On Wed, 17 Mar 1999 06:48:27 +1300 [EMAIL PROTECTED] (Chris Somers) wrote:
>> > > Oh! Wait a second! The Nikon [70-300 ED] is actually a rebadged Tamron.
>> >
>> > Has this ever been confirmed by a reliable source? All I have ever heard
>> > so far has been hearsay on this subject.
>>
>> Given that there are the same number of groups in the same number of
>> elements and the optical formula looks the same according to the diagrams,
>> and the lenses have the same physical dimensions and the same look and
>> feel, and the same zoom and focus mechanisms, I think it is safe to say
>> they are the same.
>>
>
> Of course this doesn't say the *glass* is the same. "ED" is Nikon's
> glass, manufactured by Nikon. The Tamron lens sure doesn't say "ED."
> Either Nikon wouldn't give Tamron the rights to label their lens as
> such, or indeed the Tamron lens has "Tamron" glass, and the Nikkor
> has Nikon's glass. I'm betting it's the latter.
Yes, but as someone pointed out some time ago, the optical formula is dependant
upon the refractive indexes of the glass employed. So Nikon can only use ED
glass that has the same refractive index as Tamron's UD glass (or whatever they
call it). And I'm not so sure of the quality of Nikon's ED glass in this lens
anyway, as it is extremely cheap compared to Nikon's other ED lenses.
