you're assuming that every lens has a huge
> amount of distortion at every focal length

No I'm not. I'm assuming that one selects the focal length based on
the framing one wants, not on the sweet spot of a lens. This doesn't
seem to me like a particularly controversial point of view.

> but is so incredibly sharp that any imaginable loss of sharpness
> will be acceptable.

No, not any imaginable amount: the small amount that comes from a
well-done correction of distortion. I'm stating that a lens plus a
little correction software gives better bang for the buck than a lens
without correction.

Andrew.

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Randall Ainsworth - 05 Aug 2006 20:10 GMT

Why don't you actually buy a camera and then tell us all about it?

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RichA - 06 Aug 2006 01:27 GMT

> > It doesn't look like it, but one test of it I saw shows it to be pretty
> > mediocre.
[quoted text clipped - 3 lines]
>
> Why don't you actually buy a camera and then tell us all about it?

Do you have a camera? Lets see some shots.

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