| Joined: | Thu Apr 19th, 2012 |
| Location: | United Kingdom |
| Posts: | 4424 |
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Some of the Sigma 10-20's don't respond well in the IR range, they seem to hotspot badly which may explain the vignetting, perhaps it isn't vignetting but hotspotting? I have had mixed results with my Sigma 10-20 I think Eric found it hotspotted badly on his D70 but I have had a little success on the D1, although not universal success.
I have spent days on a single image and while I may EVENTUALLY have got the effect I visualised when I composed the image, having spent so much time on it the image is badly degraded. I then try to retrace my footsteps and re-create the same image with the minimal of steps from the original NEF In my experience fiddling with an image for days ends up degrading it and making it muddy with a low IQ.
Sometime it take several attempts to minimise the steps to the clean image I know It can reveal. Then I wonder why I bothered!!! LOL But then I do enjoy the results in the end when I look back.
Too muchI am celebrating, I have got my gas cooker self ignition to work!!! Only take me three years to pluck up courage to pull the cooker apart and repair the switch! Yea, I can put my camping ignitor away!!!
I suppose having seen how badly the 24-70 hotspots, I am more forgiving of the hotspot from the Sigma 10-20. Back then it was an irritation and a let down having the centre of an image 'fogged'.
But as this failing is a feature in many, if not most lenses to some degree, I guess you have to live with it. That's why I like the 17-35....no hotspot at all (don't ask my why). Sadly it limits mid distance work. But the 80-200 AFS is also fog free. So another keeper!
I am not so sure that JKs image is hotspotting though. Usually with hot spots they are associated with high contrast areas near the centre of the image (making the 'fogging' more obvious). I don't see that scenario in JKs image...the centre is all similar tones. Also, the lighter middle does seem symmetrical. I wondered if if was a cloud effect. They do get clouds in Spain dont they...Not sure?
Last edited on Sat Jan 18th, 2014 06:41 by Eric
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Eric