Astrophotography Bulb operations with a Nikon Camera

[james brown]

First I would like to thank all the developers and people that have spent time to allow this software to be available to the public.

I am new to the group so please let me know if this should be posted in a specific location or if I am stepping over any guidlelines.

I am a retired electrical/communication engineer and long time (Film Days) Semi Professional Photographer. 

I started last year doing astro-photography as well as using some of the Linux Distro's.

I am not a programmer but understand the amount of work required as having been involved in the Software Release / Approval process while working.

Your software package is very impressive with just a few days of experience.  I understand the limit of Bulb operation in the cans of Nikon and some models of other brands.

Although some photographers consider wires a No-No and Wifi being the only way to go, Astro-Photography typically does not consider this an issue.

The ability to perform longer that 30 second exposures is a major requirement.

I have found one program that allows this to be done with the use of a DSUSB or in my case a CH340 Control Chip USB Relay, as a direct trigger through the remote trigger port on the camera.  If this is of interest to the users and a developer that would like me to provide more information please let me know.

Thanks in advance for any consideration of this idea.

James

[Daniel P. Berrange]

On Fri, Mar 15, 2019 at 08:48:39AM -0700, james brown wrote:
> First I would like to thank all the developers and people that have spent
> time to allow this software to be available to the public.
> I am new to the group so please let me know if this should be posted in a
> specific location or if I am stepping over any guidlelines.

This is fine!

> I am a retired electrical/communication engineer and long time (Film Days)
> Semi Professional Photographer.
> I started last year doing astro-photography as well as using some of the
> Linux Distro's.
> I am not a programmer but understand the amount of work required as having
> been involved in the Software Release / Approval process while working.

There's no real process around Entangle development. Mostly it
is just me doing code hacking, or reviewing patches contributed
by others.

> Your software package is very impressive with just a few days of
> experience. I understand the limit of Bulb operation in the cans of Nikon
> and some models of other brands.
>
> Although some photographers consider wires a No-No and Wifi being the only
> way to go, Astro-Photography typically does not consider this an issue.
> The ability to perform longer that 30 second exposures is a major
> requirement.

Yeah, I do astrophotography myself & the 30 second limit is majorly
annoying, so I'm relegated to using a separate programmable shutter
trigger when I need longer :-(

> I have found one program that allows this to be done with the use of a
> DSUSB or in my case a CH340 Control Chip USB Relay, as a direct trigger
> through the remote trigger port on the camera. If this is of interest to
> the users and a developer that would like me to provide more information
> please let me know.

That is interesting, such an approach had never occurred to me before.

IIUC, it is just a generic USB device that lets you control the
relay outputs programmatically, and you just use software to
provide a signal level that is suitable for controlling the
camera's shutter port.

That's certainly a conceptually interesting thing to support. I'm
not sure how we'd go about it in practice. Do you have any idea if
the USB protocol is at all standardized - eg does all the different
products basically end up using the same CH340 control chip, or are
there many different USB protocols to worry about ?

I'll admit I don't have much time for this work myself at the moment,
but its interesting to learn of it. I'd be happy if anyone else wanted
to try supporting it too.

Regards,
Daniel
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[james brown]

I have been looking at how to make this work and the programming required.

There is an open source program for Windows that I had on a XP machine a few years back, called "digiCamControl". It has an Astronomy specific tab that basically amounts to an Intervalometer, that page has a section where you can choose to use the external USB device and configure it. 

I have found a few difference DYI projects but I liked the isolation of the relay verses a diode version of a direct USB to RS232 converter.

This link is the device I have and the page contains examples from the Command Line to control it.

www.aliexpress.com/item/LCUS-1-type-USB-Relay-Module-Electronic-Converter-PCB-USB-Intelligent-Control-Switch/32827365539.html

Finding the correct connector for the camera can be painful, however the pinouts are easy to locate.  The Nikon camera auto-focus line must be triggered before or at the same time as the Shutter so it is as simple as connecting Ground to the common and both the Auto-focus and Shutter line to the normally open.

I am talking with my son about helping with the software development that is what he does, I am a Hardware guy.

I will send him a link to this group so he can follow along.

I will keep digging as it appears we have a common item to add to the wish list.

Thanks

[Henrik Ronellenfitsch]

I found this thread searching for a way to do "Intervalometer-style" astrophotography using Entangle.

While I'm still not sure if it's possible (my Ubuntu 19.04 install somehow lacks the Entangle plugins),

the gphoto2 library, which Entangle uses internally as far as I understand, is capable of taking bulb exposures

longer than 30s.

For instance, on my Nikon D7100 this command works and takes a 45s exposure:

gphoto2 --set-config bulb=1 --wait-event=45s --set-config bulb=0 --wait-event-and-download=5s

[Daniel P. Berrange]

On Wed, Sep 11, 2019 at 03:36:12AM -0700, Henrik Ronellenfitsch wrote:
> I found this thread searching for a way to do "Intervalometer-style"
> astrophotography using Entangle.
> While I'm still not sure if it's possible (my Ubuntu 19.04 install somehow
> lacks the Entangle plugins),
> the gphoto2 library, which Entangle uses internally as far as I understand,
> is capable of taking bulb exposures
> longer than 30s.
>
> For instance, on my Nikon D7100 this command works and takes a 45s exposure:
>
> gphoto2 --set-config bulb=1 --wait-event=45s --set-config bulb=0
> --wait-event-and-download=5s

That is interesting, I've always been under the impression this was
not possible with Nikon's, but I only have a Nikon D90 or D5100, so
its entirely possible this changed with the D7100, or gphoto just
got some improvements I wasn't aware of.

[Henrik Ronellenfitsch]

You're right, the gphoto documentation
(http://www.gphoto.org/doc/remote/) actually states:

> Nikon DSLR: We do not know how to do Bulb capture yet.

But the code does work. Maybe the documentation is out of date?
For reference, I used the following version:

gphoto2 2.5.20 gcc, popt(m), exif, cdk, aa, jpeg, readline
libgphoto2 2.5.22 all camlibs, gcc, ltdl, EXIF
libgphoto2_port 0.12.0 iolibs: disk ptpip serial usb1
usbdiskdirect usbscsi, gcc, ltdl, USB, serial without locking

Best,
Henrik

--
Henrik Ronellenfitsch

Instructor | Applied Mathematics
Massachusetts Institute of Technology

Office 2-181