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02-23-2014, 03:13 AM   #1
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A Few Final Questions About The K-3

Hi there, Pentax owners!

Tonight I managed to utilize the K-3's astro-landscape photo features quite a lot. I did a couple timelapses using a motion control device, (the Syrp Genie, also doing a review currently) ...as well as a couple still images using the O-GPS 1 for "star stabilization" plus the K-3's "additive" compositing for breaking the 30 sec. barrier.

Before I publish my final (pt2) review on SLR Lounge, I have a few questions. (I felt like an idiot when I stated that there was no viewfinder indicator for the current function of the 4-way control pad and a couple readers politely corrected me. Hopefully I can avoid anything similar this time!)

First and foremost, is anybody else as bummed out as I am that ONLY when using the astro-tracking option can we push past the 30 sec. barrier? When I first turned it on and saw that I could just keep cranking my shutter speed all the way up to 300 seconds, I got a little giddy. But it seems, these shutter speeds are ONLY available when using the astro-tracking function...

Speaking of going to 300 sec. with the astro-tracking function, I wish there was a way for Pentax to know which focal lengths will "max out" which shutter speeds; for example I tried a 300 sec. exposure with the 15mm f/4 and it still produced star trails. They looked like the star trails from a ~1-3 minute exposure given that focal length, so hey that's still not bad! But I wish Pentax could have put some sort of intelligent limiter on the shutter speed so that you automatically know how long you can expose before stars begin to move.

Can anybody expand on which focal lengths work at which shutter speeds, by the way? To get all the way to 300 sec. without the stars moving, do I basically need to be shooting with a fisheye? What about that fantastic 200mm f/2.8 that I've seen people post Andromeda etc. images from; how many seconds can you get away with exposing at 200mm and have motionless stars?

I mostly used the Pentax 15mm f/4 and the Rokinon 16mm f/2, and neither of them seemed to be able to shoot at more than 80-90 sec. before the stars all around the edges of the frame started to move, and by 120-150 sec. the entire frame was showing star motion blur. I did a calibration thing, and the camera seemed to think that I had done it successfully, but I just want to know if anybody has significantly different results.


NEXT, I had a little bit of trouble when using an external timelapse device to trigger the K-3 in single exposure mode. (Meaning, I didn't use the K-3's built-in intervalometer)

For whatever reason, even with the AF switch set to MF, the camera still beeps when it thinks things are in focus, and what's worse, it seems to refuse to click a shot at the command of the cable release trigger. This seemed to happen every four clicks, it would beep as if it were hunting or acquiring focus, but it wouldn't shoot.

I think I fixed / reduced this problem by switching from single point to all AF points, but why is this even an issue when I'm in MF? I also checked on my timelapse device because it does have an option to trigger AF or not, and that option was set to off. So, can anybody replicate / explain this? I was doing slow exposures in pitch-black conditions. I was also able to set the timelapse device to increase it's "fire" signal to a whole 1000 ms which seemed to improve the consistency in half-decent light. Still, I'd like to know if the camera is actually refusing to fire because of focus, or another issue that I haven't suspected. (I think it might also have to do with waking the camera up for intervals of 30-60 sec...?)

Anybody have anything they want to mention to me for testing, as far as tips go for the numerous shooting modes that the K-3 has? Stuff like the additive layer stacking is pretty awesome if you ask me, but there might be some other purposes in addition to star trails and compound exposures that I'm not thinking of.

Last but not least, I can't figure out how to turn auto-ISO on. In the quick menu and the deeper menu it gives me all the options for it, but there doesn't seem to be an on/off switch somewhere. I could have sworn I saw something about this though when I first poured over the menus and the user manual, but now I can't figure it out. Long story short, I tried to timelapse a sunset today in P mode with auto-ISO set to 100-6400, so that I could transition smoothly from a beautiful sunset to stars in the sky. Basically the camera meter was (to my surprise) able to maintain almost a perfect exposure until the aperture was wide open and the shutter speed was up to 30 sec, ...but the ISO stayed at 100 so the timelapse just quickly went to black at that point. What am I missing?


Thanks for your time and take care,
=Matt=

(The image below is a blend of a 100 sec. exposure using the O-GPS 1 for the stars, and an additive composite for the foreground of 12x exposures @ 30 sec, f/5.6, ISO 1600)

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02-23-2014, 03:56 AM   #2
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QuoteOriginally posted by Matthew Saville Quote
Last but not least, I can't figure out how to turn auto-ISO on. In the quick menu and the deeper menu it gives me all the options for it, but there doesn't seem to be an on/off switch somewhere. I could have sworn I saw something about this though when I first poured over the menus and the user manual, but now I can't figure it out. Long story short, I tried to timelapse a sunset today in P mode with auto-ISO set to 100-6400, so that I could transition smoothly from a beautiful sunset to stars in the sky. Basically the camera meter was (to my surprise) able to maintain almost a perfect exposure until the aperture was wide open and the shutter speed was up to 30 sec, ...but the ISO stayed at 100 so the timelapse just quickly went to black at that point. What am I missing?
In modes P, Av and Tv if you hold down the ISO button and press the "Green Button", it switches to Auto ISO. Hold down the ISO button and turn the back dial to change back from Auto ISO to manual.
02-23-2014, 07:04 AM   #3
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QuoteOriginally posted by Matthew Saville Quote
Hi there, Pentax owners!


For whatever reason, even with the AF switch set to MF, the camera still beeps when it thinks things are in focus, and what's worse, it seems to refuse to click a shot at the command of the cable release trigger. This seemed to happen every four clicks, it would beep as if it were hunting or acquiring focus, but it wouldn't shoot.

I think I fixed / reduced this problem by switching from single point to all AF points, but why is this even an issue when I'm in MF? I also checked on my timelapse device because it does have an option to trigger AF or not, and that option was set to off. So, can anybody replicate / explain this? I was doing slow exposures in pitch-black conditions. I was also able to set the timelapse device to increase it's "fire" signal to a whole 1000 ms which seemed to improve the consistency in half-decent light. Still, I'd like to know if the camera is actually refusing to fire because of focus, or another issue that I haven't suspected. (I think it might also have to do with waking the camera up for intervals of 30-60 sec...?)
I always set the menu option NOT to focus with remote trigger. I never have had this kind of problem using this option (don't know if it happens the option not selected as I have never tried).

-Timo
02-23-2014, 05:40 PM   #4
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QuoteOriginally posted by geomez Quote
In modes P, Av and Tv if you hold down the ISO button and press the "Green Button", it switches to Auto ISO. Hold down the ISO button and turn the back dial to change back from Auto ISO to manual.
True, but you don't have to hold the ISO button down. Press it then the green button gets you to auto.

02-23-2014, 05:48 PM   #5
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QuoteOriginally posted by reytor Quote
I always set the menu option NOT to focus with remote trigger. I never have had this kind of problem using this option (don't know if it happens the option not selected as I have never tried).

-Timo
Oh thanks for mentioning that in-camera option too. Yes, both the camera and the timelapse device were set to NOT initiate autofocus.

I understand that some cameras will beep any time they think the subject is in focus, which is helpful for manual focusers and I like that. But I just wanted to see if anybody else has ever had the same problem.

Either way, when I mention it in my review I'll be pointing out that it seems when both of the above options are set to "off", AND when the AF mode is set to all 29 points, it seems to fire every time. However the K-3 does need a little bit more of a "wake up call" before it can fire, if the timelapse device's signal is too few miliseconds it simply wakes up and then doesn't fire.

---------- Post added 02-23-14 at 04:51 PM ----------

QuoteOriginally posted by rfg Quote
True, but you don't have to hold the ISO button down. Press it then the green button gets you to auto.
Yep, I just tried this. When in P mode, I have to hit the ISO button (not hold it down) and then the green button gives me auto-ISO.

What about M mode? I guess if I want auto ISO when I'm in manual exposure, I should switch to TAV instead? IMO that's too many modes, they could have just allowed people to turn on auto-ISO while in M mode maybe?

=Matt=
02-23-2014, 06:14 PM   #6
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QuoteOriginally posted by Matthew Saville Quote
What about M mode? I guess if I want auto ISO when I'm in manual exposure, I should switch to TAV instead? IMO that's too many modes, they could have just allowed people to turn on auto-ISO while in M mode maybe?

=Matt=
The green button is already used to auto set shutter speed for legacy lenses in M mode, having a separate TAv mode is clearer imo.
02-23-2014, 06:15 PM   #7
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I think part of the problem is exacerbated by WHERE you point your camera in the heavens. Clearly, if you point it at Polaris, the sensor simply "rotates" around the center and all is well, regardless of focal length. However, turn a wide angle lens towards the celestial equator and the stars in the upper left move to the left and those in the upper right move to the right. Thus, there is no way a mere sensor shift can fix that. As the lens gets longer, the amount of movement in the corners lessens, but never really goes away. So I would suggest trying your wide angle rig pointed towards the celestial pole (or alternatively directly away from it) and see if things aren't a bit better. My guess is that the system works "best" with normal focal length lenses.

Michael
02-23-2014, 06:34 PM   #8
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QuoteOriginally posted by Matthew Saville Quote
Oh thanks for mentioning that in-camera option too. Yes, both the camera and the timelapse device were set to NOT initiate autofocus.

I understand that some cameras will beep any time they think the subject is in focus, which is helpful for manual focusers and I like that. But I just wanted to see if anybody else has ever had the same problem.

Either way, when I mention it in my review I'll be pointing out that it seems when both of the above options are set to "off", AND when the AF mode is set to all 29 points, it seems to fire every time. However the K-3 does need a little bit more of a "wake up call" before it can fire, if the timelapse device's signal is too few miliseconds it simply wakes up and then doesn't fire.

---------- Post added 02-23-14 at 04:51 PM ----------



Yep, I just tried this. When in P mode, I have to hit the ISO button (not hold it down) and then the green button gives me auto-ISO.

What about M mode? I guess if I want auto ISO when I'm in manual exposure, I should switch to TAV instead? IMO that's too many modes, they could have just allowed people to turn on auto-ISO while in M mode maybe?

=Matt=
The e-dial customization lets you set what the buttons do, or show the default. Some modes you have to go into the info screen, find iso and roll the dial.

02-23-2014, 07:06 PM   #9
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QuoteOriginally posted by ruggiex Quote
The green button is already used to auto set shutter speed for legacy lenses in M mode, having a separate TAv mode is clearer imo.
Yes but since turning on auto-ISO already requires hitting the ISO button first, and the green button alone serves a similar "reset" purpose in all other modes, it still seems easy to perform that interface change.

=Matt=

---------- Post added 02-23-14 at 06:08 PM ----------

QuoteOriginally posted by MJSfoto1956 Quote
I think part of the problem is exacerbated by WHERE you point your camera in the heavens. Clearly, if you point it at Polaris, the sensor simply "rotates" around the center and all is well, regardless of focal length. However, turn a wide angle lens towards the celestial equator and the stars in the upper left move to the left and those in the upper right move to the right. Thus, there is no way a mere sensor shift can fix that. As the lens gets longer, the amount of movement in the corners lessens, but never really goes away. So I would suggest trying your wide angle rig pointed towards the celestial pole (or alternatively directly away from it) and see if things aren't a bit better. My guess is that the system works "best" with normal focal length lenses.

Michael
That sounds about right. The above composition was created by pointing my camera South by Southeast with a 15mm lens. The upper right corner has the stars stretching while the center and other areas don't exhibit a similar shift. Thanks for the explanation!

=Matt=

---------- Post added 02-23-14 at 06:10 PM ----------

QuoteOriginally posted by derekkite Quote
The e-dial customization lets you set what the buttons do, or show the default. Some modes you have to go into the info screen, find iso and roll the dial.
Yeah the customization of each mode seems almost limitless, between the command dials and the green button. Speaking of which, does anybody have any particular configuration that they are especially proud of having on Pentax?

=Matt=
02-23-2014, 07:39 PM   #10
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QuoteOriginally posted by Matthew Saville Quote
Yes but since turning on auto-ISO already requires hitting the ISO button first, and the green button alone serves a similar "reset" purpose in all other modes, it still seems easy to perform that interface change.
Except Manual is then no longer fully Manual and you have to remember to set ISO auto on/off which I think is what Nikon does(?). Logically it makes sense to me that I don't have to think if M is full M or half baked M.
02-23-2014, 07:56 PM   #11
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QuoteOriginally posted by ruggiex Quote
Except Manual is then no longer fully Manual and you have to remember to set ISO auto on/off which I think is what Nikon does(?). Logically it makes sense to me that I don't have to think if M is full M or half baked M.
I suppose you're right, there's a down-side to any convenience. Honestly I don't mind having a "TAv" mode, it's right next to "M" and like you say it's a good way to keep the two exposure modes separate. I'm just always curious about why cameras are designed the way they are... :-)

=Matt=
02-23-2014, 10:24 PM   #12
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QuoteOriginally posted by rfg Quote
True, but you don't have to hold the ISO button down. Press it then the green button gets you to auto.
HA! You're right. Been using K5/K3 for a year and I just learned something new!

QuoteOriginally posted by ruggiex Quote
Except Manual is then no longer fully Manual and you have to remember to set ISO auto on/off which I think is what Nikon does(?). Logically it makes sense to me that I don't have to think if M is full M or half baked M.
Some Pentax cameras (I can only speak for the Q and K-01) don't have a seperate TAv mode on the dial. You can turn on Auto ISO from within Manual. I think having a seperate M and TAv mode make things more straight forward.
02-23-2014, 10:34 PM   #13
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Pretty cool
02-24-2014, 01:49 AM   #14
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Am I correct when I assume you use the O-GPS1 when doing the Astrowork? If so, it should limit the shutter speed due to where you are and where you point your lens up to 5 minutes. I have not tested the Astro mode without the O-GPS1 since I didn't think the mode would exist without it. (It didn't on the K-5)

Without the O-GPS1 there will be no astro-tracking.

The picture is with the O-GPS1 and DA*300 on the K-3 for 60 seconds @ ISO 400 and you can see the Andromeda galaxy and the faint M110 galaxy to the right of Andromeda. This pic is light polluted...

Using the O-GPS1 has a learning curve and going from the K-5 to the K-3 forces you to re-learn. The live view in Astro mode is noisy and therefor difficult to focus, going to M-mode the noise dissapears and the stars are easier to see. Also in MUP the anti shake is off so you have to use single shooting mode and M-mode when setting up the shoot and then go to astro mode, MUP, cable release or even better the IR remote...

For more astro pics check my Flickr: Astro and Night Photo - a set on Flickr

---------- Post added 02-24-14 at 10:40 AM ----------

About the Green Button. It is costumizable so it all depends on the mode you are in and how it is set in the menu. Not all modes gives auto ISO by one push.
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02-24-2014, 03:10 AM   #15
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About the AF, if you turn off AF on the camera it will not prevent you from taking the shot even if out of focus. There are settings in the C-menu, items 15-19+25 that controls if you can shot when not in focus when in AF mode. These settings should be voided when AF set to off on the camera.
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