Author Topic: Vignetting  (Read 3439 times)

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Offline GaryD

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Vignetting
« on: September 03, 2010, 08:39:12 AM »
I took a number of landscape shots last weekend (on my 850 and 24-70CZ) and when I processed them through iPhoto I noticed
some very noticable vignetting. The shots in question were at f2.8, 1/2000 and @70mm. Has anyone else experienced this? I would
have thought that a quality piece of glass like the 24-70 this would have been an non-issue???

Gary
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Offline Stef.

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Re: Vignetting
« Reply #1 on: September 03, 2010, 05:17:30 PM »
Gary, do you have any filters on your lens and how thick are they? Did you shoot in raw and your last settings included a vignette? I don't have these issues with the above lens but know them from using a thicker UV lens on my older lenses. If you have any kind of protecitve filter on your lens check how thick they are.
Hope this helps?
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Offline Rob aka [minolta mad]

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Re: Vignetting
« Reply #2 on: September 03, 2010, 09:23:51 PM »
I have also never noticed any vignetting with the CZ24-70 either, but i do have the slimline UV filter.
Any chance of posting a sample image ???


Rob

Offline GaryD

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Re: Vignetting
« Reply #3 on: September 04, 2010, 04:02:08 AM »
Here you go:

http://i887.photobucket.com/albums/ac73/GaryD_album/DSC04207-1.jpg

Shutter 1/2000, Aperture f2.8, Exp. Bias 0.00, ISO 200, Hoya CIR - Polarizing Filter + Hoya Pro1 Digital UV filter
GaryD

Alpha 850, CZ f2.8 24-70ZA, 70-200G f2.8, Sigma f4.5-5.6 12-24, Minolta f1.4 50mm

Offline rannari

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Re: Vignetting
« Reply #4 on: September 04, 2010, 06:23:12 PM »
Hi,

Have you tried without the polarizing filter. Stacking two filters (especially polarizing filter) and using smallest aperture can create vignetting like in your case.

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Offline Tom F

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Re: Vignetting
« Reply #5 on: September 04, 2010, 06:37:28 PM »
I have a feeling that the filter stacking is what's causing the problem.
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Offline Rob aka [minolta mad]

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Re: Vignetting
« Reply #6 on: September 04, 2010, 08:58:02 PM »
Tom is right, its definately down to having two filters mounted.
Remove the UV filter and the vignetting will dissapear.


Rob

Offline Stef.

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Re: Vignetting
« Reply #7 on: September 04, 2010, 09:39:07 PM »
Yes two filters is very likely the reason for the vignetting. Try it with one.
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Offline Desmo

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Re: Vignetting
« Reply #8 on: September 06, 2010, 04:52:06 AM »
my 24-70 vignettes with just one fat filter on it at 24mm let alone with 2 filters

that is most definitely the problem. The shot following was taken with this lens at 24mm:


« Last Edit: September 06, 2010, 05:04:34 AM by Desmo »

Offline Rob aka [minolta mad]

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Re: Vignetting
« Reply #9 on: September 06, 2010, 04:32:08 PM »
I have just tried mine with UV filter and the lee filter holder (2 slots) and the 105mm ring for attaching the polariser and there is a tiny bit, that is easily removed in PP.
With just one slot on the filter, there is none, tried at f2.8, 5.6, 8 and 11.

Seems like it may be like alot of CZ16-80's that were released, some really bad, and others didnt suffer at all.


Rob
« Last Edit: September 06, 2010, 04:33:59 PM by Rob aka [minolta mad] »

Offline Desmo

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Re: Vignetting
« Reply #10 on: September 07, 2010, 06:04:54 AM »
It should only happen at the wide end of the focal length and only when the lens is closed down a few stops or more. At wide apertures it might slightly dim the corners but may not be visible.

I'm surprised you're getting vignetting at 70mm GaryD and really surprised it's visible at f2.8: your filter stack must be real thick.

Note: the picture posted above was taken with what would amount to two standard filters on it at 24mm and close down to about f9


Offline FarmerDave

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Re: Vignetting
« Reply #11 on: September 07, 2010, 07:13:55 AM »
It happened once to me when my hood was bumped and twisted slightly off center.
I agree there should be very little if any vignetting at 70mm. I use slim filters on my 24-70 just to be sure.