[LFLee]

Hi,

I look at this video

You Tube

You Tube

(see 1.52) it appear that a camera with a filter can capture this "sun damage skin" kind of photo?
Do you know how to get this kind of shot?

A black and white photo done using this method looks really unique: Cara Phillips photographs subjects under UV light to reveal sun damage | Daily Mail Online

After some search, I found: A Beginners Guide to UV Reflectance in Photography
where it appear that one need a UV light source, and just shoot away?

I am ordering a UV light bulb to try it out, but if you have any tips to do this kind of photography, hope you could share your experience.

thanks!

[VoiceOfReason]

I would imagine you'd need a full spectrum camera and a filter that blocks visible and IR light.

[biz-engineer]

I would imagine you'd need a full spectrum camera and a filter that blocks visible and IR light.

humm strange , since it's been said that UV filters are useless on digital cameras because cmos sensors are not sensitive to UV light, or is there already a UV blocker in place of optical anti alias filter ?.

[VoiceOfReason]

humm strange , since it's been said that UV filters are useless on digital cameras because cmos sensors are not sensitive to UV light, or is there already a UV blocker in place of optical anti alias filter ?.

If your camera has been converted to full spectrum then you're fine. Get a UV Pass filter that does something like 300-400nm wavelengths and screw it on your lens.

[discharged]

oh that is sooo cool and the girl at the very end, she has broken her fronth tooth at some point and has had it repaired look at it in the UV light.

But on topic you need a camera that will capture UV light and most cameras today filter almost all of it out with a cut filter in front of the sensor... Another problem is that lens coatings can be harsh on UV aswell as IR.

On film it was simple, you just changed the film roll to IR sensitive film. On digital you better let professionals handle it.

[Digitalis]

Ultraviolet photography is used in forensics, injuries from blunt trauma that may have healed on the surface of the skin can be revealed as dark black splotches under UV illumination due to blood still being diffused at the site of injury.

I am ordering a UV light bulb to try it out, but if you have any tips to do this kind of photography,

If possible find a super achromatic quartz lens, these lenses are very expensive and usually very rare. Pentax did produce an 85mm f/4.5 super-apochromat M42 lens which came with all the needed filters at one point. Traditional borosilicate glass is terrible at bending UV wavelengths in the 400~300 nanometer range, Fused quartz provides the necessary refraction to accomplish this.

[romay]

It is possible to do UV pictures with unmodified DSLRs and normal lenses if you are willing to make some compromises.
You just need to make sure to use an UV pass filter, an additional IR cut filter and exposure times long enough so a sufficient amount of UV can "bleed" through the interference filter in front of your sensor. Also it's best to use an old lens with no coatings and as few elements as possible.
However, your pictures won't be tack sharp as no regular lens is corrected for UV light.
In most cases, you'll want to use an artificial UV light source. I recommend "near" UV light in the range of 400nm. "Far" UV is usually absorbed by the lens.
You don't need to drag around an UV lightbulb + extension cord. There are UV LEDs obtainable that you can use to create your own battery powered UV lightsource, but they aren't cheap. Be sure to get the high power ones (10 watts and up), the small ones are useless.
They also radiate in the visible spectrum, so it's a good idea to put one UV pass filter on your lens and another in front of your lightsource.
Don't ever look into UV light (400nm and shorter) with your unprotected eye!!! You'll develop serious conjunctivitis within seconds (been there, done that).
In the end, you'll get a purple image with low contrast and heavy abberations, but it's fixable in post.

[willskywalker93]

Glad this post is recent. I am a student attempting to use full spectrum photography for an engineering/forensic challenge. IF we manage to track down an older super-achromatic lens (or end up going the canikon Coastal Optics route, not my money), does anyone know the spectral window of most modern DSLR sensors? I know a conversion will be in order, as the approach we are considering must allow in situ evaluation of materials, therefore long shutter speeds are out. I am all up for using a legacy lens that is UV transparent to make this project work since it is much cheaper than the 6 grand setup from coastal optics.

Thanks guys!

[Digitalis]

does anyone know the spectral window of most modern DSLR sensors?

CMOS sensors have better sensitivity in the UV range from 400~280nm due to their thinner EPL*, CCD sensors are better for 700-1000nm IR as they have a thicker EPL. You will need to convert the camera to full spectrum. I would suggest removing the hot mirror and replacing it with Schott sapphire glass - which has excellent transmission from UV to IR. I'm unsure of the exact dimensions and thickness of the hot mirrors used in Pentax cameras, so you should use the filter removed from the camera as a reference.




*Electron Penetration Layer.

[willskywalker93]

You, good Pentaxian, are big help. Now the search for cheaper glass is on.

Except that I just realized that for needed application, autofocus is critical. I suppose the canikon/coastal optics route may be the only choice then, huh, since the old taks weren't AF lenses...

[VoiceOfReason]

You can autofocus in live view accurately with full spectrum. THat's why my K-01 was converted.

[willskywalker93]

Yes, except the older quartz lenses are manual focus, are they not? That was my issue.

[Digitalis]

Yes, except the older quartz lenses are manual focus, are they not?

Yes they are, some AF systems can see into the infrared to an extent, they are designed to be effectively blind to UV.