• Ultraviolet Photography
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Greetings from North East England

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#1 Jim Lloyd

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Posted 03 January 2018 - 17:02

Hi all,

Just writing to introduce myself to the group.

Firstly, thank you for accepting me as a member. I have found the information on the site extremely helpful so far.

I am a physicist by training and have worked for many years as a Medical Physicist in the UK National Health Service. My professional areas of interest are in medical imaging and in the medical uses of UV radiation.

A list of publications are here. In the UV field my chief input has been in accurate spectral irradiance measurement which is particularly critical in medical applications due to the extreme variation in skin sensitivity with wavelength. I am not directly involved in this at the moment but do have access to Bentham double diffraction grating spectroradiometer and other equipment.

However, my interest in this site has actually comes from another direction since I have taken partial early retirement in order to pursue an interest in art. I have recently completed a masters degree in fine art at Newcastle University. For this I concentrated largely on video and photography. My art website is here . My artistic interests are to do with how we understand the natural world and how our understanding might differ from that of animals. It was the realization that birds can see UV that particularly prompted my interest in UV photography. If I was speaking now as a scientist I would be able to articulate my aims, but with an artists hat on to be honest I am not sure exactly where this is heading. The idea is something like "how birds see than landscape" with a big dose of artistic licence rather than a scientifically accurate description.

Anyway I am only just getting started.

I am thinking of using a full spectrum converted Nikon dSLR as I am familiar with Nikon and I have two Nikon cameras already. Slightly unsure about this as it seems there are more possibilities for legacy "accidental UV" lenses with Canon (due to flange-focal distance) . Anyway I have a Optomax 35 mm f/3.5 lens in T mount with Nikon F converter. I have used this for visible landscape photography on Nikon d3300 and the results are rather soft, and I can't decide if this is good aesthetically or not ( a couple of examples attached - I know not strictly relevant to the forum, but partly by way of introduction to show the landscape near where I live). I also have on order a Nikon E series 50 mm f/1.8 and Photax 28 mm f/2.8 pre Ai fit - based on posts on this forum I am hopping these will be suitable. I also have on order Schott BG40 2mm + UG1 2mm filters which I plan to use together. Hopefully in a few weeks I will be able to show some results!

Best wishes

Jim

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#2 Andy Perrin

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Posted 03 January 2018 - 19:24

Hi! Welcome, and gorgeous pics!

#3 Cadmium

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Posted 03 January 2018 - 22:06

Beautiful landscape and photos.
The UG1 2mm + BG40 2mm will work. It only has OD 3.5 Red/IR suppression, which might be all you need.
A slightly better stack might be U-360 2mm + S8612 1.5mm to 2mm, has stronger suppression. Or even UG1 2mm + S8612 1.5mm to 2mm. Both of those stacks have OD 5 suppression.
You can swap the ones you have for the others if needed.

#4 Jim Lloyd

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Posted 04 January 2018 - 10:56

Thanks Andy and Cadmium

I am buying the filters from UVIROPTICS via ebay. I have had another look and I see what you mean now about the S8612 vs BG40. I spent quite a bit of time looking at this, but I think I missed that difference. Anyway I will try out when I have and let you know. How would the red/IR contamination show up?

Best wishes

Jim

#5 nfoto

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Posted 04 January 2018 - 11:33

Welcome to the UVP community !! We are small but members have a lot of information on anything UV and to a large extent, aspects of multispectral and IR photography as well.
Bjørn Birna Rørslett

#6 Andy Perrin

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Posted 04 January 2018 - 16:03

Heehee, UVIROptics is Cadmium! I have been very happy with his filter glasses. Many ebay sellers advertise Schott glass but in reality sell cheap knockoffs like QB21. I got bitten by one of them. Cadmium’s filters have performed as expected, however.

Edited by Andy Perrin, 04 January 2018 - 16:06.


#7 Andrea B.

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Posted 05 January 2018 - 18:40

Hello Jim and welcome to UVP. We hope you enjoy the website and find it useful.

I thought your story quite interesting about turning to art and wanting to bring some of your scientific knowledge into that. I had also a technical background and turned to photography as an art form after retirement. (Never had any time at all for that while working at the Labs.) UV photography can certainly go in either direction or both - a scientific documentary approach or an artistic approach. We will look forward to seeing what you discover.
Andrea G. Blum
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#8 Jim Lloyd

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Posted 05 January 2018 - 19:33

Thanks Andrea

I have actually today been trying to write a PhD proposal on this subject - that is how using uv photography could be both art and science. Or maybe it’s an artificial distinction ? Anyway it has been driving me crazy ! It’s so easy to get oneself tie up in mental knots !

Best wishes

Jim


#9 Andrea B.

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Posted 05 January 2018 - 19:49

Jim, I think that is an age old discussion topic. Is any type of photography art or is it documentation? And where do you draw the line between the two? My answer: you can't draw a line. And the distinction is always in the eye of the viewer of your work. You may think UV art. Your viewer may think UV documentation.

Here is an example of one of my landscape sets which has had both types of reactions from viewers. This set was borrowed for a university student's geology presentation, and I've also had a lot of artistic feedback about it. http://www.ultraviol...n-death-valley/

I suggest totally ignoring this dilemma for now by going on an exporation to see where UV photography takes you rather than where you take it? :D

I enjoyed Some Things I.
Andrea G. Blum
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#10 Jim Lloyd

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Posted 05 January 2018 - 21:34

Hi Andrea

I totally agree, best to get on with "thinking through making" rather than "making through thinking" - "leap before you look" etc.

Beautiful and very interesting set from Death Valley - many thanks for sharing.

Thank you for your comment of my photobook "Some things 1" - those pictures are from around Malham and Gordale scar - Yorkshire, England. But my thinking was to focus on objects and play with scale and framing and try to avoid clichéd views

Best wishes

Jim

#11 Andrea B.

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Posted 06 January 2018 - 02:34

False colour has certain rewards in UV/IR work but can easily be overdone. I am thinking now to go back and rework the Death Valley scenes in B&W to see what that approach would bring.


Slightly unsure about this [conversion] as it seems there are more possibilities for legacy "accidental UV" lenses with Canon (due to flange-focal distance)

Converting any one of a Sony NEX or Alpha, Olympus 4/3 or Panasonic 4/3 would offer you a nice short FFD for those accidental UV lenses. And there is always the very fine Pentax K5 or K1 for old lenses having M42 screw mounts with a Pentax FFD.
Andrea G. Blum
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#12 Jim Lloyd

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Posted 07 January 2018 - 23:22

Thanks Andrea,

I was writing a long post about art last night, but lost it all as I navigated away from the page ! - I will come back to that another time, but will just mention Richard Mosse an an artist working with IR photography http://www.jackshain.../richard-mosse/ - not sure if you know his work?

Thanks for your tips about cameras. I was thinking of using a converted dSLR such as Nikon d3200 as this is something I am familiar with and I had not thought about mirrorless cameras.The Sony NEX 5T looks like a good alternative option. I would be interested in any general thoughts of dSLR vs mirrorless for UV photography I am not sure how one would compose and focus the view. .Is enough UV transmitted to use the live view screen? if not presumably with dSLR you can remove the visible block filter and compose and then add it back. This seems like a pain, but then I think
on most occasions I would probably want to have a visible and IR version of the scene for comparison / processing as well the UV one. I am mainly interested in landscapes rather than flowers.

I would be grateful for any advice

Best wishes

Jim

#13 nfoto

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Posted 08 January 2018 - 06:09

Mirrorless cameras need sufficient response from their internal sensors to allow focusing at all. This is usually no problem in broad daylight even with an efficient UV bandpass filter inserted in the optical path, but once light levels drop or one moves indoors, the camera essentially becomes UV blind. The noise level in the finder can make focusing impossible under such conditions.

The combination of a "broad band" mirrorless camera and lenses designed for longer register distance (i.e. for DSLR/SLR systems) usually will facilitate using a rear-mounted filter. The filter can be inserted into the mount adapter. This will enable use of quite exotic lenses (fisheyes etc.) for UV photography. By switching adapters, one can use the same camera for various spectral ranges.
Bjørn Birna Rørslett

#14 Jim Lloyd

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Posted 08 January 2018 - 11:00

Thanks Bjørn

I have a Nikon d40 and I have read somewhere that this might work for uv unmodified. Does anyone know how many more stops would be required compared to a more recent converted camera. Just as a very rough idea ?



#15 nfoto

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Posted 08 January 2018 - 15:38

Been a while since I last used a stock D40, a ball-park estimate is perhaps 2+ stops lower response to UV? With adequate UV light present, I had no problems getting proper UV images, but hand-held use is hardly feasible.
Bjørn Birna Rørslett

#16 Andrea B.

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Posted 10 January 2018 - 16:38

** converted dSLR such as Nikon d3200
Make sure the consumer end cameras handle manual lenses as you would like.

** I am not sure how one would compose and focus the view. Is enough UV transmitted to use the live view screen?

With either of the two possible methods below, be sure to close the viewfinder window on a DSLR to prevent visible/IR light leak which contaminates the UV foto. With a DSLR, focusing UV in Live View is thus the only option. With a mirrorless camera you might be able to focus UV via the electronic viewfinder? But Live View is also my preferred method with mirrorless because one can zoom in, etc.

Note that both these methods below require a iterative learning curve for a particular lens or a particular aperture on a lens. These methods are for outdoor landscapes. (Indoors, focusing on a close subject through a UV-pass filter is accomplished by temporarily illuminating the subject with a UV-Led torch.)

1) Focus in Live View at desired aperture with UV-pass filter OFF. Replace filter. Shoot. Determine how much the resulting foto is OOF to learn the amount of "filter focus shift" for which you must compensate in initial focus. (Remember the old red mark on lenses for IR focus compensation??) Take calibration notes for future reference.

2) In good light, open lens to widest aperture for most light, focus in Live View with UV-pass filter ON. Stop down to desired aperture and shoot. Determine how much the resulting foto is OOF to learn the amount of "lens focus shift" for which you must compensate in initial focus and which might vary by aperture. Take calibration notes for future reference.

Note that even with the very best apochromatic, dedicated UV lenses there might still be small amounts of filter or lens focus shift depending a lot on how close you are to a subject. With a non-dedicated UV-capable lens you will almost always see some shifting at any distance.

Factors in various kinds of focus shift in UV work: camera mod filter type and thickness, camera mod sensor adjustments, UV-pass filter, lens, distance from subject, type of illumination (sunlight, UV-Led, UV-flash, etc).

*****

Many folks will already know these suggestions. Might help some who are learning though. :D
Andrea G. Blum
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#17 Jim Lloyd

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Posted 11 January 2018 - 17:22

That's really helpful thanks Andrea. Sounds complicated, but I guess once you have done it a few times in practice its not so bad. I was thinking that for landscapes at smaller aperture maybe there is sufficient depth of focus for a lot of subjects to not have to worry about focus shift too much?

Now have 4 lenses to play with hoping they are OK for UV transmission: Nikon E series 100 mm and 50 mm, Optomax 35mm f/3.5 and Photax-Paragon 28 mm f/2.8. Of these the Photax seemed to be disappointing on brief initial test shots (visible), although some people on the internet rated this highly. Filters should arrived today or tomorrow after having more than in week in customs! Will play with D40 and hopefully get converted camera soon

Best wishes

Jim

#18 UlfW

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Posted 11 January 2018 - 19:30

View PostAndrea B., on 10 January 2018 - 16:38, said:

2) In good light, open lens to widest aperture for most light, focus in Live View with UV-pass filter ON. Stop down to desired aperture and shoot. Determine how much the resulting foto is OOF to learn the amount of "lens focus shift" for which you must compensate in initial focus and which might vary by aperture. Take calibration notes for future reference.


I might be a bit slow, but I do not understand this statement.
What would cause an extra "lens focus shift" when stopping down after focussing in Live View?

As far as I understand, the Live View is using the sensor just as in the exposure phase.
Stopping down, will extend the DOF in both directions from the DOF-plane, obtained with the aperture fully open.

When switching between filters with a different optical path length, there will be a need to refocus, but that is a different situation.
This is mainly important in close up setups.
Example: going from a thick stack like a S8612, 2mm + UG11, 2mm to a thin Baader U.

Edited by UlfW, 11 January 2018 - 19:32.

Ulf Wilhelmson
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#19 Andy Perrin

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Posted 11 January 2018 - 21:41

I think she means from the diffraction effects when the aperture gets tiny.

Edited by Andy Perrin, 11 January 2018 - 21:41.


#20 UlfW

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Posted 12 January 2018 - 03:35

But diffraction effects due to a tiny aperture, as far as i know, do not shift the center of the focus plane and cannot be cured by refocussing.
If your pictures start to get blurred due to diffraction, when trying to achieve enough DOF, by stopping down, you have to open up again and begin focus-stacking.
https://www.cambridg...photography.htm
http://zerenesystems.com/cms/stacker

Edited by UlfW, 12 January 2018 - 03:42.

Ulf Wilhelmson
Curious and trying to see the invisible.