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Forum: Pentax SLR Lens Discussion
02-18-2012, 11:41 PM
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I own a few M prime lenses and I was wondering what the difference is between the SMC Pentax K prime range and the M prime range?
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Forum: Pentax DSLR Discussion
09-27-2011, 03:34 PM
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Ok I played with the remote assistant yesterday arvo and did a short timelapse here. Those were 250-500ms exposures. I had the interval set to 40s. That's how long it takes for one file to save from the DSLR to the laptop via USB. The average file size was 16MB in RAW.
It seems the camera won't handle very well shooting again before the previous file is saved. That is the same behaviour whether you save to the internal memory card or an outside storage via USB. So the best thing seems to let the file save, the camera come back to standby mode (after the hourglass symbol disappears) then shoot again.
Even when I tried to do 30s exposures I thought adding only 10s interval so I'd get 30s+10s = 40s enough time to save one sub. I started to run into trouble after a couple of exposures with the camera shutter activating within the exposure countdown of one of the subs.
Am I missing something or doing something wrong? Thanks for any pointers.
PS: would the *istD with the latest firmware (1.12) support a Sandisk Extreme 16GB UDMA . If it does then I'm thinking that I can store close to 13h on board with that card so I could do away with the laptop altogether during capture? At the moment I'm using a Sandisk Ultra II 2.0GB and it might also be the bottleneck with download time.
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Forum: Pentax DSLR Discussion
09-26-2011, 08:41 PM
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I was a bit worried about that Wi-FI card as one of the reviews said the pics were uploaded online prior to be downloaded back on the laptop using a web service? That didn't sound right.
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Forum: Pentax DSLR Discussion
09-26-2011, 08:39 PM
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Hi Guys, I have found an old installer for the first version of Pentax Remote Assistant. It works a treat. While it's running with the camera connected via USB you still can use a TC-80N3 but you are limited to 99 exposures. The only thing is to give a minimum interval of 35s for the image to download and save on the Laptop. Will do some testing tonight.
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Forum: Pentax DSLR Discussion
09-26-2011, 07:28 PM
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Thanks guys. The PENTAX remote assistant link is dead as it's ancient software. I sent a query to tech support to see where I can download it from.
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Forum: Pentax DSLR Discussion
09-26-2011, 06:03 PM
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Is there a way to save raw files directly from the camera to a laptop via USB rather than on the onboard memory card?
Any software available that would enable me to do this with my old *istD? I use a TC-80N3 remote to do timelapses and would like to save the subs to PC rather than clogging the memory card.
Thanks for any pointers.
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Forum: Troubleshooting and Beginner Help
06-28-2011, 03:24 PM
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No worries. A gentle brush got rid of it. I didn't have to wet anything. I have a special pencil brush that I use for my eyepieces. I use dew heater straps over a sock and dew shields when necessary when I image. I always keep the lenses dry stored with dessicant. I treat them like my other scopes. :)
Sounds good. I'll get a 49mm step down ring too then so I can use all my baader stuff.
Going to a dark site this new moon week-end. Will see what happens with the mods.
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Forum: Troubleshooting and Beginner Help
06-28-2011, 12:22 AM
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Thanks for all the links and info. Got a bit of reading to do. I got a 52mm to 48mm step down ring from eBay for the 200mm. I've just received my 100mm today. I checked the front thread and this one's 49mm - LOL. Can't win.
I've also noticed the new lens is very dusty at the back. It's loose enough to come out with a cotton tip but not with a blow up air spray. So my question is do I clean it dry with a Qtip or wet the Qtip with acetone and wipe it this way. Is the back element (sensor side) coated?
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Forum: Troubleshooting and Beginner Help
06-27-2011, 04:26 PM
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Thanks for the link. Very cool and informative.
Thanks. I've later figured 52mm. Getting a stepdown ring from eBay now.
I used an OSC. Some of the blue/turquoise still makes it in the green pixels of the bayer matrix. The pattern is RGGB so 2Gs makes the sensor more sensitive in the green as well.
The UV/IR filter I plan to use is the 2" Baader UV/IR Blocking. Frequency is 420 to 680nm. I'll try again when I've got all the bits and pieces.
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Forum: Troubleshooting and Beginner Help
06-27-2011, 02:20 AM
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Thanks for the quick reply. I actually don't mind going for longer exposure. With the Sii filter my subs were 20min. The longer the better because I get less read-out noise. The only reason I did 2min subs is that 5min burnt all the details.
I realise the light gathering increases with aperture but I wasn't aware that star bloat was also related to aperture (?)
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Forum: Troubleshooting and Beginner Help
06-27-2011, 12:37 AM
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Hi there, first post here. I recently bought a SMC Pentax-M 200mm F4. I use it primarily for astro-photography. I was able to use this lens using 2" narrowband filters Ha 7nm and Sii 8nm with success. The field is flat with very little aberrations even with the lens fully open.
This week-end I tried without a filter and did straight RGB with an OSC cooled CCD. This time I shot with one stop down. The red channel was fine but the green and blue showed a lot of star bloating. Again no field curvature or coma, just very fat stars and some chromatic aberration.
My question is would stopping the lens further get rid of star bloat or am I best to use a UV/IR cut in front of the lens altogether?
My subs were 2min exposures guided.
Thanks for any tips.
PS: What is the thread size in front of the glass and where can I get a compression ring to M48 M/F?
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