There are a couple of issues about the PTP+gphoto mode.

The first problem seems to be (I’ve only red about, never tried) the increased energy need when working in PTP mode: a DC feed would be required, and it is far from costless. I will try to make some experiments without DC feed, but I fear that it will be hard to be operational for at least 1h with only 1 battery pack.

The second problem (for astronomy/science imaging) is that unfortunately Nikon applies a low-pass filter also to RAW images before saving. The only method (called MODE3) to avoid it is to take the shot and shut down the camera when taking the dark exposure (noise reduction). In this way the camera is forced to save the data without applying the dark subtraction nor the filtering. A subsequent MODE3 shot with plugged lenses will provide the dark exposure.

Now, I suspect that all those shutting down/powering up the camera will not help so much the connection between camera and PC…

For this reasons, I would prefer to have a remote performing it, or at least something connected to a serial/usb on the pc. At the moment I’m trying to make my old toshiba satellite IrDA port working with lirc, but it seems i have some problems with modules (a lot of literature is present on the net about it)

About building the remote, fortunately I have friends knowing linux in depth and with some electronics skills. If you can give me some hints, I could ask them to do all the sw/hw work…

Thank you again, feel free to contact me directly to my e-mail if needed
Giorgio

Yes, this is possible for sure. But you might be interested in gphoto2 which use the PTP protocol (supported on most DLSRs) to drive cameras.
It works on linux only, but does a great job in taking picture sequences. You can adjust everything for your shots from the command line (aperture, speed, w/b, etc…). It’s simply great.
If you’re not a linux freak, I can give a hand if you want to build a Nikon remote. It would be pretty simple to make a special version that connects to a serial port so you can program it the way you want.

Hope it helps, cya.

I am not used to electronics nor hardware programming, but maybe my issue can be a good suggestion for you.

In astronomy the use of a DSLR is a cheap way to substitute a pro ccd imager (quite expensive). It is often necessary to use an exposure time greater than 30 ».

Surely, such long shots are possible by using the « B » exposure, but doing it manually lacks in precision (for example, I would need to take 20 shots exactly 120 » long).

Unfortunately, Nikon do not provide any tool to do it (remote sw controls by Canon can do it on their cameras) and it is a very, very, very striking lack for amateur astronomers using Nikon DSLR.

My question is: is it possible for you to modify your equipment in order to make it possible to shot exactly n-minutes « B » exposures?
I guess Nikon-based astronomers would be happy to know that you can do it!

Feel free to contact me for extra informations about this topic

Best regards
Giorgio

@dekemp : well, as stupid as it seems, I can’t put my hands back on it
Basically, it was BigMikes one with some mino modification (buttons handling, 7 segments display, and loop processing for modes). I will probably create a newer version based on TSAL 6100 IR LED one of these days. I can dump the hex firmware if you need it, just let me know.

muy buen tutorial..

Thanks