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10-05-2018, 12:26 PM   #1
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Considering Full-spectrum Conversion

I'm considering converting my K-3 to full-spectrum. I've looked at both Spencer's and Kolari. The prices are relatively equal. Spencer's indicates they can (for $50) re-enable the dust reduction system, which is a must. Kolari doesn't, that I saw, say anything on the subject.

Has anyone had a conversion performed by either source? Any input into which is better or if they're equivalent?

This will primarily be for astrophotography.

10-05-2018, 02:16 PM - 1 Like   #2
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I have a FS converted K-01 done by Isaac Szabo (Isaac Szabo) and loved it so much I bought a refurbished K-1 from Kolari.
I use mine for IR & UV photography.
Not sure what Spencers is meaning by "re-enable the dust reduction system"?
The dust removal itself is done by vibration of the sensor. For a FS conversion the hot mirror is removed from on top of the sensor but nothing else in done to the sensor. Silicon layer and all mechanical for the sensor remain the same. Perhaps Spencers is reinstalling a thin piece of clear glass to help keep dust off of the sensor.
Both of my FS conversions still function as my other cameras (second K-1 and K-3) with the exception of needing manual white balance.

The folks at Kolari were very helpful every time I called with questions. I asked about getting mine with an AR (anti-reflective) coating to avoid IR hotspots.
We determined it wasn't necessary due to the vintage lenses I'm using all perform relatively well in IR.
Perhaps this AR coating would provide a bit of dust protection also, you might give them a call and ask.
They also offer an H-Alpha conversion for Astro.

I believe Isaac does a simple hot mirror removal, but the dust shake at start up works fine. I do have to do a bit more sensor cleaning with both than I normally do with the others, but keeping on top of it with a blower seems to suffice most of the time.
10-05-2018, 03:25 PM - 1 Like   #3
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QuoteOriginally posted by pcrichmond Quote
...
Perhaps Spencers is reinstalling a thin piece of clear glass to help keep dust off of the sensor.
...
I would sincerely hope that all FS conversion services replace the hot mirror. Without a replacement piece of glass of the same thickness, the focus of the camera will shift and the camera may have problems with infinity focus especially with wide angle lenses. A flat glass sheet shifts the plane of focus on the sensor side by about 1/3 the thickness of the sheet. That may not sound like much but for a 28 mm lens, it shifts the plane of focus on the object side from infinity to only 2.4 meter.
10-05-2018, 05:05 PM   #4
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There’s a full-spectrum converted K-01 available on eBay for about the same price as converting a K3.

This auction isn’t my camera, but I did purchase one just like it from the same seller. I couldn’t bring myself to have one of my existing bodies modified, but adding another body to the stable wasn’t a problem! Haven’t tried it for astro, but seems to work just fine for IR photography. Haven’t had a lot of time to thoroughly put it through its paces, but my initial impression of it is good.

I can send a couple of test photos if you’d like - just PM me.


Last edited by dtrego; 10-06-2018 at 06:40 PM.
10-07-2018, 04:16 AM   #5
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What UV-pass filters are available?

As a result of this thread, I'm considering having my K-3 (superseded by my K-3ii) converted for Full Spectrum. Being superseded, I will not want to use it for visible-light photography.

I have a Hoya Infrared R72 which would appear to be useful on such a camera for IR photography.

But what filters would be useful for UV photography?

The B+W 77mm UV Black (403) Filter has been discontinued.
10-07-2018, 12:11 PM - 1 Like   #6
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Considering Full-spectrum Conversion

QuoteOriginally posted by Barry Pearson Quote
As a result of this thread, I'm considering having my K-3 (superseded by my K-3ii) converted for Full Spectrum. Being superseded, I will not want to use it for visible-light photography.



I have a Hoya Infrared R72 which would appear to be useful on such a camera for IR photography.



But what filters would be useful for UV photography?



The B+W 77mm UV Black (403) Filter has been discontinued.

Iím just starting to explore this so I donít have any personal experience or advice myself. Some of the references Iíve found, though:

Thereís a forum dedicated to UV that should have some helpful info - http://www.ultravioletphotography.com/

Thereís also a seller on eBay that has a selection of custom made filters - uviroptics.

Post about lenses that are better suited for UV photography without being a dedicated UV or full-spectrum lens:
http://www.ultravioletphotography.com/content/index.php/topic/1654-sticky-uv-capable-lenses/

Last edited by dtrego; 10-07-2018 at 12:41 PM.
10-07-2018, 07:38 PM   #7
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QuoteOriginally posted by Barry Pearson Quote
As a result of this thread, I'm considering having my K-3 (superseded by my K-3ii) converted for Full Spectrum. Being superseded, I will not want to use it for visible-light photography.

I have a Hoya Infrared R72 which would appear to be useful on such a camera for IR photography.

But what filters would be useful for UV photography?

The B+W 77mm UV Black (403) Filter has been discontinued.
Hi @Barry Pearson, The R72 will give very nice results. I also use the older 29F for faux color and my favorite is the #87 for more of a monochrome effect.
If you're wanting to have a great learning experience try the UV but be prepared to do your homework before shelling a lot of money out. I'm glad I did.

As @dtrego mentions there is a very nice site for UV information.
Filters are not the initial cost, more it will be a lens that has good UV transmission.
True UV lenses are very expensive but the site mentioned by dtrego has several "accidental" lenses that perform well.
None of my Pentax glass (even vintage K and M series or coated Taks) transmit good UV due to the excellent coatings.
If you are wanting to photograph hand held or on a tripod with shorter shutter speeds and low iso then the lens will be your biggest obstacle.

Older basic triplets seem to be the best and a few 4/4 configurations work too, several older enlarging lenses transmit very well if you have a helicoid to focus with.

I was lucky enough to find an old M42 mount Steinheil Cassarit 50mm in great condition that does well down to 340nm. My old Domiplan 50mm does alright at 360nm. Also I have a Zeniton 35mm I picked up on the forums that works well at 360nm but the longer focal length Zeniton I have performs poorly even though it is still a 4 element 4 group lens.
Oddly enough my old Lensbaby Soft Focus optic transmits down to 340nm (none of my other Lensbaby's have good transmission though). Depending on the lens, the cement used in combining elements into groups can deter the UV transmission quite a bit too.

Filters from uviroptics are of good quality. Note you will also need an S8612 or BG38, 39, or 40 to stack on top. UV pass filters also transmit a lot of IR and will give you more of the IR effect due to contamination if you don't use a second filter to cut out the IR. Check filter transmission charts to see which you might prefer..

One of my post using the Steinheil: Needing a challenge - UV340 - PentaxForums.com
and one using the Soft Focus optic: UV attempt with Lensbaby - PentaxForums.com
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