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Bonaire Photography & Videography: "Realness" of Digital Images
Bonaire Talk: Bonaire Photography & Videography: Archives: Archives 2003- 2004: Archives - 2004-08-15 to 2004-12-31: "Realness" of Digital Images
Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Burnham (BonaireTalker - Post #17) on Wednesday, August 25, 2004 - 9:18 am:     Edit PostPrint Post

This message follows up the thread in Diving Bonaire: Why are there no sharks? to comments made about the "realness" of the shark image I posted there. Seems more appropriate here.

Bert van Barneveld: ...looking at the colours you were in shallow waters?
Yes.

Richard Burdette: ...but was that a "real" picture of the shark?
James Thomas: ...curious as to the real deal on this photo.

What is "real"? We're talking about photons hitting electrons modifying magnetic fields, eventually tickling your brain!

DJ: Give us a break Roger, it's not even close!!!
Close to what?

Marc @ CrystalVisions: I agree; that pic is fake, the lighting is off
How do you think I "faked" it?

Here's the "real" deal. I've put together two clips (320x240, 30sec, Windows Media Files, each about 1.1Meg|:


The processing consists of two steps:
  • Sharpen each frame a bit ~ 10%. This will be harder to see in these lower resolution movies.
  • Stretch out the RGB histograms of each frame.

This last step is an attempt to compensate for the differential absorption of colors by water.

The camera I use has a separate chip for each Red, Green, and Blue channel so I can easily adjust each of these colors separately.

For example, red is absorbed fastest with depth (or horizontal distance) and a typical red histogram shows that only the low intensity reds are present. Stretching this out increases the intensity of red that is already there. A similar adjustment is done to the Green and Blue channels to try to reduce the overall (usually blue) cast to the images.

Keep in mind that this process only works with information that is already in the image data...E.g. if shot too deep so that no red is present this technique does not create any reddish pixels.

And that it is an artistic process as well. I'm attempting to create images closer to what you would see if there was no water present...
which is basically impossible; Things closer to the camera are affected less that those things farther away; no single adjustment can compensate for all distances. I try to get the things closer to the camera to look more "real" in some way.

So, which version do you think is more real?

Which do you like better?

Why?

 

Top of pagePrevious messageNext messageBottom of page Link to this message  By Linda Richter - NetTech (Moderator - Post #1938) on Wednesday, August 25, 2004 - 9:40 am:     Edit PostPrint Post

Nice footage of the shark. I'm guessing that the digital artifacting present on the photo due mainly because it was a capture off the video (which make it quite low res) may have led people to believe it was fake. But you certainly showed them that it was not.

 

Top of pagePrevious messageNext messageBottom of page Link to this message  By Brian (bcj.) (Experienced BonaireTalker - Post #116) on Wednesday, August 25, 2004 - 10:09 am:     Edit PostPrint Post

First, the question of "How do you think I "faked" it?". I'm assuming you're asking this question with your context being that you know you saw the shark and have video to prove it. Without the video footage as proof (which was the context of the previous thread), one could easily create a fictional scenario using Photoshop, taking two photos and merging them in an almost-believable fashion. See, for example, this edited photo:

dinner time

However, it is even possible for video to be edited in such a manner if somebody had the time and money to do so. In this case, I take the bait and believe what I see in the footage. The only remaining argument could be where in the world this footage was taken. (Don't worry, I'm not going to argue that point cuz I believe you.)

Second, which clicp do I prefer regarding quality/editing/color balance etc? I choose the processed clip. I find that in most photos, there is a slight haze that coats the picture, something that is easily removed with tweaking the contrast and levels. Not being a diver and using some logical thought, I would imagine that this "haze" I see topside would be compounded under water due to various "stuff" floating in the water, combined with the effects of a large body of water between you and your subject.

I would prefer not to see through the haze and just see the colors for what they are.

The only reason I would see a need for the raw version is if someone is trying to accurately portray what "underwater" really looks like. In this case, the purpose is to show a shark swimming.

 

Top of pagePrevious messageNext messageBottom of page Link to this message  By Wally and Eva (Experienced BonaireTalker - Post #486) on Wednesday, August 25, 2004 - 6:57 pm:     Edit PostPrint Post

Why are there no sharks? ....too many people

 

Top of pagePrevious messageNext messageBottom of page Link to this message  By bob (Extraordinary BonaireTalker - Post #1254) on Wednesday, August 25, 2004 - 7:27 pm:     Edit PostPrint Post

neither not enough kite surfers nor snorkers...but we are working on that...



 

Top of pagePrevious messageNext messageBottom of page Link to this message  By Marc @ CrystalVisions (Extraordinary BonaireTalker - Post #1350) on Thursday, August 26, 2004 - 8:46 am:     Edit PostPrint Post

Ok, asuming you wouldn't go to so much trouble of editing a fake video just for a laugh... I had just the one picture to go by. What you didn't tell was that it was a video capture. The quality of that combined with the fact that you overdid the sharpening a bit gave me the impression that, like Brian described, you layered the shark on the background.

 

Top of pagePrevious messageNext messageBottom of page Link to this message  By Russ Coash (Experienced BonaireTalker - Post #102) on Saturday, September 11, 2004 - 5:36 pm:     Edit PostPrint Post

nice barney pic - very cool. I like your comment bob - I guess just not eoough food for the sharks :-)
Russ

 


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