My first UV photograph

[Jim Lloyd]

My first UV image

 

View from our house after snow

 

D40 unmodified

Nikon E series 50 mm f/1.8

UG1 + BG40 2mm

f/8, 400 asa, 2 sec

 

White balance in camera auto

Tone adjustment in LR - otherwise unprocessed

 

Couldn't resist trying something, as filters just arrived, but really supposed to be doing something else right now. Will try more later

[nfoto]

Obviously it works - congratulations :D

 

I've taken the liberty of pulling this jpg into PhotoNinja to see if the excessive reddish cast could be alleviated. Result is below.

 

 

As there are no fixed rules set in stone for the "falseness" of UV "colours", this attempt is as valid as any other. It's really up to the photographer's visions.

[Jim Lloyd]

Thanks Bjorn - I like your version.

 

This is something I am going to need to investigate. My motivation at the moment to do with how birds see the world, but with artistic licence. Aiming to use science and technology but with some liberty in final application. Aiming for something that has some "otherworldliness" without that being cliched or overdone.(definitely overdone in my first attempt). The thinking is about the fact that we share the same world, but see it differently and if we could change our perspective we might act more responsibly towards the planet. Maybe?

[nfoto]

The basic point is what the camera "delivers" for UV might not be what we think is the best rendition - for whatever given purpose. We are entirely free to massage the image data to exhibit the impression we can be satisfied with ourselves.

 

Many cameras cannot do a reliable in-camera balance when used for UV and the output tends to be quite monochromatic, often in red. However, as one gains experience the actual "redness" helps understand how the system responds to UV. A lens with excellent UV transmission will typically give warmer red or even orange hues. A poor lens for UV renders the scene in cold purple or magenta. There are more than 50 shades of red in UV. And so on.

[Cadmium]

Jim, Not sure how you are white balancing in Photo Ninja, try this:

1) Open RAW photo in Photo Ninja.

2) Open 'Color correction'.

3) move your mouse / eye dropper over the photo, click any spot for white balance using that spot, or click, hold, drag, release (small area or even corner to corner) to select larger area for white balance.

 

Set your D40 to shoot JPG + RAW, large, fine...etc..

You will want to use RAW for white balance out of camera, you will not get a suitable white balance in the D40 camera for UV. White balance in Photo Ninja from RAW.

[Jim Lloyd]

Thanks Steve and Bjorn

 

I don't have photo ninja, but I do have the Adobe suite including Light room and Photoshop. Can I do the same in these rather than Photo ninja ?

[Hornblende]

Jim,

I never succeded to white balance a UV image in lightroom or photoshop. Generally the image manipulation software that you get when you buy the camera should be able to do a good white balance. You can find it here: http://downloadcente...ucts/6/D40.html in the software category, ViewNX 2

[Cadmium]

Jim, Use Capture NX2, it will work for the D40 NEF files I think. Should be free download somewhere?

I will try to find a link.

 

http://downloadcente...nload/sw/3.html

 

To white balance using Capture NX2:

1) load NEF (RAW)

2) click Camera Settings

3) click Set Color Temperature , change to Set Gray Point

4) select Use a single point, or Marquee Sample

(I usually use Marquee)

5) click Start

6) click/hold/drag mouse for area to sample, release, done.

 

Here is a photo of the process.

(this shot was U-360 alone, very similar to UG1 alone, dual band IR)

[Jim Lloyd]

Wow! definitely feel like I am at the bottom of a very steep learning curve!

 

Brief playing today:

All with unmodified Nikon D40 plus filters as above

 

Firstly picking up on a point by Bjorn above I thought I would compare a couple of lenses with a pinhole (0.35 mm in camera body cap). Just wondered if this is a good way to get a quick feel for the lenses? Trouble was that exposure time for the pinhole probably really needs to be a few minutes and I was just holding the filters in front.

 

The lenses were Nikon E 50mm f/1.8 which is a nice well known lens. The other was Samuron 135 mm f/3.5 which I have never heard of and I can find very little info on. Very cheap on ebay so I took a punt. Anyone know of this lens?

 

Here are the images with a visible one first for reference as they came out of camera (except pinhole had to have a lot of gain increase in Lr)

 

For the final image I used Capture NX-2 (thanks Steve!) and agree it is much better for white balance than Lr. Bit frustrating as I am so used to using Lr. Just a quick initial play, I can see that I am going to need to spend some more serious time on this!

 

Aperture f/8 exposures were about 10 seconds- these were taken about an hour before sunset and probably should have done a bit earlier when there was a bit more UV around.

[Hornblende]

Jim,

You are getting there, but it looks like you white balanced a Jpeg image. You will get far better result if white balance the native (RAW) image format from your camera.

You can change the setting on your D40 to shoot in RAW.

[nfoto]

The camera colours from the 50 vs the 135 support my earlier observation that a lens better for UV will tend to render more warm red or orange hues. The 135 is clearly quite cold 'red' verging on magenta. The 50 looks much better in this respect.

[Jim Lloyd]

Thanks Bjorn

 

I am trying to work out why this is. I guess its something to do with the spectral sensitivities of the RGB Bayer filters- as shown here for example: https://maxmax.com/spectral_response.htm - its rather difficult to tell and it must depend also on the position of the UG1 filter shoulder. But overall I suppose what we are seeing is really the accidental effect of the red filter having some transmission in the UV region? Lens that don't transmit as far down into UV will give relatively more response in the blue channel. - I seem to have answered my own question?

[nfoto]

You are on the right track ... Even the green channel might factor into the equation.

[Jim Lloyd]

Thanks Bjorn

 

Hi Hornblende,

 

Actually I was using the raw file (.NEF). I think maybe the problem comes when trying to white balance when there are very few counts in the the blue and green channels ? this makes the balanced image noisy. I had another go any applied some noise reduction and changed the white balance a bit and I think the result is better?

[nfoto]

There is some veiling flare on the 50 mm image, so use the longest and narrowest possible lens hood with that lens.

 

If one makes a "UV white" balance on the 135 mm image in Photo Ninja, then apply that setting to the 50 mm image it will be quite yellow instead of neutral muted greys. This shows the 50 mm image is much "warmer" straight off the camera, i.e. indicating better UV transmission.

[Cadmium]

Jim, Your last image above is closer to what I would expect.

I would try using Marquee, but select just a small tiny area of the gray stone on the side of the stone object in the center foreground.

Also try a full frame, corner to corner Marquee selection.

White balance should be easy using marquee, selecting the right area (try different gray areas) or the whole frame.

 

It also looks, perhaps, like you are getting a slight light leak, bottom center, pink color fog, but hard to say, not so important right now, just something to watch for.

A light leak is often from the lens mount or converter, and has a foggy colored look.

You can try wrapping a dark cloth around the lens and mount to see if it resolves a leak.

Also make sure your optical view finder is covered.

[Andrea B.]

Light leaks come from lens aperture windows, camera LCDs (top, usually), camera viewfinders (always close it!!), leaky mount adapters, and leaky mount fittings. Sometimes internal IR shutter monitors contaminate UV photos, but the D40 does not have that feature.

 

Jim, if you would like to make a raw D40 NEF file available, we'd all be happy to white balance it in Photo Ninja, Capture NX2 and other apps so you can see some conversion ideas. As mentioned Adobe ACR has not always been the best at white balancing a UV file.

 

If this might be helpful to you, then put the raw file into Dropbox (or some other sandbox) and provide the download link. Then we can download the raw file and provide samples of our conversion ideas.

 

As I have frequently mentioned for the benefit of those new to UV photography, there is no necessity to white balance a UV photo. In a false colour situation, you are quite free to choose your own false colours within the constraints of the raw file parameters. However there is a need to quell the detail-obscuring over-saturation that so often occurs in the red channel.

 

Also, I can run your raw NEF through Raw Digger to see the actual channel recordings from that D40, if you like.

[Jim Lloyd]

Steve, I can't see how to use marquee selection - I can only find option to select a single point.

 

Today I obtained my Nikon D3200 full spectrum conversion so I have been looking at that as well. As a starting point I am trying to decide on what lens to use. I have Photax Paragon 28m, Optomax 35mm, Nikon E 50mm and 100mm. I have also compared with a modern Nikon 24mm, just to compare with something that I know should be poor for UV.

 

Here are the images as they come from the camera, I have selected the ones with about the same exposure (around 1 sec) - all were asa 100 and f/8.

 

Based on this and Bjorn's comments above I thought that the 35mm might be best for UV (second image in sequence). I was a bit surprised that the images didn't look that different between the D40 (unconverted) and D3200(converted). So then I tried to white balance this image using capture NX-2 and struggled to get anything sensible - see below. Visible image is also shown for comparison

 

Thank for your comments Andrea - all the raw files should be accessible at this link: https://1drv.ms/f/s!...G2wnq4Y0JPTUz4a

 

Light leaks - yes I think probably because I lost the viewfinder cover - so reordered one and then found the lost one!

[nfoto]

Actually the stock Nikon D40 generation (D50 too, but not D40X) is pretty similar to a "full-spectrum" modified Nikon, except for having about 2 stops lower UV sensitivity.

[Cadmium]

Jim, here is what it should look like.

Using your NEF, quick white balance using Capture NX2, Marquee full frame. TIFF to Photoshop, auto levels, resized.

Don't know why you are not finding the Marquee feature, but your camera and filters and lens are all working fine for UV.

However, I do believe you have a little light leak at the bottom of that photo.

[Cadmium]

By the way, I picked that image above, because it looked the most 'pink', general old rule of thumb, deeper UV transmitting lens images look more pink out of the box.

Also, your D3200 NEF I tried will not do white balance in NX2, probably the NX2 needs to be patched for the D3200, or else NX2 doesn't support D3200 like it doesn't for other newer models.

Try NX-D, smaller selection area, but works the same. It will support any model I think.

 

http://downloadcente...pture_NX-D.html

 

Also, your exposure time with your D40/50mm image is a bit long, 20 seconds / ISO 400?

Not sure what aperture you used?

But seems kind of like a long exposure even for UV, but it worked.

[Cadmium]

Jim, Here is the D3200 image white balanced with Ninja. Looks good. No light leak with this shot.

1s exposure, ISO 100, f/?, looks good!

You won't need the D40 now. :-)

[Cadmium]

A couple more

 

[Cadmium]

You could of course work those more to make them look better, but that shows you the basic initial white balance.

[Jim Lloyd]

Thanks Steve

 

I am making some progress ... I have found that View NX 2 works OK, but also someone has given me a profile to be used with Lightroom that also works. Not as good as your versions, but heading in the right direction ... (see below)

 

In terms of evaluating images, I suppose that the better lenses (i.e. more UV transparent to smaller wavelengths) should give images with a greater range of colours? Maybe this would be the second image in the sequnce below (35mm Optomax f/3.5) ? Although of course this also depends on the spectrum of light illuminating the scene and the reflectivity of the objects in the scene.

 

Re D40 v D3200 the comparison here is not fair as there was probably less ambient UV around when I shot the D40 images. I will do a side by side comparison for interest at some time out of curiosity, but the D3200 will be superior i'm sure.

 

I have a question that is probably really really dumb, but does any one have any tips on how to avoid dropping filters! I haven't done so, but with taking them on and off it feels quite risky. It would be nice if there was some way of mounting them so that they could be slid in and out without having to take them off, but I guess it would be difficult to avoid light leaks.

 

As I general comment can I just say that I am finding this forum so helpful - I am sure it would have taken me far far longer to get to this point without all the helpful people on here.