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Old 24-04-2018, 07:49 AM
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Opinions re Nikon D810A

I like the simplicity of using a dslr as I can get away without the lap top which is needed for a dedicated astro camera.
Reading the adds the Nikon D810A seems to be my answer...it seems pricey but heck if it delivers the dream why not.
I suppose its really no more than a modded camera which you can buy over the counter...
I am curious if any members use this camera or what our resident experts think about the camera in general.
Alex
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Old 24-04-2018, 07:51 AM
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I realise it cant be used for much other than astronomy but that is not a problem for me.
I do wonder if you could use a ha filter however with this camera.
Alex
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Old 24-04-2018, 08:24 AM
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alocky (Andrew lockwood)
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Itís a very good DSLR with all the features of the 810 with slightly improved noise and an extra menu dedicated to astrophotography. Whoever told you it canít be used for general photography has no idea what they are talking about. Here is a selection of non-Astro shots through mine.
https://flickr.com/photos/103316752@...57655058572216
Good camera, although superseded by the D850, and Nikon has no plans to produce an ĎAí version of that. I think the D810a is also out of production, so donít think about it too long if youíre serious.
Cheers
Andrew.
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Originally Posted by xelasnave View Post
I realise it cant be used for much other than astronomy but that is not a problem for me.
I do wonder if you could use a ha filter however with this camera.
Alex
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Old 24-04-2018, 10:46 AM
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I might be a bit one sided Alex but I have found the Canon 5D model, the original 5D a superb imaging Camera, with low signal to noise ratio.
It served me very well when i was imaging and i still use it now for normal photography.
They, the Cameras are very cheap now and one could pick up a very good secondhand one for about 400-500 dollars.
Anyway that is just my 2 cents worth, have to admit i don't know that mush about the Nikon models, I'm sure they too are very good Cameras

Leon
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Old 24-04-2018, 11:21 AM
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I don't know about the D8010a but the D800 had an issue with flats. Because there is some sort of scaling done it throws off the flats.

Perhaps a D810a owner can comment if that is an issue or not.

The D810a is a very expensive camera. Its something like US$3500.
Its the same sensor in the Sony A7r with Nikon tweaks and slightly better Nikon firmware.

Its also the same sensor in the Pentax K1 and now the K11. The Pentax is cheap. So is a 2nd hand Sony A7r. I have seen a modded A7r for US$1600.

You can also get the same sensor in a QHY cooled camera for similar money.

That would be the better choice for telescope imaging. Atik may also offer a version - not 100% sure.

Greg.
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Old 24-04-2018, 02:17 PM
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Thanks Andrew your images are sentational...really.
I think I found a place suitable for me to get one...but something I only just now found out...it seems the back screen does not fold out and around... etc...strangley that feature is almost my number one demand...old and bad legs gives it almost a priceless value for me.
Thanks for sharing your views I appreciate you taking the time.
After your help I certainly feel confident about the camera.
Alex
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Old 24-04-2018, 02:25 PM
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Hi Leon...the irony is I suppose my ignorance precludes me appreciating the step past my current camera.
Tiday, because of my coloir blindness and being in the city a fair bit ...to go just H alpha...black and white is ok for me particularly when you see some of the ha stuff folk post before adding othet channels...pluss the lappy could stay set up...mmm lot to think about.
My Nikon is ten years younger than my last Canon but I am so happy with it...love the movable screen and being able to blow up a view so easily to focus...
Alex
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Old 24-04-2018, 02:29 PM
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Hi Greg
Thanks for your post.
I would love to avoid a dedicated astro camera but it seems that makes more sence.
Thank goodness its cloudy I will have time to think.
Alex
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Old 24-04-2018, 03:12 PM
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OzEclipse (Joe Cali)
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Alex,

Pentax K1 mentioned by Greg has an articulated screen, seems to have reasonable Ha pickup without modding has other built in features that assist with astrophotography.

Modded Canons seem to have very nice colour rendition (see Josh Bunn's wide fieldimages) but they are definitely a bit backward in terms of noise & performance compared to the three cameras with the new Sony 36MPx sensor - Nikon D810, Pentax K1 and Sony A7r.

The K1 and possibly the others, has an HDMI output. You can plug in a 12V HDMI video monitor, the type you attach to the back seat of a car so kids can watch DVD's and see the camera screen on a separate small monitor. Some are quite compact.

The attached image of M42 is taken with a K1 with total exposure time of 130s at f4. Obviously a bit of noise there, but outer neb was shot 15s @ ISO 12800 ;-)

If you want connectivity to software, get a Canon. If you want standalone functionality, Pentax & Sony. I have no experience with the D810 so refer you to Greg's comments.


Joe
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Old 24-04-2018, 03:32 PM
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Thank Joe
It seems rather good I am looking at stuff now but it has a feature that has the sensor moving to follow stars which I have to look into...if it can do that thru a scope that could be exciting ..but full fram and the screen and conyrol really appeal to me.
Alex
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Old 25-04-2018, 10:38 AM
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OzEclipse (Joe Cali)
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Alex,

I think you're asking if astrotracer works as an autoguider? I can tell you it definitely doesn't.

The astro tracer moves the sensor to follow the stars from a fixed tripod. The function won't work as a pseudo guider. You turn on the GPS, rotate the camera in 3 cartesian axes to "precision calibrate" the accelerometers. Then the camera knows which part of the sky it's pointing at. It moves the sensor in X-Y and rotationally to minimise trailing. It doesn't eliminate trailing and it doesn't guide. It's based on calculation not pixel guiding. Not perfect but not bad with fixed tripods and lenses but useless at the prime focus of a scope. That's not what it's designed for.

It has built in intervalometer, pixel shift (works like drizzle) and while it obviously works better at lower ISO, it's usable with care up to ISO 25600, Starstream (in-built image stacker for stacking star trails in-camera)

Quite a few images here were taken with my K1
http://joe-cali.com/astronomy/astrophotography-2/
The image at top of the page titled "Scorpius&Rho" is taken with Astrotrace.

If the articulating screen is really important to you, then the Pentax ticks that box. Not sure which of the other camera's have articulating screens. Just remember that you can get some cute little external hdmi video monitors that negate the need for an articulating screen.

This thread has some comparative information about the cameras.

http://www.astronomyforum.net/astro-...tax-k-1-a.html


In the end they are all very good cameras. None are bad, none are perfect. You just have to choose.

cheers

Joe
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Old 25-04-2018, 11:42 PM
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Quote:
Originally Posted by OzEclipse View Post
Alex,

I think you're asking if astrotracer works as an autoguider? I can tell you it definitely doesn't.

The astro tracer moves the sensor to follow the stars from a fixed tripod. The function won't work as a pseudo guider. You turn on the GPS, rotate the camera in 3 cartesian axes to "precision calibrate" the accelerometers. Then the camera knows which part of the sky it's pointing at. It moves the sensor in X-Y and rotationally to minimise trailing. It doesn't eliminate trailing and it doesn't guide. It's based on calculation not pixel guiding. Not perfect but not bad with fixed tripods and lenses but useless at the prime focus of a scope. That's not what it's designed for.

It has built in intervalometer, pixel shift (works like drizzle) and while it obviously works better at lower ISO, it's usable with care up to ISO 25600, Starstream (in-built image stacker for stacking star trails in-camera)

Quite a few images here were taken with my K1
http://joe-cali.com/astronomy/astrophotography-2/
The image at top of the page titled "Scorpius&Rho" is taken with Astrotrace.

If the articulating screen is really important to you, then the Pentax ticks that box. Not sure which of the other camera's have articulating screens. Just remember that you can get some cute little external hdmi video monitors that negate the need for an articulating screen.

This thread has some comparative information about the cameras.

http://www.astronomyforum.net/astro-...tax-k-1-a.html


In the end they are all very good cameras. None are bad, none are perfect. You just have to choose.

cheers

Joe
Thanks Joe.
I am most impressed with your photo unbelievable ... I would be happy with that.
Alex
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Old 26-04-2018, 08:18 AM
AnakChan (Sean)
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I have the Nikon D810A and a modified Sony A7S. I'd be curious to hear what the issues are with the D800 flats and see if the D810A has the same issue or not.

As for the D810A having the same sensor as the A7R, the one thing to note about the Sony Alphas are their star eater issue. I have this on my A7S too however am not affected due to shooting at 2500mm focal lengths however is readily apparent in shorter 300-800mm focal lengths.

The D810A does not suffer from the star eater issue despite the same A7R sensor. That star eater issue is specific to Sony's algorithm (post data dump from the sensor).

There are some nice extras in the D810A firmware not available in other non-Astro dedicated Nikon models. These little extras help in focusing/framing, etc.

My only gripe (but rather unfair expectations on my part) is compared to my modified A7S, is my A7S is cooled. I don't think I'd use more than 5 min (during winter, less during summer) subs due to sensor heat noise.
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Old 28-04-2018, 10:43 PM
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Regarding the star eater issue with Sony A7xxx cameras I have never found it to be an issue with nightscapes with A7r, A7r2 A7r3.

A7s models seem to be most affected due to the large pixel size. The algorithim picks up dim stars that are I think its 1 pixel across and confuses it with a hot pixel. With the A7r, A7r2 the pixel size is small (36mp and 42.4mp) so its much rarer and you won't be able to tell.

There is also a work around for up to 30 seconds to turn it off on A7r and A7r2.

I have seen tests where A7r3 does not show star eater virtually at all and I have yet to see my own images degraded to the extent I can tell.

Hot pixel noise in shadows can be an issue but the solution is to use Capture single pixel noise reduction and it cleans all that up.

The Sony has many other advantages and this has been hyped up way out of proportion.

The D850 Nikon and the Sony A7r3 and now Sony A7iii have the latest cutting edge best on market sensors bar none.

The D850 is perhaps arguably the best out there. I am not sure if flats are an issue though. Same with a Sony, flats may be an issue. It has something to do with scaling of the data ( I don't know much about it).

Greg.
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