Help.Background Affects Sharpness.

[grGreg]

Check this link http://www.pbase.com/icaros/photo_test

to see how shooting the same subject under the same conditions
but with different background can affect color tone and sharpness.

Three different backgrounds were used to demonstrate this weird behavior.( White, Blue, Gray )

You can observe that the picture with the gray background is SHARPER.

Can anyone explain WHY?

Shooting Conditions.

Canon 10D.
EF Lens 28-135.
f/16, 1/125sec
WB:daylight

Light Conditions.

Studioflash:Elinchrom (Chic 1) 2400w/s
Softboxes 100cm X 100cm

The pictures are 100% crop from the original.

[PacAce]

To be honest with you, they all look the same to me on my monitor. The only difference I can discern from your images is that the background colors are different. But as far as sharpenss and tone, etc. goes, they are all equal.

But, having said that, I do know that the eyes can be fooled by differences in background colors for the same exact subject in the same lighting conditions. There was a good article on this a month or two ago in the Discover magazine.

[defordphoto]

I'm with PacAce. They look to be the same sharpness to me. But, we look at photos differently than most people do so maybe this isn't a fair crowd to perform that experiment on.

[yb98]

colors are perceived differently by our brain depending on the surrounding colors. Look at this pic.
Can you believe that A and B are exactly the same gray color ?
Check the RGB values and you will don't believe your eyes...

http://www.chez.com/ophtasurf/illusions/illusion_adelson2.jpg

[Bruce Hamilton]

To me, the best one is the one with the white background... The grey and blue backgrounds contrast with the subject which also contains both grey and blue.

[yb98]

it seems the link doesn't work... sorry
here is the original link
http://www.chez.com/ophtasurf/illusions_extraordinaires2.htm

[PacAce]

colors are perceived differently by our brain depending on the surrounding colors. Look at this pic.
Can you believe that A and B are exactly the same gray color ?
Check the RGB values and you will don't believe your eyes...

http://www.chez.com/ophtasurf/illusions/illusion_adelson2.jpg

But they DO look like the same gray to me! :shock: ???
Maybe it's just the my brain isn't being fooled because it knows they ARE the same color. :)

[G3]

I can't see any difference in sharpness...