Camera control set when using controlled focus rail?

[bklein]

Seems to be reasonable interest in focusing rails and automating them. Probably many of you are like me - a hard core DIY'r that can't justify spending the cash for doing it right and just taking the photos... The real challenge is the DIY solution. Let's say a cost effective means is realized for the focusing stage. We are then left with camera control features. What can be done with the popular Canon and Nikon DSLR's in this regard? How does one become familiar with the command sets for each camera? What can be controlled?
Also, can focus be externally overriden by external electronic control if using an autofocus lens?

[elf]

Canon and Nikon SDKs are available for free, so you could find out what features are available. You may be able find more info online without having to apply for the SDKs.

Olympus charges for their SDK and it's more limited than the Canon SDK.

I'm using an Arduino micro controller to drive my "focus rail" See http://www.photomacrography.net/forum/v ... php?t=8348

[bklein]

wow, that's a serious setup.
where do you get that channel in the states?
Found the link for Nikon SDK's:
https://sdk.nikonimaging.com/apply/inputmail.do

Haven't opened one yet to see how it looks.

Arduinos seem all the rage. Haven't ever played with one but has to be simple given what I've seen done with them.

[elf]

wow, that's a serious setup.
where do you get that channel in the states?
Found the link for Nikon SDK's:
https://sdk.nikonimaging.com/apply/inputmail.do

Haven't opened one yet to see how it looks.

Arduinos seem all the rage. Haven't ever played with one but has to be simple given what I've seen done with them.

The aluminum extrusion is from 8020. It's probably easiest to get it from their ebay outlet store. Just search on '8020 aluminum extrusion'.

C++ is used to program the Arduinos. They provide an IDE or you can use Visual Studio. It's open source, so there is lots of code available online. The hardest part is writing programs that fit in small amounts of ram. I don't think you can drive a camera with one unless you can decode the USB signals between the camera and a tethering program. I'm using mine to trip the shutter with IR and to drive the stepper motors. It would be simpler to drive a Canon or Nikon directly from a computer.

[AndrewC]

Also, can focus be externally overriden by external electronic control if using an autofocus lens?

Look at Helicon Remote - it will usurp the focus control of an AF lens and trigger shutter release. It can not cope with Mirror up type operation though, at least not on a Nikon.

What can be done with the popular Canon and Nikon DSLR's in this regard? How does one become familiar with the command sets for each camera? What can be controlled?

Depends what you mean by "control". It is pretty easy to hack an electronic shutter release controlled by a microcontroller. Easiest way in is to buy something cheap off eBay. You can also usually control through a USB interface in which case just run something out of Visual Basic. If you are communicating through USB you have two options - you can use the WIA command set (which is limited) or try and make sense of the SDK code released by the manufacturer but should give you unlimited control - though again there seem to be issues with M-Up mode. Even Nikon's own remote control software can't seem to cope with that which is bizarre.

The other way in is to use something like VB with a USB link to a digital I/O board. The digital I/O signals can be used to move stepper motors, trigger strobes, shutter release, etc. Something like a Digi Bee:

http://www.pc-control.co.uk/digibee_info.htm

or a Phidget

http://www.phidgets.com/products.php?category=0

I'm working on a VB interface right now where I control position with stepper motors which I talk to through a DigiBee, control shutter release through the same DigiBee (because of the M-Up issue) and then have another USB link straight to the camera which I use to download images into my desktop.

Browse around the net for subjects related to "tethering". Here are a couple of links that pointed me in the (possibly) right direction:

http://www.diyphotobits.com/2008/05/23/ ... for-nikon/

http://www.vbforums.com/showthread.php?t=378126

[bklein]

The digibee looks pretty cool. I have used something similar called the Labjack. It comes with DAQFactory software - which is a fun programming environment for it. I upgraded to the pro version to get GUI icons. But using it for stepper driving may be better with a stepper interface board.

[AndrewC]

But using it for stepper driving may be better with a stepper interface board.

Yes, that is what I do - just use the DigiBee to pass step and direction signals on to a JAFmotion stepper driver:

http://www.jafmotion.co.uk/index.php?op ... &Itemid=50

The only gripe I have with the DigiBee is that I need to "bit bust" it when reading the digital inputs (sequentially divide by 2 to extract individual bits from a 32bit long word).

I play around with PIC microcontrollers and I'm used to manipulating (well, trying to manipulate anyway) individual outputs. There are some great motion control optimised PICs available with built in quadrature decoders, multiple channel PWM lines and all sorts of other goodies.

Andrew