Ultrapurple

[Ultrapurplepix]

Hello all

 

My name is Giles, also known as Ultrapurple. I have had an interest in non-visible photography for a number of years, starting with using IR filters on bridge cameras. I started seriously acquiring proper equipment in about 2010, when I got my first Fujifilm IS Pro. This was a handy purchase, as I use Nikon gear for my visible images so I had some lenses to play with straight away.

 

Near Infrared is fairly 'low-hanging fruit' so I started wondering about the shorter wavelengths. My earliest experiments were with black light tubes and various LEDs, with various degrees of success. Things took a dramatic upturn when I acquired a 2" Baader U filter and started using that with a scrappy old no-name manual focus lens. I kept playing around with the lenses to hand, which were mostly modern Nikkor AF jobs. More recently, thanks to the various 'good lens guide' lists I've started obtaining optics that perform a bit better in UV. Changing over to a Nikon Series E 35mm f/2.5 improved things somewhat; I also find the 100mm Series E f/2.8 fairly decent.

 

I lust after a Coastal optics 60mm or UV-Nikkor, of course, but such things are well beyond my pocket at present. Of course, if anyone is throwing away a box of them, I would appreciate being in the queue!

 

Very few of my images go online. I take photographs mainly for my own enjoyment, choosing only to publish a small proportion. This may change in time. In the meanwhile you can find my 'everything' photos at http://www.flickr.com/photos/ultrapurple/

 

or the UV/IR images here (starting with the oldest, mostly IR to begin with):

 

http://www.flickr.com/photos/ultrapurple/sets/72157617230652040/ .

 

I have also put some thermal images on Flickr but they are not up to date. I have much better results from a slightly more modern thermal camera but haven't got round to uploading them yet.

 

I am the admin for the Flickr group dedicated to the Fuji IS Pro - see http://www.flickr.co...hoto_9583918286 - and contribute sporadically to that and other groups.

 

Home is in Bedford, England, where I live with my partner and a stuffed aardvark called Boris, whose one claim to fame is that he has his own Facebook page.

 

Finally, here's a UV shot of me 'admiring' a somewhat worse-for-wear dandelion, taken with the 100mm Series E f/2.8, with an inset of the setup for the shoot. The UV image was taken at f/8 with a Baader U on an IS Pro at ISO 250, 1/100s. One of the six strobes is modified for high UV output. I figured the dandelion makes a straightforward 'hello world' statement in a UV image.

 

[nfoto]

Welcome to our little community, Giles. As far as I'm aware you are the first Fuji IS shooter to arrive so I'm sure members will like to hear more details on that system. Obviously as your self-portrait proves, it can record UV. However, if I remember Fuji advertising correctly, it covers "only" 380-1000 nm vs the S3 UV/IR (350-1000nm). I have one of the Special Edition S3 Pro units and while it is a quaint camera and less UV-capable than my Nikons or the Panasonics, it is really fun to use.

[Ultrapurplepix]

Thank you for such a warm welcome.

 

All the documentation currently available on the IS Pro certainly says that it cuts off at 380nm, although for some reason I think I've seen figures in the past suggesting sensitivity to 350nm. When I get a chance I'll knock up a monochromator and try to form an opinion. Some time ago I published a crude assessment of the IS Pro's spectral response - it's in the slideshow for my introduction - but as I was using a halogen lamp and glass prism I suspect the results say a lot more about the IR than UV response.

 

I'm thinking about converting a D3100 to full spectrum: has anyone got any feedback on whether they are any good on UV?

[nfoto]

I am using a broad-band converted D3200 and it certainly does the job well in UV.

[Andrea B.]

Hello Giles and welcome to UltravioletPhotography.com.

 

I totally love that slideshow you posted in your Intro !!

How did you make that? It is so cool.

I would like to add something like that eventually as a "front page" for the site

to show off some of the flowers and other work posted here.

 

Any current Nikon DSLR - with the exception of D700/D3/D3S/D3X/D4 - will make a good full spectrum conversion for UV or IR work. The only consideration is about using old non-CPU lenses and whether you will get metering or not. You could look for a good used D7100 also.

 

Have you photographed Boris in UV yet??

 

[Edited post to add exception list.]

[nfoto]

"Any current Nikon DSLR will make a good full spectrum conversion for UV or IR work."

 

Unfortunately, there are exceptions. Stay away from D3-series, for example.

[Andrea B.]

oh la !! As I was the unlucky one to discover the IR contamination in my failed D700 full spectrum conversion and wrote up the warning for our UV Sticky, you would think I would remember. I was focused on CCD sensor capabilities, I think. I will go right now and amend that remark with the exception list. Thanks!!

[Bill De Jager]

Welcome from another newbie, Giles!

 

I have a D5100 converted for broadband use and it works great in both UV and IR with appropriate filters.

 

Any current Nikon DSLR - with the exception of D700/D3/D3S/D3X/D4 - will make a good full spectrum conversion for UV or IR work. The only consideration is about using old non-CPU lenses and whether you will get metering or not. You could look for a good used D7100 also.

 

 

I'd add a caveat which is that for Nikon shooters in UV there is an advantage to getting a camera in the D3XXX or D5XXX series, in that they will safely mount the pre-AI lenses which will amount to most of the potential Nikkor candidates for UV use. While you may later wish to have your better Nikkor UV lenses AI-converted and/or chipped, it's handy to be able to just pop on any old lens initially to see whether it's worth pursuing further.

 

I just have to remember to not absentmindedly put those same old lenses on my D7000!

[nfoto]

I know Andrea disagrees, but in my opinion there is no better camera for exploring the UV capabilities of odd lenses than the Panasonic line. Currently I'm using the GH-2.

 

Reasons are as follows: adapters for various lens mounts are to be had for next to nothing, you can also mount the UV bandpass filter(s) inside the adapters thus allowing a huge range of lenses to be explored without worrying about suitable filter size, and most important of all you can profile the camera to give a near-perfect UV false-colour rendition. Thus just by mounting the lens and looking through the finder (or viewing on the rear panel), the UV potential can easily be appraised. If the image stays cold bluish or pink the lens isn't suitable for "deep" UV, if you observe warm greys or yellows it is. A split-second analysis as it were - you don't even need to take a single picture or do processing of it.

 

These sensors might not be in the Nikon class regarding dynamics and noise performance, however their UV performance is if anything better and go deeper into the UV band. They can also deliver UV video in good quality.

 

My current field kits for UV always include a GH-2 with a Coastal 60 mm f/4 APO lens and SB-140 flash. In addition, there is a Nikon D3200 (with internal Baader U2") or a broad-band D600. The Nikons do have the advantage of providing GPS recording directly in-camera; for the GH-2 I need to carry a GPS logger and merge the geodata into the RAW files later.

[Ultrapurplepix]

@Andrea: the cleverness of the slideshow is entirely down to Bjørn. He added {media}...{/media} tags (use square brackets!) either side of my Flickr set URL and made the magic happen. I had no idea it was possible to do things like that.

 

Points noted on the D700 etc being unsuitable. I love my D700 for visible work and its ability to see in the dark when it has to.

 

The little I know suggests that CCD sensors (eg IS Pro) have intrinsically better UV performance than CMOS (eg almost everything since) but on the other hand the design of modern sensors is so much better than the wacky hexagonal S and R pixel arrangement on the Fuji sensors that I'm sue they're superior.

 

@Bjørn: I hear what you say about the Panasonic cameras. I have a couple of D3100s (which are currently available refurbished quite cheaply) and am thinking of sacrificing one on the altar of full spectrum conversions. It'll be nice to be able to do video in UV and IR! But that conversion is a project for another day.

 

@Andrea: Here is Boris in (clockwise from top left) visible, UV, IR 720nm and IR950nm. All are IS Pro plus Series E 100mm f/2.8. The UV image was taken with a Baader U 2" at f/8, ISO400, with the strobes on full power. All the others were with the strobes on minimum, ISO100, a ND8 filter and (in several cases) the aperture reduced to f/22. I've never claimed that the IS Pro was particularly sensitive at UV, nor that my strobes give out very much UV light...

 

[nfoto]

The superiority of modern sensor designs truly makes the CCD/CMOS divide moot.

 

I'll make a test set up to illustrate and publish the results separately. Stay tuned.

 

Modifying a Nikon D40X is a tremendous idea for getting the most UV quality for the minimum sum. These bodies go as low as $100-150 these days. UV response is among the best in terms of sensitivity for the 350-400nm range. There is no Live View though so you should have available lens(es) with insignificant focus shift unless you do focus stacking and suchlike bracketing approaches.

 

Giles: the D3100/D3200 surely can do UV video if the cameras are converted to broad-band use. However, the colours will be awful so shooting in b/w is the better approach. No such problems doing UV video with the Panasonics though as these can be profiled correctly in-camera.

[Andrea B.]

True, I could definitely be accused of being a fanatic about a sensor's image quality. :D :D :D

 

The Lumix line is widely regarded as having superior video capabilities over most all mirrorless/dslr lines. Worth having one for that reason if UV video is an interest. And I do have a Lumix GH1-broadband still sitting around. I dont hate it. But once I saw what was possible with a good sensor, the GH1 started gathering dust.

 

Currently I think a Pentax broadband would be the better choice for experimenting with old lenses. The Pentax K5II has an excellent sensor. Pentax also has a nifty K-mount to M42-mount adapter because M42 was Pentax's older screwmount size. There is no prob getting infinity focus with all my old M42 lenses on my current (unconverted) Pentax K200D. I'm about to get that K5II Pentax going with the next paycheck. It will take awhile to get the cam in and get it converted, so stay tuned!! I have no idea what kind of in-camera white balance it is capable of, but that's not something I worry about since WB can be done in a converter.

 

The CCD/CMOS thing is a non-issue. You will find both style sensors "out there" in professional industrial UV equipment if you google around. Fortunately for us, the CMOS sensors in DSLRs work just fine for UV photography once the UVIR block filters and shaker glass is removed. We will have to be careful in the future to understand how new sensor stacks are built. If the manufacturers start fusing filters to the sensor, we would be in trouble.

 

Boris is a very fetching Aardvark and looks quite fine in his UVIR portraits !!!

[Andrea B.]

You know, you can white balance a video too. No need to live with awful colours!

[nfoto]

I'm writing up a camera/sensor shoot-out just now, Andrea. Maybe the results will surprise you? Suffice it to say D600 isn't on top of the list.

 

White-balancing a video in post processing is like massaging (and massacring) a jpg. Better to get colours right prior to shooting.

[Andrea B.]

I am always ready to be surprised !!

 

I tried to upload a video but it was too big.

[Ultrapurplepix]

The minimal amount of research I've done on sensors today indicates that BSI (back-side-illuminated) imagers may well be better-suited for UV than traditional front-illuminated sensors. It's to do with the attenuation of different wavelengths in silicon, of course. I didn't note the figures but seem to recall that blue light has trouble penetrating the gate layer of a sensor but 3000nm light goes through sensor and out the other side. If anyone's interested I'll see if I can dig up the relevant links.

[Andrea B.]

BSI in theory. But in practice some other stuff comes into play as well - Bayer array, sensor size or microlenses for example. Mostly we just convert cams and discover UV-capability empirically. Perhaps not ideal, but so far so good except for my D700 fiasco. I am somewhat surprised that we haven't run into more glitches. "-)

 

The only camera line that I do not really know anything about in terms of post-conversion UV-capability is Canon. There must be some full spectrum Canons out there but they have not yet wandered into Invisible Spectrum on Nikongear. Well, granted, it is NIKON-gear. But we have never discriminated against non-Nikon in Invisible Spectrum. Any brand is welcome there.

[nfoto]

There just appeared a new member with Pentax ... we are truly brand agnostic. Canonites knock on our door and we'll let you enter :)

 

Plus, of course, the lenses we deploy for UV tend to be of a wide brand variety.