[Rockhounds] UV photography
Tim Fisher
nospam at orerockon.com
Tue Mar 28 10:42:57 PDT 2017
Can someone forward the post with the newer UV LED light from a couple weeks
back? I meant to save it but deleted it anyway.
Tim Fisher
Orerockon.com
-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of
everbeek
Sent: Wednesday, May 29, 2013 5:53 PM
To: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
Subject: Re: [Rockhounds] UV photography
Yep, simply holding a filter in front of the lens works -- I used to do that
before I got my new camera. The extent to which blue light leaked from the
filter of a LW UV lamp becomes a problem depends on how much of that light
is reflected from the mineral you're photographing. For some minerals this
is close to zero, but for others I suppose it could be a factor. I've never
noticed the problem, but I work mostly with brightly fluorescent minerals
and not often with really dim ones. If reflected blue light is a problem,
then holding one of the old Wratten yellow filters in front of the lens will
solve that. But beware, some of those Wratten gelatin filters fluoresce, so
you have to be careful not to let UV light fall on them.
Cheers- Earl
-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of
Cessna, Jeffrey T. Mr.
Sent: Wednesday, May 29, 2013 4:46 PM
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
Subject: Re: [Rockhounds] UV photography
A quick search tells me a 52mm haze 2A filter is around $19 (not including
shipping). This should be plenty to block the lens of a compact digital. I
think Tim would definitely get more satisfying pictures than he is currently
getting, even if not all of the blue is gone. There will be fewer optical
aberrations with a real filter than the plastic I suggested. However, my
friend managed to get his piece of UV blocking framing plastic for free
because of the novelty of his question.
Jeff
-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at lists.drizzle.com] On Behalf Of
Doug Bank
Sent: Wednesday, May 29, 2013 4:31 PM
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
Subject: Re: [Rockhounds] UV photography
Unfortunately, I don't think very many point and shoots can accept filters.
I suppose you could just hold it in front of the lens. Still, I think the
blue visible light pollution is going to be just as big a problem.
Doug
On May 29, 2013, at 3:25 PM, "everbeek" <everbeek at ptd.net> wrote:
> Best fix for this problem is to use a Tiffen 2A Haze filter on your
camera.
> Do not use a Tiffen SKT 1A filter, the ones many people use as
> UV-blocking filters for outdoor photography, as these are
> insufficient. I've used a 2A filter for some years now and never
> experience a problem with minerals that fluoresce pale pink, pale
> yellow, or any other pale color registering as blue in the image.
>
> Cheers- Earl
>
> -----Original Message-----
>> On May 29, 2013, at 2:15 PM, J Bryan Kramer <codeburner at gmail.com> wrote:
>>
>>> My guess is that Panasonic has plastic lenses that may be
>>> fluorescing. If you have a pair of clear uv blocking safety glasses
>>> try putting one of
>> the
>>> lenses from that in between the camera and the rock. See what you get.
>> I'm
>>> sure it won't improve the image quality but it may reveal some of
>>> the missing colors. Digital sensors themselves are said to be
>>> insensitive to
>> uv
>>> light so the sensor should not be a problem.
>>>
>>> BK
>>>
>>>
>>> "As an artist, my interest lies in pictures and in the technical
>> procedure
>>> required to produce them..."
>>> --*Ansel Adams*
>>>
>>> J Bryan Krämer North Florida, USA
>>> photos at: http://pbase.com/photoburner blog at:
>>> http://www.photoburner.net
>>>
>>>
>>> On Wed, May 29, 2013 at 3:02 PM, Doug Bank <dougbank at alum.mit.edu>
>> wrote:
>>>
>>>> Tim,
>>>>
>>>> I do not know how your camera is working. Typically a starry night
>> setting
>>>> that takes multiple exposures is actually just comparing all the
>>>> shots
>> and
>>>> keeping the one that looks the sharpest - probably not the first or
>>>> last shot.
>>>>
>>>> The colors are (probably) disappearing because you are using a
>>>> cheap camera (or not using it properly) that does not allow you to
>>>> properly
>> set
>>>> the exposure. It sounds like it is overexposing the images (if you
>>>> want
>> to
>>>> send some to me, I can better determine the problem). The blue
>>>> shading
>> is
>>>> probably because the LW light is producing a reasonable amount of
>> visible
>>>> light, and that is polluting your pictures. I'm not sure if this
>>>> would work, but if you have a yellow filter or some kind of yellow
>>>> clear
>> plastic,
>>>> look through it at the rock being illuminated. Does it get rid of
>>>> the
>> blue?
>>>> Gary suggests that the lens of the camera itself is fluorescing.
>>>> While that is a possibility, unless you are aiming the light at the
>>>> lens, it seems unlikely. SW would make it fluoresce even more,
>>>> though it is less likely that you would actually point the SW light
>>>> at
> yourself.
>>>>
>>>> If you try hard enough on the computer with the proper software,
>>>> you can probably subtract the blue. However, that might not be as
>>>> easy as it
>> sounds.
>>>>
>>>> These rocks are almost surely going to look a lot better SW than
>>>> LW. SW
>> is
>>>> probably a lot less likely to suffer from visible light pollution
>>>> as
>> well.
>>>>
>>>> If you want me to take a stab at fixing the color on one of your
>>>> shots, you can send it. (If you want me to actually photograph some
>>>> of your
>> rocks,
>>>> I can do that too. Contact me off the list. I'm pretty good..
>>>> http://flic.kr/s/aHsjwLVhmv)
>>>>
>>>> Doug
>>>>
>>>> On May 29, 2013, at 12:59 PM, "Tim Fisher" <nospam at orerockon.com>
>> wrote:
>>>>
>>>>> I have a question for the group, it applies to a very specific set
>>>>> of circumstances. When photographing some very fluorescent rocks
>>>>> this past
>>>> week
>>>>> (namely thundereggs), I can "see" colors in longwave UV that
>>>>> apparently can't be "seen" by my camera. I am using a LW UV light
>>>>> that I believe I mentioned before, a handheld model that does a
>>>>> pretty good job at illuminating my specimens. I bought a cheap
>>>>> copy stand that hold the
>>>> camera
>>>>> about a foot above the base table, and I can usually zoom to get
>>>>> the
>> rock
>>>>> and not too much of the background in the frame.
>>>>>
>>>>> My camera is a compact digital Panasonic, it takes impressive pics
>>>>> most
>>>> of
>>>>> the time at the 9Mb size setting. I found that in order to get
>>>>> decent exposures, I had to set it on the "starry night" function,
>>>>> which from reading the manual I infer takes multiple exposures
>>>>> during a specified
>>>> time
>>>>> period (in my case 15 seconds which is the shortest option). It
>>>>> then
>>>> appears
>>>>> to blend or overlay them into the final image (or so I infer - it
>> shows a
>>>>> "hold on I'm doing something" screen for a few seconds after the
>>>>> shot
>> is
>>>>> finished). It could instead be taking only one exposure and
>>>> post-processing
>>>>> it, the manual doesn't say what it actually does with the image.
>>>>> For
>>>> those
>>>>> that fluoresce fairly bright in LW, the colors all but disappear
>>>>> in the photos. My camera turns them all to shades of blue, with
>>>>> faint hints of
>>>> the
>>>>> "true colors" that aren't already blue-ish. For example in the
>> Jackrabbit
>>>>> Spring thundereggs, which are very well known for their strong UV
>>>>> fluorescence, I see 3 or sometimes 4 distinct colors - blue,
>>>>> off-white,
>>>> pale
>>>>> yellow, pale green, sometimes even a light salmon pink.
>>>>>
>>>>> The photos show all shades of blue, if I stare at some of them
>>>>> long
>>>> enough
>>>>> at the native resolution (which s huge on my monitor) I can make
>>>>> out
>> very
>>>>> faint shades of the colors I can see. The images already look
>>>>> about
>> right
>>>>> when open them in the Windows picture viewer and when I open them
>>>>> in my editing software, in other words not too under- or
>>>>> overexposed. The
>>>> colors
>>>>> in the shortwave shots are about right, they appear to be faithful
>>>>> to
>>>> what I
>>>>> can see. Almost nothing else shows in LW, except for the
>>>>> inevitable
>> white
>>>>> specks of lint that I can't even get off the sheet of black velvet
>>>>> I am using as the background with a air duster can and a lint
>>>>> roller. Post processing them in PaintShop Pro x4 (a pretty
>>>>> sophisticated Corel
>>>> version of
>>>>> photoshop) doesn't help much. Increasing or decreasing the bright
>>>>> ness, color saturation, messing with the shadows and highlights,
>>>>> color
>> balance,
>>>>> temperature, etc. all don't result in changing the blues to
>>>>> multiple
>>>> colors
>>>>> (I can pretty much change them to any color I please, but it's
>>>>> always
>>>> shades
>>>>> of that base color).
>>>>>
>>>>> Anyone have any ideas? Another camera or different UV lights are
>>>>> pretty
>>>> much
>>>>> not an option for me.
>>>>>
>>>>> Tim Fisher
>>>>>
>>>>> OreRockOn.com
>>>>>
>>>>> Email at http://orerockon.com
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