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Forum: Pentax K-3 & K-3 II
07-13-2016, 12:33 PM
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I concur.
IIRC, you can record RAW on one SD card and Jpeg on the other. I wonder if this would help and/or be acceptable to you?
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Forum: Pentax K-3 & K-3 II
07-11-2016, 04:02 PM
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Is there a difference between K-3 PEF and DNG file size?
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Forum: Pentax K-1 & K-1 II
07-11-2016, 03:56 PM
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Way back in time, I tested data throughput (acquisition->processing->storage) on PCs and found that compressing the data in the processing stage ultimately increased data throughput to storage. The reduced load on the bus (which must be managed by the CPU) more than compensated for the increased CPU load to compress the data. Less expensive digital cameras like to omit RAW file output because creating a RAW file significantly increases CPU load and reduces throughput (in terms of frames per time unit).
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Forum: Pentax K-1 & K-1 II
07-11-2016, 12:35 PM
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Hi. Thanks for the excellent test analysis.
If the camera's computer is being overloaded, I wonder if switching to PEF format in FF mode would help since PEF features more data compression and should reduce CPU and bus load? In the same vein switching to JPG should reduce loading even more in FF mode. Also turning off all forms of background processing while using JPG output might help as well.
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Forum: Pentax DSLR Discussion
11-01-2014, 01:40 AM
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One problem that I had with my K10-D was slop in the T-ring. The locking slots were too big for the pins on the camera's flange and the camera rotated around the t-ring. My formulated fix was to use a pentax thread t-ring and then use the pentax k-mount to thread adapter.
I would have thought that you'd have lots of BF available?
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Forum: Pentax DSLR Discussion
10-31-2014, 01:07 AM
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Smigol, those shots are excellent; the K10D is still a fantastic performer.
Have you tried an OAG to tame your flexure problems?
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Forum: Pentax DSLR Discussion
10-18-2014, 11:55 AM
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Weathermon, nice photos, but with your setup I would guess that you'd get better results with ISO 100 along with longer subs. Looking at the noise characteristics of the K3/k5 and their 14bit RAW files, I'm pretty sure that lower ISO and longer subs are the way to go.
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Forum: Pentax DSLR Discussion
07-21-2013, 03:58 PM
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Fantastic! Really great work!
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Forum: Pentax DSLR Discussion
02-20-2013, 02:00 PM
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Smigol, that's excellent!
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Forum: Pentax DSLR Discussion
02-10-2013, 01:46 PM
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To Dr_who and Smigol; AWESOME!
Can't wait to see more!
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Forum: Pentax DSLR Discussion
02-09-2013, 09:56 AM
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I experimented with the AC power supply and long exposures on my K10D; IIRC, there was a considerable increase in noise when using the adapter. At the time my thinking was that some of the amps and circuits that were shut off to save power in battery only mode were being left on, when the adapter was connected. I wonder if anyone can confirm this?
My planned work around was to use the battery grip and then if more power was needed, I would try and wire a DC power source directly to the leads in the grip. However, I can confirm that the K10D has an internal battery life of better than two hours, when shooting long exposures in bulb mode.
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Forum: Pentax DSLR Discussion
01-27-2013, 12:13 PM
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Smigol, I appreciate your detailed and thoughtful reply but in my experience, it is necessary to use longer subs, especially on faint objects, since the probability of capturing faint objects is better on fewer longer subs, than on more but shorter subs - however skyglow is an issue, that I don't worry about while imaging at my preferred sight, since it has virtually no artificial skyglow. Anyways your images are extremely well done. What mount are you using?
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Forum: Pentax DSLR Discussion
01-25-2013, 12:24 AM
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I've done some long exposure testing with my K10D and a lot of long exposure work with a Nikon D50. In theory if you get good results at 10 minutes with ISO 400, you should get better results - lower noise per image with no loss in bright areas by decreasing ISO to 100 and increasing exposure time per sub. Here's some experimental work that I've done with my K10D:
https://picasaweb.google.com/102361289894036464287/Astrophotos
Images 3, 4, 5, and 6 (left to right) were done with a K10D, the rest with a Nikon D50. These were done at an extremely dark location.
The 14bit K5 should always use ISO100, IMHO because it gives the best possible dynamic range and SNR.
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Forum: Pentax DSLR Discussion
11-14-2010, 11:55 PM
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Forum: Pentax DSLR Discussion
11-09-2010, 09:02 PM
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A 300mm F4 lens+ DSLR and an inexpensive german equatorial mount (as shown earlier in the thread) makes a really great astrophoto setup. I try to avoid zooms because they tend to have more internal reflections and poorer edge correction compared to a fixed lens but that doesn't mean that yours won't work. One thing that hasn't been mentioned is the use of an autoguider which allows the mount to track accurately for very long (hours) periods of time and is essential to successfully utilize long exposures.
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Forum: Pentax DSLR Discussion
11-09-2010, 04:09 PM
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The k10D is a great camera for astrophotography, and here's a few sample images:
Picasa Web Albums - Duncan Munro - astrophotos
My main camera is a D50 which has had the IR blocking filter removed, and I intend to have this done to my K10D as well, at some point in the future.
I have tested most Pentax DSLRs for astrophoto suitability and the K10D seemed best. The K100/110 had too much dark current. The K200D seemed to have more amp glow than the K10D. The K20D, K-X and K-7 will not allow the user to turn off dark frame subtraction (DFS) for exposures longer than 30sec. However the K-R and K-5 will allow the user to turn off DFS and appear to have very low dark current and little or no amp glow as well. The K-R might be the most cost effective DSLR for astro work.
A common misconception is that high ISOs are required for astroimaging and this is incorrect. Low noise 12bit CCD cameras like the K10D will generally perform better with lower ISOs and longer exposures. 14bit cameras like the K-5 will record more information at low ISO and longer exposure than at high ISO. The ISO setting does not change the camera's sensitivity but merely adjusts the amp gain by reading out the pixel electron well before it is full. A 14bit camera gains nothing by using high ISO and actually records less information than when used at low ISO because of the reduction in DR.
This is a K10D image of the Orion Nebula, 37mins at ISO100 @ 1700mm EFL with no dark frame subtraction:
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