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Forum: Pentax K-5 & K-5 II
05-09-2011, 06:51 PM
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There has been no astrophotography thread for K-5 yet, so with your permission I'll start one. In forums without a specific forum for this kind of subject, I've seen a thread like this remain active for years. Let's see your K-5 sky photos, all kinds, including stars, planets, deep sky telescope objects, spacecraft, satellites, and atmospheric phenomena. Also advice, data, and ideas.
To start with, I want to post the data I took for the camera's built-in interval timer. It's a cool feature that the K-5 has the interval timer in the camera, so you can do without attaching an external one. In the menu, you can set the interval timer with a shutter interval, a total number of activations, and a time to begin the activations. The firmware acts like a finger pushing the shutter - that is, the interval you choose is the time between shutter activations, not the time from when the shutter last closed. That means, if the camera needs 1 second to process each shot, and you have the shutter open for 30s, you must set the interval to 31 seconds or more. That's because the camera must be ready for the next shot when the timer fires, or that shot will be skipped.
The issue is complicated by the Dark Frame Subtraction feature, DFS, which in the menu is called "Slow Shutter Speed NR". If DFS is on, after each shot the camera takes a reference frame with the shutter closed which is then processed with the image to remove hot pixels and other problems, at the cost of almost doubling the time per shot.
Using my K-5, I determined the minimum interval time for each of the long shutter times. Enter this value, or higher, into the interval time menu. Using too short a time will cause shutter activations to be skipped; using too long a time will unnecessarily waste time, and we don't want to do that if we are taking sky pictures. As you would expect, the values for DFS on are much higher than those with DFS off. You decide which you want to use.
Values in Bold are more efficient in time used, and have proportionally less dead time, than their neighbors. Use them if you can. For instance, 20s is a good choice for an exposure time - set the interval to 21s if you have DFS off, or 35s if you have DFS on.
Exp NoDFS DFSon
0.25 1. 1
0.30 1. 1
0.40 1. 1
0.50 1. 2
0.60 1. 2
0.80 2. 2
1.00 2. 3
1.30 2. 3
1.60 2. 4
2.00 3. 4
2.50 3. 5
3.00 4. 6
4.00 5. 9
5.00 6. 10
6.00 7. 12
8.00 9. 14
10.0 11 18
13.0 14 21
15.0 16 27
20.0 21 35
25.0 26 42
30.0 32 54
Some interval times are convenient divisors of an hour.
An interval of 6s gives 600 shots per hour.
An interval of 10s gives 360 shots per hour.
An interval of 12s gives 300 shots per hour.
An interval of 18s gives 200 shots per hour.
An interval of 36s gives 100 shots per hour.
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Forum: Pentax K-5 & K-5 II
08-13-2013, 04:16 PM
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Forum: Lens Clubs
12-17-2012, 12:22 PM
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Great one of the Fairy Wren, how many tries did it take before you got that one? I know how insanely fast those birds move and it more or less forces you to use a high shutter speed, and maybe burst mode too. And luck is a factor.
The smallest bird I've been chasing is these Least Sandpipers. They are like crazy fast little wind up toys which zip around at such a rate it's hard to get a decent focus without their already being elsewhere.
K-5 with Bigma at 500mm, 1/750th sec at F/6.7, ISO800, heavily overcast afternoon, at a breakwater lagoon near Moss Landing CA. Not a fine shot technically but it's the best I've managed so far of these little guys, they are approximately 4 inches long beak to tail.
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Forum: General Talk
10-18-2011, 01:49 PM
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Rupert's contribution was unique and valuable and I want him back. I went over his last dozen posts and saw nothing wrong there. He always responded to the topic, at least a little, and generally added humor. His squirrel shots were excellent. He is kind and welcoming to newbies. Bring him back! It's shameful to ban someone for - what? posting too many pictures? Being too active? Having an irreverent sense of humor? Come on! What kind of forum is this, anyway. I protest!
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Forum: Pentax K-5 & K-5 II
06-08-2011, 07:46 PM
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My parrot with the K-5 plus 43mm F/1.9 Limited, using available light only. He's thinking, "I'm upside down and obviously in need of being rescued and you should also come and give me peanuts."
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Forum: Pentax K-5 & K-5 II
06-05-2011, 01:39 AM
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I have been using this one bought on Ebay:
Pro BATTERY GRIP Pack FOR PENTAX K7 K 5 K5 D-BG4 DBG4 | eBay
I am happy with it. In fact, it seems to be solid and reliable. I noticed that some photos of other units had the bed-of-nails connector using tin-plated pins instead of gold - but this one that I received is gold plated. That's probably one of the most important things to be sure of. Aside from that, all switches work and feel like those on the camera, and it fits without problems. I recommend it.
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Forum: Pentax K-5 & K-5 II
05-12-2011, 11:54 PM
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Ok, I posted this comment in response to his review.
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