D7100 and Tam 150-600 problem

J

J-see

Senior Member
mikew said:
Focus freeze could easy be related to VR who knows at this point but not in any way the shutter speed,i just feel your complicating the freeze issue for any one reading this.
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It's not the shutter speed that is the problem. I posted here about my inconsistent focus thinking it might be related to the freeze issue. I could not explain why the one day I had nice and sharp shots and the next day, too many were out of focus. I now know the reason and that it has nothing to do with the freeze issue. The Tam does focus fine but at high shutter, VR is not beneficial.

The freeze is a separate problem but since it twice in a row occurred not long after I enabled VR, I think it has something to do with it.
 
M

mikew_RIP

Senior Member
Latest update my lens has been to Germany and is on its way back now,no idea how much of the service work is done there but i do know someone had there Canon fit unit go there for a firmware update,the next problem is there is no sun forecast for at least 5 days.
 
Scott Murray

Scott Murray

Senior Member
mikew said:
Latest update my lens has been to Germany and is on its way back now,no idea how much of the service work is done there but i do know someone had there Canon fit unit go there for a firmware update,the next problem is there is no sun forecast for at least 5 days.
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Thats good, it means you can test it out under bad situation and if it performs well than yay no issues in good light ;)
 
J

J-see

Senior Member
mikew said:
Latest update my lens has been to Germany and is on its way back now,no idea how much of the service work is done there but i do know someone had there Canon fit unit go there for a firmware update,the next problem is there is no sun forecast for at least 5 days.
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If the firmware fixes it, I might send mine in when I got the 300mm. I'm now shooting with VR disabled to check if the freeze occurs too without. This far all is good.
 
M

mikew_RIP

Senior Member
Just picked it up after four weeks to the day,its been to Germany no mention of firmware but if there was an update ime sure they will have applied it while it was there,the job sheet states Adjusted resolution and auto-focus and cleaned.
May get chance to test it tomorrow but with it not being waterproof not today,it focuses in the house so thats a start.
 
M

mikew_RIP

Senior Member
Out today 155 shots and no focus freeze,hunted a few times but thats ok and it looks like i will have to re do the focus fine tuning.
 
J

J-see

Senior Member
How's the Tam doing this far Mike?

I've shot thousands without VR now and never had an issue. Now I'm curious how fast it'll occur when I switch VR back on.
 
M

mikew_RIP

Senior Member
Third time out today and had focus freeze 3 or 4 times,have a few more ideas of what could be causing it but need to do my own tests over this coming week.
 
J

J-see

Senior Member
mikew said:
Third time out today and had focus freeze 3 or 4 times,have a few more ideas of what could be causing it but need to do my own tests over this coming week.
Click to expand...

I was looking at some information about the VR system in this Tam and contrary to Nikon, they use a 3 unit control system. One vertical, one horizontal (like other brands) but another diagonal too. I didn't give it much thought when reading but if you start to think about it, it's easy to see where problems could arise.

Now I'm no engineer and have no exact information but even so, what I think is that a three point correction system like this works well if you are correcting something spherical but when it is cylindrical like the VR lens, it's asking for problems. A two point system can't lock up because both have their freedom to move along their own axis but a three point system like this has a diagonal unit that basically does the same job the two other units combined do. That's how Nikon corrects diagonal shake.

You have to use some good voodoo to make that work perfect because each of them can now create a lock if their response is too slow or they get an impulse into a direction that's impossible.

Like I said; I don't really have anything accurate on how it exactly works (a drawing and some basics is all I discovered) and therefor this is just some abstract on the principle but if, it's either a fine-tuning problem in regards to these VR units or we trigger the problem ourselves by making a specific move while the VR is active that triggers a reaction in the diagonal unit that simply isn't possible to perform.
 
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M

mikew_RIP

Senior Member
J-see said:
I was looking at some information about the VR system in this Tam and contrary to Nikon, they use a 3 unit control system. One vertical, one horizontal (like other brands) but another diagonal too. I didn't give it much thought when reading but if you start to think about it, it's easy to see where problems could arise.

Now I'm no engineer and have no exact information but even so, what I think is that a three point correction system like this works well if you are correcting something spherical but when it is cylindrical like the VR lens, it's asking for problems. A two point system can't lock up because both have their freedom to move along their own axis but a three point system like this has a diagonal unit that basically does the same job the two other units combined do. That's how Nikon corrects diagonal shake.

You have to use some good voodoo to make that work perfect because each of them can now create a lock if their response is too slow or they get an impulse into a direction that's impossible.

Like I said; I don't really have anything accurate on how it exactly works and therefor this is just some abstract on the principle but if, it's either a fine-tuning problem in regards to these VR units or we trigger the problem ourselves by making a specific move while the VR is active that triggers a reaction in the diagonal unit that simply isn't possible to perform.
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Thats part of the direction ime checking,i decided its no use posting a diatribe about the workings of my mind and the things ime going to check,if i find a way of avoiding it and still use VR then i will post the details
 
J

J-see

Senior Member
I'm doing the same, when VR is active, I'm making funny moves checking if I can find the "lock". This far I only look ridiculous making my moves.
 
M

mikew_RIP

Senior Member
Ime looking more into focus modes,normally i use AF-C and will give AF-S a try,in AF-C though you can adjust the time before the camera decides to refocus so this is just one area ime looking into,i decided to accept if the lens has been to Germany it will be now performing at its optimum and the camera focuses well with the 55-300 on so this looks like its a setting or lighting or both area just with this combination,taking the camera shake into the equation would mean if ime looking in the right place the problem and cure could be user specific.
 
J

J-see

Senior Member
mikew said:
Ime looking more into focus modes,normally i use AF-C and will give AF-S a try,in AF-C though you can adjust the time before the camera decides to refocus so this is just one area ime looking into,i decided to accept if the lens has been to Germany it will be now performing at its optimum and the camera focuses well with the 55-300 on so this looks like its a setting or lighting or both area just with this combination,taking the camera shake into the equation would mean if ime looking in the right place the problem and cure could be user specific.
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Keep me updated since it might be related to my focus inconsistency. I'm back to zero with my potential causes since mist isn't triggering it. It might contribute but it wasn't the cause.
 
J

J-see

Senior Member
I can strike VR off the list as possible cause of freeze.

Mine froze and after first pushing the button a couple of times, I checked to be sure I did not accidentally enabled VR, MF or switched to limited. Everything was set normal. Then I checked the focal length, focus and changed the length to both ends to see if that did something. By the time I was finished checking, I pushed the focus button and it jumped into action.

About 150 shots after that, the same occurred. I checked the buttons and settings to keep track (and maybe find a pattern) and waited a bit and it again jumped into action.

Both times it occurred at the shorter end, around 250mm. It's rare I shoot the Tam short and I can remember at least one freeze that also occurred while shooting short.

Both times AF-C GrP, around 250mm, the first focus at about 6m, the second time close to infinity. Both times I was constantly adjusting the focal length around the short end.
 
M

mikew_RIP

Senior Member
Today i used the tripod and gimbal head,used AF-C and stabilizing on,this takes me out of the equation 166 shots and no focus freeze,will need to run it a few more times to see if ime on the right track as to the cause.
 
J

J-see

Senior Member
mikew said:
Today i used the tripod and gimbal head,used AF-C and stabilizing on,this takes me out of the equation 166 shots and no focus freeze,will need to run it a few more times to see if ime on the right track as to the cause.
Click to expand...

I'm writing down all my settings during a freeze since yesterday. It's very rare in my case and I was thousands of shots without any freeze when I was testing VR OFF. Since this isn't the problem I'm now suspecting something in relation to the shorter range or more likely, to the hectic movements I made while shooting gulls at close range. At the long range there's seldom a need for all that fast focus changing and moving the lens in every direction.

Btw, if yours freezes again, can you check if it jumps back into action after 10-15 seconds? Mine did the last two times.
 
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