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03-01-2008, 03:01 PM   #16
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The numbers

QuoteOriginally posted by Peter Zack Quote
I would suggest anyone that is not sure about a lens FF/BF issue use the following : http://focustestchart.com/focus21.pdf

A much more definitive method to check the lens. No need in testing against another lens and having unknown variables involved.
Thanks for the link to the chart. Hate to be called a liar.

At 50 mm f 2.8, the whole frame:
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At 17 mm f 2.8, 50% magnification :
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Pretty convincing.

Flash, center focusing sensor etc. Took many frames and they look exactly the same.

Of course I'm hoping like everyone that this is the exception (I'll never get a good one on the guarantee otherwise). I'm just telling you to check your lens beforehand or immediately at arrival.

03-01-2008, 03:17 PM   #17
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Thanks for those tests. Are you getting a replacement soon, or do you have to send it in to Tamron for recalibration etc? You could try adjusting front-focus/back-focus with the debug firmware on the K10D (though that might completely mess up your other lenses).

I have been waiting for this lens, and plan on buying one sometime before my trip to Greece in April. I really hope this was a one-off case, and doesn't become the trend.
03-01-2008, 08:48 PM   #18
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Hmmm, let's just hope this is a rare case, I am definitely considering getting this to replace my kit lens...
03-02-2008, 01:03 AM   #19
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QuoteOriginally posted by Kameraten Quote
Thanks for the link to the chart. Hate to be called a liar.
No one was calling you a liar....just pointing out the lack of evidence which you have now posted. However i am not entirely convinced as it could very well be the camera. You said yourself it is not easy to verify focus with a wide 14mm lens at 2.8 and thats why i asked if you had tested at f4 on the Tamron.
My fa50 1.4 has back focus up to f2 but after that you can not tell.

03-02-2008, 01:33 AM   #20
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QuoteOriginally posted by Tony Quote
... it could very well be the camera. You said yourself it is not easy to verify focus with a wide 14mm lens at 2.8 and thats why i asked if you had tested at f4 on the Tamron.
Not quite getting the logic. At a smaller stop the error is still there, you just don't see it as clearly.
The camera is not on my list of suspects.

QuoteOriginally posted by ankit Quote
Are you getting a replacement soon, or do you have to send it in to Tamron for recalibration etc? You could try adjusting front-focus/back-focus with the debug firmware on the K10D (though that might completely mess up your other lenses).
Got the lens Friday afternoon so I haven't been in touch with the store yet. Recalibration or replacement it has to be, either one is fine with me, replacement is quicker of course.
What's this debug firmware ? I now the K20D has a provision for individual lens AF calibration, but for the K10D it's unknown to me.
And, again the 17-50 is great when it's in focus. Just make sure from the start that it works, preferably by testing.
Back focusing is something you will blame yourself for, front focusing is something you will blame the optics for because nothing is quite sharp.
03-02-2008, 06:09 AM   #21
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To get to the "debug screen", you need to use firmware 1.10. Once you have that firmware, you should be able to adjust focus calibration in the debug menu. You can then upgrade to firmware 1.3 and the calibration information is retained. Unfortunately, this is a global setting and affects all lenses (unlike the K20D).

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03-02-2008, 09:29 AM   #22
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Not calling you a liar at all. Just found this test method the best to be sure. I had a DA*16-50 that BF'd like crazy but I wasn't sure the pics were just soft looking. So after running the test, I was sure and the lens went back. It was off by 25mm. If you were focused on the thick black line, this lens is realy bad. Ff almost 80mm @ 40Cms. That's awful. I'd ask them to test a lens for you and send you a new tested copy.

The Debug thing isn't worth it since you can't save the settings for a particular lens as far as I can find out. I know a service shop can calibrate the 2 but not sure how a user can. You'd most likely muck up your other lenses.
03-08-2008, 02:34 PM   #23
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K100D + A16 - Pentax Qװ - DCHome.net ƽXѦa׾ Ĥ@ӼƽX۾ - Powered by Discuz!

Some photos from a user in hk who has the lens. Not mine.

I am waiting for it to come to Canada...

03-10-2008, 04:52 PM   #24
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Here's a confirmation of it actually arriving at a US retailer:

Tamron 17-50, finally available in US: Pentax SLR Talk Forum: Digital Photography Review

Still not sure when it'll be more common in some of the usual big names (Amazon, B&H, Adorama, etc.), but looks like it's really here, even at a glacial pace.

Alex
03-10-2008, 11:11 PM   #25
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I decided to order from the shop of the link to the ebay seller which was posted in the second post. Only comes with a Japan i year warranty as well as a 3 year store warranty which they say they will honour without problems. They are sending as a gift so hopefully final price will be 206 quid delivered to UK. Yes it is a risk but a friend has got stuff from them before without problems and they do have a proper shop. Expect it at end of next week.

Last edited by Tony; 03-11-2008 at 01:06 AM.
03-11-2008, 12:29 AM   #26
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The jury is out

I'll be happy to hear from somebody else that has paired this lens with a K10D and made some proper tests.
Sad to say, the replacement lens I got is front focusing like the first one. I've also tested this new lens with another K10D body in a store, same result . The webstore has agreed to send this one back to Tamron for checks.
Judging from the serial numbers, my lenses were from the very first days of production.
The other possibility would be that K10D would tend to front focus with just this or just Tamron or just 3rd party lenses in general. Could that be?
03-11-2008, 01:05 AM   #27
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QuoteOriginally posted by Kameraten Quote
I'll be happy to hear from somebody else that has paired this lens with a K10D and made some proper tests.
Sad to say, the replacement lens I got is front focusing like the first one. I've also tested this new lens with another K10D body in a store, same result . The webstore has agreed to send this one back to Tamron for checks.
Judging from the serial numbers, my lenses were from the very first days of production.
The other possibility would be that K10D would tend to front focus with just this or just Tamron or just 3rd party lenses in general. Could that be?
I only have a K100D so that is what i will be pairing with. I would think mine will be from the first lot produced but will have to wait and see if i have the same focus issue. Too bad your second copy is doing the same thing.
I have several lenses but my only fast AF lens is the FA50 1.4 which when used with the camera it will FF upto f2.4. However i am aware of why this happens and it is the k100d focus points which are not aligned right so i am able to compensate this.
Sorry but i dont do the sort of testing some do. All i do is shoot off some shots at wide open at a newspaper at 45 degree angle. If they look good then thats good enough for me. Of course i also check corner sharpness but this lens should be fine at that. The real test comes in everyday use as far as i am concerned.
03-12-2008, 08:43 PM   #28
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You guys may want to read this review of the lens.
Tamron SP 17-50mm F2.8 - First Impression
03-12-2008, 10:34 PM   #29
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QuoteOriginally posted by Peter Zack Quote
I just bought a Sigma 18-50mm. got tired of waiting on this lens. I'm seeing some issue with the pics but they are dark and hard to be sure. I would suggest anyone that is not sure about a lens FF/BF issue use the following : http://focustestchart.com/focus21.pdf

A much more definitive method to check the lens. No need in testing against another lens and having unknown variables involved.
Peter
Thanks for pointing the way to the focus test. I have been struggling with how to perform the test on my DA* 16-50. The article was great.
03-12-2008, 11:27 PM   #30
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Good to see someones review on the lens but it was the result i expected. Mine will be posted tomorrow so i will have for the easter break which is good
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