I don't think that plastic has hit the 70-200/2.8 range lenses yet. Or,
if it has, the weight must be mostly glass. All lenses in this range
from Nikon, Canon, Sigma and Tokina weigh within a couple of ounces of 3
pounds or a little bit more if the lens has image stabilization. Even
the ZD 50-200 (which is not a constant 2.8) weighs 2.4 pounds.
Another indication that the weight in a fast lens is mostly glass is in
a comparision of my Tokina 28-80/2.8 and the Tamron 28-75/2.8. The
Tokina is all aluminum alloy. The Tamron is largely plastic but the
weight difference is only 4.6 ounces. The Tamron is reputed to be an
exceptional lens but I opted for the Tokina based on their MF/AF clutch
mechanism and commonality of filter sizes in zooms from 20-200mm.
Unfortunately those common filters sizes appear to be on a set of fast
disappearing lenses.
Chuck Norcutt
Moose wrote:
> Chuck Norcutt wrote:
>
>>Yes, the ATX Pro line lenses are built like tanks. All metal
>>construction. It's a shame to see that stuff apparently dwindling away.
>>
>
> Maybe the penny has dropped for many other people , as it has for me,
> that they dont' have to carry around a ton 'o glass and metal, and sales
> wouldn't support continued manufacture.
>
> I suspect that these lenses were made in batches, not continuously. And
> it is entirely possible that, like with the OM-4ti, they have been
> selling off remaining stock for some time.
>
> Much as I like the feel of quality and solidity of my old all metal
> lenses, I can't say I like carrying them around. Changes in technology
> have always meant changes in materials and manufacturing techniques.
> Someone with an engineering background posted here about brass vs.
> engineered plastics some time ago. As I recall, he said precision of
> manufacture was as good or better with plastic and it was less affected
> by temperature.
>
> He also said resistance to trauma was different in ways that were hard
> to compare. Plastic will often simply deform and return to shape under
> impact/stress that will permanently deform brass, but brass may survive
> greater impacts in repairable condition where plastic will shatter. And
> I suppose that the impact on a plastic lens structure will often be less
> from a similar mishap than on brass because the plastic lens weights less.
>
> In any case, I think it unlikely that I will buy an all metal AF lens in
> the future as long as there is an otherwise similar spec lightweight
> available.
>
> I'd sure hate to see Tokina go away, many of my favorite lenses have
> been, and still are, for MF, Tokinas. With luck, they are back at work
> reformulating the mechanical parts of these classics for the
> contemporary marketplace and they will return.
>
>>Chuck Norcutt
>>
>>AG Schnozz wrote:
>>
>>
>>
>>>Chuck, I don't know. I lost interest in Tokina when they
>>>dropped the OM mount and then again when I decided to stay with
>>>Olympus. It's a shame too, since they had a wide-angle zoom to
>>>kill for. That one lens almost drove me to Nikon.
>>>
>>>Tamron has been quite aggressive in their product placement, but
>>>most of their stuff feels so cheesy to me.
>>>
>
> That was my feeling when I got my first plastic bodied lens, a Viv S1
> 17-35. But it's been a fine lens and shows absolutely no signs of wear
> or distress from the admittedly modest use to which I have put it. I
> haven't used it all that much, but it has traveled quite a bit -
> standing by.
>
> I think it's one of those prejudices one picks up based on facts that
> change faster than the emotional component of one's value judgment.
> Optically, I think at least some of the new, plastic, Tamrons are really
> excellent. In my side-by-side tests, the Tamron 90/2.8 Di is a better
> lens than their old 90/2.5, the famous Kiron 105/2.8 and, beyond 1:2,
> the Zuiko 50/3.5. And at 1:2, it's pretty much in a tie with the 50/3.5.
> And boy is it light compared to the Kiron, the only other one I have
> that doesn't need accessories to go past 1:2.
>
> Maybe I got a special one, but I continue to be impressed by the Tamron
> 28-300 Di. Light, but with a nice, smooth zoom action and no wiggle/slop
> even extended out for 300 mm. And it's sharp. No, it doesn't feel like
> the Kiron 28-210, but is it worse, or just different? I will admit,
> though, that the Kiron could probably be used as a weapon, then go back
> to photography, and the Tamron would not stand up to that test.
>
> For flimsy feeling, the Can*n 50/1.8 is a champ. weighs nothing (and
> light in the $s, too) and feels like a nice rap with a knuckle will make
> it fall to pieces - but it doesn't. But put it on the camera and it
> focuses quickly and accurately and takes nice, sharp pics.
>
> Moose
>
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