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colinp

Northern Lights Images v QC

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image003.png0307_1816_CEKP54.png

 

 

lefthand image failed QC - sample returned by alamy.

slightly larger greener image passed QC and sold several times over.

 

part of my response to alamy:

 

"Thx for the feedback - the following is not an attempt to get you to change your mind about this particular image but just to share my thoughts as a professional photographer with some $5000 of successful sales(after commission) of similar northern lights images in my alamy collection.
Because of the nature of the image I applied some luminance/colour noise reduction which results in some loss of detail but as we are only talking about stars this is not an issue. For northern lights images most customers are looking at the overall impact of the image and in this case there is NOT any camera shake as I have used a tripod and the stars ( only detail visible) are NOT out of focus.This is specialist photography and as such needs a slightly different approach in extracting jpegs from a raw image as lens is used wide open and high iso are typical settings. These images are probably more difficult to assess and standard qc procedures harder to apply across the board. I will place this image for sale on my own website in this case so the failure is not an issue other than differences of opinion maybe on what a customer would be happy with and what standards you like your images to meet.
I have attached a sample of an approved image which looks similar in terms of quality to my failed image but has sold several times to presumably satisfied customers.."

 

 

 

Question: Any one else had any similar disagreements / failures.? To my eyes both samples look similar in terms of quality or do I need to go to specsavers??!! Your thoughts please thx v much

 

 

 

 

 

 

 

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"really soft lacking definition and has camera shake"

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What asa was the camera set to? (and is the image above the complete frame or a crop). I had several failures with Alamy QC a few years back with pure astro images (not Northern Lights, but galaxies, star clusters etc) however they were all taken up by G---y.

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iso 1600  canon 6d  -  passed image iso 400  450d   these are crops original images are here:

www.buyimage.co.uk/x/x.jpg

www.buyimage.co.uk/x/y.jpg

regards

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Left hand image looks OK to me. When using a dslr for astro work I tend to only go up to 1000asa maximum on individual frames. Many of the deep sky shots I take are stacked images comprising 20-30 individual frames and, of course, the stacking greatly reduces the noise. Another trick is to take two images, one of the Northern Lights at, say 1000 asa, with lens fully opened then a second  image for the foreground landscape at 200-400asa with the lens stopped down then combine.

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I think, by Alamy's QC standards, both images should have failed.

 

Perhaps images like these could go via the news route? (I don't know myself - I don't  do news.)

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I think that sometimes it's just the luck of the draw. Earlier this year, I had an image pass QC and later decided that I didn't like its blue cast. So I requested deletion and then uploaded a corrected version of the same shot (I also cleaned up some dust spots that both I and presumably QC had missed). This time it failed QC due to "noise." Either the image never got inspected the first time, or I somehow introduced some noise when correcting the colour cast. The slight shadow noise didn't look problematic to me (shot at 200 ISO), but whoever checked the second version obviously didn't agree. C'est la vie.

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