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Help on D810A

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#1 Spica010

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Posted 21 March 2019 - 02:45 AM

Hello to all forum members,

 

I am willing to upgrade from my 6D to a D810A. Purpose would be to do AP with my telescopes and DSLR lenses (obviously I would have to buy F-mount lenses).

But it seems very difficult to find a D810A on the market (for me, anyway). I am in Germany and except for going to Japan in person to try to find one in a camera store it seems I am out of options. There are of course ebay offers with high prices but importing one can be a game of luck because of restrictions on shipment of lithium battery packs (to Germany).

BTW, is the D810A definitely discontinued? (It seems that way in Europe but I have yet to find a conclusive answer to that question.)

 

I would appreciate any hint or information. Maybe someone can even point me to a reputable seller which has one camera in stock.

 

PS: I am aware of the possibility of astro-modifying my 6D but I do not intend to.

 

Thx and Regards


Edited by Spica010, 21 March 2019 - 02:46 AM.


#2 whwang

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Posted 21 March 2019 - 06:55 AM

If you go to Tokyo, you can try Map Camera in Shinjuku. You can check their website to see if they have new or used ones in stock. Remember to bring your passport to enjoy duty-free, which makes a huge difference.

Other big camera shops to check are Yodobashi and Bic Camera.

Cheers,
Wei-Hao

#3 KLWalsh

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Posted 21 March 2019 - 06:37 PM

There are currently 2 D810A (used) camera bodies for sale on Amazon.
I bought one a few years ago and am very happy with it. Though, for various reasons, I have not done any imaging with it for a while.
I shoot ‘regular’ photography with it too, using a pale cyan filter on the front to correct the mild red excess it has vs a standard 810.

#4 Spica010

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Posted 22 March 2019 - 05:36 AM

Thanks for the responses.

 

 

There are currently 2 D810A (used) camera bodies for sale on Amazon.
 

I assume you mean amazon.com. I have looked it up and I have not seen a D810A listed. Maybe you can send a link.

 

Anyway, thank you.



#5 OldManSky

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Posted 22 March 2019 - 09:49 AM

https://www.amazon.c...ting/B00TE4YL6C

 

That shows two used.  One is "prime" eligible.



#6 KLWalsh

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Posted 23 March 2019 - 09:17 PM

https://www.amazon.c...ting/B00TE4YL6C
That shows two used. One is "prime" eligible.

Yep, those are the ones I saw earlier. Thanks for getting the link.

Edited by KLWalsh, 23 March 2019 - 09:18 PM.


#7 sgwells

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Posted 24 March 2019 - 11:15 AM

Maybe try the Fred Miranda classifieds section. There are a number of global users there, though finding a d810a may still be a challenge.

https://www.fredmira...orum/board/10/1
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Edited by sgwells, 24 March 2019 - 11:16 AM.

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#8 nofxrx

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Posted 25 March 2019 - 08:46 AM

May I ask why not have a D810 (or D800/D850) modified for AP instead? It would seem to me to be the less expensive option given the rare D810a seems to get a very high price tag even for a pre-owned one.

Is there any difference between the D810a and the D810 other than the filter(s) in front of the camera? As far as I know, there is no difference..(edit: it appears Nikon added a Manual exposure function allowing for up to 900sec exposures in camera without the need for an external trigger/USB connection to start/stop long exposures. This is an awesome feature and should be included in all cameras IMHO, but not worth the massive price difference, again IMO).

You can find used D810's for $1100-1200 or so, add $400 for a modification and you are at ~$1500. Less than the ~$2200-3000 for a D810a.

 

If you are concerned with warranty, most modification services provide a warranty (I cover for one year).

I know being in Germany may be a limiting factor for some businesses, although I have never had an issue shipping there.

 

Just trying to think outside the box.

Good luck!



#9 whwang

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Posted 25 March 2019 - 09:45 AM

Those who own both a D810A and regular D8XX told me that D810A clearly has lower thermal noise.  It is quite possible that Nikon selected the best chips (in terms of noise performance) and put them in D810A.  Whether that (plus the differences in functions) worths the price difference is another question.

 

Personally, I would either pick a D810A, or a hacked modified D800 to enjoy the true raw files provided by the hacked firmware.  D810 cannot be hacked and lacks D810A's astro-friendly functions.  Among D800, D810, and D810A, D810 is actually the worse option for astro.


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#10 Jerry Lodriguss

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Posted 25 March 2019 - 06:10 PM

Those who own both a D810A and regular D8XX told me that D810A clearly has lower thermal noise.  It is quite possible that Nikon selected the best chips (in terms of noise performance) and put them in D810A.  Whether that (plus the differences in functions) worths the price difference is another question.

 

Personally, I would either pick a D810A, or a hacked modified D800 to enjoy the true raw files provided by the hacked firmware.  D810 cannot be hacked and lacks D810A's astro-friendly functions.  Among D800, D810, and D810A, D810 is actually the worse option for astro.

Also, Nikon is doing some different stuff in handling the data off the sensor because the lowest ISO is different in the D810a than the D810.

 

The D810's lowest ISO is 64, I believe, and the D810a is 200.

 

For those who think Nikon is so much better than Canon because they are ISO invariant and you can use the lowest ISO to get the most dynamic range, you should wonder what the Nikon engineers know that you don't to set the lowest ISO on their astro camera to 200 and lose all that precious dynamic range...

 

Jerry



#11 sgwells

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Posted 26 March 2019 - 10:56 AM

For those who think Nikon is so much better than Canon because they are ISO invariant and you can use the lowest ISO to get the most dynamic range, you should wonder what the Nikon engineers know that you don't to set the lowest ISO on their astro camera to 200 and lose all that precious dynamic range...

 

Jerry

Jerry, could you clarify what you're implying here? I'm genuinely curious.

 

I own a D810a and the first thing I did after receiving it was test the ISO variance by taking 10 shots across the ISO range. My results showed that the D810a is indeed ISO invariant, though I will be the first to admit I'm no expert and my conclusions could be wrong. But given my test results, I'm really curious to know what Nikon did to raise the minimum ISO to 200, and why.

 

Would love to hear your thoughts, thanks!


Edited by sgwells, 26 March 2019 - 10:59 AM.


#12 Jerry Lodriguss

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Posted 26 March 2019 - 03:28 PM

I own a D810a and the first thing I did after receiving it was test the ISO variance by taking 10 shots across the ISO range. My results showed that the D810a is indeed ISO invariant, though I will be the first to admit I'm no expert and my conclusions could be wrong. But given my test results, I'm really curious to know what Nikon did to raise the minimum ISO to 200, and why.

Hi sgwells,

 

I didn't say the D810a wasn't ISO invariant.

 

Why did nikon raise the minimum ISO to 200?  I don't know for sure, but I think it's because Nikon felt an astronomical camera was for shooting faint stuff, and a higher ISO will record that faint stuff better in terms of how much of the bit depth is devoted to the shadows.

 

Jerry



#13 sgwells

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Posted 26 March 2019 - 03:40 PM

Why did nikon raise the minimum ISO to 200?  I don't know for sure, but I think it's because Nikon felt an astronomical camera was for shooting faint stuff, and a higher ISO will record that faint stuff better in terms of how much of the bit depth is devoted to the shadows.

 

 

Sorry to confuse - I didn't think you were saying the D810a is ISO variant. I know you're an expert on DSLRs so I was hoping you had some knowledge on what changes Nikon made "under-the-hood." Despite extensive googling, I still have no idea why the min ISO is 200 instead of 64 and what other changes Nikon made in the ISO and noise-reduction areas.

 

Seems like there just isn't much info available about the D810a, which isn't too surprising since Nikon only sold a (relative) handful of them.

 

Anyway, thanks for the response!



#14 whwang

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Posted 26 March 2019 - 04:43 PM

D810A is a unique camera.  Its gains are different for R, G, and B (https://www.cloudyni...view/?p=6670965).  And I don't know any other cameras that do this.

 

The reason for a lower gain for its R is very easy to imagine: more R photons caused by the broader R bandwidth.  However, I can't understand why it requires different gains for G and B.

 

My guess is that the higher base ISO for D810A has something to do with the lower gain in R.  The higher ISO can compensate the lower gain, so you get roughly equal numbers of R electrons with D810A at ISO 200 comparing to D810/D800 at ISO 100.  If you ask further: why is this necessary?  I don't know.  Perhaps to lower the risk of saturation.


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#15 Jerry Lodriguss

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Posted 26 March 2019 - 05:29 PM

Sorry to confuse - I didn't think you were saying the D810a is ISO variant. I know you're an expert on DSLRs so I was hoping you had some knowledge on what changes Nikon made "under-the-hood." Despite extensive googling, I still have no idea why the min ISO is 200 instead of 64 and what other changes Nikon made in the ISO and noise-reduction areas.

 

Seems like there just isn't much info available about the D810a, which isn't too surprising since Nikon only sold a (relative) handful of them.

No problem, I confuse easily. :-)

 

No one really knows because Nikon doesn't reveal their secret sauce.

 

All the info we have on stuff like read noise doesn't come from the manufacturers.  It comes from some smart folks 'reverse engineering" the parameters from tests they do with flats and bias and test frames.

 

The camera manufacturers consider this stuff proprietary info, but when someone knowledgeable like Wei-Hao makes a guess, it's probably a really good guess.

 

And even then, you get weird stuff going on, like problems with flats with the D5300.  And I think I see some weird stuff in the deepest shadows with the D5300 that I don't see with the Canons.

 

Jerry



#16 sgwells

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Posted 27 March 2019 - 12:08 PM

Wei-Hao, Thank you for sharing that info. Very interesting.



#17 KLWalsh

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Posted 27 March 2019 - 10:24 PM

There is a Lo1 ISO setting for the D810A which is listed as equivalent to ISO 100.
I haven’t used it, so I can’t say if there is any reason to use it for AP.
I’ve used the Hi2 setting (ISO 25600 equivalent?) but only to make sure I’ve framed the object properly and that my focus is still good. A 10 sec shot highly magnified in BYN lets me check focus, and a 20 or 30 sec shot lets me check image centering.

#18 whwang

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Posted 27 March 2019 - 10:49 PM

Those Hi/Lo ISO settings typically use digital post-processing to boost/suppress the image brightness, which is identical to changing the image brightness in Photoshop.  Using such settings will not give you the benefit of lower read noise (Hi cases) nor larger dynamical range (Lo cases).  Personally I do not find them useful, except for the Hi ISOs for quick framing preview on the camera LCD.



#19 KLWalsh

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Posted 28 March 2019 - 12:19 PM

Those Hi/Lo ISO settings typically use digital post-processing to boost/suppress the image brightness, which is identical to changing the image brightness in Photoshop. Using such settings will not give you the benefit of lower read noise (Hi cases) nor larger dynamical range (Lo cases). Personally I do not find them useful, except for the Hi ISOs for quick framing preview on the camera LCD.


I was suspecting that to be the case. Thanks for the reply.

#20 nofxrx

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Posted 09 April 2019 - 06:16 AM

@Spica010 One just hit the classifieds...for what it's worth.

(No affiliation with seller!)

https://www.cloudyni...ro-d810a-36-mp/



#21 andysea

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Posted 10 April 2019 - 11:40 PM

I have not used other Nikon cameras but I do have the D810a. What I see is that the calibration is always impeccable. I wonder if the D810a does less behind the scenes manipulation of the RAW files with respect to other models?

Coming from a modded 6D I find the D810a a big improvement.


Edited by andysea, 11 April 2019 - 10:40 AM.

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