Author Topic: D800 - v - D810?  (Read 574 times)

Birna Rřrslett

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Re: D800 - v - D810?
« Reply #15 on: November 27, 2018, 08:56:09 »
Moving the entire bellows thus having a fixed magnification and altered subject distance would be the better approach. However, as you are round 1:1 magnification, the practical difference against other methods might be slight.

This is a task well suited for an automated solution such as the Stackshot by Cognisys (or similar products).

Seapy

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Re: D800 - v - D810?
« Reply #16 on: November 27, 2018, 09:43:10 »
Thank you Birna, this is a conundrum I have often considered, not quite the same circumstances as a three dimensional subject but similar.

I tend to very slightly crop the image in camera, or occasionally close in on a detail.  I also have quite a few 110 negatives which of course need magnification.
Robert C. P.
South Cumbria, UK

Řivind Třien

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Re: D800 - v - D810?
« Reply #17 on: November 27, 2018, 12:16:00 »
Thank you all for a good discussion. It all helps to focus my thoughts and resolve a solution.

Since I got my D3 and realised it has it's limitations especially for repeated night time exposures.  I get progressively worse banding using the intervalometer after the first few exposures. I have been trying to plan a solution.  The realisation that repeated long exposures lead to noise and banding has now sunk in.  With this realisation come a search for a solution.  The D3 was the first of a new generation, FX sensor and new standards of high ISO usable range.  Things have moved on, I can't afford new kit but have to capitalise on perfectly usable kit becoming affordable.

My enthusiasm for photography is  somewhat dependant on getting reasonable results, yet I constantly want to push the boundaries.  Achieve new things and to a reasonable standard, the best I can.
...

Robert, have you tried to stack frames using dark frame subtraction (the latter based on almost as many frames as the light frames)? That should help cancel part of the pattern noise. Also if pattern noise occurs at low ISO, turning up ISO can cause it to be drowned out in other noise (as happens with my D7100). DeepskyStacker (DSS) takes care of these tasks automatically.
Řivind Třien

Seapy

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Re: D800 - v - D810?
« Reply #18 on: November 27, 2018, 14:51:06 »
No I haven't taken dark exposures, for star trails, found it didn't work, for time-lapse (the first time encountered banding on the D3 and a huge disappointment) it gets complicated, in fact I don't know how you would apply dark frames to time-lapse, for Star stacking I have tried dark frames but although it seemed to work to some degree, star stacking process actually tends to cancel out the banding naturally, because of the sky rotation.

One of my objectives is to create a time lapse of the tidal flow in the nearby estuary at night with the stars apparently rotating in the sky above the estuary and clouds passing by, possibly illuminated by a full moon.  I have tried it but the banding is obvious and intrusive.

According to Ralph Hill

https://sites.google.com/site/starrylandscapestacker/capturing-images-quick-guide

He is now casting doubt on the process of recommending against using dark frames.
Robert C. P.
South Cumbria, UK

Řivind Třien

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Re: D800 - v - D810?
« Reply #19 on: November 27, 2018, 15:23:11 »
Yes, neither star trails or non-stacked time lapse is a god candidate for using dark frames. For some sensors with good dark current suppression it is best to drop them, in other cases with a sensor more fixed pattern noise, poor hot pixel suppression and inadequate dark current suppression it makes sense to use dark frames.  However as it is correct that they can add noise, the number of dark frames should approach the number of light frames to reduce their noise contribution. Sticking to 10 dark frames is way to little if one tracks for one or more hours.
Řivind Třien