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06-06-2009, 04:19 AM   #76
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One last note. Although capable, dslr's are probably not the best choice for startrail work. Give me a MF camera, a 45 to 55 mm lens, a tripod, and Provia 100F. No batteries needed. Massive enlargements, par excellence!

06-06-2009, 03:09 PM   #77
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nightfly:

MAG 7+ and Bortle 2/3, I envy you. My back yard is MAG 4+ and Bortle 7 on a good day, usually in February or March. Now that summer approaches I'm about MAG 3+ on the, "Little Dipper Scale." In spite of that I identified 25 galaxies down to MAG 19.1 in this SBIG shot of 13 frames 6 minutes each. A photographer for the Hartford Courant inverted the image and told me there are over 100 galaxies there.

http://pages.cthome.net/astroleo/n6050.jpg

Some night I'll see how deep my Pentax can go. I've seen MAG 14 with 22 frames of 1 minute each, I'm sure it can do better.

Your web site is very good.
06-07-2009, 06:48 AM   #78
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Didn't know that the Canon 50D added multiple exposure. Good! Does it have the ability to auto EV adjust like K10/20D? Haven't seen any others do that (there may be some now).

Just tried using the mirror lens with a 2x converter on a Canon XT. Guess what? Still won't work. When I posted about this problem originally on Dpreview about 1.5 yrs ago, many EOS 1D... folks told me no Canon would work in this situation. Don't think its been fixed.

Firmware and hacks can't fix every thing! Canon tried to fix their focusing challenged pro camera a while back with it. Didn't work. Last I heard they had to be sent in for repair.

thanks
barondla

Check out POINT & SHOOT CONTEST #19 WINNER in compact camera forum. Enter #20. Any brand camera. Enter now! ( thread is now open).
06-07-2009, 10:03 AM   #79
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Leo,

Love your photos. One day perhaps I'll be as proficient as you. Of course, I don't have an SBIG.... Should I aim to get a Toucam at some point, since it's less money?

06-07-2009, 03:34 PM   #80
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i havnt really read the whollllle thread but my nikon d40 (when i had it) had it setup so you press the remote button once to start the exposure and press it again to close it.

it was pretty nice, but im still very happy with my new k10d
06-09-2009, 07:46 PM   #81
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Power consumption of K110D camera

QuoteOriginally posted by pentaxmz Quote
I must apologize for my comment about not believing your current measurements. It came out kind of harsh. I am very surprised and it makes me curious and concerned about the current drain on the K20D. If the current drain is similar and with a stock battery of only 1520 mAh, I should expect even less than 1/2 hour of open shutter time. That seems unreasonable and perhaps.... unlikely.
Hi pentaxmz,

I'm back with new measurements. The original current tests were done rather crudely using a small analog meter on the battery pack. Still, with 35 years at Hewlett Packard (4 years were repair and calibration of precision measuring equipment) I can do pretty well. The watt values I posted before are within the 10% accuracy I suggested.

New test setup:

A large 7.5 AH 12v battery pack to a 9 v switching supply to a 6.56 volt linear supply to my K110D. Camera set to 8 seconds with NR. I inserted a 1 ohm 1% 2 watt resister in series with the input of the linear supply. Why the input? Past results show the camera can oscillate if it sees much impedance in the power leads. The regulator has negligible idle current so the input ~= output current. I measured the voltage across the resistor with a DVM which conveniently equals the current at 1 ohm. The power during exposure is the 4 watts I listed previously. I have killed AA Alkaline batteries in 10 minutes flat. I use external AC power at home, external battery packs when in the field.



New Measurements:

087 ma = 0.6 watts Idle

178 ma = 1.2 watts 12s Delay

260 ma = 1.7 watts LCD Display

436 ma = 2.9 watts NR Dark (fluctuates as the top LCD is flashing)

606 ma = 4.0 watts Exposing image

805 ma = 5.3 watts 2s Delay

The unusually high current during the 2 second delay repeats what I measured previously. The only thing I can think of the the RED display on the front of the camera is flashing during that delay only.
06-09-2009, 08:11 PM   #82
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QuoteOriginally posted by sholtzma Quote
Leo, Love your photos. One day perhaps I'll be as proficient as you. Of course, I don't have an SBIG.... Should I aim to get a Toucam at some point, since it's less money?
I'm not that good. I'd be somewhat better if I lived at a dark location. I enjoy the hobby and that's what counts. My SBIG has been pretty idle lately since I'm running out of interesting things to do with it (after 8 years and 400+ keepers). If you have a Pentax DSLR it can do a lot more astrophotography than a ToUcam. The only thing I use my WebCam for is planets and the Moon. When you need hundreds of frames in a minute a WebCam can't be beat.

My filterless K110D is out with me on most every clear night. I use a rather unconventional 2 minute exposure + 2 minute NR + 40 second idle cycle. The immediate dark frame helps track the aforementioned noise rise and the idle helps keep the sensor cooler. My lovely wife gave me an IDAS Light Pollution Filter which helps with the glow over New Haven. I've learned what objects work with the Pentax and what does not.

Last edited by LeoTaylor; 06-09-2009 at 08:13 PM. Reason: typo
07-01-2009, 05:56 AM   #83
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QuoteOriginally posted by pentaxmz Quote
I am very curious about how the camera performed for such a long exposure. Can you post an example.
Right, so herewith a sample pic. Granted, only 52 minutes (rather than < 2hrs), but no sensor melting or other unpleasantness.




Last edited by LensScribe; 07-01-2009 at 06:05 AM.
07-03-2009, 08:12 AM   #84
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device to accomplish more than you asked for

Gadget Infinity::Digital Camera::Shutter Release Cable::Timer Remote Cord for Canon / Pentax / Samsung

Got one, used with my K10D - perfection

Fun for time lapse type stuff too!
07-03-2009, 07:02 PM   #85
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QuoteOriginally posted by tmoses Quote
Gadget Infinity*::*Digital Camera*::*Shutter Release Cable*::*Timer Remote Cord for Canon / Pentax / Samsung

Got one, used with my K10D - perfection

Fun for time lapse type stuff too!
Wow, finally something to compete with the $135 Canon TC-80N3 timer. If I saw this two years ago I would have bought it rather than make my own (less capable) timer.
07-03-2009, 07:22 PM   #86
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Damn, that's even cheaper than the Ebay ones by about $20.
07-05-2009, 02:49 PM   #87
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QuoteOriginally posted by LensScribe Quote
Right, so herewith a sample pic. Granted, only 52 minutes (rather than < 2hrs), but no sensor melting or other unpleasantness.
Okay, I need to know.... Was this with the K7??

Also, what ISO did you use, and did you do any post processing? Can you please post a 100% crop?

I ask b/c my first star field tests with my K20D absolutely suck! I'll post a sample shortly.
07-05-2009, 03:14 PM   #88
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5 minute star trails with the K20D at ISO 800

Living in the city of Vancouver lately doesn't allow for opportunities to capture star fields of any sort of dark sky photography.

The following is one example of dark sky test (100% crop and minimally processed) I did this past weekend from Alice Lake Provincial Park in B.C.

I really hate to bad mouth the K20D any more... believe me, I really wish I could say something nice about its long exposure capabilities but I can't! The K20D sucks for long exposures!

Not only did this 5 minute exposure take 10 minutes to complete, it is also unacceptably noisy (with hot spots not removed by DFS) at 800 ISO.

I will purchase the K7 in a heartbeat if it can do significantly better than this!

P.S. Any astronomy buffs in this group? Can you identify the prominent summer constellation in the right-lower corner? Hint... the brightest star in this constellation was written about in Carl Sagan's book, Contact.
Attached Images
 
07-05-2009, 03:17 PM   #89
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QuoteOriginally posted by LeoTaylor Quote
Hi pentaxmz,

I'm back with new measurements. The original current tests were done rather crudely using a small analog meter on the battery pack. Still, with 35 years at Hewlett Packard (4 years were repair and calibration of precision measuring equipment) I can do pretty well. The watt values I posted before are within the 10% accuracy I suggested.

New test setup:

A large 7.5 AH 12v battery pack to a 9 v switching supply to a 6.56 volt linear supply to my K110D. Camera set to 8 seconds with NR. I inserted a 1 ohm 1% 2 watt resister in series with the input of the linear supply. Why the input? Past results show the camera can oscillate if it sees much impedance in the power leads. The regulator has negligible idle current so the input ~= output current. I measured the voltage across the resistor with a DVM which conveniently equals the current at 1 ohm. The power during exposure is the 4 watts I listed previously. I have killed AA Alkaline batteries in 10 minutes flat. I use external AC power at home, external battery packs when in the field.



New Measurements:

087 ma = 0.6 watts Idle

178 ma = 1.2 watts 12s Delay

260 ma = 1.7 watts LCD Display

436 ma = 2.9 watts NR Dark (fluctuates as the top LCD is flashing)

606 ma = 4.0 watts Exposing image

805 ma = 5.3 watts 2s Delay

The unusually high current during the 2 second delay repeats what I measured previously. The only thing I can think of the the RED display on the front of the camera is flashing during that delay only.
Thanks for those details; very interesting!

I will have to try a similar test on the K20D.
07-11-2009, 02:45 PM   #90
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QuoteOriginally posted by pentaxmz Quote
I really hate to bad mouth the K20D any more... believe me, I really wish I could say something nice about its long exposure capabilities but I can't! The K20D sucks for long exposures!

Not only did this 5 minute exposure take 10 minutes to complete, it is also unacceptably noisy (with hot spots not removed by DFS) at 800 ISO.

I will purchase the K7 in a heartbeat if it can do significantly better than this!

P.S. Any astronomy buffs in this group? Can you identify the prominent summer constellation in the right-lower corner? Hint... the brightest star in this constellation was written about in Carl Sagan's book, Contact.
I'm no astro geek, but I've done several star trails with minimal noise to speak of, though I approach it quite differently. I see no need to go to ISO 800, but should I ever do so, I'd be making sure that intended exposure is either nailed or slightly to the right of the histogram. Then there would be no amplification of noise by PP.
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