Ghost shadows in light tent

Looking at your image here on a real budget generic 17" LCD monitor and
can't see a trace of what you are describing. As a hobby photographer myself
I must compliment you on a nice piece of work. Hope this is helpful.
--
Peter in New Zealand. (Email address is fake)
Collector of old cameras, tropical fish fancier, good coffee nutter, and
compulsive computer fiddler.

"tony cooper" wrote in message
...
On Sun, 24 Feb 2008 08:17:14 -0800 (PST), salmobytes
wrote:

I'm trying to learn how to make closeup images of trout flies.
I use a NIkonD70 with a closeup ring and a 105mm macro lense
(and sometimes a belows).

I place the subject inside a small light tent made from foam
foundation board and thick translucent curtain material.

I put a small square of aluminum foil behind the subject,
in order to outline the subject from behind with directional light.
All other illumination is (tungsten/halogen) light shining
in from the outside of the light tent. I use a blue background.

I'm getting there. But I'm starting to see and increasing number
of weird color artifacts I don't know how to describe.
If you look at the following Uri, to a photo of a 50 year old
trout fly, you'll see what looks like vibration-like shadows
following the contour of a deer hair frond, at the top right
edge of the fly.

This can't be a shadow on the background, as the blue cardboard
background is almost 30" behind the subject. Well, maybe it is.
I do expose approximately 3 seconds at F-32, in order to get
good depth of field at high magnification.

What causes this (I'll try a large F-stop, but I doubt that's it).

Check your monitor for scratches on the screen. Any complaints you
have about that image are unfounded. Nice pix.

The only distraction is the somewhat vertical thread-like bit directly
above the hook.
--

Tony Cooper - Orlando, Florida

On Sun, 24 Feb 2008 11:53:06 -0600, George Kerby wrote:
wrote:
salmobytes wrote:
I'm starting to see and increasing number
of weird color artifacts I don't know how to describe.
If you look at the following Uri, to a photo of a 50 year old
trout fly, you'll see what looks like vibration-like shadows
following the contour of a deer hair frond, at the top right
edge of the fly.
http://montana-riverboats.com/Pages/...ley/index.html

I don't see what you describe.
Dittos.

Just a guess, but I think the OP is using a monitor configured at only
"256 colors". The last time I observed the effect(s) that the OP
relates was on an under-powered PC running OS/2 -- where I set the
display configuration for "256 colors" to achieve anything amounting to
'performance' from the box. The effect was always most notable on blue
(blue sky) backgrounds.

HTH
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

On 2/24/08 12:08 PM, in article
,
"salmobytes" wrote:

On Feb 24, 10:58 am, Paul Furman wrote:

I still don't see anything, sorry. The white hairs burn a ghost on my
eyes for a moment when I zoom way in & stare then move to the background :-)




Thanks guys. This is getting interesting now.
This must have something to do with cheap Dell monitors.
I have two such 17" monitors, sitting side-by-side, one IE XP Windows
and the other Firefox Ubuntu linux. I see vibration-like interference
mirroring the contour of the upper-most white hair on both.

But I just went upstairs and looked on my wife's high-quality,
hotrod 21" Mac monitor and I see nothing. So what I'm seeing
is probably not in the image. It has something to do with low-end
lcd monitors. Must be you get what you pay for.

Your wife has good taste. Maybe you need to come over from the "dark side".
;-)

On Feb 24, 11:17 am, salmobytes wrote:
I'm trying to learn how to make closeup images of trout flies.
I use a NIkonD70 with a closeup ring and a 105mm macro lense
(and sometimes a belows).

I place the subject inside a small light tent made from foam
foundation board and thick translucent curtain material.

I put a small square of aluminum foil behind the subject,
in order to outline the subject from behind with directional light.
All other illumination is (tungsten/halogen) light shining
in from the outside of the light tent. I use a blue background.

I'm getting there. But I'm starting to see and increasing number
of weird color artifacts I don't know how to describe.
If you look at the following Uri, to a photo of a 50 year old
trout fly, you'll see what looks like vibration-like shadows
following the contour of a deer hair frond, at the top right
edge of the fly.

This can't be a shadow on the background, as the blue cardboard
background is almost 30" behind the subject. Well, maybe it is.
I do expose approximately 3 seconds at F-32, in order to get
good depth of field at high magnification.

What causes this (I'll try a large F-stop, but I doubt that's it).


The image looks good to me, my monitor is a 19 inch HP LCD, decent but
not top of the line for photoediting. I have shot a lot of macro under
a light tent. One main thing:
Try to work at f11 or at the most f16, if you look at lens charts
there is a definite drop off in sharpness after f11, at f32 the result
are often awful. This will also shorten your exposures.
Otherwise i think you have a nice setup for the images you are taking.

Tom