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12-06-2013, 05:15 PM   #46
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QuoteOriginally posted by Sandy Hancock Quote
The DA*16-50 is a brilliant lens. Yes, I have have had a couple of copies experience SDM failures, but now my remaining one is converted to screw drive I need never worry again. It is my most used event lens and is a total joy. Some recent output:
Yes, those are very nice photos. For the OP, I have seen many very nice shots by the 16-45 as well. I almost chose that lens when I elected to choose the DA 17-70, which has been quite nice except the SDM on it just failed. It is measurably better than the 18-55 II that I used before, and that was not bad at all. Depending on the cost of repair, I may elect to not repair, and just buy a 16-45, I think they are that good. I have not tried the 16-50, but by reading all the reviews my response is hmmmm........I quite honestly don't know what to think. The reviews for it are very mixed; however, the photos taken by the 16-50 posted here and on flickr are, imho, much better than photos from any other standard zoom. Maybe only the photos from the good copies of 16-50 get posted, and we don't see the photos from the bad copies.

12-06-2013, 05:29 PM   #47
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QuoteOriginally posted by GlennG Quote
Yes, those are very nice photos. For the OP, I have seen many very nice shots by the 16-45 as well. I almost chose that lens when I elected to choose the DA 17-70, which has been quite nice except the SDM on it just failed. It is measurably better than the 18-55 II that I used before, and that was not bad at all. Depending on the cost of repair, I may elect to not repair, and just buy a 16-45, I think they are that good. I have not tried the 16-50, but by reading all the reviews my response is hmmmm........I quite honestly don't know what to think. The reviews for it are very mixed; however, the photos taken by the 16-50 posted here and on flickr are, imho, much better than photos from any other standard zoom. Maybe only the photos from the good copies of 16-50 get posted, and we don't see the photos from the bad copies.
Sorry to hear that you have a fault with SDM. I just got a DA*300, which is my first SDM lens (although I have other non-Pentax lenses which have the motor built-in). I'm amazed how quiet the SDM is. I know what you mean about the DA*16-50; people have said to me that it got a bad rap because of SDM issues, but looking at the results of technical reviews, it seems that it doesn't stack up optically against similar lenses from Sigma and Tamron. However, owners of the lens seem to swear by it (or at it when the SDM fails). There seems to be some "feel" to the results in the photos which are more appealing then the results from other lenses. Anyway, I'll try to give the Tamron a workout and see how it goes!
12-06-2013, 05:42 PM   #48
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QuoteOriginally posted by RobG Quote
Anyway, I'll try to give the Tamron a workout and see how it goes!
Thanks, and please let us know how that goes. Best wishes for a great experience. Good post and thread here. Glenn
12-08-2013, 03:14 AM   #49
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I'm sorry to say that it seems like the Tamron has a fault. The lens isn't sharp edge to edge at wide angles - specifically, it's fuzzy on the right hand side. Strange that it's not fuzzy on both sides, but there you have it.

I've uploaded the full resolution jpeg of this image to Flickr. It looks fine at low resolution, but look at the detail in the trees in the middle and on the left compared to the right.





Last edited by RobG; 12-08-2013 at 03:20 AM.
12-08-2013, 03:38 AM   #50
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And another one. Follow the ridge on the horizon at 100% and watch the sharpness fade near the right side. The left side is fine.


12-08-2013, 07:29 AM   #51
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The tamron lens is probably decentered if it is only sharp on one half of the frame. I would send it back IMO.
12-08-2013, 07:57 AM   #52
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Send it back immediately, exchange it for another one. If there's one fault with Tamron it's that what you get from the factory seems to have a higher rate of "not functioning properly on arrival", as high as 10% on some of the lenses in the data base. People who get a good one are happy forever, those who don't need to exchange them immediately.
12-08-2013, 08:42 AM   #53
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Swap it for another one it looks de-centered
But just to be sure pick a flat focal plane like a wall or something and take some shots at various focal lengths. Lenses are rarely 100%, but there should be a mostly equal performance across the frame, test at various apertures and focal lengths.


Last edited by Mr Spocko; 12-08-2013 at 09:22 AM.
12-08-2013, 02:36 PM   #54
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QuoteOriginally posted by normhead Quote
Send it back immediately, exchange it for another one. If there's one fault with Tamron it's that what you get from the factory seems to have a higher rate of "not functioning properly on arrival", as high as 10% on some of the lenses in the data base. People who get a good one are happy forever, those who don't need to exchange them immediately.
I hope that swapping it isn't too much of a hassle, although this probably means I'll have to go on holiday with my original set of lenses. I've asked the vendor how I get a return authority.

QuoteOriginally posted by Mr Spocko Quote
Swap it for another one it looks de-centered
But just to be sure pick a flat focal plane like a wall or something and take some shots at various focal lengths. Lenses are rarely 100%, but there should be a mostly equal performance across the frame, test at various apertures and focal lengths.
The right hand edge seems to be OOF at both ends of the zoom range. I was going to print out a test chart and try it at a short distance to see if the difference on the left and right can be made a bit more obvious.
12-10-2013, 02:30 AM   #55
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OK, this is bizarre. The vendor said that Tamron advised them that the lens may not be fully compatible with the K5iis. I'm not sure what that means, but they asked me to try a different camera. I tried my K7, and the issue doesn't seem to be there. Can anyone explain to me why the same lens would appear to have a sharpness issue on the right side on a K5iis but not on a K7?

I need to look back through more of my photos, because I'm wondering if the problem was there with the DA16-45 but I didn't notice it. I'm going to have to set up a resolution chart and try both the Tamron lens, DA16-45 and both the K5iis and K7. I may even dig the K200 out...
12-10-2013, 04:17 AM   #56
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Makes no sense, can you get more information off of the seller ie what Tamron said (specifics of the problem)?
To eliminate any AF issues I'd use live view and a tripod and do some tests with that, use manual focus if needed and pick a flat object. If the lens is decentred it will show up across the focal range.
At the wide end there is some field curvature on the lens (as per photozone review) though real world it's not usually an issue, even allowing for that you should see a mostly even performance from the lens.


ie not one side significantly softer than the other.
12-10-2013, 04:46 AM   #57
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Thanks for the suggestions.
12-15-2013, 03:24 AM   #58
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QuoteOriginally posted by Mr Spocko Quote
Makes no sense, can you get more information off of the seller ie what Tamron said (specifics of the problem)?
To eliminate any AF issues I'd use live view and a tripod and do some tests with that, use manual focus if needed and pick a flat object. If the lens is decentred it will show up across the focal range.
At the wide end there is some field curvature on the lens (as per photozone review) though real world it's not usually an issue, even allowing for that you should see a mostly even performance from the lens.
ie not one side significantly softer than the other.
I've tried some shots of a resolution chart and at least at a distance of a metre and a half, I can't see any sign of the drop in sharpness that appears in the landscape shots. The edge is certainly less sharp at 17mm focal length than at 50mm but at both extremes it compares well with the DA 16-45 ie it's sharper. I still don't understand the behaviour at infinity focus.
12-15-2013, 10:01 AM   #59
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QuoteOriginally posted by RobG Quote
I've tried some shots of a resolution chart and at least at a distance of a metre and a half, I can't see any sign of the drop in sharpness that appears in the landscape shots. The edge is certainly less sharp at 17mm focal length than at 50mm but at both extremes it compares well with the DA 16-45 ie it's sharper. I still don't understand the behaviour at infinity focus.
The behaviour is caused by infinity focus, but not by any fault of the lens. The closer areas in your image are out of focus because the zone of acceptable focus does not included them. You need to focus at the hyperfocal distance.

Please note carefully that I said "zone of acceptable focus", not "zone in focus". Acceptable focus, in the film days, was usually defined as the focus combined with an aperture that rendered a point that appeared sharp on an 8x10 inch print, when viewed from 12 inches.

There is an on line source for calculating depth of field, DOFmaster. I just popped out there, and the hyperfocal distance (bottom right corner of their screen) for a 16mm lens at f/8 is 5.3 feet. The "circle of confusion" is defined as 0.02 inches.

Try your pictures again. Move to 5.3 feet (1.6m) from something, focus and switch the lens to manual focus to keep that focus point, then take your picture. The trees will probably seem a bit out of focus in your viewfinder, but when you examine the picture on your monitor, you will be surprised at the better focus near to you.
12-15-2013, 03:09 PM   #60
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QuoteOriginally posted by Canada_Rockies Quote
The behaviour is caused by infinity focus, but not by any fault of the lens. The closer areas in your image are out of focus because the zone of acceptable focus does not include them. You need to focus at the hyperfocal distance.
OK, why does it affect the right hand side of the image and not both sides?
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