In my opinion, there seems to be some variability in the quality of some Tamron 28-75, resulting in some having bad copies and some having excellent ones!
From a separate thread, there seems to be two versions of the Tamron, sourced from different places:
1. Made in Japan
2. Assembled in China, Tamron Japan.
There might not be any difference in quality between these two lenses, but I'd be interested in seeing where your Tamron comes from and whether you found your copy acceptably sharp
Edit: modification request!
Edited by 1000words on Sep 08, 2004 at 05:28 AM GMT
I would guess that when the production facility in China first went live, as with all things, there were problems. I would think that the difference at this point would hardly be noticeable. Mostly the assembly is being done in China, but the parts are still made in Japan.
Mine was assembled in China and it is fine. I think it is a little....arrogant for us to assume the Chinese cant put together a lens as good as the Japanese.
Seems like there were two virsions when the lens was introduced. One made in Japan, the other one made in Japan assembled in China. AND some people with the latter version had some focus problems, and Tamron Japan accepted exchanges if they confirms the problem.
There are several posts at kakaku.com but those are all in Japanese.
My Tamron says "Made in Japan." I pulled out the Adorama receipt and I bought it in 10/03. How time flies....... I don't think my copy would be as competitve with the 50mm primes, but it is just fine, and is as sharp or sharper than any L zoom I have compared it with at f/4 and smaller. If I get time I'll have to compare it with my 50mm f/1.8.
1000words wrote:
In my opinion, there seems to be some variability in the quality of some Tamron 28-75, resulting in some having bad copies and some having excellent ones!
From a separate thread, there seems to be two versions of the Tamron, sourced from different places:
1. Made in Japan,
2. Made in Japan. Assembled in China.
There might not be any difference in quality between these two lenses, but I'd be interested in seeing where your Tamron comes from and whether you found your copy acceptably sharp
It should be:
1. Made in Japan
2. Assembled in China, Tamron Japan.
I have seen both versions. I believe the 2 is newer than 1. The quality variation might or might not have caused by the version difference. Anyone compared both versions?
My 28-75mm XR Di is "Made in Japan" with SN: 004627
I am using it with an EOS ELAN 7E. Images are sharp wide-open and I do not have back-focus/front-focus issues.
As I understand it, the problem with some copies of this lens is that they back-focus causing soft images wide-open. I am not sure if this is isolated to certain mounts (Canon, Nikon, etc.) or certain cameras (film SLR, di SLR, or specific models).
In any case, if you do have the back-focus problem I am pretty sure you' will be able to tell right away. The images will look like out of focus more than they will look like they are soft.
Test it using a large diameter candle. It is best to use a candle about 2" to 3" across at the top and preferrably burned down so that you get more defined edges. Stage the lens about 3" above the top of the candle. Zoom to 75mm and move close to the lens' minumum focus distance from the candle. Focus at the candle wick (it should not be lit) and shoot the picture at f/2.8. If the wick is sharp in the image and the front and back lips of the candle are out of focus you are OK. If the front or back lip is sharper than the wick then your lens is not focusing correctly (i.e. images will tend to appear soft wide open).
Before the Tamron, I used to have the Tokina 28-70mm f/2.8 PRO SV. Very sharp lens stopped down! BUT, it has a significant front-focus problem. The result is that if you shoot at close distance wide-open the images look horrible -- unusable by any measure. Thus, that lens is useless for people and event photgraphy, especially indoors where large appertures are the norm.
So, check your Tamron for front-focus or back-focus. If you have none, then you have a "good one".
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