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05-26-2007, 04:15 PM   #1
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Modifying a Pentax K110D for Astrophotgraphy

My long story of modifying a Pentax DSLR for Astro or InfraRed photography will be of limited interest unless you are considering astrophotography, IR imaging, or Pentax Repair Service.

I bought a Pentax K100D DSLR in part because of the number of "K" lenses we own. I was aware was limited support for Pentax in the Astroimaging world. I love the camera, but was concerned about all the handling going from daytime photos to nighttime imaging. I was constantly blowing out dust from all the lens/telescope changes. I was also concerned about the camera’s poor response to red nebulas.

When I spotted the K110D on sale for $349 I decided to buy a second Pentax DSLR for nighttime work. I also wanted to remove the "IR Filter" found in front of most camera sensors which attenuates visible Red light at 656 nm which is emitted by many nebulas. The camera was low cost enough to dedicate to astro photography and the IR photography I would like to explore. Once the filter is removed, the images are too red to reasonably color correct. I could not find anyone who provides this modification for any camera except, "The Big two."

I tested the new camera 4 days then opened it up. It took a bit over an hour to reach the filter, which is easily removed from a K110D. I suspect the movable sensor of the K100D would be more difficult. Unfortunately once re-assembled the camera did not work. The top display would come on for a second, then the camera would go dead. I recognized the symptoms of "memory card door open" but could not find the door switch. After numerous openings of the case I realized the switch lever was broken off the circuit board so there was nothing for me to find. By then I had done too much damage to the board to continue.

I boxed up the camera and threw myself at the mercy of Pentax Service in Colorado. I shipped the camera with a note explaining what I had done, why I did it, and how I want the camera returned with the filter still off. After 3 weeks with no response I called Pentax, worked my way through the menus to a person, and asked for status. He said the quote was $211. It was more than I hoped, but to get a working Nikon or Canon modified for Astro costs even more. I said go ahead. I did not ask how long the quote was ready before I called.

All contact with Pentax was cordial. I was given a repair number so I could check status on line. I later emailed Support for a PIN number, both are needed for status checks. I got a prompt reply. Curiously the status showed quote approved but it took a week before it showed quote sent (I never got one).

It took two more weeks for the camera showed a ship date with UPS tracking number. Total time in Colorado was over six weeks. I’m glad I had the K100D to use in the meantime. When the repaired camera arrived I was concerned they may have ignored my request and put a filter on since the camera can’t be calibrated without it. I was delighted when my first photo of a neighbor’s tree looked bright red, even had the IR glow. For $349 + $211 I had a modified Pentax DSLR!

The night sky has not been clear since. The below link compares the K110D with the K100D on a night when I could not see any stars in the Southern Constellations around the nebula. The first two images are 3 frames stacked, dark subtracted, no flat, and minimum processing. The unmodified camera shows a very weak nebula and is oddly white when it should be red. The modified camera is too red but the nebula is bright. The third image is 22 frames stacked with dark, flat, and bias frames and some color correction so brighter stars look white. When the sky is clear it will look a lot better.

http://pages.cthome.net/astroleo/filterdemo.jpg

JPEG is 800 * 1800, be sure your browser shows it full size.

What is the bottom line? I’m very pleased with my modified camera. If I had it to do over I’d call Pentax first and see if I could convince them to remove the filter. It should cost less then $211 since my camera required a new board. If someone is crazy enough to try the modification themselves write me first and I’ll type up some notes. I also have a few photos of the open camera I wish I looked at sooner since one shows the switch BEFORE I broke it off.


Last edited by LeoTaylor; 05-26-2007 at 04:17 PM. Reason: Added comment about JPEG size
05-26-2007, 04:55 PM   #2
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Very interesting, I kinda think that Pentax might like to see those pic's.
Who knows, they might decide to make their own Astroimaging camera
05-26-2007, 06:48 PM   #3
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Hello British Columbia!

I've visited Vancouver and Victoria. Beautiful locations.

I stopped at the Pentax booth at the North East Astro Forum to chat. They attend the show because of the excellent telescope optics they produce. I suggested they consider their cameras for astronomy and perhaps provide a filter removing service. They listened but did not think it worth, '"All the effort and expense." It is certainly less effort for the Pentax repair team in Colorado to remove a filter then all the work they did to fix my camera!

Canon once produced an Astro camera for awhile, I believe it was Model 20D-A (A=Astro). Unfortunately it was more expensive than buying a standard camera and paying someone to modify it.
05-27-2007, 09:26 PM   #4
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Very interesting posts Leo and thanks for the posts you replied to my thread about the remote assistance questions. I still hav'nt tried any prime focus photography through my 6" reflector telescope with my k100 as I still don't have a T-adaptor or a motor drive for the mount. I'm curious as to what kind of results I will get for different objects both solar and deepspace. From what I've read in astrophotography forums the canon cameras perform the best and not many people use anything other than canon and nikon. One more question, was it worth spending all that cash on a modifiying your k110? Does it perform as well as a dedicated astro imaging ccd that would maybe cost a similar price?

05-28-2007, 08:42 AM   #5
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don't know if you visit dslreports but noelC over there produces some of the best astro photography i've ever seen.
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05-28-2007, 03:32 PM   #6
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QuoteOriginally posted by Broonie Quote
... I'm curious as to what kind of results I will get for different objects both solar and deepspace. From what I've read in astrophotography forums the canon cameras perform the best and not many people use anything other than canon and nikon. One more question, was it worth spending all that cash on a modifiying your k110? Does it perform as well as a dedicated astro imaging ccd that would maybe cost a similar price?
Hi Broonie,

I've only had the K110D back less than 2 weeks, and clear nights are not too common this time of the year so I'm still a beginner with DSLR astrophotography. With the K100D I soon learned the limitations: most nebulas and galaxies were invisible (except M42 and M82). I hope the modified camera fixes the nebula problem, early results show it will. As to galaxies, my SBIG does them well enough. You don't need lots of pixels for galaxies because you reach a limit of telescope resolution first.

"All that cash on a modifying your k110"? I think $211 to fix my K110D was reasonable, I broke a switch and connectors on the main board. It was a risk I took with eyes wide open and I lost. The camera only cost $349. Compare that to most Astro modified DSLRs from the "Big Two." From what I've seen it would cost more for the camera and the people modifying DSLRs are charging $250-$500. That means my modification and repair was cheaper than their modification only. I suspect someone could talk Pentax Colorado into removing the filter for well under $211.

Why a DSLR vs dedicated astro camera? I have an SBIG, the quintessential astro camera albiet a small one (0.39 megapixel cost me $3000 in 2000). I love the camera for galaxies but wanted to do wide angle nebulas and clusters. To get 6 megapixels in an SBIG is over $5000. I now have enough pixels to do clusters, the SBIG did not have the resolution to show globulars packed with zillions of stars. I also will be able to IR photography, my wife bought a book on the subject and I await a Hoya IR filter for our lenses. Some people sacrifice DSLRs just to do IR.

I'm happy with my decision. I have opened many new objects I could not do with the SBIG, the Pentax will complement but not replace the astro camera.
05-28-2007, 03:49 PM   #7
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QuoteOriginally posted by roy Quote
don't know if you visit dslreports but noelC over there produces some of the best astro photography i've ever seen.
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Hello Roy,

Yes, neolC does have some excellent photos. I did not find camera details on many of them, but those I did were taken with a Starlight Express SXV-H9C astro camera (over $3000).

My favorite semi-amateur astrophotographer is Rob Gendler. I bought his book at a recent astro show. But his main camera costs $7000 (his 20 inch RCOS scope costs >$20000).

We're getting far astray from a $349 Pentax.

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07-22-2007, 03:45 PM   #8
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hey, i would like to shoot some meteor showers with K110D.. this means that i would love if there is any chance to lock the release with the bulb exposure.. i just tried it for the first time and i saw that u cant move the on/off switch in order to lock the release button pushed.. so the only way to push it and stay pushed with hands free is to get a remote control or cable release cord or ?? i still hope there is a way to do it without any of these things.. i remember it was so easy with Zenits and Minoltas maybe.. u just push the button and move this ring below it and it's locked.. and when u decide it's enough for this shot u just pull gently the ring backwards..any suggestions ?

07-22-2007, 04:58 PM   #9
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Hello,

My wife and I also want to try the Perseids meteor shower with our Pentaxs. We hope to beat the odds in Connecticut where we have been rained out of all but 2 or 3 in the last 15 years.

To the best of my knowledge there isn't any way to take photos longer than 30 seconds without some kind of external hardware (or a tired finger). You might want to do some advance test shots away from the Moon to see how long an exposure you WILL need. if you are near a city 30 seconds may be as long as you can do. If you are in a dark location then a couple of minutes is desireable. You will need to decide whether you want to use the camera's Noise Reduction (dark frame subtraction). Without it the frame will be very noisy, with it you lose half of your imaging time. My wife, she will use JPEG with N.R. Myself, I will use RAW and subtract dark frames later.

It is interesting that you know some cameras with a shutter lock, I've never seen that.

I have the Pentax cable release which is essentially a two step button with lock. It will pre-focus by pressing part way, release the shutter when pressed fully, and slide upward to lock. There are several people who have described making a shutter release with a switch or two, a small box, and a cable from Radio Shack. I bought a curly extension cord from Radio Shack to let me get further away, the Pentax cable is only about 18 inches. With that cable plus a switch and packaging you have what you need.

I have made a more elaborate shutter controller for taking multiple long images of selectable length unattended but that is an overkill for what you need.
07-29-2007, 06:40 AM   #10
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QuoteOriginally posted by LeoTaylor Quote
Hello,

My wife and I also want to try the Perseids meteor shower with our Pentaxs. We hope to beat the odds in Connecticut where we have been rained out of all but 2 or 3 in the last 15 years.

To the best of my knowledge there isn't any way to take photos longer than 30 seconds without some kind of external hardware (or a tired finger). You might want to do some advance test shots away from the Moon to see how long an exposure you WILL need. if you are near a city 30 seconds may be as long as you can do. If you are in a dark location then a couple of minutes is desireable. You will need to decide whether you want to use the camera's Noise Reduction (dark frame subtraction). Without it the frame will be very noisy, with it you lose half of your imaging time. My wife, she will use JPEG with N.R. Myself, I will use RAW and subtract dark frames later.

It is interesting that you know some cameras with a shutter lock, I've never seen that.

I have the Pentax cable release which is essentially a two step button with lock. It will pre-focus by pressing part way, release the shutter when pressed fully, and slide upward to lock. There are several people who have described making a shutter release with a switch or two, a small box, and a cable from Radio Shack. I bought a curly extension cord from Radio Shack to let me get further away, the Pentax cable is only about 18 inches. With that cable plus a switch and packaging you have what you need.

I have made a more elaborate shutter controller for taking multiple long images of selectable length unattended but that is an overkill for what you need.
Personally I would be very interestedi in your solution to timed exposures.
07-29-2007, 03:55 PM   #11
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Most likely his solution involves a 555
07-31-2007, 10:22 AM   #12
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Alas, though I've designed many an electronic project I did not design my timer. Yes, it does contain a 555 wired as a 1 second oscillator feeding a CMOS counter to give exposure times of 8 seconds to many minutes.

I got my inspiration from John McDonald in British Columbia. His web site is:

John McDonald's Astronomy Page

Click Astro Images, scroll to Projects, click Camera Control

He uses two $20 timer kits cross coupled, one for on time and one for off. Never one to leave well enough alone I made mine with one timer by adding circuitry and soon regretted it.

For those not into building stuff from scratch I've heard the $140 Canon TC80N3 Timer Remote Control will work by replacing the connector. Dan Ratledge posted this:

Digital SLR Astronomical Imaging
08-12-2007, 02:48 PM   #13
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My first night of trying to photograph the Perseids Meteor Shower with a K100D was unsuccessful. I used a Pentax 50mm prime from my K1000 days giving me a 23 degree Field of View. From about Midnight to 2:30 AM the clouds cleared and I took 47 RAW images of 1 minute each, plus 1 min Noise Reduction and 1 minute cool down. I did not catch a single meteor trail. My wife and I looked up around midnight for about 30 minutes in our semi-urban location and she saw 5 meteors to my 1. Each time, I glanced at the camera and it was between exposures. Just bad luck!

Tonight, if the clouds allow, the meteor rate should be higher. I will also reduce the exposure to 30 seconds, no Noise Reduction, with only 7 seconds gap to allow writing to memory. I will do dark subtraction afterwards. This 3:1 increase in duty cycle should help my chances to catch a meteor with some reduction in image quality.
08-12-2007, 04:26 PM   #14
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my first attempt at the perseids

This was the first shot I attempted last night and the ONLY one that got a meteorite on it of about 40 attempts...
I wasnt really set up properly at all. I had SR turned on (I forgot to shut it off since I was using a tripod), I forgot to use the self timer so my focus isnt really that great on this shot. This was my first time trying longer exposure times. I also used the bulb setting later on in the night with some not so great results. So anyway, with about 2 seconds left on this 30 second exposure I see a nice, bright light streaking across the sky and I was hoping I was able to capture it. I was pretty happy when I saw the preview and saw the result. I hadnt even really planned on taking out the camera last night, it was sort of an afterthought. I might try again tonight if all these clouds clear out. I was finding with longer exposures, the sky was getting a red cast to it, is this normal for star pics on longer exposures? I fooled around with the pic just a little in photoshop and made it look a little better. I tried to darken it a little to get rid of the red at the expense of losing some of the fainter stars.
Hopefully I can get some good results tonight!!

Photo was taken with k100d, 30 sec. exposure, iso 200, and 50mm lens at f1.7
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08-12-2007, 08:51 PM   #15
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Leo, thanks for sharing. It is really interesting!

Btw, I admire your braveness to dissert your new DSLR too, although it is really cheap for the price your purchased it. Indeed, it is a tough and difficult task to do the thing you intended and thus the successful rate is low :-) You need to be a qualified technician plus you should have some basic servicing information to do this :-))

Also, do you remove the AA filter or there is another IR filter in front of the CCD. Just curious to know..

Well, btw, besides using DSLR, I think another viable option is to shoot IR film..
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