Focus Nikon Z6

[jbandes]

I watched your video and was very excited to finally be able to focus on stars with great accuracy. I have a Nikon Z6. I was very disappointed to learn that it does not seem to work.
There is no focus control displayed in the application.

When I connect a native Nikon Z6 lens (14-30 mm Wide Angle) there is no focus control in the Back Yard Nikon app. I thought well OK I will just focus manually on the lens itself but when I turn the focus ring manually the Focus number reads 64 and does not move. If I go way out of focus the number either stays at 64 and never moves or moves a tiny bit. What is strange is if I drag the focus around in the larger window the number does change to 59 or 62 but not by a great deal. I have tried lenses using the Nikon FTZ adapter and native lenses and lenses that are manual focus only. Basically it just does not work with my Nikon Z6. I dont think based upon this that you should list Nikon Z6 as a supported camera. I should have tested first but I purhcaed it for $50 and now cant really use it. I hope I am just doing something wrong.

 

 

[s3igell]

Perhaps if you search the Forum for "Nikon Z6", you'll find some hints that will shed light on how you are to set your Camera and Lens switches in order to be able to Focus, as other users have reported they are able to Focus using their Z6 ( https://www.otelescope.com/forums/topic/3887-nikon-z6-frame-and-focus/ ).

Just understand that BYN doesn't have an Autofocus Routine in the sense of DSLR attached to Motorized Scope Focuser (not what you are attempting, per your OP).

 

[astroman133]

With a short focal length wide angle lens, the stars are soooo small that the focus metric may not be useful.

I assume that you are trying to focus with LiveView. If that is not working, manually set the lens as close to infinity as you can get and try taking a couple second snap image. This may help you where LiveView is failing.

 

[admin]

The Z6 is supported and warrants being the supported list, full stop.

Driving a lens is not a camera function, the is a lens function.... that is where the lens motor is.

In order to drive the lens, it must have the ability to be driven by the SDK and the camera must also be capable and handing over the command to the lens.  It's been long documented and talked about here on the forum.  It's the same for Canon.

The other issue is that most lens must be put in AF mode to engage the motor... but when you want to take a picture at night you want/need it to be set to MF.  It's one of those features that is simply not meant to work in the dark, and even if it would work you would need to touch the camera between focusing and imaging to move it from AF to MF.  It's a lose-lose situation to begin with sadly  

Regards,

[jbandes]

On 6/17/2020 at 5:30 PM, admin said:

The Z6 is supported and warrants being the supported list, full stop.

Driving a lens is not a camera function, the is a lens function.... that is where the lens motor is.

In order to drive the lens, it must have the ability to be driven by the SDK and the camera must also be capable and handing over the command to the lens.  It's been long documented and talked about here on the forum.  It's the same for Canon.

The other issue is that most lens must be put in AF mode to engage the motor... but when you want to take a picture at night you want/need it to be set to MF.  It's one of those features that is simply not meant to work in the dark, and even if it would work you would need to touch the camera between focusing and imaging to move it from AF to MF.  It's a lose-lose situation to begin with sadly  

Regards,

I know how difficult it is to write a program like this and I love your software. I apologize if the tone of my last message was offensive. I was testing inside with my Nikon Z6 using a Native 14-30 mm zoom lens) and when I drag the zoom position box all over the screen in the Frame and Focus mode using live view the focus number changes quickly (As you would expect) however when I double click on an object in the room and manually focus the lens the focus number sometimes does not change or when I visually see the object in focus the number is not as low as it can go. This made me think it was not working properly. What I need to do is take it outside and point it at the sky and do a proper test. Also will use a 70 - 200 2.8 lens to test. I am so happy to hear that it does work with my Nikon Z6 because I am just starting out in this hobby and dont want to have to buy another camera to get started. I bought a guide scope and an Sky-Watcher AZ-GTi GoTo Altazimuth Mount and an ASIAir and want to use your amazing software to run my live captures on my Nikon camera. I will take it ourside when my AZ-GTI arrives Monday and give it a proper test. Once again, thanks for making such a fantastic peice of software. To be honest, I would raise the price (Grin). 

[astroman133]

The BYE focus metrics like FWHM and HFD really need a point source of light, like a star, to be able to measure its diameter.

You can simulate a star by poking a small hole in a piece of poster board and putting a light source, like a desk lamp, behind it. Then move the camera across the room and use BYE with a lens try to get a good diameter for focusing.

You may want to rethink using an alt-az mount for prime focus astrophotography. The motion of horizontally-oriented alt-az mount does not match the movement of the stars and is vulnerable to the effects of field rotation. Field rotation causes the stars at the highest and lowest declination to be elongated even while the stars across the center of the image may be pinpoints. In your images this causes an unappealing mixture of round and elongated stars. There are 4 solutions. 1) use a wedge to equatorially mount the telescope, 2) replace the mount with a German equatorial mount, 3) find a way to de-rotate the camera, or 4) keep your exposures very short. Each of these options have drawbacks. The wedge makes the telescope less stable and there may not be a wedge for your mount. Replacing a new alt-az mount with a GEM costs $$$ and may not be feasible. Low-end de-rotators are not very popular and may not provide a satisfactory solution, if you can even find one. Keeping the exposure duration short may prevent you from capturing the dim detail that is the hallmark of deep sky astrophotography and so your targets my be limited to brighter objects.

Depending on what your goals are, you may want to consider returning the Alt-Az mount without even taking it out of the box. The supplier may be able to suggest a better alternative, if you share your intended use with them. Or you could decide to use it solely for visual work and buy a different mount that is suitable for astrophotography.

[s3igell]

While an Alt-AZ Mount is not recommended for AP Imaging, it is Unfair to say that you Cannot Do AP Imaging with one.  There are numerous examples of What Can Be Done with ALT-AZ posted on Astrobin and CloudyNights.

Field Rotation is an Issue - and is a greater Issue with Short Focal Lengths such as your Lenses.  In general, you will start to capture Field Rotation after about 30 sec of Exposure for Short FL and before 60 sec for Long FL (800-2000mm).

However, with your f/2.8 Lens, you can capture a Lot of Photons in 30 sec.  You can expect to capture Nebulosity in Brighter Objects - M8, M16, M17, M20, M42-43, etc.  And you will capture detail in the Larger / Brighter Galaxies - M31, M81-82, M51, M101.

Your mount being Alt-AZ actually comes in handy for a different aspect of AP Imaging - Nightscape Imaging where you don't want the Horizon to Twist as the Mount follows the Earth's Rotation.

Your SW AZ-GTi will likely be outgrown, or relegated to Wide-Field AP Imaging, sooner or later for a different reason:  Lack of AutoGuiding and Lack of Wedge/Polar Alignment.

In the meantime, enjoy your Entry into the AP Imaging World.  Learn what you Can and Can't Do for yourself.  Then decide if you want to Upgrade your Mount - it will always be serviceable for Nightscape Imaging...