Manuel fine tune in Auto Focus is that ok?
Jul 1, 2016 14:24:49 #
amfoto1
Loc: San Jose, Calif. USA
NormanTheGr8 wrote:
Couldn't find anything in archives
I was wondering if I were to fine tune focus while holding in back button focus can I damage anything?
Shooting 7Dmk2 with Tamron 16-300 and having trouble getting pinpoint focus on insects resting on leaves (those little dragon flies don't give much profile to focus on !) I was thinking I could fine tune it with the focus ring once Auto focus was locked with the back button. would doing this damage the lens or camera?
Thanks
Norm
I was wondering if I were to fine tune focus while holding in back button focus can I damage anything?
Shooting 7Dmk2 with Tamron 16-300 and having trouble getting pinpoint focus on insects resting on leaves (those little dragon flies don't give much profile to focus on !) I was thinking I could fine tune it with the focus ring once Auto focus was locked with the back button. would doing this damage the lens or camera?
Thanks
Norm
You should be checking with Tamron.
Canon's own micro motor lenses (not marked either "STM" or "USM"), you'd damage the lens focusing mechanism. With those you MUST turn off the AF at the switch first, before manually focusing the lens.
Other Canon focus drive systems.... STM and USM lenses... no problem. Those allow for "FTM" or Full Time Manual override of the AF. Won't damage the lens.
But, those are Canon lenses and you're asking about a Tamron lens. It likely uses a micro motor or piezo drive (PZD), which are pretty similar. But that might be designed so that manually overriding the AF won't do damage. Only Tamron can say. I know for sure it's okay to manually override the focus of a Tamron macro lens that I use (60mm f2.0). It's not specified, but probably uses a micro motor/piezo drive.
Some of the more expensive Tamron lenses have a USD autofocus drive that's similar to Canon USM, and probably is fine with FTM.
All Tokina lenses use micro motor, but they have a "focus clutch" mechanism that makes it impossible to manually override AF on them. When set with AF on, the manual focus ring just spins freely and doesn't do anything.
Some Sigma lenses are micro motor, I have never used any of them and can't say if they can do FTM. I have used some Sigma HSM, which are similar to Canon USM and can do FTM without any problems.
Something that might be a hint... When the lens autofocuses, does it rotate the focus ring itself? If not, it's probably safe to manually override. But, if it does, I'd avoid it.... at least until I checked with the manufacturer to see if it's okay.
In no case would you do any harm to the camera.
EDIT: And, I just looked it up and it appears the 16-300mm does support full time manual focus... so you won't do any harm to the lens overriding AF manually. (The Tamron 18-270mm that it replaced was not able to do FTM... and it's focus ring rotated during AF).
Jul 1, 2016 21:58:39 #
Thank you all was just a thought that came to mind although I had been up for 26 hrs by the time I wrote that .For that pic I was at 300 mm focused on the df than pic is cropped ,getting closer would probably help too😆
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