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UltravioletPhotography

UV Camera Conversions


colinbm

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Hi Everyone

I have tried & cried with my DIY efforts to convert my Sigma dSLR to UV capable photography.

I have another Sigma dSLR coming that I don't want to kill !

 

Who do you trust to convert your dSLR to UV capable photography, Please ?

 

I have got so close to succeeding in the swapping of the sensors cover glass to quartz, that the last try I had a slight slip-up in cleaning, that I damaged a gold wire connection in the sensor, before finally placing the quartz over the sensor. Do I continue being brave & try again to convert this latest camera or trust the work to another ??

 

Cheers

Col

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Thanks Alex

I would rather succeed in doing this conversion myself too.

This is an older Sigma Foveon digital camera model SD9, that I want to try with for a number of reasons. Least of all I want to see the results, how the Sigma preforms, then I can make a decision to proceed with a later model or change tack & go the proven Nikon way ;)

My biggest hurdle is breaking the bond of the cover glass from the ceramic base of the sensor, it is an epoxy resin. I would rather remove it as least destructively as possible. My last effort was with a 1 watt 435nm laser, that is capable of burning the epoxy on the surface quickly, but under the glass it is proving very difficult & only in random places, not continuously.

Any help & tips you could give me will be appreciated. Failing that I will have to get the services of someone who is capable.

Cheers

Col

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Now, re-reading your original post again, I see that you are talking about removing the cover-glass, and not the ICF, from your camera. My original ansver to you does not change.

 

I do not know of any company that will do it for your Sigma camera. But I do not think the sensor cover glass is a limiting factor in UV sensitivity of Foveon sensor.

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Thanks Alex

That is what I want to find out........what I can get without the UV absorption of the cover glass & any coating it may have. Then I can move forwards after this fact is known.

Col

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UV absorption of the cover glass & any coating it may have.

 

How do you know the cover glass absorbs anything? Is there a reference about it anywhere?

You do have the cover glass from your first camera saved, don't you? Before endangering another camera, just find the way to check the transmission of the cover glass.

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Thanks Alex

This camera is the first Sigma Foveon digital SLR, SD9. Unlike its successors it has the IRC mounted on the sensor & also unlike its successors it has no micro-lenses.

This is why I want to try it out for UV photography & replace the IRC with quartz.

Col

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Colin, in your original post you use the therm "cover glass" and do not specify exact model of your camera. So, if is difficult for anyone to guess that in your particular camera, the "cover glass" also functions as ICF (or IRC as you say). In the majority of cases, when people say "sensor cover glass" they refer to a protective glass on the sensor that is separate from any ICF and AA filters, and which transmission properties are not as well publicized as for example transmission curve of ICF.

 

So sorry, that I can not give you any useful advice on this particular matter.

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Thanks Alex

It doesn't matter about the cameras model, the cover glass is the last defence before the sensor.

This one is the Sigma SD9 & the sensor has no micro-lenses, that is why I want to try it for UV photography & replace the cover glass with quartz. I can find no information about the transmittance of any dSLR's micro-lenses or what they are made of ?

Later, if this is conversion is successful, I maybe tempted to try a later model, Sigma dSLR, but I will have to be sure about the micro-lenses properties or maybe remove them too. The removal of the micro-lenses from Bayer CFA cameras doesn't seem to be an issue.

Cheers

Col

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Actually, I think it is very important to specify which exact camera model is discussed, not only so that the respondents can give useful reply, but also to avoid any generalizations, which may lead to confusion. Your Sigma SD9 seem to be an exception, with its ICF functioning as a cover glass. I am actually having hard time finding such information using Google, for example. I do not doubt you, but I wanted to read up on it more.

 

As far as cover glass on the sensor goes, in my personal experience with NEX5N camera, it does not affect UV capture if pictures are taken through the quartz lens and Baader U2 filter. But I can only wouch for this particular camera-lens-filter combination. I can not speak for sensor cover glass properties of any other camera model, or if NEX5N is used with different kind of filter. So you see, it is important to know which camera model is discussed.

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Hi Alex

From tests with a amici prism spectroscope & mercury discharge lamps, I have determined that the Sigma SD15 (a later model then the SD9) is able to see down to at least the mercury emission line at 365nm, with just the bare cover glass in front of the sensor, no IRC. You can see the tests on my Flickr page UV Spectroscopy The spectroscope is centred on the cameras mount, so the distance from the left is relevant. Please note that the amici spectroscope's scale is logarithmic, that is the UV end is an expanded scale compared to the IR end which is a compressed scale.

Cheers

Col

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Col, this is off topic but I have a question: how did you create that preceding slideshow for posting here? Or is it something that Flickr does which can be linked here? Thanks !!

 

You are our Sigma pioneer. ;) Thanks for posting the insights and results you get !!

I hope it works out - although I suppose I still have my "doubts" about that Foveon sensor being entirely useful for UV.

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Thanks Andrea

The slide-show just 'happened' when I pasted the Flickr link to the 'set' ;)

 

I don't mind being the Sigma Foveon Pioneer, but I am getting closer to my goal of just finding out what it will do in UV.

I have persisted where others have given up & proceeded past where government agencies have stopped, what is at the end is what I want to find. Win, lose or draw !

 

Cheers

Col

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(OK, it is a Flickr thing. Thanks!)

 

Well, Col, carry on as our Sigma Foveon Pioneer ! ;)

 

Have you read up on the newest Sigmas ? Quite the interesting outer design change there. And some kind of sensor change too. Wonder what they have cooked up this time ? It will be interesting.

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Thanks Andrea

Don't worry, I don't give up easily.

The new Foveon Quattro sensor, DP fixed lens, compact cameras are looking impressive. They will be unequalled in B&W mono photography at a 20 full MP. How they go with an IR conversion will have to be seen, the red channel will only be 5MP, But that is OK.

Cheers

Col

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