LOL! Rick said you have to use the full name of the product in the title description.. if you are pedantic and need it all.. you're going to have to wait all night, as I'm a rather slow typist(ie. it's a very long product name!! )

OK. IQ is fantastic, build quality is great, AF is.....

AF is good. A lot has been said of the slowness of this particular lens to auto focus and even mentions of 'loud'(I read somewhere??.. I'll try to track that down too.)

I think the issue here is that those people are using those ring type ultrasonic motor type lenses as comparisons to the 'poor ol Tammy' ... quite unfair I reckon as it's in reality a screw driven lens.. BUT with an inbuilt micro motor to focus automatically with the AF-S only Nikons.. hence on Tamrons site they state that this lens has 'BIM' which I presume is Built In Motor, but only in Nikon mount.. that is(if someone else can confirm this) all other mounts may rely on screw driven focusing method.
How this affects other mount types I don't know, but I only have a Nikon mount version and I can tell 'yas all that focus is not slow! It;s not slower when compared to most other screw driven lenses and is on par with the 80-200/2.8 AF-D(there's an AF-S version of that lens, so we're not confusing the issue!!).

Quick note!! I have seen a comment from someone, somewhere(and not necessarily on here) that this lens is loud in it's focus noise... maybe that's true if you are listening for church mouses.. but compared with the screw driven 80-200Nikon.. it seems quieter in general.. but about on par with that lens. I think the comment is hardly worth the effort... it's definitely not ZZZZZZZZZ!!!!!!! loud... it sounds about normal to me and I have many screw driven lenses and couple of AF-S/HSM lenses. ultrasonic type AF systems as almost whisper quiet.. when you compare them with any non ultrasonic lens ... the non ultrasonic lens is always going to sound louder!

As for the slow to focus issue???
Maybe the comment are for non Nikon cameras.. so I went out to play with it tonight on the D70s(which is less able than the D300 in the AF department) and I found no real issue to complain about!
While AF occasionally did stutter or not initiate immediately it wasn't in general terms.. anything to worry about!
In fact so much so, that I think the comments about the Tamron's slowness to focus are all a beat up. Yeah, yeah.. a 70-200VR?HSM/SSM or whatever is going to focus faster.. it damned well should, and if it wasn't perfect every single time you wanted AF!!! I'd be taking it back to the dealer and asking for my (approx) $2K more .. back.. and investing in a better body and this Tammy!!

I've used a Nikon 70-200VR briefly and I do remember it being blazingly quick. that was over two years ago tho.. and I have to say I have no regrets in accidentally getting my Tammy(even considering how much nicer I'd have been to have the VR and AF-S.. as I'm a sucker for AF-S)

So I tried to nail a specific situation where the Tammy may be a liability in it's ability to AF for a given situation.. and I basically found nothing that other lenses wouldn't have done in the same circumstances.. I thought maybe low light was the issue or that a specific camera was the issue.. maybe the comments are for the screw driven lens mounts only.. so the D70s was chosen as it's set up for single shot AF mode(I have the D300 set to continuous) it was low light so some images appear noisy, and I'll try to explain as best I can when I had issues what happened...


No issues! Single shot focused from near to 'spot on' in micro seconds. Single shot clicked and the shot nailed(as best I could). If anyone had experienced this AF speed and complained that it was slow.. they need to have their camera gear revoked!! I can imagine faster AF, but we'd only be measuring hundredths of a second.. of course that could be an important spec, if you photograph ballistic projectiles at the point of exiting long metallic barrels!!


100% crop of above. Focus was spot on.. handheld technique was sloppy and not very well controlled and rushed.. but it serves the point that this lens is both sharp contrasty and fast and accurate in focusing.


here we had problems! I couldn't for the life of me get the lens to misfocus at all light was relatively low(exif : ISO640, 200mm, 1/60s, f/4) 100% crop looks noisy so I cropped to 50%.
Remember 200mm and 1/60s!! my technique is not 100% perfect at the best of times but three frames in sequence saw that at least 1 image was presentable, considering the light conditions.


50% crop. I defocused and refocused may times trying to get this lens to misfocus or become slow to focus or even to procrastinate about focusing at all.. but it just focused perfectly time and again.. so I took three shots to confirm that it wasn't just being lazy in pretending to have focused. it actually focused each time spot on(I hope??)

BUT!!


It did stutter! It wouldn't lock focus on this shot for a long time. Not much I could do to coax it into focusing on the flower stem here.. eventually I did manage to get it to focus but it was painfully slow. Reason! the background was very cluttered.. madly so and this image actually shows that it does a reasonable job of bokeh too. The background was mixed leaves and more stems, so the af sensor(size) was obviously confusing the lens.
Too much clutter in the view of the AF sensor, and the lens hunts. Similar to the situation where you have no contrast to detect.. point your lens at a blank white wall in low-ish light and that's basically what happened here(but the opposite) too much contrast to detect and the lens and AF system didn't know which one to choose. Lens did focus, but usually on the background clutter. This test was to see if I could get it to differentiate what exactly I wanted to focus on.. eventually I did with small half presses to creep the focus point closer.


and again!!
I had trouble focusing on the coiled up section of the antenna. Wonder why??

It's silhouetted against the power pole and of course every now and then it would focus on my chosen point but would once again return back to the power pole..
also the chosen AF point was one on the side which doesn't have cross sensors only the vertical sensor... reality is that it should have focused correctly as this sensor point(orientation) was perpendicular to subject.

My understanding of the best use of a sensor(where sensors are orientated like | or like _ ... if your sensor is perpendicular to the subject, or contrast or detail in the subject matter then AF is likely to be easier to achieve. where the sensor is a cross type looking like this + it doesn't matter. With the majority of bodies the center sensor is cross type and the peripheral sensors are vertical types. Higher end bodies have more cross types.

SO when I moved an inch to the right ...


Af was spot on and quick to reacquire every time... once again I defocused(manually) and auto focused. Each time was quick(less than a second.. in other words almost immeasurable).

Does the Tammy 70-200/2.8 have any focus issues.. nup!! Not that I can see with my usage. Maybe against the $2K supersonic competition, it may seem that way, but the reality is that it doesn't. It's a good lens with great IQ.

My only complaint is that the tripod foot is 'taller' than the old 80-200/2.8 and therefore when hand holding and the most natural way to hold the lens is to cup the tripod foot in the palm of your hand.. well I have a Manfrotto RC5 QR plate and it digs deep(the corner) into my palm and feels uncomfy after a few mins.
Tripod collar is removable and as I use a tripod most of the time anyhow(except in these samples ).

Any reservations??? NUP! it;s a good lens.. will keep up with my kids 'bouncing across the room' just as the 80-200/2.8 did. Maybe an occasional missed shot, but that happens anyhow regardless of lens(usually known as 'operator error')

whaddya reckon out of 10 as a points score??

I reckon if you want a good value fast telezoom.. get it.. no more questions!
if you want the best.... then save your pennies and get the best(shouldn't have wasted your time reading this )

two caveats!
I don;t shoot sports either on a personal or professional basis. It may or may not have focus issues in a very fast paced environment.. pointing the lens at kids on bikes zoomng this way and that is about the fastest pace I've experienced... well not exactly but you get what I mean.. occasional birds, one time an equestrian event.. and so forth.
This lens should autofocus fine for most situations like these. That's a simple judgement based expectation going by feel rather than actual useage experience.
If that turns out not to be true, I'll add an updated post to explain that/why.

other caveat!! this is for Nikon mount on a D300 and D70s. D80, D200 D100 etc.. etc... should perform better than this lens has on my D70s(they have better AF systems!) How it fare on a Canon/Sony/Pentax.. I have no idea ...

if someone could do a quick sample test by walking in to a store and at the least, checking AF performance on any other mount type.. I'd love to hear their experience.

I was initially in two minds about trying this lens based on the 'slow to focus reports' .. I can tell 'ya it's bogus!!

next Melb meet I will demand ... that the other Nikon owners at the meet try this lens and play with AF and get a general consensus on this (non) issue.

hope this helps
(actually I hope it makes sense?? )