shutterbug guy wrote:
Short answer and I'm sure to be badgered over this response.
It's all about the light, some bodies perform better than others with limited aperture. At f6.3 we're seeing this, plain and simple.
Roger
Isn't the 1DmkIV rated to f8 for AF though?
Also do if this is the case, it is a poor showing for Tamron not to list compatible cameras. I find it hard to believe that they conducted all their field testing on certain bodies and ignored the widely used 7D...
Just got my 150-600 yesterday, and I've been putting it to the test for still shots in the T4i. Haven't even mounted it on the 5D3 yet.
So far, so good, but I've only shot static subjects, using both AI Servo and one-shot modes. Today's weather really isn't conducive to great bird images, still or otherwise, with this combination. Today's a full-frame, f/2.8 kind of day. In other words, it's pretty dark out there with occasional snow.
shutterbug guy wrote:
Short answer and I'm sure to be badgered over this response.
It's all about the light, some bodies perform better than others with limited aperture. At f6.3 we're seeing this, plain and simple.
Roger
No badgering, and agree that light impacts AF performance. However, how do you explain that the lens can acquire initial focus, and can track when focus is "bumped"? If it can achieve focus in those instances, why can't a user simply hold down the focus button and have the lens track focus, as is typical AI Servo performance for other lenses? BTW, I don't recall users having this specific complaint about other slow telephoto zooms. Tony has used the Tamron 200-500, so maybe he can opine on that.
mitesh wrote:
No badgering, and agree that light impacts AF performance. However, how do you explain that the lens can acquire initial focus, and can track when focus is "bumped"? If it can achieve focus in those instances, why can't a user simply hold down the focus button and have the lens track focus, as is typical AI Servo performance for other lenses? BTW, I don't recall users having this specific complaint about other slow telephoto zooms. Tony has used the Tamron 200-500, so maybe he can opine on that.
I've had difficulties with 2 Canon f5.6 lenses and tracking but none with the 70-200L f2.8 and the 500L. A big difference imho
shutterbug guy wrote:
I've had difficulties with 2 Canon f5.6 lenses and tracking but none with the 70-200L f2.8 and the 500L. A big difference imho
Hmm... sorry to hear that. I've used Canon's 400/5.6, 600/4 with 1.4X, and currently shoot extensively with the 800/5.6 on both a 7D and 5D3 without those issues.
mitesh wrote:
Hmm... sorry to hear that. I've used Canon's 400/5.6, 600/4 with 1.4X, and currently shoot extensively with the 800/5.6 on both a 7D and 5D3 without those issues.
No need to be sorry, none of those lenses were the ones that struggled with light. The 400L has to be a champion for focusing for sure.
arbitrage wrote:
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.
I found my 7D/150-600 will run and keep tracking something like a car...but if you quickly switch over to, say, another car going the other direction and try tracking that...it needs the user to release the shutter, give it a second, and then it'll re-acquire focus.
jjbird wrote:
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
Like you, I have a 6D as well as a 7D. So you're saying that so far on the 6D, the AF Servo is rock solid in all conditions? I'll have to try my 6D with the same panning exercise I did with the 7D and see if I come to the same conclusion as you.
The unfortunate thing is that this is just encouraging me to buy a d*mn 5D3 to replace the 7D as opposed to waiting on a new 7DII someday...
gocolts wrote:
Like you, I have a 6D as well as a 7D. So you're saying that so far on the 6D, the AF Servo is rock solid in all conditions? I'll have to try my 6D with the same panning exercise I did with the 7D and see if I come to the same conclusion as you.
The unfortunate thing is that this is just encouraging me to buy a d*mn 5D3 to replace the 7D as opposed to waiting on a new 7DII someday...
Why not buy a 70D to replace your 7D and use the extra cash for more glass?
The Tammy supposedly works pretty well with the 6D and 70D bodies.
cameron12x wrote:
Why not buy a 70D to replace your 7D and use the extra cash for more glass?
The Tammy supposedly works pretty well with the 6D and 70D bodies.
Yea...I've thought about that too...as I sold my 400 DO when I picked up the Tammy, so I have a decent amount of cash sitting in my Paypal account begging to be spent on something... I guess for now I'm holding out hope it gets fixed by Tamron. And I still haven't determined if this shortcoming is something that'll really affect the way I use the lens. Gotta think some more....
shutterbug guy wrote:
It's all about the light, some bodies perform better than others with limited aperture. At f6.3 we're seeing this, plain and simple.
So my 1D4 has no problem focusing with a 1.4x TC on a 400 f5.6 or 100-400 f5.6, and my 400 DO has no problem focusing with a 2x TC on it, all now at f8, and you say my 1D4 has a problem with the Tamron is because it is f6.3 Yeah, sure.
And once again, the problem has nothing to do with the focus-limiter setting, focus-search on or off, poor lighting, or a poor contrast subject.
Maybe the lens isnt the problem but people expectations are.
The problem is that people expect a $1200 dollar lens to be able to function as well as a lens that is 5-6 x the price?
If you expect AI performance from a consumer grade piece of glass to match that of a 500II or a 200-400 i think your expectations are just a little bit high.
In short you want Ferrari performance for a Hyundai price tag..sorry aint going to happen.
I have yet to see anyone claim that the Tamron should perform as well as a 500II or 200-400.
And I guess it is just silly people that expect it to work as well as a 100-400 with a 1.4x TC on it.
And I guess people should not expect a reputable lens manufacturer such as Tamron to produce a lens that refuses to change auto-focus under ideal conditions with certain Canon bodies.
Hardly a Ferrari versus Hyundai comparison. I have owned a Hyundai and the automatic transmission worked just fine, even when my wife drove it.
I think it is reasonable to have decent AI Servo performance across all the modern bodies. I mean the 7D is likely going to be the #1 body that people would mount this lens to based on the price point. The fact that it doesn't function as it should on that body is down right unacceptable. And Tony is correct, no one expects 500 and 2-4 results but 1-4 bare and 1-4 with TC should be comparable and so far on the 7D and 1D4 it isn't. However, we know that it is workable on a lot of other bodies (5D3, 6D, 1DX, 70D) so that is very promising for maybe Tamron figuring something out....although their reaction to this matter may determine their future success. We still haven't seen the Nikon version/results/issues and that will also be interesting.
However, we know that it is workable on a lot of other bodies (5D3, 6D, 1DX, 70D) so that is very promising for maybe Tamron figuring something out....although their reaction to this matter may determine their future success. We still haven't seen the Nikon version/results/issues and that will also be interesting.
The problem is - as I see it - whether it will work well with future Canon bodies. The incapafability issue suggests that a future change by Canon might require another trip back to Tamron. (This is why Sigma's dock was a good idea).
shutterbug guy wrote:
It's all about the light, some bodies perform better than others with limited aperture. At f6.3 we're seeing this, plain and simple.
and on top of this the Tamron is cheating and telling the camera "Hey, I'm f5.6" ... and the camera is going to use the AI servo algorithm which it believes is suitable for this
This is why I'm in the process of selling my Tamron lenses. I've since switched to Sigma lenses on my Nikon bodies and have not had any issues whatsoever.
greenfield wrote:
and on top of this the Tamron is cheating and telling the camera "Hey, I'm f5.6" ... and the camera is going to use the AI servo algorithm which it believes is suitable for this
So what? The same thing happens when you attach a non-reporting TC to a Canon f5.6 lens or Sigma f5.6 lens, yet they still manage to focus better than the Tamron, and they are doing so with even less light reaching the sensor at f8.
Yeah, sure.