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07-05-2017, 04:07 PM   #1
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645Z...Strange Issue with Wireless Cable Release & Exposure Time? Help Please

Hi All,

Noticed something strange right off the bat last night while shooting 5-15 second exposures with the 645Z mounted on a tripod in single frame shutter release with "no"" 3 second delay and "no" mirror lock-up. Camera set in "B" (bulb) mode. Fired shutter with a number of different wireless cable releases. Lens set in manual focus.

If in a test shot, I press the shutter button with my finger, shutter opens as expected and as fast as I can let go of shutter button, it instantly closes. Shutter of course will remain open as long as I hold shutter button down but the moment I let go of shutter button, it instantly closes.

If I use any of the Pentax branded wireless cable releases in same scenario, I press remotes button to open the shutter, but if I let go of button instantly or at any point, there is sort of a 2 second (approx.), delay before shutter closes. Line of sight to IR sensor is perfect. Is it possible with IR, there is a delay in the signal getting to the 645Z in responding to letting go of shutter firing button but not when initially pressing it? That doesn't make sense and why shutter closing time with these wireless remotes should respond differently than pressing the shutter with finger directly and letting go. I don't have a wired remote to try.

I don't recall every experiencing this before and had little time to explore it when shooting last night.

Any thoughts or ideas would be appreciated. Something tells me user error and I'm overlooking something in the settings. Thanks very much!

Dave (D&A)

07-05-2017, 04:42 PM   #2
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I am not a 645Z owner , but am familiar with using an IR wireless remote for "B" exposures on Pentax cameras*. Your camera supports two "B" modes in the custom settings menu. Type "1" is the traditional "B" behavior where the shutter remains open as long as the shutter release is depressed. Type "1" works well with the shutter release button and with wired releases where the action directly emulates an actual button press. Type "2" is the traditional "T" behavior where the first push of the release opens the shutter and the second closes it. IR wireless remotes are designed to emit a pulsed signal to perform various operations, not a sustained beam. Likewise, the receiver on the camera is not designed to interpret a sustained beam. I believe you will find that the type "2" behavior will provide less surprises.


Steve

* Similar issues exist for non-Pentax cameras too.

Last edited by stevebrot; 07-05-2017 at 05:03 PM.
07-05-2017, 07:31 PM   #3
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Steve, I very much appreciate your reply and explanations. I am familar with the T mode vs. B but unfortunately that was not the cause of the issue I described above. My physically pressing and releasing the shutter buttom in B mode should be emulated by the wireless cable release but with the wireless there was a second or two delay of the closing of the shutter. I dont recall this happening previously and still trying to rectify the situation. Again thanks.

Dave (D&A)
07-05-2017, 10:48 PM   #4
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QuoteOriginally posted by DandA Quote
Steve, I very much appreciate your reply and explanations. I am familar with the T mode vs. B but unfortunately that was not the cause of the issue I described above. My physically pressing and releasing the shutter buttom in B mode should be emulated by the wireless cable release but with the wireless there was a second or two delay of the closing of the shutter. I dont recall this happening previously and still trying to rectify the situation. Again thanks.

Dave (D&A)
My pleasure. I have never been able to get "B" to work with an IR remote unless set to type "2". The expected behavior if set to type "1" is for the shutter to open and immediately close. If you have a remote that holds the shutter open when continuously pressed, that behavior may be unique to the 645Z.*

It would help if you identified the remote(s) you are using and the camera(s) they were made for. (Some third-party units are advertised as working with multiple camera brands/models.)

Edit: I did some additional research and apparently, behavior depends on the remote. The model "F" support continuous press, so apparently the protocol is rich enough for that feature. Sorry for the confusion from me.


Steve

* Your camera's operational settings are essentially similar to my K-3, otherwise I would not have commented.


Last edited by stevebrot; 07-05-2017 at 11:02 PM.
07-06-2017, 07:35 AM   #5
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I just tried this on my 645Z with my Pentax-branded O-RC1 infrared remote. Action is slightly laggy, but essentially the shutter opens and closes immediately upon pressing and then later releasing the IR button. There is no long delay before the shutter closes. As Steve points out, using an IR wireless release in bulb mode can have some issues, so normally I work in mode 2, requiring separate button presses to open and close the shutter. But mode 1 seems to work as one would expect in my case.

Dave, is the O-RC1 one of the Pentax IR releases you tried? If not, give it a go. If it is, perhaps there is some other camera setting that's interfering here.
07-06-2017, 11:21 AM   #6
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Stevebrot is right that IR remotes are pulsed devices. Even if the model "F' supports continuous press, the implementation would still a sequence of pulsed & coded transmissions because a continuous beam would be indistinguishable from ambient IR in sunlight and artificial light. Thus, instead of the remote saying "DDDDOOOOWWWWWNNNNN" for the duration of the button press, it is saying "DOWN...DOWN...DOWN...DOWN" with short delays between each coded pulse. The software in the camera might be waiting a little extra time after the first received "DOWN" before it assumes that the absence of more "DOWN"s actually means anything.

It's also possible that your wireless remotes are actually emitting for a full second or two of pulses even if you release the button immediately. Try hitting button, holding it down, but immediately covering the remote's emitter lens with your hand. If using your hand to block the beam causes the camera to quickly end a B-mode-1 exposure, then the delay is the remote's fault. Because the remote has no clue whether the camera has gotten the signal (or is in B mode), the only way to make a reliable remote is to emit a longer stream of pulses to ensure the camera gets at least one of them.
07-06-2017, 11:40 AM   #7
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Again I appreciate everyones continued support and responses to this issue I encountered. Let me provide a few facts. In the past I believe I used the Pentax wireless waterproof control for B mode of opening and closing the shutter. In other words press to open shutter snd anout 6 seconds later, let go of the waterproof wireless button and shutter closed instantly upon letting go of the button. No different than if I had used my idex finger on the shutter button to do the same.

This time I had only taken Pentax brand wireless controls (two different small models)...I think one was model F, the other not sure of, and both operated with the same delay when I lwt go of their button in b mode. The shutter would still stay ipen for approx 1-2 seconds before the shutter finally closed.

This happend both during daylight hrs as well as that night in near total darkness.

I cant be certain my waterproof Pentax wireless remote didnt habe this issue of shutter closing delay but from memory it didnt. I have to dig that one out and try. Thats why I didnt takenit that night.

I also have to try what was suggested and put my hand in front of the remote IR and see if that instantly closes the shutter.

Royce, with the remote F I believe you have, can you do the following test? Put 645 Z in B mode and press shutter and hold down for 5 seconds and then let go. Shutter should instantly close. Then do the dame thing with wireless remote F. Press its button, hold down for 5 seconds and then let go. Did the shutter close just as fast? Any detectable delay in closing?

Ahain I appreciate all the suggestions and explanations. I guess since I always previously used the waterproof remote and never noticed this delay, it took me by surprise when I took along two other wireless remotes (both Pentax) but immediately had the 1+ second delay of shutter closing upon release of their button.

Dave (D&A)
07-07-2017, 06:29 AM   #8
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How old is that wireless remote? When the batteries of my wireless remotes for my other devices (Roku, TV remote, etc) get lower on charge they begin to behave oddly---they don't necessarily stop working altogether.

07-07-2017, 08:03 AM   #9
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Dave, that's basically what I did when I reported above. I just did it again, and the results are the same. There is no significant difference in behavior between the camera shutter button and my wireless IR remote button. When the bulb mode custom setting is set to type 1, as soon as I let off the button in either case, the shutter closes effectively immediately. There is a very, very slight lag with the IR remote in the initial response, if I was to judge super critically, because of the nature of how the IR sensor is polling for input. But it's extremely short, nothing like 1 - 2 seconds.

I can't speak to type "F" wireless remote. All I can report is what's on the back of mine -- it's model Pentax O-RC1, Remote Control Waterproof. Made in China for Ricoh Imaging Co. Ltd.
07-07-2017, 10:59 AM   #10
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QuoteOriginally posted by photoptimist Quote
Stevebrot is right that IR remotes are pulsed devices. Even if the model "F' supports continuous press, the implementation would still a sequence of pulsed & coded transmissions because a continuous beam would be indistinguishable from ambient IR in sunlight and artificial light. Thus, instead of the remote saying "DDDDOOOOWWWWWNNNNN" for the duration of the button press, it is saying "DOWN...DOWN...DOWN...DOWN" with short delays between each coded pulse. The software in the camera might be waiting a little extra time after the first received "DOWN" before it assumes that the absence of more "DOWN"s actually means anything.
Also possible is that it sends a short sequence (~2s) of "button down" signals and short bursts of same at interval followed later on by a short sequence (~2s) of "button up" signals when the button is released. Mouse buttons work sort of that way. I don't have the 645Z and should probably keep my mouth shut since I barely got my foot out a few minutes ago, but I believe that the sequence proposed may explain the OPs experience.

In short, signal attenuation due to distance and/or low battery may make reception of the "button up" event a little sketchy such that the camera will fail-over by closing the shutter after a period of zero communication (say 2-3 seconds).

The developer of the dSLR Remote phone app is a Pentax user and I believe is a member here. They would be intimately familiar with the protocols and might have a definitive explanation. Too bad I don't have the user name.


Steve
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