Since it is not super fast, it may occasionally loose focus on continuous focus (AF-C) mode.

Seriously though, the focus and clarity on this bad boy is wonderful.

Works great with Canon M adaptor, with fast focus on M3 or M5.

fast focusing and very sharp for a zoom of this price bracket

Other pros on the lens - fast and quiet auto focus

I personally have problems with getting consistent focus

Really, that is my only real gripe, I know this lens is not an expensive lens like my 400mm, my expectations were at a reasonable level when I purchased the Tamron, and my only other small dislikes are the slow focusing and the problems in low light

This lens seemed to work OK on my Canon T5i, although when I added a Tamron 1.4X Tele converter it would only auto focus up to 300mm.

The ability to switch from near to 45+ feet helps achieve fast focus when needed.

Focus was fast and accurate, at least for the still objects I tested

Very quiet and accurate auto-focus

I do not notice any focus lag between this camera and other more modern and faster cameras (like the Nikon D810) that are out of the ordinary

Focus is pretty fast.

I love how quietly this lens focuses.

I used the Group focusing points, which work great

AF worked as good as manually focusing (pics weren't sharp either way

Despite the somewhat slower focusing, I've still managed to get some awesome bird photos (even hummingbirds hovering over flowers).

PRO:-Integral focus motor is very quick and accurate with Phase Detection AF.-So much reach for so few dollars.-lens collar includes integrated tripod food with grip.-Minimal distortion for a long lens.-Minimal vignetting on APS-C bodies.-Weighs only 4 lbs, which is very light for a lens with 600mm focal length

Awesome lens, works, really good, fast focus, sharp pictures

A slight miss focus can be interpreted as a soft lens

Fast focus, very good image stabilization handheld "VC"

L lens provided and this lens has a much faster focus and the quality is comparable.

It is heavy .A little slow focusing on moving targets.

Though I had some problems with the lens seeking to stabilize focus, it is actually due to the nature of my Nikon d610 camera

Super quiet auto focus

Originally unreliable focus

The glass is great, focus is fine for most scenarios

The images tend to get a little soft focus when fully zoomed out, need to use a smaller aperture to fix that

I based my purchase on other reviewers and they were right -- fast focus, sharp lens.

The group focusing is a new focusing selection available on the D810, D750, and D4/S only I believe

anyway)AF - Amazing - focused all the way to f/11 on 500mm - (used D750) and the drive is silent and VERY quick!AF tracking - extremely well all the way to 600mm (on the long end the 15m-infinity switch should be enabled as it drastically enhances performance of AF in the long focal rangeBuild quality - amazing - it feels like its made out of metal and not plastic - vary solid

I spent a day at a wild fowl recovery center shooting wildlife pictures and have found photographs to be crisp and well-focused.

This is my favorite focusing method

I may try 21 point dynamic focusing on the D700, I heard this

The focus can be a little slow, but I set up at turn 4 and anticipation was more of an issue than focus speed

Fast focus, sharp photos at a great price.

It does focus slower than my 400 mm lens, but for the extra reach it is worth it.

It's a bargain for an upscale camera having a fine focus

The focus was fast and reliable, its very silent and I am very excited about wildlife photography with it, will post the images as I capture them.