biases and auto flats with DSLR and shutter release cable in autorun

AntoonH

I have a canon 5DmkIV attached to my asiair plus with a USB cable.

Now, when I create an auto run with

bias at the lowest shutterspeed (1/4000)
darks at 30 sec
lights at 30 sec
auto flats

This all works as expected: The autorun produces all the frames I selected.

However, when I connect a shutter release cable (to achieve > 30sec exposures) and enable the cable in main camera settings, I set an autorun like so:

bias at the lowest shutterspeed (1/4000)
darks at 2 minutes
lights at 2 minutes
auto flats

This sequence just fails to take exposures for flats and biases.
When I split the autorun in 2 parts:

-- shutter cable enabled --

2 minute darks
2 minute lights

-- shutter cable disabled --

biases (at lowest shutterspeed)
auto flats

This works.

My thinking is that enabling the shutter cable disables short exposures, causing both the very short bias frames as well as the auto flats (which look like it does a sequence of exposures at various lengths) to fail.

Am I missing something? Surely this can't be expected behaviour?

nicolas

Hi @"AntoonH"

Where did you see that you need a shutter release cable to achieve > 30sec exposures?

I'm quite sure this is not true because I have used many Canon cameras with an Asiair without a release cable (but not this particular model) and the ZWO documentation clearly states that you only need the shutter release cable for a small number of Nikon models.

AntoonH

Well. When I just connect the 5Dmk IV with USB (and not using the shutter cable), the max shutterspeed I get to set is 30 seconds!

This behavior never struck me as out of the ordinary, because 30 secs is just the max exposure that you can set in the 5D mk iv. For more general nightscapes and long exposure shots, I resorted to using a canon TC-80N3 timer. Similar to my previous 5D mark II.

nicolas

AntoonH
But what exactly happens if you set your 5d mk IV to bulb mode and try a 1 minute exposure?

I've used at least half a dozen Canon cameras with an Asiair and have always been able to get exposures longer than 30 seconds.

AntoonH

I can get darks and lights just alright at any exposure over 1 sec. biases at 1/4000 and auto flats (which goes through a cycle to evaluate the correct flat exposure) don't. To be precise, if I create an auto run sequence with lights, darks, bias, flats... the capturing of images just hangs at the bias stage.

The way I "overcome" it is by doing an autorun with lights and darks, followed by disabling the shutter cable in the menus, then reset the autorun and do a bias/flat run.

nicolas

AntoonH

You didn't answer my question. I understand you have a problem doing bias ant autoflats with the shutter cable but my point is you don't need it. The correct way to use your Canon with the Asiair is without the shutter cable (and with the option turn off in the settings).

If that does not work for you, please explain exactly what is happening.

CKAJCA

From what you described, I have a VERY similar problem with my Nikon D700.

AntoonH

here's some screenshots...

asiair explicitly provides feedback: limit for EXP/s max 30 secs. (it shows when I manually enter an exposure value when creating a light sequence in autorun mode.
Similarly, the shutter choice in preview doesn't exceed 30secs.

However, when I go and enable the shutter release cable I can select all the way up to 1000secs in preview mode. (I tested up to 300 seconds) as shown here in preview mode whilst selecting exposure:

From my experience with both 5DmkII and 5DmkIV, that 30 seconds is just fixed in the camera. If you want more... use a TC-... exposure timer connected with the shutter release port. That's just how these particular two camera models work (note that I'm limiting my specs to the camera's I own(ed) and used for long exposures regularly.

And here's the thing:
in autorun (and plan) mode, I want to do sequence runs that have not only darks and lights, but I'd like to include bias and flats too. And this is where autorun and plan modes have an issue:

For exposure reasons I need 5 minutes of exposure on my lights/darks. Thus I need to enable the shutter cable.
However when I add biases at 1/4000 to that autorun, the biases simply don't get taken (the camera stays quiet infact).
Similar for the auto flat mode (where asiair goes through an exposure seqence to determine optimal flat exposure time), no flats get taken, presumably due to similar causes as the biases.

Jumping the gun a bit: a way of addressing this in the software would be for the asiair to decide (based on exposure time required) to use either the bulb cable or trigger exposure manually when the bulb cable is enabled.

Hope that clarifies/answers your question?

summed up: it is what it is with this camera model. however, when enabled, asiair "borks" autorun plans with short biases and auto flats.

nicolas

AntoonH

Thanks for the detailed answer. I still think you haven't explored all the possible settings.

To my knowledge, all Canon SLRs are limited to 30 seconds in normal mode and they have to be set to Bulb to be able to exceed this limit. In this mode, all the Canons I have tried can exceed 30 seconds with the Asair without a shutter cable and I find it hard to believe that the 5D is any different!

The way to set Bulb mode is different for each model, but for the 5DmkIV, you have to set the Dial button to "B". Did you do this in your tests?

AntoonH

Yup. Tried both M and B.
For what it’s worth: The Eos utility behaves similarly.

Corsair

Please double check your camera settings.

To quote the manual (https://www.yuque.com/zwopkb/asiair/dslr-ml-connections):

The DLSR must be in M, Bulb, RAW and Large/fine (maximum image size) mode. You have to disable energy saving mode, long exposure noise reduction, mirror locking...
WiFi, Bluetooth and/or NFC tethering communication functionlities on the DSLR need to be in OFF position.
If your DSLR or MILC supports dual memory cards, please insert only one card when you use the camera with ASIAIR, or some unexpected problems may occur.