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Forum: Pentax K-70 & KF
09-21-2023, 11:18 AM
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I purposely raised the exposure level and brightness to show the issue a bit better. Now, come to think of it, it might not be related to the flat-frame I posted before.
It looks more of a straight line and thicker on the bottom.
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Forum: Pentax K-70 & KF
09-21-2023, 11:12 AM
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Hello Bob! Thank you for your reply.
When I take day time shots, I just used regular camera lens. I tried blaming the telescope (80mm aperture refractor), but I got other cameras (Nikon, Canon) and those do not produce discoloration on the same telescope. I'm leaning towards low ISO issue , I will do more tests with higher ISO I will also test the camera with another telescope too.
I thought about heat, but lately it's barely in the 50s at night, so it's not very warm, the camera is usually cold to the touch. There are no filters used at all. just the bare sensor looking through a field flattener and the telescope prime objective lens.
I'm also thinking as another idea, that the tethering to a mini pc via usb cable and the mini pc converts the raw files into .fits files that maybe possibly something happening during conversion. I will also test it, by not allowing the conversion and checking the camera raw files (.PEF) if they produce the same artifacts.
Yeah, lol, I know, I'm answering my own topic, but i'm interested to figure out the real issue and hope that maybe someone else experienced similar issues before and found a solution already.
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Forum: Pentax K-70 & KF
09-21-2023, 10:35 AM
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Hello All!
I recently tried to use my K70 for astrophotography. For those who aren't familiar and to tell what I did was taking subframes and stacking them, the camera is connected to a telescope and also to a mini pc, running Stellarmate. (the only way I can actually have a tethered connection).
So anyway, I took some images, (and I'm showing the final -stacked image) but I noticed a discoloration in each sub, some sort of yellowish-brownish tint on the top and the bottom of the frame in each shot.
The settings were bulb- 90 second exposures (on an equatorial tracking mount) at ISO200.
The final image is made from a stack worth of 3 hours of exposures.
Now, I tried blaming the telescope, but I don't get the same discoloration with other cameras on it.
I tried blaming that my viewfinder was uncovered, until recently I tried it with the viewfinder taped off but the yellow/brownish discoloration on the top and bottom of each frame still present.
I tried blaming light pollution, but the yellow brown discoloration still shows up in short exposures (I'm talking about stretched images) , like 1/50 seconds. So it's not something like getting into the image from the viewfinder, but its' like it's inherently in the image already as soon as the shutter fires away.
Again, the discoloration only on stretched images only, not on daylight-brightness -normal images. I don't see any discoloration in normal photos with plenty of light.
Even if I shoot a fraction of a second flat frame (with a diffused light) and stretch the single shot, the colors still present.
I tried shooting darks (with the lens cap on, complete darkness) and the discoloration doesn't show up at all in the dark frames. Only in light frames- at whatever exposure settings.
The camera settings is in Bulb mode- every preprocessing option turned off. Everything all the options you can think of inside the options menu is off, and "natural" color scheme used.
One thing I haven't tried yet is trying a different ISO.
So I'm at the point, that I have no idea what's causing it.
If you look carefully, you gonna notice the bottom and the top of the image has a yellow/brown tint.
This is the 3hrs integration of Andromeda Galaxy:
Anyone has any idea why I got this discoloration?
Below is a stretched file of a flat file (about 1/25 seconds at ISO200, using a flat panel) If you notice, the top blue hue and the bottom yellow/red hue somehow doesn't show up in the dark , but still makes it into the image and I cannot calibrate it out. I am aware of the dust motes , that's fine, those calibrate out, so is the vignette, but not the top/bottom colors.
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Forum: Pentax K-70 & KF
01-12-2023, 07:56 AM
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I just did a search on reviews on the Pentax Kf. It's not only Tony and Chelsea, but plenty of others saying, this camera was a pointless release by Ricoh.
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Forum: Pentax SLR Lens Discussion
09-22-2021, 03:27 PM
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Forum: Pentax K-70 & KF
06-19-2021, 05:27 PM
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When you have the Camera as it is- meaning you haven't changed any options, you have 3 user modes you can save your settings. It's marked U1 , U2, U3. By default one is set to "ASTROPHOTO", the other is HD Landscape and there a third one.
You have to use ASTROPHOTO, which is actually a custom BULB mode . You can make one of your own too.
Here is the problem.
Set your camera on ASTROPHOTO and go into the exposing menu. ,
The right button on the cross button menu. There is : Single frame shooting; Self Timer; Remote Control M.UP (Mirror Up: Multi -Exposure.
Now, rotate to the "Manual mode" and look at the same menu and you gonna see "INT" in which you can set the number of exposures at certain intervals at a certain release .
I want that menu in either the "ASTROPHOTO" settings or the "BULB" settings.
Not having a an INT (Interval shooting) option in the exposure settings is an oversight, because the M (Manual) settings only allows a maximum of 30 seconds of exposure, but what if I want 30x 1 minute in Bulb mode? I will need to use an external remote control/intervalometer to do that.
Why not just have the INT- option in the Bulb menu too?
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Forum: Pentax K-70 & KF
06-17-2021, 07:52 PM
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So nearly a year later, I sort of figured out. If I switch on the astrotracer and shows green satellite icon is not enough. Must be on the "astrophoto" mode, not Manual or Bulb on the dial. I really hoped that just switching to M- manual and having the green sat icon showing means that the astrotracer is doing it's tracing work. No. Must be on the "Astrotracer" mode, where there is that little indicator showing in the info that I got 2'20" or similar, otherwise it won't work.
And yeah, in this mode, there is no interval-mode to be selected, which I think is a serious oversight from Ricoh. Having only the M-manual mode with interval settings is not enough and defeats the astrotacer option. where many of us are taking 10s or 100s of subframes that can be stacked.
I'm using a wireless intervalometer and taking no more than 20 seconds, but mostly just 10s shots with 135mm prime lens. There are certain times I can take it to 2 minutes, but looking at the individual frames shows that sometimes I had rounder stars, other times they were trailing. So to get almost perfect stars , I had to keep it at 10 second exposures and my lens need to be dialed back from F2.0 to F4 to avoid stars bloating.
Also I don't use Zoom lens , they cause more abberation , unless it's one of those that cost 1k. Prime lens only.
Here is a mosaic sort of stacking I did with Astropixel Processor, photographing the Milky Way, pointed towards South and the ecliptic.
Milky way by the Meridian ( frankszabo75 ) - AstroBin |
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Forum: Pentax K-70 & KF
02-13-2021, 10:36 PM
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Do you have High ISO SNR and Long Exposure SNR turned on?
If you do, your camera is taking darks to calibrate your shots. Your camera is not really turned off, but it looks like it is.
If you want to exactly have your camera do as the intervalometer programmed, then you will need those off.
Having Long exposure SNR on, your camera is gonna take twice as long to take the the exposures , because it's matching the previous shot exposure time with a calibration frame to reduce noise.
But to remind you, if you turn it off, it's best to take dark shots (with the dust cap on, same ISO same length of exposure, same aperture) after you are done taking pictures. and you have to manually stack those images in one of the many image stacking programs. (sequator, deep sky stacker etc. )
Also turn off Moire control (those grey lines) and all the other tid bits they have it set on the astrotracer program. Basically all the fancy options off and for WB, use daylight and of course no autofocus. If you won't be using your viewfinder, it's also a good practice to cover that with a piece of tape or similar, to stop light entering there (it can, i had that issue) .
A
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Forum: Pentax K-70 & KF
12-21-2020, 07:33 PM
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Ok, so further investigation, I found some other threads regarding this astrotracer and its limits here and some other discussion places too and my own experience:
1. Needs to be calibrated very slowly. It can take even 5 minutes. (My issue is the camera seem to have buttons at every spot and hard to hold without pushing some stuff, especially in the dark)
2. Needs to be calibrated more than once. What I did is, after I went through the first time, did a second time regardless it said it was calibrated.
3. The device manual says, it'll retain the calibration as long as the battery isn't removed.
4. Instructions suggests, once it's calibrated it doesn't need to (until a battery pull) do again, but I advise against it. I would calibrate it every single time before a bulb shooting session.
5. Doing test shots can save time (to see if it's really calibrated) by taking a quick 20 second image and enlarging it on the screen and if trails show up, it's not calibrated, regardless of the green icon or not.
Try re-calibrating again, if doesn't help, find another location/take the cellphone out of the pocket also check some of these hat-lights/head-lights they sell, some has magnets in their clips (I just discovered this in my case, sold as a sort of eyesight saving-red light LED for people doing astronomy, but they put little magnets in them :lol:, obviously whoever designed it, didn't count on the fact, that compass is frequently used by people using telescopes or astrophotography or how about people hiking and navigating with a compass in the dark ? )
6. Once it's calibrated (even more than once) and turned on , I had it sit on the tripod for about 1-2 minutes without doing anything, let it more time to figure out the exact position where it is, especially in a poor GPS reception (towns, cities) area.
7. Do no more than 1 minute (my personal experience) or even less. 30 seconds should be ok if it's calibrated well. Once some single test shots done and they look good, then it's best to do like 15-20 shots and stack them, use deep sky stacker or some other free software out there, then edit the average final image in photoshop.
8. Use external intervalometer! I think this is important. I know the K-70 has the built-in, but shooting stars is one of the most challenging task a dslr is put against. Even the smallest vibration can start creating star trails. And pushing the expose button can still cause vibration, even if it's timed 3 seconds delay. I bought a wireless intervalometer, because even the wired one, I would have to stand close to the tripod on a softer or vibrating ground or accidentally pull on the cable etc and I don't want to wait and stand around near the tripod for 10 -15 minutes while it's taking pictures, and I'm afraid to let go of the wired intervalometer, which would cause vibrations again.
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Forum: Pentax K-70 & KF
12-15-2020, 08:18 AM
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That looks very good!
So I'm coming to a conclusion, that in my case, a town/city center is just not great for anything operated by GPS. I noticed that my iphone app- compass is also off. I wanted to confirm it, so I have an android phone, also showing the same issue. Then just to be sure I'm not getting fooled here, I took out a good old physical compass (pro level), which is also off by quite a lot. I can literally see how it's seeking North and ends up pointing several degrees towards Northwest instead. I just know, because I know where Polaris is as well as where the sun goes down.
Not sure what causing it, I moved away from cars and didn't have anything metallic on me. I am trying to find a reason for this magnetic issue. Walking away from the property into the street and the compass returns to a more correct North. My house built out of magnet or what? LOL!
Someone mentioned "local magnetic declination" on one of the astronomy forums in my search. Also, just remembered that my neighbor told me, having a hard time flying his drone and keeping it steady, somehow the drone receives bad GPS or some sort of interference.
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Forum: Pentax K-70 & KF
12-13-2020, 03:40 PM
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Andromeda galaxy, single shot. 80 seconds, f.5.6 ISO 800 135mm
---------- Post added 12-13-20 at 03:43 PM ----------
On a tracking mount. (I find the astrotracer feature unreliable and useless for me, there is a topic)
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Forum: Pentax K-70 & KF
12-13-2020, 02:45 PM
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Please back your claims up. Manufacturers' promise is not enough.
I challenge anyone to take a 1:00 exposure bulb photo without getting star trails appearing, and zoom in on a nebula or the andromeda galaxy! Again, the picture may look great at 55m or a wide angle shot, but try zooming on anything!
Here is the point when I stopped using it:
Here is a shot with Astrotracer (ON), completely undependable, the rest of the info is on the screenshot.
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Forum: Pentax K-70 & KF
12-11-2020, 11:07 PM
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Yes, just reverse dial down the interval and after 00001 it's gonna say "minimal".
Makes sense, not sure why would anyone want to wait around if we can just tell the camera "do your thing as much time you need, but not longer" .
---------- Post added 12-11-20 at 11:09 PM ----------
Unless of course, someone wants to reposition the camera or change a settings and want to add some time.
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Forum: Pentax K-70 & KF
12-11-2020, 09:54 PM
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Having the camera for 2 weeks, haven't learned all the features yet, but the "manual" mode is bugging me a bit, not having all the options available, as I said, if it's full manual, then be a full manual, including dialing beyond 30 second exposures. The other is better communication. Sometimes the camera goes into complete silence after shooting many shots. I start guessing, because not knowing whether it's processing, if the shutter still open or did it turn off, didi it lock up, did it freeze, or did the battery die. If it's processing the images or doing something, give us a life sign lol! When it's done, let us know, let some light flashing somewhere, like a tiny strobe light with a morse code whether "I'm still working on something" or "I'm done working" , don't let me just stare at it on the tripod and debate whether to touch it or not lol!
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Forum: Pentax K-70 & KF
12-11-2020, 09:42 PM
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Thanks for all the answers. I've found a quicker solution. Basically dial back on the interval menu and there is a "minimal" option instead of a number input. Basically the camera will take as long as it needs to, but not longer.
It's working 100%.
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Forum: Pentax K-70 & KF
12-11-2020, 02:09 PM
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Hey thanks Steve!
That's kind of a bummer, but I'm gonna give it a shot. I guess I as pushing it hard with the 2 second breaks.
2 second passes by and it's still processing so the camera just ignores the following interval commands, because it's out of time. Makes sense.
I'm gonna try a longer interval and see what happens.
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Forum: Pentax K-70 & KF
12-11-2020, 01:21 PM
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I got this issue , brand new camera ( a week old, used 4 times so far) , that maybe I'm missing something or the camera's fault, I don't know. That's why I'm asking.
Assume I'm in manual mode and nearly all the little options are off and shooting in RAW mode. (all little options like AA filter simulation, noise reduction, etc. )
The intervalometer (the built in) set to take 22 shots with 2 second intervals, each shot is 30 seconds.
Conditions:
Fresh battery
Formatted/empty card (Sandisk Extreme Pro 64GB)
So what happens?
The camera takes 1 shot and that's it.
I tried it at least 20 times, make sure I'm selecting the "INT" function and the second is correct and the number of shots are in!
The camera does 1 shot no matter what.
I tried this in M- mode as well in Bulb mode.
It won't do it.
I attached an external intervalometer and select the intervalometer in the timed exposure menu.
What happens?
1. The camera ignores the meter and takes 1 shot.
Someone can help me with this?
Thanks for any ideas, other than packing it up and returning the camera to the seller.
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Forum: Pentax K-70 & KF
12-11-2020, 01:13 PM
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I'm a new member and I tried the astrotracer (with the extra mount piece attached) and the results vary. (I have an issue with the camera, but that's another topic)
First and foremost, "ASTROPHOTO" - option only allows you no more than 30 seconds exposure at max.
BULB- you set the time, and if you go into the custom option on the camera, you can set it to infinite -meaning whenever you push the shutter button again.
Also, important to note, The Astrotracer option only works with the Pentax lens, and mostly just wide angle hosts of the sky. It's only "astro tracing" and it's really only meant for that sort of a shot.
Not deep sky objects! And definitely not with the camera attached to a telescope, which doesn't communicate to the camera. Your astrotracer is calculating the stars shifting (Earth rotation) while takes in account the lens and zoom level etc. Attach it to a telescope, and you gotta forget about it and turn it off, the camera has no clue what you have on, it actually acts like nothing is attached.
Another thing. The little astrotracer gadget has a very limited battery life. That 1 AAA battery lasted me about 30 minutes, before it started to flash red, that the battery is weak.
So, is the astrotracer option even useful? Yes, (IMO), to a certain level, but it cannot replace an equatorial tracking mount for deep sky objects, and I also question the camera's capability to be used with a telescope (after 1 long frustrating night trying to set it up ), since the "MANUAL" mode restricts shots to 30 seconds but allows the internal intervalometer to take multiple shots at certain intervals, while the BULB mode won't allow that? Who made that decision not to have intervolumeter option for the BULB shot?
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