Odd Image Anomaly

[woodbyte]

<p>So just throwing this out there to see what you folks think.</p>

<p>The image below is unaltered, just converted to jpeg direct from raw file. From today at a swim meet. My interest in focused on why I can see the reflection of the LED Heat and Event numbers in the water, but not on the actual display board.</p>

<p>My theory is, that as the shutter window descended the LED was out, or 'blinked' when the shutter window passed the top section of the image, but illuminated as the shutter window passed the reflection area in the lower area of the image.</p>

<p>Am I right?</p>

<p>rgds,<br /> james</p><div></div>

[peter_j2]

<p>You probably are right if your 5D is of the <strong>vertical-travel</strong> focal-plane shutter.</p>

[scott_ferris]

It does and that is almost certainly the reason.

[fmueller]

<p>I think you hit the nail on the head. Very interesting. I bet you couldn't reproduce that result if you tried ;-)</p>

<p>Here is a very nice video showing how a 5D shutter moves - I had to check if the 5D has a vertical travel shutter.</p>

<p>http://api.smugmug.com/gallery/8945351_aVDzo#594124511_2CUHh-A-LB</p>

[thomasly]

<p>Wow..... very interesting!<br>

but, being Halloween is close, can I say " Ghost in the machine?" hehe</p>

[David_Cavan]

<p>Thanks for that video, Frank. I guess I'm surprised to see the mirror flopping around like it does, but I suppose that is better than trying to tighten it down - the stress would be considerable. I can certainly see why mirror lockup reduces camera movement.</p>

[fmueller]

<blockquote>

<p>I'm surprised to see the mirror flopping around like it does.</p>

</blockquote>

<p>I noticed that too, and wonder if that isn't so by design. I guess the kinetic energy from the mirror movement needs to go somewhere. If you tighten it down, it will produce camera shake. If the mirror can flop around a bit, energy gets consumed that way. I bet if you took an old-style film SLR, like an FTb, there would be a lot less mirror flopping than in a 5D, but definitely more camera shake!</p>

<p>A bit like the old cars that were built to last, even through a head-on collision. These days they have crumple zones, so the car will be smashed, but the driver has a far better chance of coming out alive.</p>

[woodbyte]

<p>Frank - that's a neat video, thanks, and yes, I could never reproduce it.</p>

<p>Agree with David, I never realised the mirror bounced round as much as it does.</p>

<p>So I think my theory is close, but I think my sequence is reversed. If I remember well the image is inverted on the sensor, so probably what happened was the reflection was captured first and the LED blinked out as the shutter window travelled down, captured no light emisions as the window neared the bottom of it's travel which was the top of the image.</p>

<p>rgds,<br /> james</p>

[zensphoto]

<p>Here's what I think happened, you caught the reflections of the board and while it was changing the board blacked out for a fraction of a second. So you can see the numbers in the water but not on the board. I say this because I to have caught some kind of reflection in the water with a Canon SX30 IS from frame to frame or from just a few seconds like 12 seconds later the image appeared but I didn't see the image in the photograph.</p>

<p>Here's the photograph http://static.photo.net/attachments/bboard/00Z/00Z7eE-385053584.jpg and a close up of the colorful captured XII that I didn't see when I was looking at it with my eye in the view finder. There is a bridge to the right of the photograph and the sun is real bright, a car passing may have thrown a reflection down off the water for just a fraction of a second when I was shooting the photograph.</p>

<p><img src="http://static.photo.net/attachments/bboard/00Z/00Z7fb-385083584.jpg" alt="" width="258" height="235" /></p>

<p>Photo.net forum post about this. <a href="../casual-conversations-forum/00Z7eE">http://www.photo.net/casual-conversations-forum/00Z7eE</a></p>

<p>And as you mentioned the way the shutter moves as we saw in the video, that is probably exactly what happened.</p>

[alan_bryant1]

<p>Another possibility is that vampire bats were hanging in front of the display. They blocked the light in the direct view, but they have no reflection, so the lights are visible in the water.</p>

[alexey_nosal]

<p>James, have you used CPL filter for this shot?</p>

[briany]

<p>That was my guess as well - were you using a polarizer on your lens?</p>

[woodbyte]

<p>@ Alexey and Brian - nope: no polariser was used.<br>

rgds,<br>

james</p>

 

[woodbyte]

<p>...and here's the final image post processed....</p>

<p>rgds,<br>

james</p><div></div>

[Landrum Kelly]

<p>It's a cool image both when it shows demonic possession as well as after the Photoshop exorcism.</p>

<p>--Lannie</p>

[fmueller]

<p>Since I get so many compliments on the video, I feel obliged to point out that I just posted a link to it. I couldn't produce a video like that if my life depended on it!</p>