[stickman]

Hello all
I purchased the pentax lens 18-250 from Ritz Camera price $499.00.
I was told two maybe three weeks, today 11-09-07 was the third week.
Not in yet but was told they would ship between 11-20-07 to 11-29-07
so just have to wait and see
.

[ogl]

Hello all
I purchased the pentax lens 18-250 from Ritz Camera price $499.00.
I was told two maybe three weeks, today 11-09-07 was the third week.
Not in yet but was told they would ship between 11-20-07 to 11-29-07
so just have to wait and see
.

I think that Pentax could has better color and contrast than Tamron.
The glass and coating of Pentax are different.

[Snowcat]

I think that Pentax could has better color and contrast than Tamron.
The glass and coating of Pentax are different.

Different coating - probably. But not glass. As far as I know there are only two optical glass manufacturers in the world, that produce high quality glass for photo lenses. One is Schott in Germany, and the other is Hoya in Japan. No other choises for photo lenses.
Tamron uses Hoya glass, and or course Pentax uses the same glass, specially now, when it is part of Hoya.
So Tamron's and Pentax's lenses are made of the very same glass for sure.

[ogl]

Pentax buys Hoya's glass for some lenses,
but it could be unusual for you, but Pentax makes glass too. )))
Anyway...
Pure glass could be from one source, but postprocessing of glass by Tamron or Pentax are different. Have a look at the same Tokina and Pentax. Microcontrast, contrast and colors of Pentax are better.

[Snowcat]

Nope, Pentax never made the glass. It is a very difficult manufacturing process, starting from the sand, finishing with thick glass planes. Pentax has no sand-diggind facilities, and no melting facilities, that's easily checked in the Internet. Pentax made LENSES (i mean those round glass things lol in this case) from Hoya's glass, right. And they make their famous coating of course.
Based on the exactly same optical scheme of two 18-250's (Tamron's and Pentax's are the same), and the fact that Pentax's is made in Japan, while Pentax has it's plants in Vietnam, Pentax's 18-250 is made on Tamron's plant. If so, they even use the same lenses inside of them. It's quite traditional for Japanese manufacturers to share lenses manufacturing between eachother. That's not a surprise.
The only difference might be the coating. The coating affects mainly parasitic lights, some contrast (not that much).
Of course it would be interesting to comapre the performance of the two lenses to see if there is any noticable difference...

[jeffkrol]

Pentax buys Hoya's glass for some lenses,
but it could be unusual for you, but Pentax makes glass too. )))
Anyway...
Pure glass could be from one source, but postprocessing of glass by Tamron or Pentax are different. Have a look at the same Tokina and Pentax. Microcontrast, contrast and colors of Pentax are better.

Hmmm.. adding more "stuff"
Thought Pentax sold their glass making plant years ago.
How about Ohara???
Optical Glass Manufacturers - Ceramics Supplier - Polished Substrates

[Confused]

Hi ogl

I think what you actually intended to say was that "Pentax buys Hoya's glass blanks" from which they produce their range of lenses. There are relatively few glass blank manufacturers in the world (I believe Schott are the other major producer), so I am in agreement with Snowcat when he said that Pentax don't actually make the glass blanks.

Best regards
Richard

[creampuff]

Snowcat there are more optical glass makers other than Schott and Hoya. And we are not talking about glass blanks. Even Canon and Nikon do makes some of their own glass elements.

Here is an informative site from Canon
Canon Camera Museum | Technology Hall

[Snowcat]

creampuff, thanks for the link, it's interesting...
I was pretty sure that only 2 glass blanks manufacturers are available for high-quality glass used in photo lenses. I've read a big article on that somewhere... It said, that other's glass, like Ohara's are used only in P&S, not SLRs' lenses... But obviously, seeing that Canon's video, that article was wrong... hmmm...
However I am pretty sure that Pentax has no glass manufacturing facilities...

[Confused]

Hi creampuff

I am not questioning the accuracy of your statement when you say that:

there are more optical glass makers other than Schott and Hoya

or that:

Even Canon and Nikon do make some of their own glass elements

Nevertheless whilst not wishing to appear overly pedantic, it is simply factually incorrect to claim (as ogl did) that
"Pentax makes glass" when they actually don't !
Unless you can prove otherwise, kindly explain to me how a company goes about commercially producing a photographic lens without first involving a glass blank at the beginning of the manufacturing process ?

Best regards
Richard

[creampuff]

Let's all not get worked up about this. I for one cannot say for certain whether Pentax make their own lenses or not, my guess is they probably do. Now we need to qualify what me mean by "make". Does it mean produce the glass itself, to shaping the glass blanks to final lens assembly? Or limited to grinding/polishing to lens assembly after obtaining glass blanks from a supplier like HOYA.

To me it is immaterial whether the glass is made by HOYA or made by Pentax themselves (which is not inconceivable). Years back I actually met a Minolta lens designer who said they made some of the glass themselves. A small company like Cosina makes lenses for a lot of people for different applications (incidentally they are the market leader for lenses for projectors). An industry insider told me that Leica and B+W filters are now done by HOYA. Another example, who makes Sony's lenses? The evidence points to Tamron. In this era of globalisation, I am not surprised as there is quite a bit of cooperation among the trade.

Back to the question, whether Pentax currently make their own glass is anyone's guess. They probably did in the past and are probably doing so but with a limited capacity for their key products (ref Pentax making a public apology for not being able to meet demand for the DA* lenses).

By way of history, they did downsize and close some of their factories in Japan when the FA series were discontinued and their so-so AF film cameras were commercial flops. Then again they were not alone in relocating their production facilities outside Japan. The rising yen has forced a large proportion of precision manufacturing to neighbouring Asian countries in order to cut cost.
Even Nikon is not spared. Only the D3 is made in Japan while the D300 is made in Thailand.

At any rate this discussion is bordering on silliness because come next year Pentax will formally cease to exist as a company but exist as a brand name following Hoya's takeover. So the question who makes the glass is irrelevant as no one will be foolish enough to dispute that Hoya can actually make glass.

[creampuff]

BTW Confused, I merely pointed out a link on the very informative Canon video that outlines their lens making process for their high-end lenses. I never made any claim about Pentax making their own glass, yet you are asking me to prove this claim.

Similarly you have made a couple of assertions. Can you actually prove your assertion that Schott and Hoya are the only ones who can make optical glass blanks?

Do you have any definitive and concrete evidence to back up your statement..."it is simply factually incorrect to claim (as ogl did) that "Pentax makes glass" when they actually don't !"

In the same light, if you are unable to adduce any proof, then please don't go telling other people to prove anything.

[Confused]

Hi again creampuff

In order to ensure that I had my facts straight, I researched the matter some while ago in reply to another post a few months back, before I entered into this discussion. There are indeed other alternative manufacturers of glass 'blanks', but they are not major corporate suppliers in the way that either Hoya or Schott are, supplying vast numbers of glass blanks to the photographic lens manufacturing industry !

For that reason, I just wish you had carefully read what I actually said regarding Hoya, which was:

There are relatively few glass blank manufacturers in the world (I believe Schott are the other major producer)

Nowhere did I actually say as you implied (to quote your words) that "Schott and Hoya are the ONLY ones who can make optical glass blanks ?", which would be both wholly incorrect and also utter nonsense !

Hence your statement that:

Can you actually prove your assertion that Schott and Hoya are the only ones who can make optical glass blanks?

.....makes little sense.

Which brings me back to ogl's erroneous statement that:

Pentax makes glass too

I am equally puzzled when you said that:

To me it is immaterial whether the glass is made by HOYA or made by Pentax themselves

I'm sorry to argue the toss, but if like Pentax you don't physically 'make' the glass 'blanks', it is erroneous to claim that
"Pentax makes glass too" !
Admittedly that situation may well change in the very near future following Hoya's recent takeover of Pentax,

Best regards
Richard

[creampuff]

Confused, you are truly confused by your own semantic wordplay.
You still haven't come up with any concrete evidence to validate your statements but instead you choose to nit pick on my words.

Again, all I did was merely post a link to Canon's lens making video (post #113). I didn't make any inference in my post about Pentax.

[thibs]

You are both wrong to some extent and none of you admit there's any little bit of wrongness in your words.

Stop acting like 15 years kids and try to actually debate something.