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WeMacro continuous light delay
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Saul



Joined: 31 Jan 2011
Posts: 913
Location: Naperville, IL USA

PostPosted: Thu Nov 30, 2017 10:09 am    Post subject: WeMacro continuous light delay Reply with quote

My Nikon D7200 does not have EFCS, so in order to reduce first curtain vibrations (1.8s-2s), using long exposure (in my case - 3s) with continuous light, I made a small add for WeMacro ( I think, it could be used for any controller with proper connectors).

Of course, nicest way to do that is by changing the code, app little bit and adding output relay to the controller for the light.

My mockup consists from the timer delay relay (ebay item 322604880846), couple 12v DPDT relays (in order fully separate signals) and cheap 2.5mm earphones extension cable.

Shutter signals from the WeMacro are controlling relays, which send the same signals to the camera and the start signal (4th photo) to the timer delay relay. LED lights are connected through the S0-S1 dry contacts. I'm also using simple switch in parallel to these contacts (not shown in photos) to override delay mode and for modeling purposes. Later will post connection diagram.

In the mirror lock-up mode, shutter signal sends start signal to the timer relay, output relay is 2s off and 3s on aftewards. Small drawback of the existing mockup - because there are two clicks in mirror lock up mode - lift & shutter - I have two 3s light-on intervals (first is not necessary). It is not big deal, 2nd click cancels 1st cycle, but annoying ... Confused To eliminate it I bought bistable 12v relay which will be used to supply every 2nd start signal to the timer delay relay (182867160982, on the way from China)

Front panel


Back panel


Insides


Start signal


Cables

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Chris S.
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Joined: 05 Apr 2009
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Location: Ohio, USA

PostPosted: Fri Dec 01, 2017 12:41 am    Post subject: Reply with quote

Saul, thanks for this post!

As it happens, I have a project with the same goal on my workbench at this very moment: An Arduino-based build to cycle solenoid shutters on my halogen illuminators, after delay for dissipation of shutter-induced vibration, for using continuous light with my Nikon D7100 (which like your Nikon D7200, lacks EFSC).

So you and I are aiming at the same ends by different approaches. Thanks for calling out the “timer delay relay (ebay item 322604880846)”—I had no idea this class of products existed. Looking at them, they look like inexpensive, ubiquitous problem solvers.

I hope you continue to post as your build continues, so we can keep learning from it.

The approach you’re following may be simpler and more cost efficient than what I’m doing. Conversely, my path may have more flexibility and a more explanatory readout, at greater cost. I intend to do as you’ve admirably done here, and post out what I end up doing.

Saul wrote:
Small drawback of the existing mockup - because there are two clicks in mirror lock up mode - lift & shutter - I have two 3s light-on intervals (first is not necessary). It is not big deal, 2nd click cancels 1st cycle, but annoying ... Confused To eliminate it I bought bistable 12v relay which will be used to supply every 2nd start signal to the timer delay relay (182867160982, on the way from China)

Have you considered using shutter delay mode instead or mirror-up mode? While I also like mirror up, I no longer use it for automated studio stacking. For this work, I’ve mostly switched to shutter delay mode. As you likely know, this mode requires just one shutter button press, but accomplishes nearly all of what mirror-up does, by delaying the actual exposure by a selectable number of seconds.

Cheers,

--Chris S.
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Saul



Joined: 31 Jan 2011
Posts: 913
Location: Naperville, IL USA

PostPosted: Fri Dec 01, 2017 8:23 am    Post subject: Reply with quote

Chris S. wrote:
...Have you considered using shutter delay mode instead or mirror-up mode? ...


Hi Chris,

I thought about that, but did not try yet. There is enough time delay settings in the camera menu (up to 3s).
Is there difference in the vibration dissipation time between mirror lock & shutter delay modes ? Other things ?
In the mirror lock mode I tested up to 20x, results are good (will try at 50x).

Cheers,
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Saul
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Yawns



Joined: 20 Dec 2015
Posts: 89
Location: Portugal

PostPosted: Fri Dec 01, 2017 11:31 am    Post subject: Re: WeMacro continuous light delay Reply with quote

Saul wrote:
... first curtain vibrations (1.8s-2s), using long exposure (in my case - 3s) with continuous light, ......


where did you get that figure? .. 1.8 to 2 Seconds?

if that's right I'm not exposing long enough, because I aim for 1-2 seconds exposures... Sad

Thank you,
António
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Saul



Joined: 31 Jan 2011
Posts: 913
Location: Naperville, IL USA

PostPosted: Fri Dec 01, 2017 12:04 pm    Post subject: Re: WeMacro continuous light delay Reply with quote

Yawns wrote:
where did you get that figure? .. 1.8 to 2 Seconds?


Hi Antonio,
You can find posts about it on the our forum , sorry, now do not remember who posted it.
Of course, it depends also on your camera, your rig etc.
In my case it does not go more than 2s (tested with Sensor Kinetics)

Quote:
if that's right I'm not exposing long enough, because I aim for 1-2 seconds exposures... Sad


Most probably it is true - I saw a big difference
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Saul
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Pau
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PostPosted: Fri Dec 01, 2017 12:19 pm    Post subject: Reply with quote

Quote:
Sensor Kinetics

Is this app really useful to measure camera vibration?
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Saul



Joined: 31 Jan 2011
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Location: Naperville, IL USA

PostPosted: Fri Dec 01, 2017 12:22 pm    Post subject: Reply with quote

Pau wrote:
Quote:
Sensor Kinetics

Is this app really useful to measure camera vibration?


Perfectly - no, but gives very good idea. You can use free version, if you like it - pro version gives some filtering, which improves graphs.
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Saul
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Chris S.
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PostPosted: Sat Dec 02, 2017 1:03 am    Post subject: Reply with quote

Pau wrote:
Quote:
Sensor Kinetics

Is this app really useful to measure camera vibration?

Individual experiences may vary widely, depending on one’s hardware. On my rig, Sensor Kinetics displayed no vibration at all during shooting, even though I know that mirror-slap and shutter shock were inducing significant movement that emphatically had to be dealt with to use continuous illumination). So in my case, the Sensor Kinetics app was useless. This does not mean, of course, that it is useless for everybody.

Saul wrote:
There is enough time delay settings in the camera menu (up to 3s).

Agreed, Saul. In my experience, there is more than enough time delay available to dissipate mirror flop as effectively mirror-up mode would do. I use a one second delay.

Saul wrote:
Is there difference in the vibration dissipation time between mirror lock & shutter delay modes?

Yes! My sense is that mirror flop imparts much more movement than shutter shock, and that the former dissipates in one second, while the latter dissipates in about 1/4 second on the camera bodies I've used. I wouldn’t bet my life on these values, as I’ve not tested them with much rigor. But they serve well when shooting on my rig.

So when I shoot, I set shutter delay at one second, to dissipate mirror flop. Then I use an eight-second continuous light exposure, in a dark room, to reduce the shutter shock period to an insignificant portion of the exposure duration. This eight-second shutter speed is based on empirical testing: At shutter speeds of 1 second, 2 seconds, 4 seconds, 8 seconds, and longer, each longer shutter speed above 1 second was sharper until 8 seconds; at longer shutter speeds 8 seconds, no additional sharpness was recorded.

I should ideally run this test again, as some of my hardware has changed. But have been putting it off, as the described project to gate my continuous light will hopefully render it moot.

A similar experiment run on someone else's hardware might easily result in different "ideal" shutter speeds.

Cheers,

--Chris S.
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Yawns



Joined: 20 Dec 2015
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Location: Portugal

PostPosted: Sat Dec 02, 2017 2:49 pm    Post subject: Reply with quote

Saul wrote:
Pau wrote:
Quote:
Sensor Kinetics

Is this app really useful to measure camera vibration?


Perfectly - no, but gives very good idea. You can use free version, if you like it - pro version gives some filtering, which improves graphs.


Thank you very much .. this is really great. Even if it is possibily not accurate it is better to have "an idea" than just guessing and wondering ... I did a a few tests with my poor rig...

A,B & C were added with photoshop

A is the moment the curtains opened ..
A to B is the vibration dissipation interval ( I guess) .. around a second
C is the end of the exposure and curtains closing ( 3 seconds exposure with exposure delay)


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Pau
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PostPosted: Sat Dec 02, 2017 4:12 pm    Post subject: Reply with quote

Thanks, I will try it
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Saul



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PostPosted: Sat Dec 02, 2017 4:31 pm    Post subject: Reply with quote

Yawns,
I'm glad that it worked for you !
Looks like android version works better than iPhone. After your tests I installed it on the simple tablet and saw some settings, which are not available on my phone. And interface is more user friendly.
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ChrisR
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PostPosted: Sat Dec 02, 2017 5:10 pm    Post subject: Reply with quote

ChrisS were you using the Android phone app? After clamping a phone to the camera (elastic band) and expanding the scale (spread two fingers apart) I could see the relative strength of the vibrations, including the "tick" of a not-quite-motionless Canon EFSC. That was a 2011 Samsung SII.
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Chris S.
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PostPosted: Sat Dec 02, 2017 5:36 pm    Post subject: Reply with quote

ChrisR wrote:
ChrisS were you using the Android phone app?

No, I don't have a smartphone. I used my iPod Touch gen 5, which is like an iPhone without the phone. It had no trouble displaying light taps or bumps, but the workings of my camera did not register any change in the flat line.

--Chris S.
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Chris S.
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PostPosted: Sat Dec 02, 2017 5:51 pm    Post subject: Reply with quote

Yawns wrote:
A is the moment the curtains opened ..
A to B is the vibration dissipation interval ( I guess) .. around a second
C is the end of the exposure and curtains closing ( 3 seconds exposure with exposure delay)

Yawns, are you certain you were not using a 4 second exposure after a 1 second exposure delay?

Pulling your image into Photoshop, and using the custom measurement tool, I measure 1 second between A and B, and 4 seconds between B and C.

It also appears to me that your mirror slap dissipates in about 1/5 second, and your shutter shock dissipates in well under 1/10 second.

What do the long, straight diagonal lines designate? For the Z axis diagonal after C, was your stacking controller slewing the camera after the shutter closed? Is there some other motion being measured? Or are we seeing some limitation in the accelerometers or software?

--Chris S.
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PostPosted: Sat Dec 02, 2017 5:57 pm    Post subject: Reply with quote

I just checked the phone - the vertical scale ( 5m/s² per division above) will expand to 0.002 m/s² per division.
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