I am a the camera conversion expert who made the cameras for the viral video How The Sun Sees You. AMA

What did you learn with this project?

I convert many different cameras each week. This was one of my regular conversions, but the customer is a British/American artist who is an interesting guy. He asked me to make him a UV-Only monochrome camera, and he came up with the idea for the video.

Learning how to do some of these conversions has taken over a decade and lots of R&D into how to deconstruct an integrated circuit. It has taken lots of money and lots of killed sensors to figure it out.

So what this is showing, is that white people REALLY need to use sunscreen?

Looking at skin in UV shows damage before it is visible in normal light. So, for example, forensics uses it to see skin bruises that aren't visible in normal light. Sun damaged skin will show up in UV before you can see it. Using sunscreen is a good idea - even though I enjoy a bit of sun anyhow.

How does the camera see in Ultraviolet?

The surface of the sensor was modified to remove the CFA and microlenses. Then a special UV-Only pass filter was installed over the sensor. The artist used a standard camera lens which passes UV to about 360nm. Below that, you need a special and expensive lens.

Are lenses not made using glass? Doesn't seem like that would work very well for UV applications.

Most consumer camera lenses are made of BK7 glass (its a type of glass) which is transparent until about 360nm. So a consumer lens can see some UV. Below that, you need something like a Jenoptik APO lens which runs about $5,000.

If someone like me wanted to mod a DSLR in the same way, what websites/resources would you recommend?

To see UV monochrome? I think I am the only guy in the world who knows how and can do it. I don't recommend that people try modding cameras on their own. Aside from the possibility of breaking something, you need special tools and equipment to do it right. The glass going over the sensor has to be really, really clean else you end up with dust spots because the glass is very close to sensor. You can't use wipes or clean room swabs because those leave tiny particles as well. Very small particles get glued to the glass by electrostatic forces. With manual cleaning, you will just end up pushing the particles around. For our final cleaning step, we built a machine that burns off a thin layer of glass to get the glass clean to an atomic level - at least for a few seconds. There are various shops that offer to do camera conversions, but you want to do your homework because there are some guys doing these on their kitchen tables using the wrong dimensioned glass which screws up the focal plane.

We are pretty much the top shop in the world - IMHO.

And to convert to monochrome, you have to remove epoxied coverglass off the sensor, and then remove about 5 microns of the CFA and microlenses off the surface of the sensor in a precise, even way. For comparison, typical human hair is 45 microns. The CFA and microlenses are photolithography printed on the surface of the sensor. It's not like you can just peel the layers off. If touch the surface of the sensor with about anything, it will leave a mark.

To see UV monochrome? I think I am the only guy in the world who knows how and can do it.

Well then there are the engineers and physicists that created and continue to improve this technology.... I'm pretty sure at least a couple thousand or tens of thousands would know how to go about doing it.

Knowing what needs to be done and being able and having the equipment are two very different things.

Ever work on a Fuji W3? (it's a 3D camera) Also is there anything you can do with a foveon based camera that you can't do with a conventional type?

Yes, I have modified W3's though not for monochrome or UV-Only. The monochrome and UV cameras I do are just certain DLSRS. I have modified lots of Foveon sensors as well, but not for monochrome or UV. Foveon sensors aren't the best sensors for conversions because of the way they work - if you are familiar with them.

The W3 I modified was setup so one side to an infrared picture and one side took a visible picture.

What are some of your tips for cleaning image sensors and lenses? I get scared if I ever have to go near my sensor, and I've read a lot of different suggestions.

Also, what advice do you have for cleaning sensors if you're shooting in the field and have no proper cleaning tools with you?

Good question.

First off, don't clean a sensor unless you really need to. If you are shooting white fields at f22 and then looking for something in Photoshop, you are going to find something. Even on a brand new camera, you find dust. Do yourself a favor and don't fool with the camera unless it is really a problem.

With most lenses, sharpest pictures are at f8-f10. Lens sharpness is a whole different discussion, but depth of field is not the same thing as maximum sharpness. If the dust is a problem at f8, then maybe you should do something about it.

I have seen people destroy their ICF/AA stack (part in front of the sensor) by cleaning it too much. Canon, Nikon and Sony don't replace the stack anymore - you have to buy a new sensor. On a Nikon D800, a new sensor will cost you over $1,800.

If you do have to clean, start off with the least invasive methods such as canned air. With canned air, you have to be careful not to tip the can too much because it can spray liquid which will stain your sensor.

Secondly, use a dry, clean-room swab to gently wipe the sensor from one side to the other. Any time you touch the sensor you will leave particles from the swab on the sensor. The particles may be really small, but they will be there.

Lastly, any sort of wet cleaning. Don't even try it unless you really have to. Even 5 9's solvent (lab grade 99.999%) pure will leave a visible mark where the solvent evaporates. Oils from the metal around the sensor can dissolve and leave stains on the sensor. At this point, you might be better off sending your camera to a professional. Not worth the risk. I would never wet clean myself because it just doesn't work well.

When we clean sensors, we take the camera apart, remove the sensor, and clean under a microscope. We have various other tools to help clean some of which are custom built (like one that evaporates a thin layer of glass from the stack) to others that are very specialized.

What lens was used?

Not sure of the model, but I think it was a standard Canon lens.

What was the most intriguing or interesting application of one of your conversions?

Well, there are lots of cameras I work with and lots of different conversions. I have customers all over the world using the cameras for many different things such as fine arts, forensics, scientific, remote sensing, astronomy, etc. The most interesting thing is hearing from the customers all the different sorts of things that they do with them.

The most technical conversions are the monochrome ones because I have to modify the surface of the sensor.

I made one camera that could see X-Rays. I used an X-Ray phosphor scintillation plate on a fiber optic plate that was directly coupled to the surface of the sensor. It worked, but could only see X-Rays in the surface area of the sensor. I could take pictures with no lens and the body cap in place up to about 20x40mm.

That's actually fascinating. I have a little hand-held toy (one of these deals) that operates on a similar principle but of course is just for entertainment. What was that X-ray camera eventually used for (if you can say)?

I've always loved anything that "reveals the unseen" as it were. I know that there's all this other energy outside of visible light out there, from infrared to ultraviolet and microwaves, and anything that allows a glimpse at that is amazing.

What kind of background led you to this work? Did you start out as an optics guy and end up working on electronics, or vice versa? Or something different entirely?

The X-Ray camera was made for a company that makes dental equipment. Not sure exactly what they were doing with it.

What I do now is not what I trained for in school. I have always been a technically oriented person. I spent the first 20 years after college working for 2 companies where I learned a lot of stuff though not directly related to what I do now. I started this business in my basement because I was frustrated I couldn't do more at work. Eventually it grew to the point where it became a full time job and I own a small commercial building (with no debt). The growth has been about listening to what customers would like and then trying to figure out a way to do it. Some projects have taken 5-10 years to figure out. Cool thing about the internet is that there is a ton of knowledge out there if you can find it.

A year or so ago, I had an MIT doctoral student contact me to learn how to measure the spectral response of a camera. It's not an easy thing to do, and the camera companies won't release that data on consumer cameras. I had to laugh because I figured it out on my own without an special training.

The camera geeks can get a little crazy, which is probably why companies are reluctant to share info. Don't want your new $4500 geek toy losing market share because someone noticed 405, 630, and 720nm all have response dips. :D

Sort of like the dawn of the HiFi age when everyone wanted a flat response curve from 10 Hz-35,000 Hz, even if they could only hear from 35Hz-9000 Hz. ;)

Years ago, i was converting a Fuji S3 Pro to UV-VIS-IR. Fuji learned what I was doing when some customers sent their cameras in for a memory upgrade. Later that year, Fuji had a big stock of S3's in the USA and they were coming out with the S5 in a few months. S4 was an unlucky number in Japan, so no S4.

Fuji talked with me about modifying some of their S3's for UV-VIS-IR so they could sell it at a forensics camera and get rid of their S3 stock. They decided to do it in-house in the end, but they copied what I was doing. On my UV-VIS-IR conversions, I put in a Schott WG280 glass that is transparent from 280nm past the sensor limit.

Fuji started off marketing the camera saying that the camera could see to 280nm. Having a color sensor with microlenses, the camera could barely see UV at all and certainly not to 280nm. The problem was that Fuji Japan wouldn't tell Fuji USA what the camera's real response curve was. So Fuji USA was marketing a camera without even knowing what they were doing.

That's common with camera companies. Even if you went to Canon, Nikon, Sony etc USA headquarters, they couldn't tell you the response even if they wanted to - and they wouldn't be allowed to anyhow.

Your spinthariscope might be a fun camera type for me to make. Looks like I would need to make a scintillation plate for Americium or Thorium. Hmmm, maybe not such a good idea since those elements are radioactive.

X-rays are tricky to focus, but they've worked out a lens for it. Weird looking though. :D

http://www.x-ray-optics.de/index.php?option=com_content&view=article&id=63&Itemid=74

http://en.wikipedia.org/wiki/Superlens

I wonder if I could build the shape on my 3D printer and then spray it with metal paint?

Yeah, but the metal has to be something x-ray reflective like tungsten. :D

Now that's not necessarily a deal killer. Chemical Vapor deposition is a standard process these days.

Supplies

http://wqtb.en.alibaba.com/product/549911589-50243807/Stranded_Tungsten_Wire_for_vacuum_deposition.html#!

And one place that does it, out of probably thousands.

http://vacpro.com/CVD-Coating.html

Some theory

https://en.wikipedia.org/wiki/X-ray_optics

and some hard x-ray mirror examples.

http://www.ntt-at.com/product/xraym_h/

Interesting. One idea I have wondered about is if it would be possible to make an X-Ray lens for a DSLR that I converted to see X-Rays using a scintillation plate. I have an X-Ray generator here and X-Ray phosphors, but not enough time for playing right now.

what's the simplest camera conversion trick that you know of for someone getting started in this?

Most common camera conversion is a 715nm IR-Only. The camera will see about as much light in IR as a stock camera sees sunlight. The 715nm gives you options like Red-Blue channel swapping so you get deep blue skies, contrasty clouds and white vegetation leaves. Not sure if that is a trick though.

How did you get involved in the field of light science?

In addition to converting cameras, what are some of the other cool things that you do in your field?

I originally started my company with some computer hardware and software that did various sorts of home automation. That never really went very far. One day, I was talking to a friend who mentioned to me about how some older Sony camcorders could sort-of do an X-Ray effect with an infrared filter (not really X-Ray but you could sort-of see through some thin materials). Anyhow, the infrared filters being sold seemed vastly overpriced, so I decided to make some myself. Then someone asked me to modify a camera to see infrared. I had worked in high school in a TV and Stereo repair shop (do they exist anymore), and so I took a camera apart and modified Then it was just one thing leading to another, and listening to customers desires.

I also do a lot of work with invisible inks (UV and IR), special phosphors, camera filters, UV and IR lights and generally areas having some light aspect.

An area I have been working a lot recently is making special cameras for vegetation remote sensing. Chlorophyll reflects light strongly at 680nm while it absorbs blue and red light well. The chlorophyll reflects at 680nm because the photons don't have enough energy to support photosynthesis. When a plant is not healthy, it doesn't reflect IR as much. By looking at a mathematical relationship between where the plant absorbs light and reflects light, you can see if the plant is healthy, needs fertilizer, estimate biomass (for harvesting), figure out optimum plants for a particular soil type, etc.

I make some cameras that can see both infrared and visible light in discrete channels. People put them in UAV's or fixed wing aircraft and look at things like farmer's fields. The pictures are run through a computer program I wrote that creates a false color image of a vegetation index. Then the data is use to inform the farmer what is going on. They are starting to do things like program robotic tractors to only spray fertilizer where needed. It is all about optimization of resources.

What kind of equipment do you use to do sensor modification like this?

Class 100 clean room, various microscopes, lots and lots of custom made glass (usually each camera needs custom glass), various tools, special glass cleaning machine. In addition to that I have a lot of other equipment like various spectrometers, light integration spheres, variable frequency light sources, fiber optic cables, CO2 laser,,, Anyhow, I have a lot of scientific equipment here.

have you ever made a camera that can see multiple IR/UV bands? like instead of RGB it would bas 665, 715 and 830?

Also have you ever modded a camera to see luminosity like our eye does only in the greenish band (Rods)?

What are the simplest and most difficult mods you've done?

Well, you are limited by the response of the CFA. For example, the blue dye shows visible blue blocks green and red and then opens up in the IR at about 800nm. With the CFA on, you couldn't get 665nm and 715nm because the red channel is open for 600-1100nm. Theoretically, you could remove the CFA and photolithography print a new CFA, but you would need really expensive equipment and find the dyes that had the response you want. So, realistically, no.

Have you ever covered a camera to capture light fields? I'm not quite satisfied with Lytro and it would be cool if someone else started competing with them.

Yes, I did that for a scientist in Singapore. I researched a little bit, but have been too busy with other sorts of cameras.

Soooo... What SPF level sunscreen was used in the video?

Not sure, but probably a high SPF.

I have a quadcopter and I have a Sony Nex 5r.

Every gram matters for flight times and gimbal operation.

The camera weighs 276 grams, including battery. 16mm pancake lens weights another 70 grams.

Do you think the camera could be stripped of some things to make it substantially lighter? As long as I can connect video out, I don't really need the LCD screen/hotshoe/etc. And if I can connect external power, I don't need the battery, either... Thoughts?

Common issue for they guys using our remote sensing cameras with UAV's for agriculture. I happen to have a monochrome 5n right next to me.

Biggest weight savings would be the battery. Not too much that you can take out of the NEX series. They don't even have a chassis. More of a unibody construction. Just various plastic and stamped metal parts screwed together. Sony didn't leave much in there that isn't used.

Would you happen to know if I can ditch that battery and use power from the quad? (Not sure if there are any proprietary tricks that force you to use stock Sony battery...)

Ditching 42 grams in such an easy way would be a decent win...

Not sure. The camera and battery do talk to each other. I know that 3rd party battery manufactures sometimes have to figure out how to get their batteries to communicate. You might have to do something like take the battery apart and remove the cells and connect there so that the 'battery' can talk to the camera.

Also, some cameras have the option for using a A/C adapter that looks like a battery pack. You might be able to use the adapter and then ditch the power supply for a direct power connection.

Wow, what's up with that website? Takes me back to year 1990.

Yes, I know. We have been around since 1997. We started really rocking in 2000. Although we are still a small business, the tools we used to build the website are from the early 2000's.

The problem we found is that most web site creation software is either Content Management Software (CMS) or web shopping carts. There is, amazingly, very little software even today that will do both CMS and shopping cart functions. Most CMS software doesn't have much in the way of shopping carts. Most shopping carts, have really poor CMS.

Our sales approach is to have 98% customer information pages to educate the customer about the technology. Very few pages are sales related. Our website is about 450 pages with about 600 SKU's of products. Converting all the pages and all the products is not a quick thing. The options to convert are very limited. I am really surprised that 15 years after we built the site, the options are very poor if you want to own your site.

We have been looking at a Joomla + shopping cart solution, but it is a lot of work to port over. We have also been so busy making new products and filling orders, that we haven't changed yet.

Maybe you need to play Devo or Talking Heads while using our site.

What's your favorite hobby ?

Ummm. Well... I have a lot of hobbies. I am not your average guy.

Some of those people in the video look like old and modern pictures taken with the wet plate collodion process. The plates were sensitive to blue and ultraviolet light and a lot show freckles.

I also want to find a used dslr body and want to create an ir dedicated camera by removing the filter glass and replace it with an ir pass filter. Any tips on doing a conversion like that on a budget?

Budget? Well, converting to monochrome and UV is an expensive deal. That being said, we bought a batch of cheap, used Nikon D70's for R&D. I could sell some of those a lot less than a typical new camera. You should contact me if your are interested and see if we can work something out.

Yes, the UV monochrome pictures have reminded me of the 1930's depression era black and whites. You can see fine details that a stock camera can't see (being monochrome) and the UV makes people look 10 years older. You end up with a really gritty, detailed, stark images where faces show their wear and tear.

If my face is shot is UV, I look 10 years older. In IR, I look 10 year younger. So if you are taking wedding pictures, go with IR. If you want to make hyper-realistic, gritty images, go with UV.

I have some nasty aliasing/moire with my D7100. Is it possible to add an anti-aliasing filter?

Yes, but you probably don't want to do that. How exactly are you seeing the aliasing? Shooting a test chart? The camera companies are finally starting to eliminate the Optical Low Pass Filter (OPLF) or Anti Aliasing (AA) filter from consumer cameras. My guess is part of this is because we charge $450 to get rid of it! Other than shooting test charts and perhaps shooting finely patterned clothing, an OLPF degrades your image. No medium format back (expensive large sensor cameras) has an OLPF because those guys buying wouldn't allow it. They know the deal.

An OLPF reduces the amount of information in the picture. Yes, the OLPF can eliminate moire, but moire is only going to happen when a finely repeating pattern happens to almost match the pixel spacing of the sensor. As soon as you pull in a bit or pull out at bit, the problem goes away. The problem is related to a digital sampling device when the high frequency of the sample approaches the limit of the sample rate of the sensor (Nyquist Theorem) .

I think the use of an OLPF for consumer DLSR's is largely a marketing issue where the manufacturers are worried that a site like DPreview will proclaim a camera is not good because of moire.

Why would a Nikon D70 have a much lower OLPF than a Nikon D200 even accounting for the pixel spacing? One of my first customers for this was a Nikon D200 owner who was bothered than his Nikon D70 shot sharper pictures. I put in a Nikon D70 ICF/AA stack and compensated for the thickness change and his sharpness increased. Then I made some custom ICF's for his D200 to keep his focal plane correct, and sharpness increased even more.

If you are shooting real world stuff, your D7100 will outperform your D7000. There is a reason the manufacturers are starting to stop with OLPF nonsense - perhaps because we charge $450 to get rid of it.

Here's some of the worst I've got. I have plenty more.

I think the problem comes from choosing to shoot at higher ISO and use flash which means lower flash power and therefore short flash times. I think the flash is fast enough to freeze any vibrations that would slightly blur the image. I've mostly see it in these circumstances.

Edit: I don't want to changes my settings because the photos look good, they are just prone to moire.

If you are shooting a lot of finely detailed fabrics, moire can be a problem. If you move in our out a bit, then you will change to spacing of the fabric patterns on the sensor and the problem will go away. If you are shooting someone where fabric like that, you might want to take some pictures further away and some closer so you can choose later. You can fix in post, but that is a pain. You could add a blur filter to your lens, but then everything will be blurry. You could use a crappier lens that has less resolution than your camera.

That is your classic problem of a real world analog signal getting sampled by a digital device that doesn't have enough resolution. Your lens has more resolution than your camera and the thing you are photographing are more resolution (high frequency information) than your camera.

You could step up to a D800 and I doubt you will see the problem.

I'm an engineer. Supposing I wanted to design a board with a CCD or CMOS sensor that could do a decent job with monochrome UV, what sensor would you recommend? (Resolution not important).

CCD vs CMOS is no longer a relevant debate. Both are made of silicon and the term just refers to how much of the processing the chip can do. In the early days, a CMOS sensor had some much physical real estate dedicated to the processing, that the photodiodes were smaller. The smaller photodiodes meant smaller photon wells which meant they couldn't hold as much charge which meant more noise. For today's chips, CMOS sensors have the photodiodes edge to edge. However, it is less expensive to design a CCD since it is simpler so you still see some CCD's around. CMOS cost more to design but less if you are building volume.

The sensors are built of silicon so you start off with the same basic sensitivity. Where the UV get blocked off is with the addition of the Color Filter Array (CFA), microlenses and sensor coverglass. If you are designing your own sensor with maximum UV sensitivity, I would leave off the CFA and microlenses and then use something like a quartz coverglass. Also, go with larger pixels since that means larger photon wells which means better dynamic range.

Thanks for the reply. I should have been more specific - can you suggest a specific sensor (or sensor family) from a particular manufacturer that would be suitable for use in such a project?

Currently, the best sensors for that sort of project are Canon DLSR's.

You would need to give me more details so that I understand what you are trying to do exactly.

What's good mid-range camera to buy. I'd like to get at least a starter lens and body? budgets around $1500-2000

There are a lot of cameras out there that I don't know about, so I am not an authority. The best camera for someone depends on their preferences, abilities and budget. I have various rigs depending on what my needs are for the particular event. I have big, heavy DSLR rigs with nice glass (lenses). For a particular sort of shooting, I will choose a certain lens. The big heavy stuff is good when I want to get the best picture possible and I don't mind lugging around 10-20 lbs of gear. More often, I don't feel like carrying that much, and I will bring something small like a Sony NEX or alpha series setup. Below that, I have point and shoot cameras, and below that I have my phone.

I have seen great images taken with crappy cameras. The image is more about the photographer. One of my customers, Mitch Dobrowner ( http://www.mitchdobrowner.com ) , started off taking pictures using about the worst IR-Only cameras possible that would get terrible IR hotspots above f6. However, he was making pictures that were getting awards. He has since graduated to better equipment and he has done worldwide acclaimed work.

You also need to decide what sort of camera you want? Are you looking to take normal picture? Infrared pictures? If IR, do you want a dedicated body (the simplest). If so, you probably want a regular body and infrared body and then choose depending on your bent.

For taking normal pictures with that sort of budget, I would start looking with something like a Sony NEX or Alpha series. They are within your budget, they take nice pictures and are decent value.

The best spot to invest money in cameras is in the lenses. The bodies will depreciate quickly and be outdated technology. A really good lens will still be a really good lens.

Interesting! So it's the monochrome modification (scraping off the Bayer array) that makes the sensor sensitive enough for motion video? I own a full range modified T3i/600D with a quartz lens and Baader U filter, but even in the full sun I have to choose between ridiculously high ISO or long shutter. The best photo I've taken so far was 1/30 ISO 800 on a tripod.

If I ever get rich I'll invest in a full frame camera, have it converted to full monochrome by you, and get one of those ridiculously expensive focus corrected quartz lenses. Hey, I can dream, right :P

Scraping? Not that. If you touch the bare sensor die with about anything, it will leave a visible mark later. There is a guy in New Zealand or somewhere who uses sharpened sticks to scrape at the sensor to remove the CFA for astronomy. That cracks me up. He says he knows there are problems with the sensor but he can fix it post. That's like do it yourself brain surgery with a cordless drill.

We have figured out how to remove the microlenses and CFA very precisely from edge to edge. Note, that we don't convert many types of cameras. Some cameras have coverglass that is glued with very strong epoxies that is hard to get off. Each sensor needs to have custom stainless steel fixtures built. Each sensor usually involves multiple killed sensors learning the paramenters, so there is an R&D cost.

So what is the light sensitivity gain from taking off the CFA? I notice in my UV RAW photos that the green channel is mostly garbage, yet with an RGGB array that's half of the photosites.

Removing the CFA and microlenses increases sensitivity by about 6x in the UV, about 2X in visible, but it is a net loss in the IR because the CFA is open past 800nm and the microlenses increases sensitivity.

Yes, pretty hard to take UV pictures with a stock camera sensor. BTW, our XNite330C is slightly more open in the UV than a Baader Venus.

You can check with us too to see if we have some R&D cameras that wouldn't be terribly expensive.

Wow! Keep up the good work.

Why do you think manufacturers won't offer this as a default? I mean, with a small premium (like the D800's lowpass removal), camera makers could offer different types of sensors a la cart. Smaller manufacturers could even use this to satisfy niches that Canon or Nikon won't. I mean I guess we have the Leica Monochrome, but I can hardly shell out $8000 for one. I understand you don't work for CaNikon, but any insight is appreciated.

Probably not. The big manufacturers look for big volume. While making specialty sensors is easy for them to do, to change a manufacturing line for a small run costs a lot of money. I have heard that Leica loses money on their monochrome cameras because the volume is so low.

Texas Instruments makes a DLP chip that costs less than $100. The same chip with a quartz coverglass costs over $1,200 because of the low volumes.

Which particular TI chip is that?

I don't remember the model number at this point. That project was back in 2010. The chip is used maskless lithography. The company was using UV light to create the because the UV wavelengths are shorter allowing finer details. The standard TI chip is used in consumer light projects but has a typical glass cover. TI makes a special version with UV transparent glass that costs a lot more.

A friend of mine mentioned there are 3 dead pixeles in your camera. I know nothing about cameras and stuff. Can you explain? Did you notice?

If he is seeing 3 dead pixels out of the 18 million on the sensor, he has good eyes. But, he might be seeing some dust on the lens, dust on the sensor, pixels that got killed during conversion or something like that. My first guess is that the camera may have gotten some dust on the sensor. I made that camera for him over a year ago. If it is dust, it is way more than 3 pixels - maybe 3 dust specs.