# Problem with 5D III?



## sovietdoc (Aug 4, 2012)

I am currently testing my new Sigma 180mm f/2.8 macro lens with my 5D 3 and I am having a weird problem. When I take a photo and look at it on the rear screen of the camera, it shows black circular lines at the edges. Depending on the magnification factor of the lens it can be in the corners of the screen (at 1:1.25) or almost a full circle (at 1:1) But if its at 1:30 or something higher there are no lines.







Here is the same thing zoomed in on the camera.






But when I copy the image to computer and open it up in photoshop or lightroom, everything is fine.





It only happens when shooting at 1:1 or close to it, when I take images at 1:10 or something, everything is fine.

When I look through the viewfinder, there are no lines.
When I look through Live View there are no lines.
When I open the RAW on my computer there are no lines.

When I look at the picture on the camera, there are lines.

I've never had this problem with 70-200 II or other lenses but I never had a lens that had 1:1 magnification and this ONLY happens at 1:1 mag or close to it.

It seems like there is some issue with camera's software that creates a preview of the shot, so it can display it very quickly.

Has anyone seen anything like that before? It's really annoying.


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## bdunbar79 (Aug 4, 2012)

It's probably the lens, unfortunately. That particular sigma lens is making it do something it shouldn't.


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## cliffwang (Aug 4, 2012)

bdunbar79 said:


> It's probably the lens, unfortunately. That particular sigma lens is making it do something it shouldn't.


That should be the 5D3's firmware problem. If the image is fine on computer, that means the image is really no problem. However, when 5D3 resized the image to a 3" LCD, it just didn't compute the output right.

sovietdoc, you should let Canon know the issue, so Canon could fix it in the next version of firmware.


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## sovietdoc (Aug 5, 2012)

Are you sure I can contact them about it? They're just gonna say "oh its a Sigma lens, gtfo"

It's clearly not a problem with the lens because in viewfinder, in live view and on the computer there are no lines. Most importantly that on the computer when looking at the actual RAW there are no lines.

It seems like a bug with 5D III's resizing algorithm. Does anyone else have 1800mm macro they could try with 5d 3 at 1:1 magnification?

I will also try to0 reproduce this issue at f/3.5 because besides this very lens, there are no f/2.8 180mm macro lenses out


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## pwp (Aug 5, 2012)

A big hair in the mirror box? Wouldn't it be nice if it was that simple. Check if it happens with other lenses and you'll discover immediately if it's the lens or the body.

PW


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## Mt Spokane Photography (Aug 5, 2012)

If it only happens with that one Sigma lens, you are right. Canon is not going to fix something caused by the lens. Sigma has reverse engineered Canon protocols, and tells the Camera that it is a certain Canon lens, and the camera responds accordingly. There is a table of Canon lenses and camera corrections for them internal to the camera. It its making the wrong correction for the lens, then sigma is at fault, and they are the only ones who can fix it.
If you have the lens correction feature enabled in your camera, turn it off and see what happens.


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## sovietdoc (Aug 5, 2012)

pwp said:


> A big hair in the mirror box? Wouldn't it be nice if it was that simple. Check if it happens with other lenses and you'll discover immediately if it's the lens or the body.
> 
> PW



It doesn't happen to other lenses but as I already explained in my post, this isn't a lens issue because on the computer, the image is fine, so is in the viewfinder so is in the liveview. The ONLY time this issue is there is when I am looking at the already taken photo on the camera. So it seems like its a firmware bug. AND it only happens at 1:1 mag of the lens or close to it.


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## sovietdoc (Aug 5, 2012)

Mt Spokane Photography said:


> If it only happens with that one Sigma lens, you are right. Canon is not going to fix something caused by the lens. Sigma has reverse engineered Canon protocols, and tells the Camera that it is a certain Canon lens, and the camera responds accordingly. There is a table of Canon lenses and camera corrections for them internal to the camera. It its making the wrong correction for the lens, then sigma is at fault, and they are the only ones who can fix it.
> If you have the lens correction feature enabled in your camera, turn it off and see what happens.



Yes I do have lens correction enabled, I'll turn it off and see whats up.


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## sovietdoc (Aug 5, 2012)

RESOLVED. Turning off illumination correction solves the issue. Usually, the camera detects that the lens is wrong and it wont use correction, in this case it didn't so it was using EF 180mm profile and was messing it all up.


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## neuroanatomist (Aug 5, 2012)

Makes sense. As Mt. Spokane stated, 3rd party lenses 'spoof' the camera by using Canon lens codes - this has caused other issues in the past, and it isn't Canon's job to fix them.


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## bdunbar79 (Aug 5, 2012)

cliffwang said:


> bdunbar79 said:
> 
> 
> > It's probably the lens, unfortunately. That particular sigma lens is making it do something it shouldn't.
> ...



Turns out it's both


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