Well I cancelled my order and sent Tamron Japan an e-mail in regards of the AI servo focus issues on certain camera bodies. Looks like I will never be buying one of these, as obviously they do not see it as a problem. We just have to get all of our birds in flight to hover, then fly again, as we try each of these "fixes", per Tamron.
This is the response I got.
Thank you for your patience.
Regarding the AI servo issue, the more zoom position comes to tele, the shallower the depth of field gains. At a very tele end, the depth of field turns to be so shallow that AF may not find an object precisely and AF stops searching when AI servo function in use.
When AF stops to search the object, please try to do following:
- Apply a limiter switch depending on the object distance under AI Servo function.
- or re-press shutter button.
- or rotate the focus ring roughly to get the object on focus and then once again
shoot the object by pressing shutter button halfway.
(Note) Please do not rotate the focus ring when AF is running.
probably standard ass covering while they examine issues behind the scene. I don't expect a quick resolution or an admission there is a problem, at best a quiet fw upgrade and/or a running change on hardware.
Well, after testing the Tamron out with my 7D today from my office window which overlooks an interstate, I can additionally confirm the issue exists. 6D seems ok. However...as was suggested above, taking your finger off the shutter button and basically letting the lens "catch it's breath" for a second seems to wake it up to the fact that it's gotta track something new.
On the positive, it retained AF on moving objects over 10-12 frames no problem. So for me and my uses, I don't see this issue stopping me from enjoying the lens (racetracks etc.) but if I were a birder I'd consider it a bigger issue.
I guess the reality is that at $1k and 150-600mm zoom range, something had to give. The IQ seems to be very good, build good, and good VC, so an AF system that seems to struggle with certain Canon bodies under a demanding AI Servo usage appears to be the "give".
For me, it isn't a big deal, but for others I could definitely see this being a deal breaker.
surfinrobin wrote:
....."unless you happen to own one of the latest bodies in the Canon line up, in which case your lens will work as you'd expect in AI Servo"...
Sounds like that's just an excuse for me to buy a newer Canon body for sports stuff....
surfinrobin wrote:
....."unless you happen to own one of the latest bodies in the Canon line up, in which case your lens will work as you'd expect in AI Servo"...
Yeah, all those idiots with their lame ass trailing edge 7D's and 1D IV's expecting an AF lens to to actually AF. How naive can you get! Wake up and smell the coffee people.
Anyone thought to check:
On the 1DIV CFn 111-5 (may be different depending on body) "Lens Drive when AF impossible"
0 = focus search On
1 = focus search Off
PaulB wrote:
Anyone thought to check:
On the 1DIV CFn 111-5 (may be different depending on body) "Lens Drive when AF impossible"
0 = focus search On
1 = focus search Off
Default is usually set at 1.
Try setting to 0.
A few people did have this being their problem on the 70D but the 7D and 1D4 users that I have seen post have confirmed they have that setting to "on". I know Tony did as he surely knows his cameras.
Then it really isn't a 'fault' but just the way the AF reacts to a massively out of focus image where there is no contrast.
I have seen similar from macro lenses where there has been plenty of illumination but a very low contrast subject, as well as from long lenses (including Canon L's) which are asked to go from extremes of focus.
PaulB wrote:
Then it really isn't a 'fault' but just the way the AF reacts to a massively out of focus image where there is no contrast.
I have seen similar from macro lenses where there has been plenty of illumination but a very low contrast subject, as well as from long lenses (including Canon L's) which are asked to go from extremes of focus.
The issue is not about moving focus from near to far which is a difficult task in such huge focal range lens. The issue is that once locked on the AIServo won't run and keep tracking the subject. Totally unrelated phenomena.
Have been talking to Tamron for over two weeks on this Aiservo issue and the fact it does or does not work on certain canon bodies. Yesterday I sent them the lens and my 7D, so I am hopeful they will now experience the issue first hand from a registered owner. I have shot well over 1500 BIF images with my Canon 6D body and have had good results using Aiservo. Some of these are posted on my website. http://jjbird.smugmug.com/Photography/Tamron-150600-Lens/i-GKtJqV8
There dealings with me have been vary professional, and I sure hope this will be resolved as I really like this lens.
Jay
