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Forum: Pentax K-3 III
07-16-2023, 02:56 PM
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My apologies for a very late reply to an oldish thread. I don’t normally read the K-3III forum. (I have a K-3II.) But I felt I had to reply to correct some particular misinformation with respect to the original Mode 1 Astrotracer that regrettably comes up on the Pentax Forums every now and then and seemingly won’t die.
I’m afraid your guess is wrong. Astrotracer does indeed rotate the sensor as required for true tracking, in all modes of operation. Aim it at the celestial pole with, say, a 50mm lens and see for yourself what happens. It tracks properly. If all it did was altazimuth tracking, it wouldn’t be able to do that.
As further evidence, have a look at my own Astrotracer images, both those on Astrobin (here) and DPReview (here, here and here). I have been able to do up to 60-second exposures with a 200mm lens on the K-3II with no trailing anywhere in the image.
The only time I see trailing (assuming a good calibration, which can sometimes be tricky) is if I exceed what experience has taught me is the limit of exposure time for the lens attached (which is always much shorter than what the camera tells me I can do based on the focal length and where I am pointing). Trailing at the edges but not in the center, specifically, does not happen for me except at focal lengths shorter than 50mm (specifically, 35mm and under) due to Astrotracer’s well-known problem with wide-angle lenses (which still applies to Mode 3). And even then, it is only objectionable (to me) if I go much beyond 30 seconds or so.
The images in the original post are great and Mode 3 is a really nice advance. But good-ol’ Mode 1 (Mode 2 is just half-speed tracking, which I would never use) _can_ work really well. And it remains as a back-up for K-3III users when Mode 3 won’t work for whatever reason, provided you have an O-GPS (1 or 2) on hand.
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Forum: Pentax K-3 & K-3 II
07-28-2020, 07:48 PM
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The pixel scale is result of a 50% downsizing and then a crop. I downsized because I was using a 32-bit version of rnc-color-stretch to do stretching and it couldn't handle the full 24 MPixel frame. I didn't really need to downsize that far (to 6 MPixel) but that also made rnc-color-stretch run faster. I now use the 64-bit version of the program (actually, of Davinci, which rnc-color-stretch requires) and don't need to downsize. The additional crop was probably to get rid of edge artifacts from stacking but also for aesthetically pleasing framing.
Like you, I am just being safe. I have actually triggered the shutter using my finger when using a 200mm lens and seen no effect in the image. But the mirror-up delay costs me only two extra seconds per shot, so why not? As for the black paper trick (ages ago they used to talk about using a black hat), shooting a hundred or more subs with Astrotracer is enough work already!
Shooting the moon through a 762mm telescope, on the other hand, definitely needs mirror-up delay. It could also really use an electronic first-curtain shutter but the K-3II doesn't have that and never will. (I think we saw what will be the camera's last firmware update some time ago.) However, I have been successful with Pixel Shift Resolution a few times.
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Forum: Pentax K-3 & K-3 II
07-27-2020, 09:08 PM
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Thanks. I just tried it and it worked as you said in your first reply (I had no real doubt). I should have mentioned that when I couldn't seem to get it to work, I was using it in the dark for astrophotography (Astrotracer). I must have failed to switch the shooting mode to the 2-second delay, as I most often use an IR remote with Astrotracer and hence choose the IR remote 3-second delay. It's easy to make mistakes in the dark. :)
Luckily, I was using a very sturdy tripod and a 28mm lens, so I doubt lack of a mirror-up delay made any perceptible difference. But if I had been using a 300mm lens it might have been a different story. (My link on "300mm", not an auto-generated link.)
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Forum: Pentax K-3 & K-3 II
07-27-2020, 08:38 PM
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How can I get a mirror-up delay with an external, wired intervalometer? Triggering the shutter through the wired remote port seems to ignore any of the delays I would normally choose when using the shutter button or an IR remote. I must be missing something obvious.
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Forum: Pentax K-3 & K-3 II
10-24-2018, 06:12 PM
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Yup. One piece of news, 60 pages of speculation. Wake me when something happens.
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Forum: Pentax K-3 & K-3 II
10-13-2018, 06:43 PM
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There is news in this thread somewhere? Could have fooled me.
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Forum: Pentax Forums Giveaways
09-01-2018, 07:14 PM
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Forum: Pentax K-3 & K-3 II
08-25-2018, 05:16 PM
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As others say, dry humor like that doesn't come across well in text. But let's return to our regularly scheduled game of predicting with no real information what is coming from Ricoh. It's far more entertaining. :D
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Forum: Pentax K-3 & K-3 II
08-24-2018, 10:46 PM
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You are trying to be funny, right? If so, don't quit your day job to do standup, as they say. It's surely common knowledge that "Junior" here refers only to the number of posts.
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Forum: Pentax K-3 & K-3 II
08-22-2018, 06:41 AM
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Kids? I wish. Is that photo in your avatar really you? If so, I got thirty years on you, at least.
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Forum: Pentax K-3 & K-3 II
08-18-2018, 04:30 PM
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Oh, now I get the "caustic" reference. I'm a little slow on the uptake, I guess. :D
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Forum: Pentax K-3 & K-3 II
08-18-2018, 06:34 AM
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According to the Urban Dictionary KPH can stand for Konichis Per Hour, and "is a term (relating to Kilometers Per Hour, where faster is generally better) used to describe events and/or objects that add fun, entertainment or a positive spin to a gathering of friends/relatives/homies." I don't know about the homies part but my K-3II has definitely added to my fun.
So, no caustic comeback here. :)
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Forum: Pentax K-3 & K-3 II
08-17-2018, 10:18 PM
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If the card were half its current price I would try it, problems, bugs and all.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 10:14 PM
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I have found that giving it extra iterations of rotations in the three axes can usually get me a successful fine calibration, even when I am quite sure I have rotated more than 180 degrees in all axes on the first iterations. I have also found that trying to do a fine calibration near a car or with a cellphone in my pocket usually doesn't work at all.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 10:07 PM
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While doing astrophotography on a tripod using ASTROTRACER, when I need to look through the optical viewfinder to compose a shot without the distraction of the LCD, which I have already reduced in brightness to the minimum and selected a "reddish" color scheme, I momentarily turn the power switch to the optical preview position. It's easier than trying to half-press the shutter and there is no danger of accidentally triggering an exposure. I don't turn the LCD off entirely because I do need to use live view at times for focusing.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 09:46 PM
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For astrophotography (AP) with lenses on a tripod, the best accessory for a K-3 is the O-GPS1 in order to use ASTROTRACER (built in to the K-3II and K-1/II models). It really does work (although the required fine calibration can be tricky). Here is one recent example, using a 200mm lens. If you have that you won't need an external intervalometer for exposures up to the limit determined by the lens focal length (up to 5 minutes).
For astrophotography through a telescope, an external intervalometer will be required for any exposure over 30 seconds, which will generally be required for deep-sky objects. (Lunar and/or planetary, OTOH, will use very short exposures.) But thIs will be by far the least expensive accessory you will need for that if you count the telescope, its mount, and an auto guiding set-up as "accessories." You will spend a lot more than the camera on all of that (I certainly did) and it will take you a while to get up to speed with it. It's another world of hurt. AP through lenses using ASTROTRACER is child's play in comparison.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 09:24 PM
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For tripod-mounted applications where either the camera is very low (e.g. ground level) or it is pointing up very high (e.g. astrophotography), I use this new-fangled device called a compact mirror (invented around 1908). I realize that this will not work for everyone or every situation, but it works for me. Reading menus can be problematical but fortunately mirror-image text is not a problem for me. I can read it almost as easily as normal text, and the more you know your camera the less of a problem that is in any case.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 09:13 PM
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Re image processing software, I think that Picture Window Pro is pretty good, especially for the money. As in, free. The developer, Digital Light and Color has discontinued further development and is offering the last version, 7.0, for free. How appropriate to use discontinued software on a discontinued camera. Get it while you still can.
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Forum: Pentax K-3 & K-3 II
08-17-2018, 08:53 PM
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It's been so long since the K-3II was introduced, which after all was an update model, and now five or six months since it was discontinued, I'm sure the new top-of-the-line APS-C model will have an entirely new name, not just a K-X number (which would have to be an even number now in the unlikely event they do that). I'm surprised there isn't already a pool to guess it. But I do like K-π.
Of course, maybe Ricoh won't ever release a replacement. Owners of the KP seem to be pretty happy with that model, which has perhaps unintentionally been plugging that hole in the line-up. Personally, it wasn't the camera for me - I chose the discontinued K-3II instead - but I don't think my needs were typical (e.g., built-in AstroTracer functionality was a big draw for me but won't be for most people). I know Ricoh has said they are working on a K-3II replacement, but in the end it's a business decision. If sales of the KP and K-1II are good enough, they may decide not to do it and instead divert whatever development they were doing on it elsewhere. I worked on product development (design engineering) for 35 years and saw that happen multiple times.
PS. Perhaps I should have put my asbestos suit on before typing that last comment in a thread entitled "The K-3 line will continue!"!
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Forum: Pentax K-3 & K-3 II
08-15-2018, 08:43 PM
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Distortion corrections don't seem to add all that much time to an image save that a four second gap wouldn't handle. OTOH, for star trails he might want to use the raw images, which AFAIK aren't affected by lens corrections of any sort. So there would be little point in keeping them on.
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Forum: Pentax K-3 & K-3 II
08-15-2018, 08:33 PM
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Good to know that the K-3II is still available from some retailers. I too bought it after it was officially discontinued. I chose it over the current K-70 and KP models and I don't regret my choice in the least.
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Forum: Pentax K-3 & K-3 II
08-15-2018, 08:30 PM
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I find it interesting that everyone is using K-3III as a working name for the K-3II successor. But has Pentax ever used a "III" on a model name before? I do find it interesting that Pentax's retrograde, single-digit, odd-integer numbering scheme for their prosumer models has backed them into a numerical corner, so to speak. Now that we're at "1" no odd numbers are left. It's perhaps why the "KP" has the name it has.
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Forum: Post Your Photos!
08-15-2018, 07:51 PM
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Superb. Love the way the tracks head off toward the Milky Way. It's a bit of a walk so we better get started! :D
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Forum: Pentax K-3 & K-3 II
06-17-2018, 06:58 PM
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Re the FluCard, I initially wanted to buy one for my new K-3II as well. But the various reviews I read on-line and the relatively high price dissuaded me. "Flawless" is not a word I would associate with its operation based on the majority of reviews. Nevertheless, if I saw one for half the current price I would give it a try.
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Forum: Pentax K-3 & K-3 II
06-17-2018, 06:14 PM
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FWIW I bought a K-3II in March as my very first DSLR. I bought it knowing that it had been discontinued the month before. In fact, I had been on the fence about it and hearing that it was discontinued made my mind up to buy it while old stock was still available at distributors. (But you can still get one at many places even today.)
I was sure I wanted a Pentax (I started in photography 43 years ago with a K1000) primarily because of the in-body stabilization and my collection of decent Pentax primes, but I dithered between the K-70 and the K-3II. (A K-1 was too expensive for my budget and the KP didn't appeal to me.) Was the K-70's image accelerator chip, on-sensor PDAF pixels and articulating screen (not to mention substantially lower price) worth more to me than the K-3II's built-in GPS (and hence Astrotracer functionality without need of an O-GPS1 accessory), top LCD and magnesium-alloy body? Would the lack of piezo-based sensor cleaning on the K-70 be more problematical to me than the lack of built-in flash on the K-3II? According to reviews video is about the same on both cameras: "usable" but nothing to write home about. Both cameras have weather sealing.
My primary use for a DSLR is astrophotography, with a secondary use as a landscape camera. Incidental use might be capturing the grandchildren in motion (haven't tried yet), although the Pentax AF-C might prove challenging for that without practice. I don't need a DSLR for video. I wanted Astrotracer for certain. I'm sure I would have been satisfied with a K-70 (with an O-GPS1 accessory); it's a lot of camera for the money. But I'm glad I spent more and bought the K-3II. (I actually bought it with the 18 - 135 kit lens, since carrying around and continuously swapping primes isn't something I want to do except for specific tasks, including astrophotography.)
Regarding lenses, for astrophotography the Rockinon 14mm f/2.8 and the Samyang 135mm f/2 seem to get a lot of love. In between those focal lengths and longer you can do well with SMC M or A lenses on the used market. I have several (28mm, 50mm, 100mm, 135mm and 200mm) and they perform well with mininal stop-down (one stop in most cases).
BTW, for astrophotography decent response to the Hydrogen alpha emission line (deep red) is important for many nebulae. As you can see by the various astrophotos posted to the Pentax forums, recent models are quite decent in that regard to the point where I feel they don't _need_ to be modified (which removes the camera's IR filter and optionally replaces it with one with a flatter, wider passband).
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