[sascha]

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When I use my 5d3 in AI Servo mode, continuous shooting, ISO >approximatelly 1600 and with my Tamron 70-200 VC, 1 out of approximatelly 15 photos has banding in lower part of the photo (or upper part of the sensor) by lanscape orientation. VC has no influence.

 

I tested my lens with 4 different canon 5d3 cameras (1 is mine and other 3 brand new cameras in 3 different shops in Stuttgart), and I test also 1 brand new tamron 70-200 on my camera. In all cases I got the same problem: banding lines in lower part of sensor yby landscape orientation. I also tried my lens on my old camera Canon 550d and I did not have this problem in that combination.

I did not notice this issue with other lenses.

 

Crop of the example photo: http://i1225.photobucket.com/albums/ee39...zfjnpw.jpg

 

2 RAW files in landscape and portrait orientation: https://drive.google.com/folderview?id=0...sp=sharing

 

I use Lightroom 6, but I also checked this issue with DPP and it is the sam thing.

Both, Canon and Tamron in telephon conversation told that the problem belong to the other side, but they also told to send camera/lens to check it.

 

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After some testings and researching in the net, the most possible scenario to me is: AI servo force USM motor continuiusly to run. This causes continuous RF radiation. USM drive is on the upper side of the lens, the banding is appearing on the lower part of the photos, i.e. on the upper part of the sensor, means on the same side as banding. Due to any reason camera/sensor/processor are not capable to handle this RF and this is causing banding...

 

As fare as I am concerned, this is system failure of  canon or both....this problem was common for canon EOS 5D with canon lenses, with 5d3 this is happening only with Tamron 70-200 VC....as already told, I tested 2 lenses on 4 cameras with the same results/failures....

 

i send both pieces of equipment to the corresponding services with identical sample RAW photos and with identical description...completely transparent and politically correct now i can only wait to see what an answer i will receive...

 

Do you folks have any comment or an idea what can I undertake in order to overcome this issue?


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[Brightcolours]

Obvious answer (which you won't like): don't use the Tamron lens, or at least not with Ai-Servo.

[sascha]

you´re right, I did non like the answer   although it´s obvious...or it´s not...anyhow, i blame both sides....

[popo]

This is one of the risks we take when we buy a 3rd party lens.

All electronic devices have to be made to appropriate standards, where they have some level of immunity to receiving interference, and they also must not generate excessive interference. Such testing will never cover every possible combination of use cases. It is possible to be in compliance and still encounter problems like the one described here.

If you had used Canon lens on Canon body, of course any problems will be with Canon. Here we have Tamron saying their lenses work on Canon. Canon do not say you can use Tamron lenses. Therefore I think this is up to Tamron to sort out in the first instance.

[sascha]

you are right, but it is somehow odd that this lens doesn´t  make such a problem on other bodies, or at least i tested it on my 550d. That´s why i told that i blame prtly canon as well

[JJ_SO]

The 550D is APS-C, so sensor surface is smaller and maybe better protected by body material. There is no obstacle / protection shield between emitting motor and FF sensor, so the sensor gets the full load of radiation.

 

Interesting problem, I heard from other Canon users about banding as well. So it could as well be caused by the lens? Didn't imagine that. So I learnt something new.

 

But with regard to mirrorless FF like the Sony A7R and colleagues: how is this sensor protected? And could you do something against?

[sascha]

550D=plastic body

5D3=magnesium...

[JJ_SO]

Magnesium is no better shield against high frequency - and in front of the plastic body is a metal bayonet. Also, the mirror box is not only plastic?

 

If I look at this explosion drawing, I see at least two parts potentially made of some cast or sheet metal, which are in between the sensor and the radiating HS drive of the Tamron - this could be enough to prevent banding.

 

[Brightcolours]

The 550D is APS-C, so sensor surface is smaller and maybe better protected by body material. There is no obstacle / protection shield between emitting motor and FF sensor, so the sensor gets the full load of radiation.

 

Interesting problem, I heard from other Canon users about banding as well. So it could as well be caused by the lens? Didn't imagine that. So I learnt something new.

 

No you didn't. Banding is a word used for many different things.

[sascha]

but it is unfortunatelly not....