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UltravioletPhotography

Comments please about Image-Laboratory camera conversion ad on Ebay


Andrea B.

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I was asked about this Ebay seller named Image-Laboratory in Massachusetts. This Ebay seller is new to me, and we have no information or reports about their conversions. In their Ebay ad they are offering a "Full Spectrum UV+Vis+IR Nikon D3200 Infrared Camera".

LINK: http://www.ebay.com/...K%3AMEBIDX%3AIT

 

In reading through the Image-Laboratory Ebay ad I notice a few things that need clarification aside from the interestingly weird "UV+Vis+IR Infrared" designation.

So I decided to list these concerns for everyone to read and comment on.

 

1) Claim of Full Spectrum by using AR coated borosilicate glass as the new protective filter.

 

We need to look up the transmission charts for AR coated borosilicate glass.

AR = anti-reflective, so how is that affecting transmission across UV, Vis and IR?

It sounds good, but I want to see charts.

 

What thickness of AR-coated borosilicate glass is used in the conversions? What about its refractive index. This is not given.

 

We need to determine whether AR coated borosilicate glass fluoresces under 365nm illumination. There is no mention of this on the Ebay ad page.

 

2) Claim that "NO ONE ELSE CAN DO THIS" with reference to retention of ultrasonic cleaning system (in those cameras which have this).

 

Well, to be clear, anyone can do this if they want to. Maybe the seller means to say that No Conversion Shop Is Currently Doing This, which is true as far as I know.

 

The method illustrated in the Image-Laboratory ad involves cutting off strip of the glass under the shaker mechanism's fused "transducer" strip and re-fusing that glass strip to the new borosilicate glass replacement filter.

ADDED: 24 Dec. I could certainly be wrong about the exact way the dustshaker is stripped from the old glass and re-fused to the new glass. In one part of the ad it seems like there is a reference to cutting. In another part of the ad, not so.

 

Retention of the dustshaker mechanism is typically not done by the usual commercial conversion shops. I do not know why, but I can think of two possibilities why the Image-Laboratory method may not work well in the finished product:

  • The re-fused strip and filter might be too thick on one end to refit well over the sensor thus creating a minor bulge on one end. This could permit dust leaks.
  • The re-fused strip and filter may no longer "shake" evenly because it is now weightier on the re-fused end. This could make the shaker thing wear out sooner or maybe cause scratches on the underlying sensor package.
  • I'm not saying this type of re-fusion of the dustshaker filter cannot work. I am simply saying that I would want to investigate my two listed concerns to ensure that the shaker mechanism would continue to function properly.
  • Added: It is probably not cost effective for most conversion shops to deal with maintaining the dust shaker.

3) Claim that converted "camera can perfectly focus on all range of distances like the unchanged camera".

 

Does he mean auto-focus or what? Any camera converted or otherwise can focus perfectly if focused manually or focused through Live View.

 

If two old filters are removed and replaced by only one new filter of AR-coated borosilicate glass, then I think I would want some assurance that the one piece of glass has the same thickness as the combined thickness of the two old or that the refraction index is the same so that the expected focus shifts when using non-parfocal lenses will not be too extreme - at least in the Visible range.

 

And if I wanted to get really picky, then I would want some information about the refractive index of AR-coated borosilicate glass as compared to the same for the old filters. I'm thinking that even if original filter thickness is maintained, a changed refractive index could make for focus problems.

 

Additionally, I feel that no one should ever claim "perfect focus" for a camera which will be used as a full spec cam because you are making unwarranted assumptions about the lenses that people will be using on such a converted camera.

 

4) "Add Sapphire window orientation for Full Spectrum conversion for $99".

 

I would have the same questions about transmission and fluorescence of sapphire.

Also, is sapphire glass used in place of the borosilicate or in addition to the borosilicate?

That's not clear.

 

5) Image-Laboratory offers UV conversions made with Hoya U330, U340 or U360 filters, but does not mention the effect of their IR leakage on a reflected UV photograph.

 

This is a serious dis-service to potential purchasers of UV conversions. The naive purchaser of such a conversion may not realize that they are not really recording reflected UV.

 

See 6 and 7 below for two photos - obviously misinterpreted - made with these Hoya filters and shown in the Ebay ad.

 

ADDED: For those who object to the photographer's shorthand term "IR leakage", we can refer to the Hoya U filters as "dual bandpass" instead. The Hoya U filters pass both UV and IR. Although the IR passage is much less than the UV, it is enough to contaminate any UV photo made with such a U filter unless the U filter is stacked with an additional IR blocker.

 

6) Demo Photo labeled: "Original picture made with Olympus E-PL1 converted to UV + IR."

 

A UV+IR photo? Really? This must be the only such photo in existence as the rest of us are unable to simultaneously record UV + IR in sunlight. :D

 

The Hoya U330 filter was used. And indeed its transmission chart (shown elsewhere on the page) depicts transmission in both the UV and IR range. But apparently Image-Laboratory is not aware of the composition of sunlight and how a converted digital camera would really record almost nothing but IR under the U330.

 

7) Demo Photo labeled: "Effect of different filters (UV, IR Cut & IR) on image".

 

Note that the UV-pass image on the left looks suspiciously like the IR-pass image on the right except for a little blue false colour. Could it possibly be that - again - IR has completely overwhelmed the UV when using the IR-leaky U360 filter? Of course.

 

Geez. This one really frosts me because it is evident from the photographs that UV has not been recorded.

 

8) Claim that "if you will not use any filter.....[then] inside buildings with custom white balance it will be pretty much the same picture as there is not much IR light inside buildings".

 

This is just flat out untrue. You cannot custom white balance a full spectrum camera and shoot it filterless and get a normal-looking Visible photograph either inside or outside buildings.

 

*****************************

 

Please let me know what you think about the Image-Laboratory ad.

It seems obvious that someone has decided to set up shop as a converter without knowing much at all about UV-pass filters or what an actual UV photograph looks like. It is possible their conversions are carefully done even though some of the claims need further investigation or are simply untrue.

 

But have I been too harsh?

Have I misinterpreted their claims?

Should I report Image-Laboratory to Ebay as having misleading advertising because they are ignorant?

Should we try to contact Image-Laboratory and explain things?

 

Thank you in advance for any comments and input.

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You read the shaker conversion differently than I did. The eBay listing says:

 

"
Ultrasonic transducer (Sensor cleaning system) has been separated from original IR Cut filter and was fused to replacement Double Side Anti-Reflective coated window! Converted camera has sensor cleaning system intact!"

 

I read that to say the transducer is re-glued to the replacement shaker window. However later a figure in the listing clearly states "...transducer is cut out and fused..." so perhaps my read is assuming to much. I can well imagine that aggressive solvents which might dissolve adhesive holding the transducer to the window would probably not be compatible with the ribbon cable.

 

The borosilicate replacement will likely have a UV spectral cut-off, defined as 50% transmittance of ~315-325nm depending on quality and thickness. Sapphire sensor window specs are generally above 50% T for wavelengths >~200nm so it seems intriguing given the scratch resistance that it would provide.

 

Thanks for the review!

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1) The thickness of the anti reflective coating(s) determine the wavelength function. Basically, at the designed wavelength range, it creates destructive interference for the multiple reflected wavelengths and constructive interference for multiple transmitted wavelengths. For a wide wavelength range a BBAR (Broad Band Anti-Reflective) coating is typically used but unfortunately does not play nicely at high angles of incidence.

A question I have considered asking Brian Caldwell - I have never fully understood how an AR coating works for an APO lens covering UV through IR without compromising itself.

3) It is optical thickness that counts not physical thickness (due to differing refractive indices). As for being parfocal throughout the range - seems like a big claim.

4) Optical quality sapphire transmits down into the SWUV and should not fluoresce if it is high optical quality synthetic sapphire.

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I wonder if you could contact people who have already bought a converted camera from them. There have been over 20 in the past month alone.

It would be just as easy to act as a buyer and ask those questions in the "ask a question" spot at the bottom of the listing

 

-D

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The examples of a "UV" image taken with a "full spectrum" camera is just IR with an in-camera swap to give a blue sky. Exactly what happens if you use say B+W 403 for IR photography to save you the trouble of swapping the R and B channels later. Thus the advertising does not show real UV, but anyone understanding the characteristics of U-330 and suchlike filters would know that already. Other people are given false hopes.
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It would be just as easy to act as a buyer and ask those questions in the "ask a question" spot at the bottom of the listing

 

As a legitimately interested party I did ask the seller a question regarding the dust shaker option for my G3. Interestingly the answer indicates the use of the term "...fused..." describes a thermal process for the attachment of the borosilicate replacement window. My inquiry was in reference to the sapphire replacement but I was told that was not possible because the melting point of sapphire is to high and that much heat would destroy the transducer.

 

Given the considerable lack of standardization of nomenclature in this area I do not assume intentional misrepresentation on the part of this seller. For example the term "UV photography" is often incorrectly used to describe what we call UV-induced visible fluorescence photography.

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Well, whether it is 'true UV' or UVIFL approaches, IR photography is exempt. Showing an IR image and designating it 'UV' is misleading to say the least.

 

No wonder we see such amounts of rubbish 'UV' photography on the various net forums when people fail to understand what IR contamination is.

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From UQG Optics we have this transmission chart for double-coated AR Borofloat glass in a 1.1mm thickness.

 

http://www.uqgoptics...orosilicate.pdf

 

There is approximate 97% transmission from 400nm to 800nm. Beyond 800nm is not shown.

 

Between 400nm and 350nm (approximately) the UV transmission drops from about 90% to about 75%.

 

Between 350nm and 300nm the UV transmission drops from about 75% to about 40%.

 

Remember that the AR Boro chart must be "combined" with the transmission of your UV-Pass filter

to get a true feel for how useful the combo would be.

 

******************

 

Now I wonder if there isn't a better choice for a clear full spectrum filter than AR Borosilicate?

Well, YES.

Fused silica (silicon dioxide0) transmits at about 85-90% between 200nm-1000nm.

Nice flat chart.

 

******************

 

Chart for LifePixel's full spectrum filter shows flat transmission of 90% between 330nm - 1100nm.

From 330nm - 300nm the UV transmission drops from 90% to about 80%.

This would also be a better choice for a full spec filter over AR Boro glass.

 

******************

 

In summary I think I would not choose either of Image-Laboratory's AR Borosilicate or Sapphire full spectrum conversions.

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I used the "ask questions" section on Image-Laboratory's Ebay ad

to ask them about some of the points I raised above.

  • 8) Custom wb restores normal colour to filterless full spec cam when used indoors.
  • 3) Perfect focus in converted cam.
  • 5,6,7) Using Hoya U filters for UV photography.

My message to Image-Laboratory ******************

 

Dear Image-Laboratory,

 

It is misleading to claim that custom white balance will restore normal colour to a filterless full spectrum cam when shooting indoors because "there is little IR indoors". Not true, there is quite a lot of indoor IR. The only way normal colour can be restored to any full spec cam is by use of an external filter which mimics transmission of the removed internal filter.

 

It is misleading to claim that your full spec camera focuses perfectly unless you can demonstrate that the optical transmission of the replacement filter matches that of the removed filter. Also I see no warning about natural focus shift between UV, Vis & IR wavelengths inherent in all lenses except for extremely expensive APO lenses like the Coastal Optics 60mm f/4.

 

A serious error: Hoya U filters leak IR and cannot be used for UV photography without added filtration as your sample photos clearly show. Foliage is not bright in UV - it is dark. You have recorded about 98% IR, not UV. Please correct all these errors.

 

- uvir23

 

Response from Image-Laboratory ***********

 

Dear uvir23,

 

Hello

Thank you for comments.

While some of your comments could be considered as accurate they are not always there.

 

If you illuminate indoor with modern LED light bulbs they practically

do NOT have UV or IR constituencies in their spectrum.

So no UV/IR cut filter will be needed.

 

Hoya U-330,340 and 360 filters have IR transmission by design.

They do no leak IR, that is their native transmission.

Camera can see MORE with U-whatever filter in IR

as optics is LESS transparent for UV then for IR

You can use IR blocking filter to effectively remove IR part

 

About focusing.

Cameras I convert can perfectly focus with standard kit zoom lens in UV, Vis and IR

 

Common sense is a good idea in any case and it is good idea to do some research before buying something new.

 

P.S. Thank you for your letter. I am really happy to read comments from someone who understand in the subject they leave comments.

Thank you

 

- Image-Laboratory

 

 

******************

 

Well, you can imagine my surprise to learn that Hoya UV-Pass filters do not leak IR.

Instead they transmit IR on purpose.

Okaaaaaay..........

 

I think many of you will also be happy to learn that your kit lenses will make perfectly focusing UV lenses. Which will save you a lot of money and and save a lot of time spent searching for those elusive UV-capable lenses.

 

Now what?

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Seems to me the cameras probably do focus perfectly with UV because it is not really UV as we know it to be.

How can UV reach the sensor through a modern kit lens? Of course--technically he may be right if you have a 10 minute exposure. :)

 

-D

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Is it just me or does this eBay seller sound like a non-native English speaker? My earlier communication with them hinted at a degree of language barrier, but that does not excuse misinformation. Andrea's last post seems more obviously "lost in translation" despite the Framingham, Massachusetts, address.

 

I must confess, regarding "filter leaks", I was a bit perplexed when I first encountered that terminology. In my 20+ years of scientific experience with these specific types of filters, the only "leaks" we ever dealt with were radiation coming through cracks or somehow around a filter mount, properly called stray radiation. Fortunately I quickly realized that in the lexicon of UV photography these "filter leaks" were referring to the secondary passband of the filter. I understand many areas of specialization have unique jargon and am not suggesting the usage be considered incorrect.

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John, yes, saying that Hoya U filters "leak" IR is probably photographer's jargon or colloquial speech. I don't know where that terminology came from. One does have to ask why, if the purpose of a UV-pass filter labeled "U" is to pass UV, does the filter also pass Infrared? Just a rhetorical question, really. The Hoya U filters are what they are. :) Ditto Schott.

 

HOWEVER, in the case at hand, specialized jargon or labeling is irrelevant to the fact that it is deceptive for Image-Laboratory to present an IR photograph as being a UV photograph when it simply is not. It is also deceptive to claim there is such a thing as a UV+IR photograph when, again, the presented photograph shows only IR having been recorded.

 

*****

 

Damon, you can make a UV foto through almost any lens with a long enough exposure. Some even turn out to be pretty good. Many do not.

 

I have no idea what Image Laboratory's "perfect focus" statement is intended to mean. Does he mean focusing with an internal UV or IR filter? Does he mean auto-focus or manual focus? Does he mean focusing with an external UV or IR filter using Live View? If the latter, is Image-Laboratory aware of the need for large amounts of supplementary illumination necessary for such focusing when using a Baader-U or an 830nm IR-pass filter? Bottom line, it is misleading as a stand-alone statement.

 

*****

 

Now about that AR borosilicate glass or sapphire glass conversion --- anyone else besides me think it is not the ideal choice for a full spec camera? Why didn't Image-Laboratory at least present the transmission charts for the particular AR Boro that he uses? I do like to think that anyone here would not purchase such a conversion without asking for a trans chart. Link to charts above in post #8.

 

*****

 

English as a second or third or whatever language is no excuse for bad advertising. If you don't fully understand the language you are advertising in, then you hire someone to vet the advertising to ensure that no deceptive or misleading claims are made.

 

Someone is going to eventually report Image-Laboratory to Ebay as a deceptive advertiser.

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Andrea, have you considered that your questions were a "Turing Test" and that the response failed which may indicate you were talking to a BOT?

Dave

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One does have to ask why, if the purpose of a UV-pass filter labeled "U" is to pass UV, does the filter also pass Infrared?

It's expensive to reduce the IR content in these filters however when UV filters exhibiting an IR passband were used for UV film photography the IR "leakage" wasn't really a problem. Not so with digital.

 

Now about that AR borosilicate glass or sapphire glass conversion --- anyone else besides me think it is not the ideal choice for a full spec camera?

 

Chart for LifePixel's full spectrum filter shows flat transmission of 90% between 330nm - 1100nm.

From 330nm - 300nm the UV transmission drops from 90% to about 80%.

This would also be a better choice for a full spec filter over AR Boro glass.

According to personal communication with Lifepixel (granted it was 2008) they were using borofloat glass. It is really suited to UVIR broadband unless you are really trying to squeeze out that last fraction of UV below ~330nm that really is not practical for a converted CCD/CMOS sensor.

 

 

In fact optical sapphire is a very good choice for UV through IR. Fused Quartz has higher transmission but typically not as far into the UV as sapphire. However given the practical UV limit of a converted digital camera borofloat, sapphire or fused quartz would work fine.

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Andrea, two things from me:

 

1) We are again forgetting the transmission of the sensor cover glass. In my experience with Sony cameras, it does not transmit much, if at all below 300 nm. So, it does not matter if one uses quartz, fused silica or sapphire - the differences will not relate to the transmission of the glass used, but rather their reflective and mechanical properties.

 

2) Focusing the camera: as long as he means focusing using imaging sensor, either contrast detection autofocus or main-sensor live view, he is right. But it does not make his statements any less misleading.

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It could be that Image-Laboratory's "perfect focus" with a kit lens simply means that they preserve the original flange focal distance (register distance) of the camera?

 

**********

 

Thanks Shane and Alex for additional remarks about the filter glass. It is important to remember that the sensor pack has a glass cover too.

 

If LifePixel is using borofloat, then the transmission chart they show is certainly different from the AR borofloat chart I found (linked above).

 

**********

 

Well, we are not here to be the Ultraviolet Police & Fraud Detection Squad, so I'm going to drop this for now. If Image-Laboratory is a reputable shop, then they should eventually realize that they need to correct & clarify their advertising.

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It is unavoidable any field of life gets specialised vocabulary. My middle brother occupies himself with ocean-going sailing vessels and I'm lost within a minute when he starts elaborating his adventures in crossing the Atlantic. In my former scientific career I did ecological studies on human-mediated impacts to aquatic systems and found I could easily share vocabulary with Canadian and Swedish colleagues, but not Finnish or central European scientists as their ecosystems were too different. When I went into the study of underwater optics, I rapidly had problems communicating even with fellow Norwegians. So it goes.

 

I find the phrase 'filter leak' a convenient short cut to the more stringent 'secondary lobe of transmission' as it implies the out-of-passband transmission is unwanted and potentially damaging the filter's intended usage. A 'leak' is used in similar connotations elsewhere for something you don't want so why not in UV?

 

The Hoya U-3xx filters were developed in an era of film in which the film itself would be the additional filter to mitigate the secondary range of transmission. However, as witnessed by using colour film for UV photography, you do get unwanted transmission in deep red so the IR contamination was present even then, but perhaps not well understood. Even with b/w films (such as Tri-X or Ilford XP-2) one can detect traces of IR leakage. As I understand the secondary lobe in IR is a characteristic of these silver-based film filters themselves. Labelling this IR transmission as "by design" indicates something really is lost in translation, because one should realise that a modified digital camera may be an order of magnitude more sensitive to IR than to UV, and thus even a small amount of unwanted IR will significantly alter the way the camera responds - from the advertised UV to predominantly being an IR capture. Then we haven't taken the lens characteristic in account meaning that most systems will be even further biased against UV (unless UV-capable lenses are attached to the camera).

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If LifePixel is using borofloat, then the transmission chart they show is certainly different from the AR borofloat chart I found (linked above).

AR coatings can be designed for different wavelength ranges and this one seems specified for 420-680nm although the spectrum itself does not exhibit that.

I think Lifepixel were using uncoated Borofloat but I can't be sure about that.

 

One should consider the little comment at the bottom of the spectrum "WHILE EVERY ATTEMPT HAS BEEN MADE TO VERIFY THE SOURCE OF THE INFORMATION, NO RESPONSIBILITY IS ACCEPTED FOR ACCURACY OF DATA.".

 

Uncoated Borofloat 33 http://www.us.schott.com/borofloat/english/attribute/optical/index.html

 

My comment on the IR "leakage" of the UV pass filters was really directed towards their application with orthochromatic film. However, in B&W panchromatic film it was rarely an issue depending on the film type, type of lighting and type of U filter selected. For colour films it could be more of a problem however, Fuji RTP colour film seem to be the least affected but not totally immune.

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some little notes:

 

-the borosilicate glass with anti reflective coating seems to be a kind of commodity

(some -more detailed- nice infos from schott here: http://psec.uchicago...ofloat_33_e.pdf e.g. look at the chart for radiation degradation p.22, also interesting p24, the influence of the AR coating on reflectance at lower UV wavelengths, for deep UV the coating might not be an advantage;-)) )

 

 

-with respect to sapphir, he mentiones that he uses glass with the (0001) orientation, this is an important hint, as sapphir (=corundum) is bifringent because of its hex crystal structure. A couple of weeks ago I had the chance to look at (and through) a really big piece of optical sapphir with polished surfaces: it was impressive clear, even looking through 6cm of glass.

 

Happy X-mas!

 

Werner

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Sapphire is uniaxial so if you cut it on the 0001 orientation (parallel to the base of the crystal) the light will be traveling down the optic axis and is not therefore subject to birefringence (double refraction). If you cut it any any other direction you would be seeing "double".
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I remember a friend communicating with this guy, some time ago....... he advertises, conversions, on the DPR, For Sale forum, with the user name of Rensol .My friend was asking about having the cover glass removed & replaced with quartz. He explained that he used a 500w laser to remove the glass from the sensor. From what I remember his English was poor.

Col

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I have an older Canon 20D. The full spectrum conversions for these is the cheapest he has. I could just buy it and test it out. It may go a long way for others/future buyers interested to actually know first hand. Although I do not own a UV lens that attaches easily for canon, nor have I even tried Canon within anything outside visible--so forget that...

 

My D70 would work though, and I do have a baader U, El-nikkor among others-and it's also among the cheaper conversions.

 

These conversion people seem to be popping up everywhere now--what's up with that? Is it really that easy? Can I just remove the hot mirror of my D70 and be good to go?

Is this like changing your car oil--you take it to a shop when we all know in reality if you spent a little due diligence you could do it yourself?

 

So do you think/suspect his full spectrum conversions are legitimate?

 

-D

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It is not that difficult to DIY your own 'full spectrum' camera conversion, you just need to be a bit dexterous & have some familiarity with servicing, small mechanical & electronic equipment.

The point & shoot cameras & the mirrorless cameras are generally the easiest, as they use the 'contrast' to auto focus. DSLR cameras are much more difficult & may need focus correction. Of course you would need a good insurance cover if you were doing this commercially.

It is also the case of, there is always someone willing to do something cheaper, but they rarely last long.

I do attempt my own conversions, but there are only a few cameras (Sigma), that I would convert for a friend.

I will be looking at converting an Oly EPL in the new year, for myself.

Many of these conversion people, don't do everything they say they do, even the big players. Getting the cover glass replaced is not an easy task on most cameras, though Camon & Sony seem to be easier, most larger converters don't do that & for good reason. The sensor is hermetically sealed under the glass cover in an inert gas to exclude moisture & corrosion gases, like oxygen. The DIY person is not worried by that.

Whether Mr 'Rensol' of Image Laboraries, is genuine, I can't know. But if he has access to a 500watt laser & is able to 'properly' replace sensor cover glass, I would really like to know. I have a camera I want this done too, but I can only afford one shot at it.

Perhaps an official invitation for him to explain / introduce himself on these forums, or better still a tour of his facilities & a report written.

He is in Framingham, Massachusetts, United States, I am in Queensland, Australia......I can't just go & knock on his door :D

Cheers

Col

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enricosavazzi

On a different note, a couple of other eBay sellers are currently offering full-spectrum converted cameras. I have no direct information on conversions methods, quality etc.:

 

infraredtechnology (Spain)

kolari_vision_IIc (USA)

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