Tamron 18-250 focus problem

suenalex · 10-15-2015, 04:20 PM

I have a Tamron 18-250 1:3.5-6.3 (IF) which I bought new about 7 1/2 years ago. It has always performed well (as a one-size-fits-all travel lens) on a K100D and a K-r until a recent trip when it began to produce some slightly out of focus shots.

I did some test shots and it seems that the autofocus is not doing well at short focal lengths and distant subjects. Here are some figures.

At 18 mm focal length: subject at 0.5 m, focus perfect; at 3 m, focuses at 2 m; at 7 m, focuses at 3 m; over 50 m, stays at 3 m.
At 50 mm focal length: subject at 0.5 m, focus perfect; at 3 m, focus perfect; at 7 m, focuses at 3-4 m; over 50 m, stays at 3-4 m.
At 100 mm focal length and above, focuses well at all subject distances.

I tested the lens on my brand new K-3 II (wow, what a camera) and got the same result so I think the problem is in the lens. There is no AF problem with the 18-55 and 55-300 kit lenses on either the K-r or K-3 II bodies, or with the new 18-135 WR (wow again).

Is it worth getting a technician to look at it? Thanks in advance, Alex

tibbitts · 10-17-2015, 11:46 AM

Given the likely cost of even getting an estimate, you'd be well on your way to a sigma 18-250, which I think is generally believed to outperform the tamron. You wouldn't be quite as far along toward a sigma 18-300, which some indicate outperforms the sigma 18-250.

Primarily the advantage of a new lens would be that if you don't like your copy, you can send it back for no or low cost. If you send your lens for repair, and aren't happy with the repair, you have to battle back and forth and might still end up stuck with a bill and a lens that doesn't work to your satisfaction.

suenalex · 10-17-2015, 04:33 PM

Thanks for the reply - just about what I thought. Cheers.

**Des** · 10-27-2015, 06:04 PM

Alex, I'd suggest you contact Ben at Camera Checkpoint in Dubbo: Camera Check Point services for photographers He's a guru in lens repair, and his charges are very reasonable. He'll tell you whether fixing the lens is likely to be economic.

As a rough indication, Ben serviced a lens for me for $88. Postage (from Victoria) and insurance cost an extra $28. The authorised Tamron repairers (Maxwell International?) will probably charge much more than that.

I've got the same lens (also bought when I got a K100D). Been a great workhorse - as Photozone said the IQ is "fairly amazing" for a superzoom. But now you have the 18-135 and 55-300, I'd guess you won't have the same degree of use for the 18-250 (I don't now that I have a range of other lenses). Rather than spend too much on repair or replacement, a different lens might complement the rest of your kit better. If the repair is going to be much over $100, I'd suggest spending the money on a cheapish prime (like the plastic fantastics, DA 35 f2.4 or DA 50 f1.8) instead.

Edit: I see from your profile that you have the FA 50mm macro, so I don't need to preach about sharp primes!

My experience with the superzoom was that I shot a lot at 18mm and 250mm - which told me I needed something wider and something longer. That's where I looked for my next lenses (I ended up with 12-24 and 170-500).

Last edited by Des; 10-27-2015 at 06:18 PM.

10-15-2015, 04:20 PM	#1
suenalex Junior Member Join Date: Oct 2010 Location: Brisbane, Queensland Posts: 28	Tamron 18-250 focus problem I have a Tamron 18-250 1:3.5-6.3 (IF) which I bought new about 7 1/2 years ago. It has always performed well (as a one-size-fits-all travel lens) on a K100D and a K-r until a recent trip when it began to produce some slightly out of focus shots. I did some test shots and it seems that the autofocus is not doing well at short focal lengths and distant subjects. Here are some figures. At 18 mm focal length: subject at 0.5 m, focus perfect; at 3 m, focuses at 2 m; at 7 m, focuses at 3 m; over 50 m, stays at 3 m. At 50 mm focal length: subject at 0.5 m, focus perfect; at 3 m, focus perfect; at 7 m, focuses at 3-4 m; over 50 m, stays at 3-4 m. At 100 mm focal length and above, focuses well at all subject distances. I tested the lens on my brand new K-3 II (wow, what a camera) and got the same result so I think the problem is in the lens. There is no AF problem with the 18-55 and 55-300 kit lenses on either the K-r or K-3 II bodies, or with the new 18-135 WR (wow again). Is it worth getting a technician to look at it? Thanks in advance, Alex

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10-17-2015, 11:46 AM	#2
tibbitts Pentaxian Join Date: Apr 2007 Location: Oklahoma USA Posts: 2,196	Given the likely cost of even getting an estimate, you'd be well on your way to a sigma 18-250, which I think is generally believed to outperform the tamron. You wouldn't be quite as far along toward a sigma 18-300, which some indicate outperforms the sigma 18-250. Primarily the advantage of a new lens would be that if you don't like your copy, you can send it back for no or low cost. If you send your lens for repair, and aren't happy with the repair, you have to battle back and forth and might still end up stuck with a bill and a lens that doesn't work to your satisfaction.

10-17-2015, 04:33 PM	#3
suenalex Junior Member Join Date: Oct 2010 Location: Brisbane, Queensland Posts: 28 Original Poster	Thanks for the reply - just about what I thought. Cheers.

10-27-2015, 06:04 PM	#4
Des Loyal Site Supporter Join Date: Jan 2014 Location: Victoria Australia Photos: Albums Posts: 6,424	Alex, I'd suggest you contact Ben at Camera Checkpoint in Dubbo: Camera Check Point services for photographers He's a guru in lens repair, and his charges are very reasonable. He'll tell you whether fixing the lens is likely to be economic. As a rough indication, Ben serviced a lens for me for $88. Postage (from Victoria) and insurance cost an extra $28. The authorised Tamron repairers (Maxwell International?) will probably charge much more than that. I've got the same lens (also bought when I got a K100D). Been a great workhorse - as Photozone said the IQ is "fairly amazing" for a superzoom. But now you have the 18-135 and 55-300, I'd guess you won't have the same degree of use for the 18-250 (I don't now that I have a range of other lenses). Rather than spend too much on repair or replacement, a different lens might complement the rest of your kit better. If the repair is going to be much over $100, I'd suggest spending the money on a cheapish prime (like the plastic fantastics, DA 35 f2.4 or DA 50 f1.8) instead. Edit: I see from your profile that you have the FA 50mm macro, so I don't need to preach about sharp primes! My experience with the superzoom was that I shot a lot at 18mm and 250mm - which told me I needed something wider and something longer. That's where I looked for my next lenses (I ended up with 12-24 and 170-500). Last edited by Des; 10-27-2015 at 06:18 PM.