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Forum: General Photography
10-21-2020, 02:18 PM
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I don't know about the iPhone but my good old Samsung S6 is way better than the K1-ii. I haven't yet managed to make one single decent phone call on my K1-ii despite meticulously studying the manual cover to cover three times.
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Forum: Troubleshooting and Beginner Help
10-12-2020, 07:32 AM
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The graininess is due to the narrow aperture. You will see the same also on shorter lenses if you stop down the aperture (with the DOF preview lever), but to a lesser extent. What happens is the light strikes the focus screen more parallel at narrow apertures and this brings out the grains of the 'ground glass' focusing screen.
Normally it is not very visible at wide open but super zooms are narrow even wide open. Also make sure the aperture blades are actually opening fully as they could be jammed.
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Forum: Pentax K-1 & K-1 II
10-09-2020, 12:26 PM
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I have a K-30 and a Q10 with that problem, but they're about 8 years old. My K-3 (age 7) is still OK until now. My K1-ii is just months old so no problem there for sure.
Since quite a few years ago I stopped leaving the camera without a battery precisely to avoid this problem, in other words whenever I remove a battery to recharge I immediately replace it with another one to avoid discharging the clock battery. It may be why the K-3 internal battery still works long after the K-30' battery gave up.
It is quite a problem if you're going to leave the camera unused for a period of months as it is usually advisable to remove the battery from equipment that is not being used for along time but doing that will probably ruin the internal battery rather quickly.
I'm also wondering if by not replacing the faulty internal battery it might end up leaking acid and ruining the internals of the camera, as often happens with desktop PCs that are left unused for a period of time.
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Forum: Pentax K-1 & K-1 II
07-22-2016, 08:55 AM
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It is not just a matter of rectilinear or not. With linear sensor shift it is never possible to accurately track the angular motion of the subject over the whole sensor. The issue is not only with Astrotracer but even with shake reduction. The only reason we don't worry about it with shake reduction is that with wide angle lenses shake is not usually much of an issue anyway.
It can be geometrically shown that shifting the sensor can never fully compensate for an angularly moving target regardless of how perfect the lens is. Briefly explained, if a target at the centre of the image moves by x degrees it will correspond to a linear movement of y pixels on the sensor. However a target towards the edge of the image moving the same x degrees will shift more than y pixels on the sensor. (The amount is determined by the trigonometric 'tangent' function)
The further (in degrees) the target is from the lens axis the larger will be the linear shift (in terms of pixels or microns) on the sensor for a given focal length. The longer the focal length (and hence the narrower the field of view) the less will be this difference, so for instance at 300mm there is hardly any difference between the centre and the edges of the image.
This all applies to a theoretically perfect rectilinear lens - it is a function of physics and geometry and not imperfections in the lens.
Any lens distortions and imperfections will of course add onto this problem as well.
To get good very long exposures with wide angle lenses you will need to limit the individual exposure times and re-aim the camera before each image of the stack. The re-aiming doesn;t need to be extremely accurate but if you can get an easy to see star at the centre of the view finder it makes it a lot easier.
PS: now only after posting I realise that there were more posts after the one I was responding to. My apolgies for repeating a lot of what has already been said and explained in those subsequent posts
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Forum: Pentax K-3 & K-3 II
11-09-2013, 03:07 AM
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For some reason whenever there is a discussion on focus and tracking one important feature is nearly always overlooked - the Expanded Area AF. This first became available on the K-30 and works quite well. It's main problem was that there weren't enough focus points but even so it worked quite well.
On the K-3 I am expecting its usefulness to increase a lot, not just because of the many more focus points now available but also the 86K AE sensor which provides more 'intelligence' to the AF tracking algorithm.
I think it is a feature which is way too much underutilised and not enough understood and appreciated.
Keep in mind that is still gives you control over which focus point to start from - you are not subjected to the unpredictablility of automatic AF point selection - but it then still makes use of all the focus points to actively track the subject.
The expanded area AF was one of the main things that made me upgrade to the K-30 (from K-r) and Ithe improvements I expect in the EA-AF is also one of the major reasons I finally decided to get the K-3. Hopefully I will not be disappointed when I receive it next week.,
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Forum: Pentax K-3 & K-3 II
07-30-2014, 12:25 PM
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I don't think it likely to be a matter of weak design but more likely the occasional manufacturing defect resulting in some seal which doesn't do its job properly. Manufacturing defects are something that can only be minimized but never eliminated completely. What perhaps should be different is the response from Pentax. I think it would be much better for everyone, and also the Pentax name, if they just admitted to the existence of the occasional manufacturing defect that slipped past QC and repaired that,
I have two weather sealed Petaxes, the K-30 and K-3. The K-30 has had its fair share of drenchings and I even rinse it thouroughly after using it in heavy sea spray and never had any issues. If there had been some systemic design fault I'm sure it would have caused me problems at some time or other but it never did. There are some things I think they could design better but it is by no means poorly designed.
The K-3 has had some experience with water but not nearly as much as the K-3. No problems at all to date
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Forum: Pentax K-3 & K-3 II
12-19-2013, 11:27 AM
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I have the Metz 58AF-2 and it works great with the K-3.
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Forum: Pentax K-3 & K-3 II
12-23-2013, 04:17 PM
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Figured it out - if I switch from AF.C to AF.S the light works just the same as it does in green mode.
What was in common between the User modes and green mode is that all four were doing AF.S or AF.A (which includes S).
I don;t know if this is a bug or design intent.Could be some sense in not using the focus light for AF.c but not so sure when I think about it.
Strangely enough then in live view it works both in af.c and af.s
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Forum: Pentax K-3 & K-3 II
06-05-2015, 01:02 PM
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Regular shooting means different things for different people. The two types of subject I can think of that will benefit most are macro and architecture.
Of course it would always be better to use a 645Z if you can afford it and don;t mind carrying the weight but even for occasional use having a better resolution for some of your shots is always better than having it for none.
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Forum: Pentax K-30 & K-50
05-06-2014, 01:43 PM
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Rice is widely said to be a good drying agent but it is not reliable and not the most effective either. For starters rices is not always dry, especially if it is packaged in a porous cardboard box as it often is. It will have already been absorbing moisture for days or even weeks so will not be very effective.
The best drying agent I know of is calcium chloride. It is widely available at supermarkets as a 'refill' for small dehumidifiers that don't use electricity. The 'dehumidifier' being just a plastic container with holes or slots and you pour the 'refill' into it.
Just buy a bag of the stuff, empty it into a bowl, not filling more than half and place the bowl together with the camera into an airtight plastic box, the sort of which is used to preserve food. Alternatively just poor the stuf into the botom of the box and then place the camera on something to keep it out of contact with it. That way you have a larger surface area of the drying agent, making it more effective.
Placing the box in a warm, or even mildly hot location will speed up the drying process.
Also, remove the lens and open all ports/doors on the camera to ensure the vapour has an easy way out.
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Forum: Pentax K-3 & K-3 II
03-16-2014, 03:19 AM
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So I've just spent a couple of hours setting up and testing. I could only do the K-3 and K30 though because none of my IR remotes are working.
I tested both cameras with internal flash and with a Metz 58-AF2 first in manual then in P-TTL
Internal flash:
K-30: 20-30mS to preflash and 120-135mS main flash
K-3: 170-200mS to preflash and 280-320mS to main flash
Metz Flash in P-TTL
K-30: 20-40mS to preflash and 130-160mS for main flash
K-3: 190-220mS to preflash and 310-330mS for main flash
Metz Flash in manual
K-30: 120-130mS to main flash
K-3: 115 to 125mS to main flash
I used wired remote and triggered the oscilloscope timebase on the contact of the full push of the shutter. For all tests I pressed and kept half press for about 5 seconds to make sure I don't include any wakeup or AF delays and then pressed all the way to shoot. The delays are both from the full press, so when I say 170mS to preflash and 280mS to main flash the 280mS is not in addition to the 170, so the main flash fires at 280mS after full press of the shutter.
* With internal flash or external flash with P-TTL the K-3 is about 150mS slower than the K-30. As far as the delay to the main flash is concerned that is more than double the K-3.
* It seems to make very little difference whether using external or internal flash, the external only adding some 10 to 20mS.
* With an external flash in manual mode both cameras are pretty much the same
* The additional delay for the K-3 seems to be entirely due to the excessive delay for the pre-flash. The time between pre-flash and main flash is the same for both cameras - about 110mS
To summarise, with the K-3 the exposure occurs a full third of a second after pushing the shutter release whereas the K-30 does it in just over a tenth of a second.
The K-3 seems to spend much more time doing nothing (200mS) than it does calculating the exposure, lifting the mirror and all the rest (110mS).
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Forum: Pentax DSLR Discussion
04-03-2014, 03:31 PM
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I finally got to work on the O-GPS1 protocol but it turns out it was not as straightforward as I was hoping. The communication seems to work in the exact same way as the P-TTL communication in terms of the synchronisation pulses, the formatting of the bits and so on.
Here is just a preview of what I am seeing - but I haven;t understood much of it yet - it will need some more time.
From what I can see the camera still starts off sending and expecting data to/from the flash but the flash return is just empty (because the flash isn't there) whereas the camera then proceeds anyway to send the ISO, focal length, aperture and such details to the non existent flash a few time but after a few tries just sends all zeros in that slot.
What changes with the GPS is that after conclusion of that sequence the exchange between the GPS and camera then takes place. It is still early for me to figure out what exactly is going on at this point. There is no obvious NMEA encoded as ASCII in the bit sequences but I haven;t ruled out it being buried in there somewhere.
Just to get an idea, this is a typical sequence I get from my decoder with the P-TTL flash in place:
<-+_-+-+_014411380D0C_-+_-+_08638750004_-+-+-+-+-+_E8D0_-+4C50_00-+>
The first sequence being the data the flash sends to the camera and the second one is from thecamera to the flash. The third one I can;t quite remember what it was but I think it has something to do with AF
Whereas this is a typical sequence with the GPS:
<-+_-+-+_00000000_-+_-+_000000000_-+4C50_C0-+-+4C14_C036FF007F-+>
Here we see the first two sequences being all zeros, as there is n othing to communicate between the flash and the camera, but it seems that slot is still reserved for that. Then there is the same 4C50 as with the flash, which I think is the closing sequence of the flash communication, but now instead of being followed by a final 00 we get a C0, presumably signalling the start of GPS communication. The main content of the message being the C036FF007F in this example. A few of these messages are sent every second, with the C036 being always present and the remaining characters changing between one message and the next.
In addition there is occasionally a longer ,essage such as this one:
<000000300000000000000000000000036FF30DF800000000000018060FF8000007F80E6FFC07F80CC7F9980F9FFFFE07F800000F7-+-+4C14_C036FF006D-+>
I'm not sure how often it occurs but it seems somewhat irregular.
On another note I think I figured out why the extension cables cause problems and also why some third party flashes can be unreliable. It is just a silly 'mechanical' problem regarding the way the ground terminal connects and black paint on the camera hotshoe bracket. It seems the way grounding is achieved is not so standardised and where some accessories put the ground terminal coincides with where Pentax puts black paint and where Pentax puts the metal contact the accessoriy has plastic or anodised aluminium.
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Forum: Pentax K-3 & K-3 II
03-24-2014, 01:50 PM
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It is just a matter of overexposure. The red channel is considerably saturated. This is a common problem because the exposure meter looks at the overall brightness and will underestimate the brightness of an individual channel as it averages out the red, green and blue.
What surprises me though is when this happens with the K-3 since its exposure meter, unlike almost any other camera, measures the red, green and blue separately so this should never happen.
In playback mode if you switch to the RGB histogram view the red channel overexposure should be clearly visible.
Three things I can think of that could result in overexposure:
Do you have perhaps some +ev compensation?
Are you using an aftermarket focusing screen, perhaps a split prism one?
Are you using the histogram in live view to set the exposure manually?
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Forum: Pentax K-3 & K-3 II
03-18-2014, 10:55 AM
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I have a K-r and the mechanical SR in video is just fantastic. I think the K-x is very similar to the K-r in many ways and probably has it too.
It's a real pity that in later they dumped something that worked so well and replaced it with a lame software stabilisation system which doesn't even use the gyros.
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Forum: Pentax DSLR Discussion
03-16-2014, 03:25 PM
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I have a DSO and an O-GPS1. I had decoded quite a lot of the P-TTL protocol a year or so ago. Never had a look at the GPS yet but maybe it's about time I do. The flash protocol isn;t too difficult to reverse engineer. My guess is that the GPS will be easier - I might give it a try the coming weekend.
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Forum: Pentax K-3 & K-3 II
03-16-2014, 10:59 AM
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From what I understood it refers to the AA filter simulator and not shake reduction. That generally consumes more power than shake reduction because there is a permanent and high speed movement, so
much so that it required a redesigned SR mechanism as the actuators in the earlier in earlier models are not powerful enough.
In any case even if they refer to SR I'd much rather be given the opportunity to choose whether I'd rather drain the battery quicker and have some noise in the recording rather than being stuck with an almost useless stabiliser. In my particular case I usually don't need sound when I most need stabilisation (distant subjects) and even if I did I would need to use an external microphone anyway which wouldn't be affected by the SR noise.
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Forum: Troubleshooting and Beginner Help
03-15-2014, 03:34 PM
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The wired remote has the added advantage that you can even keep the SR switched on when using it, unlike with the IR remote which causes it to be disabled.
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Forum: Pentax K-01
03-13-2014, 01:33 PM
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I don't have a K-01 but I have a K-30 which I believe in live view mode is identical to the K-01 in most respects so what I describe might also work on the K-01.
I couldn't get it to do exactly what you need but a possibly useful alternative.
In the Live view options there is one called AF autozoom. If I tick that then when I half press the shutter (or the back AF button) the camera will focus and once focus is ready it will magnify the image 6x. It will stay magnified for as long as you keep the shutter half press during which time you can shift focus. In this state you can also change the magnification by turning the rear dial - unfortunately you can only reduce it as 6x is the maximum it will go.
On the positive side though focus peaking stays active even in the magnified image.
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Forum: Troubleshooting and Beginner Help
03-03-2014, 11:19 AM
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That is actually a beautiful picture. I would never have thought it came out that way by mistake if you hadn't said so!
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Forum: Troubleshooting and Beginner Help
02-11-2014, 12:24 PM
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I depends how you define focus time. It very quickly reaches good focus, I would say somewhere around a quarter of a second or less but can then spend a considerable time perfecting that focus, even well over a second sometimes when lighting is poor. In bright sunlight the initial focus takes about the same but then the microadjustments add very little or none at all to the overall focusing time.
However I must stress that even if I release the shutter as soon as the lens first reaches the 'approximate' focus the shot is still accurately focused - it is not that much an approximation. The refinement it then goes on to spend quite some time doing may or may not improve the focus enough to matter. Generally unless you pixel peep or need to crop down a lot it won't make a difference. Whenever I am shooting 'action' type photos I don't wait for the beep, instead I just shoot when the lens initially stops moving.
So in practical terms I would say focus does not take a long time but waiting for the final beep does take an awfully long time. If I were Pentax I would make an option to beep when the first focus is reached and then possibly a second different one on completing the micro adjustments.
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Forum: Pentax DSLR Discussion
02-17-2014, 01:34 PM
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Rather than 'stripping off the layers of ugly' it seems more to me like they poured some standard issue Canikon blobby-goo over it, though thankfully they did not pour the whole bottle.
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Forum: Pentax K-3 & K-3 II
02-18-2014, 12:11 PM
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Except that the interval between the preflash and main flash is very short and just barely discernible with the unaided eye. What Sinus is seeing is probably the red-eye reduction flash.
I had done some reverse engineering on the P-TTL flash system a recall that the interval between the pre-flash and main flash was of the order of a few tens of millisecond or less and is just barely discernible as being two flashes. Normally the interval exists mainly because of the time it takes to lift the mirror and actuate the iris and for the shutters first curtain to open fully - the mirror needs to be down and the aperture blades fully open for the exposure meter to measure the pre flash but then the mirror needs to get out of the way and the aperture blades closed to the chosen aperture before the shutter is released. Then once the first curtain is fully open the main flash burst will be fired,
The camera will of course need to do some calculations based on the light measured from the preflash burst and then instruct the flash at what intensity to fire the main burst. That however should take far less time than the mechanical activity that has to take place between the preflash and main flash so it does not really add any further delay to what already exists when not using the flash.
The odd thing with the K-3 is that having the flash switched on introduces a delay between pressing the shutter the mirror lifting. That is an interval during which there is absolutely nothing that needs to be done except ordering the pre-flash to go off. So the camera is just sitting doing nothing for several tenths of a second or else making itself busy doing something useless.
It is worth noting that on two other cameras I own, the K-r and K-30, there is no noticeable delay introduced by the flash. Some have mentioned that perhaps the K-3's delay is because it does more complex calculations and gets the exposure right rather than hurrying and getting it wrong. That the K-3 gets it right far more often than previous Pentax DSLRs is true but the flaw in this argument lies in the fact that any complex calculations needed would be done in the interval between the preflash and the main flash burst, which is determined solely by the time needed to physically move the mirror, aperture blades and shutter and not between pressing the trigger and issuing the preflash so it cannot possibly explain the delay we are experiencing.
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Forum: Mini-Challenges, Games, and Photo Stories
02-14-2014, 01:23 PM
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Tamron 90mm F2.8 Macro
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