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Author Topic: Is this about Normal for Canon 15-85  (Read 2119 times)

bklein61

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Is this about Normal for Canon 15-85
« on: January 01, 2012, 11:25:07 AM »
These were taken about a 45 degrees from where the sum was coming down.  There is quite a bit of purple fringing on the tree's. I am shooting them stop down at least 1 stop some 2 from maximum aperture.  Could be that use to of the 70-300l is and it being able to shoot wide open

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Is this about Normal for Canon 15-85
« on: January 01, 2012, 11:25:07 AM »

elflord

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Re: Is this about Normal for Canon 15-85
« Reply #1 on: January 01, 2012, 12:51:46 PM »
These were taken about a 45 degrees from where the sum was coming down.  There is quite a bit of purple fringing on the tree's. I am shooting them stop down at least 1 stop some 2 from maximum aperture.  Could be that use to of the 70-300l is and it being able to shoot wide open


Depending on the focal length you're shooting at, you could get substantial CA. I would notice this when shooting trees at 15mm  against the sky as in your pictures. According to photozone's testing, the effect is most pronounced at both extremes of the focal length range and stopping down doesn't make a whole lot of difference. All the more reason to shoot raw.

http://www.photozone.de/canon-eos/465-canon_1585_3556is?start=1

bklein61

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Re: Is this about Normal for Canon 15-85
« Reply #2 on: January 01, 2012, 12:58:57 PM »
The first one was at 19mm

The second shot was at 50mm

Mt Spokane Photography

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Re: Is this about Normal for Canon 15-85
« Reply #3 on: January 01, 2012, 01:49:19 PM »
You have confused readers with your terminology "down at least 1 stop some 2 from maximum aperture"  Aperture is not measured in mm in the camera settings, but by f stops.

Just giving the actual settings would be more informative rather than have readers guess if you meant a focal length of 19mm, which is 4mm from the shortest focal length.

elflord

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Re: Is this about Normal for Canon 15-85
« Reply #4 on: January 01, 2012, 02:28:25 PM »
The first one was at 19mm

The second shot was at 50mm

Maybe I'm missing something, or maybe it's  these are scaled down jpegs and not 100% crops -- but I see a kind of blue haloing in the 19mm shot (maybe that's CA after you rescale the jpeg ?) but I don't see much evidence of CA in the second shot. 

Anyway, I would expect visible CA for a shot like this.

Here's a 100% crop of a shot I took, 15mm at f/11

bklein61

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Re: Is this about Normal for Canon 15-85
« Reply #5 on: January 01, 2012, 02:47:19 PM »
I am sorry I should of been more specific.  I was only trying state that was not shooting the lens wide open and had it stop down a few f stops.

The reply I gave was to Elford when he was wondering what focal lengths I was shooting at,  this is where the 19mm and 50mm focal lengths came.  Sounds like I may have to use a stop this lens down to a f11 to get rid of that fringing

elflord

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Re: Is this about Normal for Canon 15-85
« Reply #6 on: January 01, 2012, 03:03:05 PM »
I am sorry I should of been more specific.  I was only trying state that was not shooting the lens wide open and had it stop down a few f stops.

The reply I gave was to Elford when he was wondering what focal lengths I was shooting at,  this is where the 19mm and 50mm focal lengths came.  Sounds like I may have to use a stop this lens down to a f11 to get rid of that fringing

No, if you read the photozone review, you will see that stopping down does not substantially improve CA when shooting at around 15mm or 85mm. If you look at the picture (100 percent crop from the corner of the frame)  I posted, you will see that it shows substantial CA even though it was taken at f/11.

The conclusion is that to get rid of that fringing, you either need to shoot raw and use software to get rid of it, or stay away from the extremes of the focal length range when taking this kind of shot.

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Re: Is this about Normal for Canon 15-85
« Reply #6 on: January 01, 2012, 03:03:05 PM »

bluewolf37

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Re: Is this about Normal for Canon 15-85
« Reply #7 on: January 01, 2012, 07:05:28 PM »
i used that lens a lot when i first got it and yes ca was noticeable on the photos i took with it. It is also the only lens purchase that i felt wasn't worth the money, because i could have waited a while longer and gotten the 24-70mm. Then i would have had some L quality glass and the ability to upgrade to a full frame sensor sooner. In the end i spent even more money to get the 24-70mm and love it. That being said the 15-85mm was still a way better lens than the kit lens.

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Re: Is this about Normal for Canon 15-85
« Reply #7 on: January 01, 2012, 07:05:28 PM »