Nikon D90 IR sensor switched off by SGP when starting an exposure

I want to use my Nikon D90 camera for long exposure astrophotography.
For exposure times longer than 30 seconds I bought a DSUSB-IR which should operate similar to the DSUSB.
When I connect this setup to SGP, shooting exposures shorter than 30 sec. is not a problem.
But for exposures longer than 30 sec., and using the DSUSB-IR in bulb mode, I run into a problem.
In order to use IR, I have to manualy enable the IR sensor of the D90.
But when I try to start an exposure, either by a sequence or in Frame and Focus mode, SGP disables the IR sensor on the D90 at the moment the exposure should begin.
I can see, by the camera of my cell phone, that the IR led lightens up at the start of the exposure but with a disabled IR sensor on the D90, nothing hapens.
SGP is still thinking that the exposure has begun.
It lights up the IR led at the and of the exposure time but freezes at the download from the camera, since there is nothing to download.
The only thing that can be done in this situation is to end SGP, no other control is functional anymore within the program.
This seems to be an SGP problem since this same setup does work with Maxim dl.
How can this be fixed?

I am using SGP verion on Windows 10.
It is not Windows nor PC related because I encountered the same problem on a Win.7 PC.
A logfile is availeble on: Dropbox - sg_logfile_20160121181949.txt - Simplify your life

Regards, Bart Veltman


I’m not really sure. I reviewed the code looking specifically at cameras that require DSUSB for long exposures. We don’t call anything specifically in the Nikon SDK to explicitly disable the IR sensor. Maybe it’s a side effect of some other call… not sure.

Anyhow… so after setting the IR sensor to “on”, the first attempt to take any image toggles this back to “off”? You can actually go back into the camera menu and see that it is now set to “off”? If so, can you determine if it is set back to “off” for < 30 sec exposures, longer than 30 sec exposures or both (by checking the setting immediately after each one of these types)?

A log file might be helpful here (the one you linked shows no attempt to capture an image).

Hello Ken,

Yes SGP toggles the IR sensor back to off at the moment the first exposure should begin. The LCD display on top of the camera shows an IR symbol when the sensor is on. This symbol disappears when SGP starts an exposure and the sensor is indeed off. There is no specific IR on/off setting in the menu of the D90. Setting the sensor on of off has to be done by a physical switch on the camera. The only feedback is the IR symbol in the LCD display.

I have create two new logfiles. The first one of a failed 35 second exposure. The IR sensor was initially enabled on the camera but toggled off by SGP at the start of the exposure. The second one of a succeeded 10 second exposure.

The logs, with the used sequence file can be found here: Dropbox - - Simplify your life

OK. Thanks for the logs. I’m sorry to report that I don’t know how to address the issue you are seeing. On top of that I don’t see any way in which the Nikon SDK could override the state of an IR sensor hooked up to a physical switch on the camera. I looked through the logs to see of the camera reported on it. Unfortunately I don’t think it does.

I know your rig works elsewhere and I’m sure it’s somehow in the way in which we’re handling the camera, I just have no idea what it could be.

Maybe @Jared has some ideas… I’m all out.