Andre's Blog
Perfection is when there is nothing left to take away
Tamron 18-270 f6.3 PZD - impressions of a daily shooter

After going through two Sigma 18-250 lenses in two years, I decided to give a Tamron 18-270 f6.3 Di II VC PZD a try. Tamron promised improved AF performance with a new ultrasonic AF drive and offered a five year warranty, which was definitely something I could use after spending over $800 on a Sigma 18-250 designed to last only 50K shots. The new lens was also much smaller and lighter, which made it easier to carry it around, given that sometimes I spend hours with a camera in my hand.

Every new lens takes some time to get used to and with a Tamron 18-270 on a Canon body this time was a few weeks until my muscle memory adapted to the opposite direction in which zoom and focus rings rotated. Less obvious, but more important were the technical parameters of the lens, which took me a long while to figure out and work around one way or another.

One immediate difference with the Sigma 18-250 I noticed was the chromatic aberration (CA) pattern. While it was easy to correct CA produced by the Sigma 18-250 with the CA plug-in in GIMP, CA produced by the Tamron 18-270 took more elaborate tweaking for each image with visible CA.

One day I was shooting an event at a restaurant with very limited light and used the IR AF assist beam of an external 430EX flash mounted on the camera to focus. After reviewing the shots later that night I found most of them were front-focused quite a bit. At first I blamed how the AF system was using the IR focusing pattern, but after a series of experiments it turned out that the Tamron 18-270 was front-focusing on the wide end, approximately between 18 and 50 mm. Starting at approximately 70 mm and all the way to 270 mm, focusing worked as expected.

Once I figured out this little problem, I started to add +10 AF micro adjustment (MA) every time I had to shoot wide angle. Sometimes it presented quite a challenge or was simply impossible because the subject was moving towards me too quickly. I did my best by making a shortcut to the AF MA function in my EOS 7D and switched between +10 when shooting wide angle and disabling AF micro adjustments when shooting 70mm and above.

Flash • ISO 1600 • 1/160 • f/5.6 • 18mm • +10 AF MA

After a few months of using the lens, I noticed that zooming became very stiff. Upon closer look it turned out that the rubber zoom ring warped slightly and extended evenly onto the body of the lens, creating extra friction. It was inconvenient to zoom at first, but then I realized that this malfunction took care of the zoom creep problem and I just learned to live with it and I never had to touch the zoom lock switch again.

When Spring came along, I started shooting more in manual focus and learned about another deficiency of this lens - the manual focus ring didn't move smoothly, but instead moved in little jumps that can only be noticed if the focus ring was moved gently and in small amounts. This became a major problem for all shots where I needed to focus manually.

ISO 800 • 1/1600 • f/8 • MF

After about a year and a half auto focus started to fail more and more and I noticed that the focus ring was often stuck around the 7m mark on the focusing scale. When in this position, the lens wouldn't focus at all until I jogged the ring slightly. Given my experience with consumer grade lenses, it wasn't much of a surprise and it was time to give the five year warranty a try. This is how the lens looked a couple of days before I wrapped it up.

Tamron 18-270mm f/6.3 PZD after ~50K shots

I sent the lens to Amplis, which is an affiliate of Tamron's in Canada, and described not only the AF problem, but also asked them to look into AF front focusing and the jerky focus ring. My first surprise was a response from Amplis that the lens was dropped and cannot be fixed under warranty. I suppose they never saw one of their lenses after about 50-60 thousand shots before. I explained that the lens wasn't ever dropped or even bumped against anything and that it was just used extensively, as a lens should be. After a few calls and emails, Amplis apologized and acknowledged that their technician made a mistake. They also told me that the AF was totally shot and needed to be replaced.

I got my lens back after a few more days, which was much quicker than a few weeks it took Sigma to fix the Sigma 18-250. My first check was the movement of the focus ring in MF, which remained as jerky as it was and may be even got a bit worse, probably because of the new parts they put in, which indicated to me that the problem was not with just my copy of the lens, although this may be just my interpretation.

My second test was focusing at a wide angle. The lens was still front-focusing and required +10 adjustment. "Oh, well", I thought to myself, but in a few days I noticed that I'm getting more out of focus shots on the long end now. After doing a series of tests I figured out that the lens needed about +10 micro adjustment across the entire zoom range now, which actually made my life easier, since I didn't need to switch AF micro adjustment on and off all the time now.

After getting back the lens, I debated with myself whether I should switch to some other lens while I still could recover some money for this one, but in the end decided to use it a bit more because at the time there was not much alternative for anyone who wants a super-zoom lens and shoots a lot, which given the build quality of these lenses does require an extended warranty. However, things may change with Sigma's introduction of a 4-year warranty on all of their products purchased after July 1st, 2013.

Tamron 18-270 is not a bad lens and allowed me to capture some great shots, but it also requires quite a bit of skill to work with and a camera that supports AF micro-adjustments. I suspect this lens will work well for somebody who only posts non-cropped images on social sites, but for those who push their camera and the lens to capture better pictures, the extra 20mm is just not worth it to justify the nagging feeling of disappointment when you see out-of-focus shots you just captured and can't help but wonder if it turned out better if the focus ring moved smoothly or if you picked the right amount of AF micro adjustment.

If you decide stick with the Tamron 18-270 for whatever reason, make sure to test AF accuracy at all major focal lengths and at those distances that you shot most of the time. Remember that most AF tests and AF micro-adjustments done at home from a couple of meters from the wall are useless. Pick a high-contrast target outside (e.g. a traffic sign), make sure your shutter speed is over 1/1000 and take a series of shots at +10, -10 and 0 AF micro-adjustment, taking at least three shots in each setting and refocusing between each shot. Delete the least focused shots while looking at them at a 100% on your camera's LCD screen, but leave those that just slightly different - the amount of AF micro-adjustment you need is between those numbers.

January 2014

At the end of November in 2013 I started to notice that the AF is becoming unresponsive at times. It wasn't as bad as it was in June of 2013, but I started to miss shots and that was the end of Tamron for me. On December 6th, 2013 I picked up the new Sigma 18-250, which was much smaller than my original Sigma lens and was covered by a warranty for as long as seven years in Canada. I switched the Tamron with the Sigma right at the store and, aside pushing the zoom and focus rings in the wrong direction for a few weeks, couldn't be happier to be able to focus with confidence again.

ISO 6400 • 1/1600 • f6.3 • 270mm
Posted Sun Oct 13 05:39:58 EDT 2013 by Maurice

Good read, thanks. I've the same lens and have a hard time getting sharp images at all lengths. I found it's front-focussing at least at 18mm.

Posted Thu Nov 21 07:17:00 EST 2013 by Jake

 Thanks for the info. I too, seem to burn through the Sigma lense .Perhaps I will give the Tamton  try

Posted Sat Apr 19 10:11:04 EDT 2014 by Ant West

I stumbled upon your article while searching for a solution to the slipping of the rubber zoom ring on the Tamron 18-270 mm

The only issue I've experienced is that after a year or so, the rubber ring on the zoom seems to have stretched and is slipping, which has become rather annoying.

However, I must mention that I have not experienced any of the issues you refer to with front focus and issues at 270. 

I'm incredibly satisfied with this lens and use it as my all-purpose lens when not shooting my favourite macro or landscape with a 10-22.


Posted Tue Jun 3 06:53:56 EDT 2014 by Manasvi Sareen

I too facing problem with auto focus, but it occurs only when I try to do the focus in color mode, (Using the screen, instead of view finder) and lens autofocus does not work then.  

Posted Mon Oct 27 12:12:32 EDT 2014 by Dean Singleton

 Tamron 18-270 is becoming quite a problem for me.  My first one started the slipping within 2 months.  Sent to Tamron USA for repair, came back with the auto focus not working properly.  Returned and found it had been hooked up incorrectly.  Came back perfect for another two months and began slipping so bad that I could not shoot up or down without a complete drop.  Sent back in and they wanted to fix again.  I had obtained the manager's name and talked direct to him and they agreed to send me a new lens.  Better luck this time it did not begin to slip for six months but within a week was almost as bad as the final week with the previous lens.  It's due back from repair today.  I have the strong feeling that this is a design defect with the lens.  it will probably be my last Tamron product.  If you have one and it works well, more power to you.  Good luck.

Posted Fri Aug 28 07:20:15 EDT 2015 by Derek
From Scotland, bought a Tamron 18-200 and noticed it would not allow focus lock at between 22mm and 32mm at a distance shot beyond 30m, but worked on all other. Took the lens back and was sent to Tamron, after 1 week returned with the same fault. Got my money back and bought the Sigma 18-250, great lens. Tamron sucks.
Posted Sat Oct 8 01:43:08 EDT 2016 by Anonymous

 We have two Sigma 18-250 and one Tamron 18-270; all three are the newer models that use the 62mm filters.

Both of the Sigmas are tack-sharp and very quick to achieve AF

The Tamron gets about one sharp picture out of five and now the AF struggles to find focus in jerky lurchy movements and seldom succeeds; I have read that this is a common fault with the Tamron due to a plastic gear that easily gets stripped.

If I could get this gear, I would fix it myself.