Tamron 18-270 Focusing Problems

Having owned the original - non PZD - version of this lens for about a year, I upgraded to the PZD version, looking for a lighter, shorter lens. Unfortunately my PZD lens does not focus accurately on my 60D, whereas other lenses, including the older Tamron, do. I was ready to send the lens back and get another.

But while doing some tests today, I discovered that the lens does focus accurately when I tell the camera to use only the center focusing point, or perhaps exactly one of the other focusing points. But when I tell the camera to use all of the focusing points, the lens mis-focuses.

As I am on a trip and don't have my older 30D with me, I cannot repeat the test with the other camera. (I will do so when I return home.)

Has anyone else seen this problem, either with the 60D or with other Canon (or Nikon?) cameras? Is there an easy fix or should I send the lens back?

My other observations about the PZD, when compared to the older lens:

* The PZD seems much lighter and less imposing than the older lens, making it much easier to carry around.

* The PZD does not have the "sticky point" between 70mm and 100mm, making it easier to zoom than is the older lens.

* The PZD seems not to have quite the zoom range of the older lens. Comparison shots of the same subject at the same distance seem slightly less wide at 18mm slightly less telephoto with the PZD than with the older lens.

**** Edited 1/3/2012 ****

Having returned home, I tested my new PZD with my older 30D. It focused accurately, even with multiple focus points selected.

I think the PZD lens I bought was defective. I just sent it back and got another one. The replacement lens seems to focus just fine, even with multiple focus points, and with both of my cameras.

RodneyCyr wrote in post #13601878
* The PZD seems not to have quite the zoom range of the older lens. Comparison shots of the same subject at the same distance seem slightly less wide at 18mm slightly less telephoto with the PZD than with the older lens.

I haven't tried this lens but probably you'll just have to work around its limitations until you get back. I don't think there is a simple fix as it doesn't sound like anything is wrong that you could have caused.

Marked focal lengths on lenses are measured at infinity focus and vary considerably with focus distance with some lenses more than others. Marked focal lengths are said to vary ±5% or so from the true focal lengths so your PZD might only go to 19mm or maybe the previous one actually reached closer to 17mm and this one is really 18.

RodneyCyr wrote in post #13601878
...But while doing some tests today, I discovered that the lens does focus accurately when I tell the camera to use only the center focusing point, or perhaps exactly one of the other focusing points. But when I tell the camera to use all of the focusing points, the lens mis-focuses....

Using all focus points (Auto AF Point select) will cause almost any lens to mis-focus. See this thread for one recent discussion of it. You're far better off manually selecting your focus point regardless of which lens/body you're using.

I thought mine was misfocussing on my 60D but realised it was a soft image due to large(small number) aperature setting, I was even initially blaming the VC for poor images.

I am now in the habit of normally shooting between f8 and f11 with ISO on auto in AV mode and the images come out nearly as sharp and contrasty as my primes and I shoot more at 270mm than any other focal length.

I normally do manually select my focus points so have not encountered this problem.

At one point I was ready to send it back to the manufacturer, but now I have learned how to drive it properly you need a crowbar to seperate it from me.

I live in a small country area so dont have the benefit of going to larger shops and choosing from a variety of lens copies

blanchy1969 wrote in post #13664127
I thought mine was misfocussing on my 60D but realised it was a soft image due to large(small number) aperature setting, I was even initially blaming the VC for poor images.

I am now in the habit of normally shooting between f8 and f11 with ISO on auto in AV mode and the images come out nearly as sharp and contrasty as my primes and I shoot more at 270mm than any other focal length.

I normally do manually select my focus points so have not encountered this problem.

At one point I was ready to send it back to the manufacturer, but now I have learned how to drive it properly you need a crowbar to seperate it from me.

I live in a small country area so dont have the benefit of going to larger shops and choosing from a variety of lens copies

During my early tests I found that sometimes the lens was sharper at a wider (lower number) aperture than it was stopped down. Normally lenses improve when stopped down (within certain limits.) This suggests some sort of inconsistent focusing issue.

I sent the first lens back and ordered another. I took the new lens out on a field trip today to check it out. It focused much better than did the first one. The images appeared quite good, even at wider apertures, but I do see some chromatic aberration at the long end -- more than with my older non-PZD lens. What mis-focusing I did see with the new lens was probably caused by the camera selecting the wrong focusing point. This means that I should take the advice of several responders to this thread and select the focusing point myself.

I'm not so happy with the clarity of the photos taken with Tamrom 18-270 PZD especially at higher focal lengths (above ~170mm).
I have Canon EF-S 18-55 mm that takes better pics in 18-55mm range and Canon 55-250mm that takes better pics in 55-250mm range than Tamron 18-270mm PZD.

I'm going to exchange it with either
1. Canon EF 28-135mm f/3.5-5.6 IS USM Standard Zoom Lens or
2. Canon EF-S 18-200mm f/3.5-5.6 IS Standard Zoom Lens

My interest is in taking pics of people performing in theatre (speech/drama/dance/et​c) and outdoor shooting birds, animals, etc.

Any suggestions on which of these is a better choice?

Although, at first, my replacement PZD lens seemed to focus better than the first one, I now find that it, too, is mis-focusing. A few pictures I took this afternoon were quite blurry.

I tried a new test: On my 60D I set the focusing point to center-only, sat in a chair, and focused on a textured lamp shade across the room. The lamp was ON, so there was plenty of light. I pressed the shutter release half-way to focus, waited for focus confirmation, but didn't take a picture. Repeating this test several times, I found that the lens did not focus at the same distance each time. Indicated focusing distances ranged from "beyond infinity" to less than 10 feet. (The actual distance was about 12 feet.) Although I realize that the indicated focusing distance is not accurate, at least it should be the same each time.

I repeated the test with my 30D and got similar results.

Unfortunately, thinking at first that the lens was OK, I sent in the rebate form. The mailing deadline was last Saturday. The lens seller will probably not take the lens back as I removed the bar code from the box to include with the rebate.

I expect that, if I send the lens to Tamron, they will probably say the lens is working correctly and that my camera is the problem. This is unlikely as I have the same problem with two different cameras, each of which focuses properly with other lenses.

Tomorrow I will call both Tamron and the camera seller and see what they say.

Any other suggestions?

How are you getting on with the lens now? Im having same problem's plus on autofocus if you lock on a flower head for example the focus box wanders.. canon 7d

[QUOTE=andyhyw1210;170​19121]How are you getting on with the lens now? Im having same problem's plus on autofocus if you lock on a flower head for example the focus box wanders.. canon 7d I have sent the lens back for repair as this can't be right, at cost to me£31.80 insured, not fair consumer has to pick up the postage!

[QUOTE=andyhyw1210;170​19133]

andyhyw1210 wrote in post #17019121
How are you getting on with the lens now? Im having same problem's plus on autofocus if you lock on a flower head for example the focus box wanders.. canon 7d I have sent the lens back for repair as this can't be right, at cost to me£31.80 insured, not fair consumer has to pick up the postage!

I got rid of the PZD and replaced it with the Canon 15-85 and 70-300L, both of which focus just fine.

I have sent mine back for repair even that has not gone well, sent via city link @ £31.80 next day as I am up against time for holidays, go in a week, and as bad luck with the lens the did not deliver to repairer so may not get it back in time, will update once back with me..Len's is only 6 weeks old, and dropped my 17-85 cannon last weekend awaiting parts for that! now that's bad luck!!

Had lens repaired, Can't fault the service provided by intro ( 2 days ). and yes it had a fault with the focusing unit and was replaced. Now very happy with the lens pics are sharp and full of colour, the more I use it the happier I am..