Tamron 150-600mm AF servo issues?

[philmoz]

After reading the posts here I did some experimenting with the lens on a 6d and a 70d. At 150 it works fine but at the longer focal lengths with the cameras set to ai focus and if you focus on a distant point and then quickly move to a near target or vice versa, the camera does not try to refocus unless you let go and repress the AF on button. This has never been a problem but I see its there once I looked for it. I use the lens in ai focus mode most of the time and it seems to track okay but it seems it will quit if there is a drastic change. Its not a big deal to me but something to keep in mind

you are the first who reports this with the 5D MK3, 6D and 70D.

unless it´s the typical behavior you also see with other original canon telephot lenses too.

this kind of "issues" attract people to test things and notice behavior they have not notice before and blame it on the lens.

there are no report from 5D MK3 user that the lens behaves strange.

for comparison i tried the same test using the sigma 120-300 and found that the bare lens is fine but if you add tc's then you get this same behavior so it seems an issue of max aperture and how well ai servo functions and not an issue that is specific to the tamron.

It could have something to do with the max aperture and non-Canon lenses.

I did some more testing today, and found the Tamron lens would sometimes re-focus to a more distant object if there was sufficient contrast for AF to lock onto.

I tried my Canon 100-400L with a Kenko 1.4TC. At 560mm (400mm x 1.4) the camera registers the aperture as f/8; but the lens was still able to re-focus between near and far objects most of the time. It would occasionally refuse to refocus on a more distant object like the Tamron.

I still like the Tamron, and mine is sharper at 600mm than the 100-400L + 1.4TC.

If I hear anything from Tamron, I'll post it here.

Phil.

 

[weixing]

Hi,
I also just got my Tamron. From my observation for 1 session with my 6D (center point AF), the AF servo once in a while (notice 2 times) will go out of focus a bit on a stationary subject... but I'm not very concern at the moment unless it happen very often.

Anyway, the result look quite good... 500mm and 600mm @ F6.3 is slightly sharper than mine EF400mm F5.6L + kenko 1.4x Teleplus Pro 300 (560mm) @ F8.0, but EF400mm F5.6L had less vignetting than the Tamron.

By the way, the EF400mm F5.6L + kenko 1.4x Teleplus Pro 300 (560mm) reported in my 6D correctly as 560mm @ F8.0, but on the Tamron, it reported 600mm @ F6.3... without the TC.

Have a nice day.

 

[Lightmaster]

By the way, the EF400mm F5.6L + kenko 1.4x Teleplus Pro 300 (560mm) reported in my 6D correctly as 560mm @ F8.0, but on the Tamron, it reported 600mm @ F6.3... without the TC.

i don´t get that sentence.
you mean concerning the max aperture for AF?

the 6D will focus with the tamron + 1.4 TC from kenko... but only if contrast is good.
otherwise it´s hunting forever.

 

[weixing]

Hi,

By the way, the EF400mm F5.6L + kenko 1.4x Teleplus Pro 300 (560mm) reported in my 6D correctly as 560mm @ F8.0, but on the Tamron, it reported 600mm @ F6.3... without the TC.

i don´t get that sentence.
you mean concerning the max aperture for AF?

the 6D will focus with the tamron + 1.4 TC from kenko... but only if contrast is good.
otherwise it´s hunting forever.

I mean when I use the EF400mm F5.6L with the Kenko 1.4x TC, it'll reported the actual focal length and f-stop correctly to my 6D (560mm @ F8.0), but when use the kenko 1.4x TC with the Tamron, it'll report the focal length and f-stop without the 1.4x... ie 150mm @ F5.0, 400mm @ F5.6, 500mm @ F6.3 and 600mm @ F6.3.... just wonder how the focal length and f-stop reporting work??

Have a nice day.

 

[Lightmaster]

got an email from tamron germany.

i asked if there is a firmware update or a new revision of the lens (both internet rumors i heard).

it says the AF on the tamron works and if not.. then it´s a single problem with my lens copy.

i would qoute the email here.. but it´s not allowed.

Any review, reliance or distribution by others or forwarding without express permission is strictly prohibited.


well i have no issue with my copy, i just asked if there is a new firmware or a new revision of the lens.

so i guess the talk about shipping delays because of a new revison and a firmware update are just that... rumors.

 

[florianbieler.de]

I got a copy from the second batch now last week and it works fine on my 5D Mark III. It does not make extreme jumps like from a roof in 10m distance to a tree in 50m distance (although it does make the jump from far to near, just not in the other direction), but AI servo works fine when tracking a subject and smoothly follows it.

 

[philmoz]

After reading the posts here I did some experimenting with the lens on a 6d and a 70d. At 150 it works fine but at the longer focal lengths with the cameras set to ai focus and if you focus on a distant point and then quickly move to a near target or vice versa, the camera does not try to refocus unless you let go and repress the AF on button. This has never been a problem but I see its there once I looked for it. I use the lens in ai focus mode most of the time and it seems to track okay but it seems it will quit if there is a drastic change. Its not a big deal to me but something to keep in mind

you are the first who reports this with the 5D MK3, 6D and 70D.

unless it´s the typical behavior you also see with other original canon telephot lenses too.

this kind of "issues" attract people to test things and notice behavior they have not notice before and blame it on the lens.

there are no report from 5D MK3 user that the lens behaves strange.

for comparison i tried the same test using the sigma 120-300 and found that the bare lens is fine but if you add tc's then you get this same behavior so it seems an issue of max aperture and how well ai servo functions and not an issue that is specific to the tamron.

It could have something to do with the max aperture and non-Canon lenses.

I did some more testing today, and found the Tamron lens would sometimes re-focus to a more distant object if there was sufficient contrast for AF to lock onto.

I tried my Canon 100-400L with a Kenko 1.4TC. At 560mm (400mm x 1.4) the camera registers the aperture as f/8; but the lens was still able to re-focus between near and far objects most of the time. It would occasionally refuse to refocus on a more distant object like the Tamron.

I still like the Tamron, and mine is sharper at 600mm than the 100-400L + 1.4TC.

If I hear anything from Tamron, I'll post it here.

Phil.

Update on my 5DIII AI Servo issue with the 150-600 lens.

Tamron asked me to send the lens to the service center, unfortunately this took a long time after the train it was travelling on derailed.

The service center finally got the lens last week, have assessed it, and it is now on it's way back to me - should arrive next week (fingers crossed).
As far as I know they have just done a firmware upgrade - will post more after I've had a chance to test it again.

Phil.

 

[AlanF]

Could you find out for sure if there is a firmware upgrade as it would be useful to know.

 

[philmoz]

Could you find out for sure if there is a firmware upgrade as it would be useful to know.

Lens is back - according to the report they 'carried out rom data update to ver 1.05 to overcome servo focus issue'

A quick test shows improved behaviour with AI Servo.

Phil.