Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Strange Dots -- Help?

Reply
Thread Tools

Strange Dots -- Help?

 
 
cjcampbell
Guest
Posts: n/a
 
      03-22-2006
These two photos were taken just a few seconds apart. The first was
taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.

http://homepage.mac.com/christopherj...blem%20Photos/

I can understand the star filter effect might be caused by stopping
down, but where did the dots come from?

The lens used is the 12-24mm f/2.8 AF-S Nikkor. A tripod was used for
both pictures, which are a night scene of Heritage Street in Vigan. No
processing, color balancing, or sharpening was applied to both
pictures. These are just JPGs taken straight from the original raw
files.

 
Reply With Quote
 
 
 
 
John
Guest
Posts: n/a
 
      03-22-2006
"cjcampbell" <(E-Mail Removed)> wrote in message news:(E-Mail Removed) ups.com...
> These two photos were taken just a few seconds apart. The first was
> taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
>
> http://homepage.mac.com/christopherj...blem%20Photos/
>
> I can understand the star filter effect might be caused by stopping
> down, but where did the dots come from?


No idea, but are black people allowed in your church?


 
Reply With Quote
 
 
 
 
cjcampbell
Guest
Posts: n/a
 
      03-22-2006

John wrote:
> "cjcampbell" <(E-Mail Removed)> wrote in message news:(E-Mail Removed) ups.com...
> > These two photos were taken just a few seconds apart. The first was
> > taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
> >
> > http://homepage.mac.com/christopherj...blem%20Photos/
> >
> > I can understand the star filter effect might be caused by stopping
> > down, but where did the dots come from?

>
> No idea, but are black people allowed in your church?


Eh? Strange question, but yes, black people are allowed in our church.

 
Reply With Quote
 
Steve Wolfe
Guest
Posts: n/a
 
      03-22-2006
"cjcampbell" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ups.com...
> These two photos were taken just a few seconds apart. The first was
> taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
>
> http://homepage.mac.com/christopherj...blem%20Photos/
>
> I can understand the star filter effect might be caused by stopping
> down, but where did the dots come from?


They appear to be out-of-focus highlights, or "orbs". My guess is that it
was raining, snowing, or at least very humid. Something in the air
refracted the light from the street lamp. You typically see this when a
flash reflects off of dust, rain, or snow, but the same can occur via
refraction as well.

steve


 
Reply With Quote
 
cjcampbell
Guest
Posts: n/a
 
      03-22-2006

Steve Wolfe wrote:
> "cjcampbell" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed) ups.com...
> > These two photos were taken just a few seconds apart. The first was
> > taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
> >
> > http://homepage.mac.com/christopherj...blem%20Photos/
> >
> > I can understand the star filter effect might be caused by stopping
> > down, but where did the dots come from?

>
> They appear to be out-of-focus highlights, or "orbs". My guess is that it
> was raining, snowing, or at least very humid. Something in the air
> refracted the light from the street lamp. You typically see this when a
> flash reflects off of dust, rain, or snow, but the same can occur via
> refraction as well.


Seems possible. It is very humid here all of the time, but I had not
seen this before. Something that lends support to your idea is the haze
around the lights in the first picture. It was not raining or snowing,
though -- especially not the latter, this being the Philippines and
very tropical.

 
Reply With Quote
 
pltrgyst
Guest
Posts: n/a
 
      03-22-2006
On 21 Mar 2006 18:00:48 -0800, "cjcampbell" <(E-Mail Removed)>
wrote:

>These two photos were taken just a few seconds apart. The first was
>taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
>
>http://homepage.mac.com/christopherj...blem%20Photos/
>
>I can understand the star filter effect might be caused by stopping
>down, but where did the dots come from?
>
>.... These are just JPGs taken straight from the original raw
>files.


jpeg artifacts? Either that or micro-UFOs. That's my guess and I'm sticking with
it.

-- Larry

 
Reply With Quote
 
cjcampbell
Guest
Posts: n/a
 
      03-22-2006

pltrgyst wrote:
> On 21 Mar 2006 18:00:48 -0800, "cjcampbell" <(E-Mail Removed)>
> wrote:
>
> >These two photos were taken just a few seconds apart. The first was
> >taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
> >
> >http://homepage.mac.com/christopherj...blem%20Photos/
> >
> >I can understand the star filter effect might be caused by stopping
> >down, but where did the dots come from?
> >
> >.... These are just JPGs taken straight from the original raw
> >files.

>
> jpeg artifacts? Either that or micro-UFOs. That's my guess and I'm sticking with
> it.


Can't be jpeg artifacts. They show up on the raw files, too. According
to Douglas Adams, the last invasion by micro-UFOs was swallowed by a
small dog. You would think that they had learned their lesson. Unless
they have returned in greater numbers...

 
Reply With Quote
 
mark.thomas.7@gmail.com
Guest
Posts: n/a
 
      03-22-2006
A 12mm lens (was it set to that? -it *looks* like it's pretty wide..)
shot at f22 will have a *lot* of depth of field. Those spots look very
much like the effect you would get from (small) raindrops on a UV
filter on the front of the lens, or they could conceivably even be on
the front element.

They don't look like orbs (ie lit up dust motes) to me, and they would
have to be *very* close to the lens to be that far out of focus.
Besides, in 5 seconds, rain or dust motes will move so far they would
barely leave a trail.. These haven't.

Muck on the lens or on a filter. betcha.

((Thinks - I guess they could even be on the sensor...but if he has let
his sensor get that filthy, he needs his photography license revoked.))

 
Reply With Quote
 
Butch Lacadie
Guest
Posts: n/a
 
      03-22-2006
cjcampbell wrote:
> These two photos were taken just a few seconds apart. The first was
> taken at f/4 and 1/6 second; the other at f/22 and 5 seconds.
>
> http://homepage.mac.com/christopherj...blem%20Photos/
>
> I can understand the star filter effect might be caused by stopping
> down, but where did the dots come from?
>
> The lens used is the 12-24mm f/2.8 AF-S Nikkor. A tripod was used for
> both pictures, which are a night scene of Heritage Street in Vigan. No
> processing, color balancing, or sharpening was applied to both
> pictures. These are just JPGs taken straight from the original raw
> files.
>

Looks to me like the lens had a finger print or droplets on it
or something. Stuff like that will come into focus as you stop
down. I bet you could re-created the effect by taking a picture
like that at a distant candle in the house with the lights off
before and after smudging a filter in front of the lens.
Just an Idea.

Butch
 
Reply With Quote
 
2
Guest
Posts: n/a
 
      03-22-2006

It is dust on the lens (or if you are using a filter, it's on the filter).

You came across the ideal situation for dust to show up: dark background,
single point main light source, wide lens and tiny aperture (deep DOF).


 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
OT: EFF cracks printer tracking dots... Bob Christian MCSE 256 10-30-2005 04:38 AM
web.config does not allow section names with dots Vagif Abilov ASP .Net 4 02-11-2005 04:09 PM
Dots Per Inch Problem chris blackbur ASP .Net 2 12-18-2004 02:11 AM
float: use of comma's versus dots: 12,2 or 12.2 nicholas ASP .Net 2 11-18-2004 03:31 PM
Tazilla -- 3 dots William W. Plummer Firefox 0 10-07-2004 04:31 PM



Advertisments