Nikon D3300 astrophoto issue

grofmathias

Hello,

sometimes, mostly during colder conditions when I process NEF file from my camera there is output jpeg with specific pattern (enhanced to better imagination): http://www.imagebam.com/image/e9092d438689675 . I don´t know, if it is a software problem or sensor issue.
I take this photo with Tamron 17-50/ f2.8, 20s exposure, ISO 1600. For conversion I use Adobe Camera raw 9.1
Did it occur to anyone else?

Ironheart

Do you have LENR turned on? (Long Exposure Noise Reduction) This will remove the dark current from the photo among other things.

grofmathias

Hi. I don´t use LENR, because it is functional only for jpeg output, not for NEF raw files.

spraynpray

I wonder if it is colour banding. Next time, try ISO 3200 and ISO 800 and see what happens. If I am right, it will be worse or still there at ISO 800 and better at ISO 3200 but if it is that, I will be surprised because the new Nikon sensors are very good at night. I do a lot of this stuff and I never get problems like this with D5000, D90, D7000, D7100 or D750.

grofmathias

So, that was why I choose Nikon - better low light performance. But this gets me little bit angry. It occur when I shoot between 800-3200 ISO range. Nikon said that it will be probably conversion software problem, but this pattern is very symmetrical.

spraynpray

OK @grofmathias, let's see if it is the processing. Can you email me the full resolution raw file? Send it to floggist(at)gmail.com and I'll process it and post it here.

grofmathias

Image sent :-)

Ironheart

LENR is for raw files. It does a dark frame subtraction and removes hot spots. Try it. You might like it. However your artifact does look like something in post.

spraynpray

@grofmathias - Sorry I've been really busy for a few days but I have now had a look at the file you sent and can tell you that the original image is so over-exposed that it is beyond the result you are trying to get with it. I can't tell you why you are getting the strange pattern, I couldn't get that to happen. You have to realise that there are limits to the amount of data captured and held in a raw file and in this instance you needed to be at least two stops lower on the exposure to be able to recover anything. Possibly 3 stops would have got you a file that would have ended up right.

So don't worry about the pattern, go learn settings.

PS, you will never get good stars with so much light pollution in the picture so decide what it is you want to see and either go to a dark area for stars or forget about seeing many and expose for the rest of the picture.

grofmathias

spraynpray - thank you, so I want something, that my camera could not do Dark area is a big problem near my location.

Paperman

Just to let you know that in 2 of the 3 times I tried the link, it lead to malware ( blue screen with nasty warnings but luckily it was a fake one that I could turn off with the task manager ).

Paperman

Oh, no more "edit" option ?? ... :-O Just wanted to add that the net is full of warnings about IMAGEBAM / Trojans etc ... Please remove link or place a warning as it may be too late by the time a reader reads this ...

spraynpray

@Paperman: Move your mouse just to the right of the quote function (top right of your post) and you will see a 'cog' appear. Edit and delete are under that.

@grofmathias: Please use Flickr to host images on NR for safety reasons.

As regards the dark sky problem, well, you will have to go for a darker exposure and see how it goes, just don't under expose and brighten too much or you will get a lot of noise. There is an old maxim - 'get it right in camera' - it still applies in that if you have to push or pull your images when editing, you will get problems. I prefer to live my life in an 'aim close, miss close' kind of way so had never encountered such a problem before.

Hope this all helped.

tcole1983

Problem is you are asking for something that even the best cameras made can't do. As spray explained you have to do a multiple exposure. One for the dark and one for the light. The dynamic range in the cameras isn't capable of exposing both properly in one shot. There are many techniques that I don't even do that really do improve photos...I am a bit lazy and this is something I haven't ever tried.