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UltravioletPhotography

Conversion curation?


argus

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Does this forum maintain a list of good/vetted conversion services? I have an E-M5 I'd like to convert to full spectrum, but it looks like the most commonly recommended service would charge about what the camera itself is worth, whereas I might be able to do better than some of the Ebay services in my own shower.... Is there a middle ground? Also, I don't want to talk the Ebay guys down too harshly - has anyone given neimartphoto a try?
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Clean is a matter of personal standards... but dust is certainly better controlled in a recently used shower area than any other part of a typical house. I will give LifePixel another look - their front page suggested they were Canikon-only!
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Argus, the vetted conversion shops here in the US are listed in the Sticky: Life Pixel, Max Max and Kolari Vision.

I have personally used all three with fine results.

 

Neither Bjørn nor I have tried any of the Ebay converters. I have not been pleased with some of their hyperbolic advertising. I've had some complaints about dust and misleading advertising and misleading claims.

 

For the record, I note that even the good conversion shops can sometimes screw up. An Oslo Nikon tech found a floating screw in Bjørn's D5100 conversion from LifePixel. Stuff happens.

 

But I understand your dilemma regarding conversion price for an older camera. You might as well try an Ebay converter because if the conversion is bad, the seller should bend over backwards to make it right given that you would report a bad conversion to Ebay and ask for your money back.

 

You might want to search out a tear-down for the EM-5 to see how feasible it is for you to DIY.

 

CAUTION: Always use a grounding bracelet and mat when taking apart a camera. Do NOT go anywhere near the flash capacitor (learn where it is!!). Small rubber-tipped tweezers are useful for re-seating cables and flipping cable levers.

 

If you do decide to DIY, then take pictures and show us how it is done!! :D

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Andy Perrin
I bought a full spectrum convert from eeassa on eBay recently, and my travails are well-documented on this forum. Had a fair bit of dust in it. Otherwise, though, the camera was fine, and I got most of the dust out myself, so I'm not all that unhappy. eeassa did offer to clean it for me, but I didn't want to risk shipping the camera back (and be without it for however long...). He also sent me a free filter stack as a "sorry."
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It's a tough choice! One of the things that I find encouraging about some of the Ebay guys (despite their hyperbolic tone) is that they talk about specific issues. ie, preservation of the dust shaker-offer is gratis on certain cameras. No note about whether that cover glass has an anti UV coating, however... curious if anyone here knows?

 

Also, I note when looking at the big-three conversion services listed on this site, that the OM-D series appears to be $100 more expensive to convert than the Pen series. My guess is that means some desoldering/resoldering is involved.

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The Ebay guys do not discuss enough of the specific issues, imho. :D

 

To preserve a dust-shaker, where possible, the dust-shaker is first unsoldered, the glass is replaced, and the connection is resoldered.

The questions then becomes this: do two layers of the UV-pass glass pass UV as well as one layer?

And this: do two layers of UV-pass glass cause any kind of reflection problems or hotspots?

What kind of glass is best for a double-layered conversion? Coated? Un-coated?

And this: how is focus adjusted for two layers of UV-pass glass, when required?

 

I should preface that last question with my assumption: I am assuming that focus must be adjusted in a mirrorless camera after the internal filter(s) are removed and replaced with one or more layers of UV-pass glass having a different refractive index.

EDIT 2016.03.30: As Alex clarifies next, mirrorless cameras do not require focus re-adjustment after replacement of internal filtration.

 

You should get answers to these questions before you send in your camera even when the conversion is cheaper than the vetted conversion shops. ;)

 

BTW, I myself do not know the answers to those questions!! If I knew everything, then I wouldn't get to have any fun learning new stuff.

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So focus is all done by smoke and not mirrors in the mirrorless realm? :lol:

 

Alex, sorry, couldn't help that one. :lol: :lol:

But then I immediately worried that not everyone would know the English idiom "smoke & mirrors".

There are no doubt equivalents in other languages.

 

I was not sure about this initially because we are still required to maintain a proper flange focal distance (FFD) for a given lens in a mirrorless system. And I was not sure how a replacement glass might alter that due to refractive index changes. Like maybe a change in r.i. could confuse the system and make it think the FFD is not quite correct. So that does not happen, right?

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How does the system know FFD is not correct?

 

Autofocus in mirrorless is done using main sensor. The only problem that can happen with cameras without any glass compensating for FFD differences (but not reported yet) is that the lens may not focus to infinity because it gets to the end of its focus travel. It appears, however, that many autofocus lenses can focus past infinity to compensate for whatever is needed to be compensated for.

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I was thinking the system software might run electronic checks on FFD. Like these days the system software checks for all kinds of things - for example, the IR shutter monitor in some Nikons that keeps the shutter firing at the correct rate. Maybe there is a light beam which checks FFD or something. I'm probably just being fanciful.

 

I don't think I have really missed having autofocus in the UV realm.

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Imaging how much would it cost if it had all these things you are describing. It is a consumer camera after all, not Kepler telescope.
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So I had a useful conversation about the Olympus E-M5 dust shaker / cover slip with image-laboratory. He says its UV cut point begins around 360nm, but didn't provide any data to back that up. Even if that's accurate, it seems uncomfortably close to the imageable range to me. He did offer to replace the glass cover slip with UV-Vis anti-reflection coated Spectrosil, but might not be able to port over the dust shaker in that case (that point wasn't clear). He does deem it important to maintain some sort of cover slip, which seems true to me, too. (The image stabilization system's voice coils probably don't like dust very much).

 

BTW, he pointedly does use UV transmissive "glue" on his UG11+BG40 filters. I find I have to be very careful with my grammar when communicating with him, but otherwise he seems reasonable so far. I'll continue interviews / research until I actually choose a service!

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Alex: Imaging how much would it cost if it had all these things you are describing. It is a consumer camera after all, not Kepler telescope.

 

True. But I still have the mindset that software should be able to do anything. :rolleyes:

 

*****

 

Argus: Thank you for your report.

  • For any filter advice you might want to talk to our member Cadmium. He has extensive experience putting together filter stacks, glued or not.

  • I don't think I would be overly concerned about maintaining the dust shaker in any camera. While it would be nice, it is not mandatory. Most dust can be blown off the sensor with a rubber bulb blower. Or brushed off. Every 6 months or so, if your camera has seen hard use, you can clean off the sensor with a wet swab. The sensor will be covered with a replacement glass so you will never be directly cleaning the sensor pack itself.

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  • 2 months later...

Well, I got brave, and finally picked a conversion service! I did choose neimartphoto / image-laboratory in the end, partly because he took the time to answer a few of my questions, and without dumbing anything down.

 

The camera in question is an E-M5 m1, and it has now had both its ICF and the "dust shaker" cover slip replaced with AR coated Spectrosil. "image-laboratory" (Gary, who is Armenian BTW, not Russian) claims the AR coatings are broad spectrum, and I believe this is the case. In the visible band, the reflection is significantly less than from uncoated glass, and the UV performance is approximately 8 stops down from the visible, which I believe is typical for this type of camera.

 

Also, he claims he was able to port the "dust shaker" transducer from the stock cover slip to its replacement, and I don't have any particular reason to doubt it's working. Certainly the camera arrived without any obvious dust (its first shot was an f/45 exposure of clouds, with image contrast subsequently stretched as much as possible). Time may tell, but nobody else even claims to do this!

 

There haven't been many clear skies here lately, but I was able to compose the following scene for testing. Each band was separately white balanced from white PTFE, and is nearly straight-from camera. One particular thing to note is how little the E-M5's stock filters attenuate UV as compared to the Peca UVIR cut. The stock dust cover slip seems fairly transparent even to IR, which seems to fit with Gary's comments on the subject. Both are wrapped in protective plastic film in these shots.

 

post-110-0-29403500-1465379844_thumb.jpeg

 

Because the PTFE background was on the verge of blowing out, the UV shot is a little underexposed with respect to the other elements in the scene, so I consider its 7.4 stops down from visible a little optimistic. Anyway, I'm pleased with the results. Consider this post a vote of confidence in Gary.

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An interesting test panel, for sure.

 

I agree the UV image *is* underexposed, probably 2 stops or more. I do not believe this system is that much more UV sensitive than compatible broad-spectrum modified camera using dedicated UV optics. The estimate of -7.4 EV for UV re visible light is well within the expected range for specialised UV-capable lenses. The tendency for blowing out highlights might relate to the dynamic range of the camera.

 

However, all the above is moot if the camera delivers good results in the field, thus I am eager to see what it can do in practice in the time ahead.

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Thanks for the tests Argus, they are well done & presented.

"Who dares wins" is your new motto B)

You dared to try with neimartphoto / image-laboratory & it looks like you have a win :)

Cheers

Col

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... The camera in question is an E-M5 m1, and it has now had both its ICF and the "dust shaker" cover slip replaced with AR coated Spectrosil. ...

 

So will a native µ4/3 lens autofocus correctly now?

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So will a native µ4/3 lens autofocus correctly now?

 

Native µFT lenses do autofocus correctly on this camera, and the Olympus 12-40/2.8 is actually a lot of fun as an IR lens. With a 720nm filter it's about 0.3 stops slower versus an OM 50mm f/3.5 macro at common f/stop, and it seems to be sharp and contrasty at all focal lengths, with only a moderate hotspot when stopped down at the wide end of its focal length range. As a general rule, mirrorless cameras that focus by contrast detection (essentially a warmer/colder seek algorithm) are more tolerant of a change in flange/focal distance than those that focus by parallax / phase detection and require strict alignment, and this specific camera's conversion method shouldn't have changed that distance very much.

 

Among the other conversion services I polled, there appeared to be two popular approaches for converting this type of camera. Either discard the cover slip entirely, and thus shift the register out by a fraction of a millimetre (or compensate by commensurately thickening the replacement for the ICF, though this wasn't stated), or leave it in place, and thus sacrifice some portion of the deeper UV light. The third option, to replace it with Spectrosil (and port the dust shaker), seemed to be the best option overall.

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