First 3D images

[lost cat]

Hi All,

 

I'm still working out the details on my 3D rig but I think I'm making progress. These are high quality JPEGs of the RAW images, aside from the file conversion I've done no editing. The white block is a piece of wood wrapped with several layers of PFTE tape and the ruler is there to provide detail for focusing. The thumbprint is sunscreen as UV only feature. Lighting is provided by two stacked 40W BLB tube lights approximately 2M away directly in front of the subject. I set up the shot with visible light hoping the focus shift to UV would be minimal. Comparing the visual and UV images I did not see an appreciable difference in the focus of the ruler.

 

Cameras: Two unmodified Nikon D40s at interpupillary distance

Lenses are El-Nikkor 80mm enlarger lenses at f/8.

ISO 200

Exposure 10s.

3D crossed eye method

 

I took several shots trading ISO for exposure time and i did not see much difference between ISO 200/400/800 and 10/5/2.5s At ISO1600/1.3s I started seeing more noise. I have yet to try the apertures.

 

Aside from white balancing and adjusting the lights to minimize glare does anyone have suggestions on improvements?

 

[colinbm]

Oh, magenta = bad :-(

The CWB needs to be taken off the PTFE, which should = white.

The black lights typically give off lots of IR which needs to be cut out with a S8612 filter over the lenses or lights.

Col

[nfoto]

Agree that the heavy magenta cast is grating on the eye. Easy to avoid though by doing a proper w/b.

 

More worrisome is the difference in detail rendition. The supporting structure has surface grain resolved as stripes in image #1, not well resolved in #2. Ensure that any image processing is carried out identically on both members of a 3-D pair.

[Andrea B.]

Well he did say "aside from white balance"......

 

However, Jim, it is difficult to judge detail and lighting with the oversaturated magenta !! I'm not sure whether that oversaturation is obscuring detail in the left-hand photo or the detail just is not there. You could perhaps dial back the in-camera saturation level when shooting. That would help you see more easily what you've got while shooting.

 

With Nikons (which typically do not do well at in-camera white balance in Ultraviolet), we used to use Incandescent wb to reduce the red a little bit. I've been able to "push" the white balance in my Nikon D600 to almost match the raw, but I'm not sure if that can be done in the D40X because my push method makes use of the colour square in later Nikons.

 

I will look at these paired images this evening after I remove contact lenses and see if I can get them to cross. Is there a recommended distance for attempting this? The images are very large for attempting crossing. When the images first came up, one image was under the other. I closed bookmarks and expanded the browser and have them side by side now.

 

You did not say what filtration was used ??

 

Also, what converter/editor will you be using?? Some do better than others with UV photos.

[lost cat]

Oh, magenta = bad :-(

The CWB needs to be taken off the PTFE, which should = white.

The black lights typically give off lots of IR which needs to be cut out with a S8612 filter over the lenses or lights.

Col

 

Thanks Col. These are fluorescent BLBs so they shouldn't be putting out any IR:

 

 

Edit: Reference https://en.wikipedia.org/wiki/Black_light This is a generic spectrum of a fluorescent BLB but it should be similar to mine

 

The room was otherwise dark. The D40 also still have their original sensor filters so they should remove most of any IR present.

 

I will see about dialing back the in-camera saturation. I will also try moving the lights around a bit to see if the loss of detail is an artifact of glare and shadow of that rather than a problem with the camera itself.

 

Andrea I think the proper distance for viewing is a matter of personal preference. I'm nearsighted so I can comfortably view the images without my glasses a few feet from the monitor. Your comfortable viewing distance may vary from that depending on your prescription. I think later images will have more effect as there is not much distance between the subject and the backdrop in these images.

[Andrea B.]

references, references......where is this chart from?

 

Again, you did not mention your filtration. Are you filtering out the vis violet?

 

Try this in the D40:

Shooting > Optimize Image > Custom

Tone = 0 or -1

Saturation = 0 or -1

[Shane]

The D40 also still have their original sensor filters so they should remove most of any IR present.

 

Since the D40 has a weak ICF and was therefore a reasonably good UVIR DSLR straight off the shelf, I wouldn't count on that under your 10sec shooting conditions.

[OlDoinyo]

It would also help if stereographs are posted as side-by-side pairs; the vertical format is difficult to cope with.

[lost cat]

It would also help if stereographs are posted as side-by-side pairs; the vertical format is difficult to cope with.

 

Do you mean landscape vs. portrait?

[JCDowdy]

It would also help if stereographs are posted as side-by-side pairs; the vertical format is difficult to cope with.

 

Try zooming out with your browser until the images fall into line side by side.........

[lost cat]

references, references......where is this chart from?

 

Reference added.

 

Again, you did not mention your filtration. Are you filtering out the vis violet?

 

No filters are used other than the stock ICFs. Nothing to remove the violet leak from the lamps. I don't know if polystyrene foam fluorescences but if it does a filter may help.

Try this in the D40:

Shooting > Optimize Image > Custom

Tone = 0 or -1

Saturation = 0 or -1

 

Will do, thanks.

 

I will also try my newly arrived Astrodon Sloan 'u filter on the cameras and see if that helps.