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01-02-2008, 05:43 PM   #16
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Not quite the same, but Nikon has a 14-24 f/2.8. Seems like a pretty good lens too: Nikon 14-24mm G Test v Canon 14mm L II

01-02-2008, 05:55 PM   #17
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QuoteOriginally posted by CSpronken Quote
You think it will be f2.8? At 11-16mm that would be quite extreme wouldn't it,
About this extreme Tokina AT-X 116 Pro DX: Digital Photography Review

Tim
01-02-2008, 06:10 PM   #18
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QuoteOriginally posted by Fototim Quote
Thanks, missed that one. Well it is rather extreme compared to offerings of other brands, perhaps because the others are FF lenses?
01-02-2008, 06:54 PM   #19
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QuoteOriginally posted by CSpronken Quote
Thanks, missed that one. Well it is rather extreme compared to offerings of other brands, perhaps because the others are FF lenses?

Extreme is Olympus's 7-14mm f4 rectilinear zoom. Sure it's not f2.8, but it's 14mm at the LONG end.

01-02-2008, 07:29 PM   #20
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QuoteOriginally posted by mawz Quote
Extreme is Olympus's 7-14mm f4 rectilinear zoom. Sure it's not f2.8, but it's 14mm at the LONG end.
Yeah, but with a 2 crop sensor, so it's about the same as a 10-20mm on Pentax.
01-02-2008, 09:50 PM   #21
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I really hate the Pentax 18-250 debates and I hate having to answer this question over and over again.

Pentax officially works with many lens companies which include Tokina and Tamron. Pentax and Tokina work officially on lens designs together and Tamron has been working with Pentax, Canon, Sony and Nikon for many years. Almost every single super zoom design has been created by Tamron and they've made the most successful super zoom lenses on the market. You will soon see a Sony 18-250 and also a Nikon 18-250 this year.

The Pentax 18-250 does differ from the Tamron version in that the Pentax has 2 AS (aspherical) and 2 ED (Extra Dispersion) elements while the Tamron version has one of each. Also, the Pentax version has true SMC coatings. Pentax does not make there own glass, but still grinds some and has other manufactured to there specifications, ala Tokina.

Tamron manufactures the lens outter housing and is assembled in there factory with Pentax glass. Tamron has been doing this for years and for many makers. The Canon 70-300 is made by Tamron, the Pentax 28-200, the nikon super zooms, and many Minolta lenses have been made by Tamron and the only difference is certain specifications and coatings.

So to answer your question the Pentax is a totally different lens and I'll sya to the end of the earth because I've had multiple Tamron reps and reps bosses even agree upon this statement and also the man in charge of Pentax sales admitted this and a few other top Pentax people.

If anyone wants to question this feel free, but you're wrong.
01-03-2008, 12:04 AM   #22
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QuoteOriginally posted by codiac2600 Quote
So to answer your question the Pentax is a totally different lens and I'll sya to the end of the earth .... If anyone wants to question this feel free, but you're wrong.
I admire your confidence, but in this case, you are wrong!

QuoteQuote:
The Pentax 18-250 does differ from the Tamron version in that the Pentax has 2 AS (aspherical) and 2 ED (Extra Dispersion) elements while the Tamron version has one of each.
Just from this, you should realize that the source of your info cannot be trusted. In fact, BOTH version had 2 AS and 2 ED elements. Here's the proof.

This is Pentax version (blue=ED; green=AS):


For Tamron version, you can see it in the 2nd page (right lower corner) of this pdf file (green=ED; pink=AS):
http://www.tamron.com/lenses/prod/assets/pdfs/spec_sheets/18-250mm.pdf

As you can see, both lens design are identical.

QuoteQuote:
Also, the Pentax version has true SMC coatings.
This one is hard to prove or disprove. But if you put both versions side by side together with a Pentax DA lens, check the reflections of the coatings of the front element, and you may agree with me that the Pentax version coatings is closer to Tamron's than other SMC. However, this is very subjective, and there is no point debating over it.

QuoteQuote:
Tamron manufactures the lens outter housing and is assembled in there factory with Pentax glass.
In this case, there is very little Pentax input other than the barrel casing. Even the lens cap is identical to that of Tamron's.
01-03-2008, 07:39 AM   #23
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QuoteOriginally posted by nosnoop Quote
I admire your confidence, but in this case, you are wrong!



Just from this, you should realize that the source of your info cannot be trusted. In fact, BOTH version had 2 AS and 2 ED elements. Here's the proof.

This is Pentax version (blue=ED; green=AS):


For Tamron version, you can see it in the 2nd page (right lower corner) of this pdf file (green=ED; pink=AS):
http://www.tamron.com/lenses/prod/assets/pdfs/spec_sheets/18-250mm.pdf

As you can see, both lens design are identical.



This one is hard to prove or disprove. But if you put both versions side by side together with a Pentax DA lens, check the reflections of the coatings of the front element, and you may agree with me that the Pentax version coatings is closer to Tamron's than other SMC. However, this is very subjective, and there is no point debating over it.



In this case, there is very little Pentax input other than the barrel casing. Even the lens cap is identical to that of Tamron's.

You Are wrong my friend... sorry to break your heart.

01-03-2008, 07:54 AM   #24
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QuoteOriginally posted by codiac2600 Quote
You Are wrong my friend... sorry to break your heart.
However his link clearly proves you wrong as well. Both are identical optically, with 2 AL and 2 ED elements located in the same positions.

I suspect you are correct on the subject of the coatings. But optically the Tamron (and Sony) lenses are identical and that is clearly proven by the optical diagrams that Tamron and Pentax provide.
01-03-2008, 08:02 AM   #25
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QuoteOriginally posted by mawz Quote
However his link clearly proves you wrong as well. Both are identical optically, with 2 AL and 2 ED elements located in the same positions.

I suspect you are correct on the subject of the coatings. But optically the Tamron (and Sony) lenses are identical and that is clearly proven by the optical diagrams that Tamron and Pentax provide.
Are you 100% sure about that, if you zoom in on the Tamron diagram it seems the purple elements do look different than the green ones in the Pentax diagram. Although that could also be explained by the Pentax diagram being a less precise representation.
01-03-2008, 08:03 AM   #26
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QuoteOriginally posted by mawz Quote
However his link clearly proves you wrong as well. Both are identical optically, with 2 AL and 2 ED elements located in the same positions.

I suspect you are correct on the subject of the coatings. But optically the Tamron (and Sony) lenses are identical and that is clearly proven by the optical diagrams that Tamron and Pentax provide.
Sorry but that lens diagram is of the prototype lens from Tamron. Trust me he's wrong as multiple Tamron and Pentax workers have all said the same thing.
01-03-2008, 08:03 AM   #27
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Different, maybe by a bit.

QuoteOriginally posted by codiac2600 Quote
I really hate the Pentax 18-250 debates and I hate having to answer this question over and over again.



The Pentax 18-250 does differ from the Tamron version in that the Pentax has 2 AS (aspherical) and 2 ED (Extra Dispersion) elements while the Tamron version has one of each. Also, the Pentax version has true SMC coatings.
disclaimer.. "specs are subject to change".
Which of course just muddies the waters. No doubt the coatings are different though and you have LD vs ED ect......different?????
Aspherics vs hybrid aspherics??????
Is it semantics or truely different????????? There does seem to be some subtile shape changes in a few elements (see the back hybrid aspheric) but is that real?????


01-03-2008, 08:04 AM   #28
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QuoteOriginally posted by CSpronken Quote
Are you 100% sure about that, if you zoom in on the Tamron diagram it seems the purple elements do look different than the green ones in the Pentax diagram. Although that could also be explained by the Pentax diagram being a less precise representation.
The diagram's aren't necessarily accurate to curve detail, they're representations of optical groups, positions and general cross-sections.
01-03-2008, 08:11 AM   #29
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QuoteOriginally posted by mawz Quote
The diagram's aren't necessarily accurate to curve detail, they're representations of optical groups, positions and general cross-sections.
Could very well be, but in that case the link doesn't "clearly proof" anything. I see a stepping in the hybrid aspherical elements that I don't see in the Pentax diagram and the one on the right in the Tamron has a curved left side, where as the one on the Pentax diagram has a straight left side.

You could very well be right about these diagrams not being accurate, frankly I have no idea.
01-03-2008, 08:30 AM   #30
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QuoteOriginally posted by CSpronken Quote
Could very well be, but in that case the link doesn't "clearly proof" anything. I see a stepping in the hybrid aspherical elements that I don't see in the Pentax diagram and the one on the right in the Tamron has a curved left side, where as the one on the Pentax diagram has a straight left side.
Pentax's diagram is a low resolution one, and that's why some subtle details are not very clear. But the elements shapes and number and placing of ED/AS elements are identical (which disproves the theory that the two versions are fundamentally different in the number of ED/AS elements). And this is no prototypes, these are final official drawing of the elements representation.

ED is the same as LD, just different terms used by different manufacturers.

And if one trusts the words of "workers" more than the official printed material, what can I say?
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