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Sony Nex-7 Long Exposure noise

Paul2660

Well-known member
How well does the Nex-7 handle long exposures with long noise reduction off? Example, say a 30 sec at ISO100 or a 2 min a ISO 400. I am still waiting in three locations for a Nex-7 to get back in stock, so I can't test for myself yet.

I am interested long exposures with no noise reduction since I would like to start taking nighttime stacks with the Nex-7 and with these you need to have your Noise reduction off or the corresponding dark frame adds a gap in the stars. My only experience so far is the Canon and Nikon full frame digital lineup, but I would appreciate any feedback on how the Nex-7 does in this type of photography.

I have found several different devices that will allow the camera to work with a intervoltmeter so you can take as many images as you need for the time frame just as you would with the Canon remote. The ones for the Nex-7 all work with the IR port but still should get the job done.

Looking for feedback on overall noise and or amount of stuck pixels.

Thanks
Paul
 

Paul2660

Well-known member
Actually the reason I shoot a stack is to get best penetration of all the stars in a night sky when working with the moon for illumination.

I use stacking to get a better balance between moon light illumination and the illumination of the various stars. This allows you to use the moon to illuminate the rest of the scene just as the sun would. With a 3/4's moon, if you leave you camera open for 40 minutes, I have found that you will mostly see just the brightest stars, where instead if you figure out the right time lapse, say 2 minutes at F3.5 at ISO 200 over the same 40 minutes, you will get a series of images that still use the moon for illumination but will not lose all the stars. The difference is really quite amazing after you combine everything. This also gives you the ability to keep only the best frame of the non sky parts of the image and blend it back into the finished sky. This is important to minimize wind and shadow movement. Instead if you shoot on a moonless night, you either have a dark shadow where the horizon starts or you can attempt light painting. For me light painted landscapes don't work as well as moon light illuminated ones.

As for noise, it's a trade off, since you can't take the dark frame each time or you will eventually buffer out plus you get the gap. But shooting at 30" at ISO 400 with a 5D MKII still will give you some noise, however it's a level of noise that so far I can work with. Sure if you turn on long noise reduction the image will be much cleaner, but you have all the other issues to work around.

That's what I was curious on the Sony. From what I read on other reviews the noise on the Nex-7 seems to be better than noise on the A77 due to the fact that the translucent mirror robs some of the the light. But with a long exposure of 30" or more I figure you are looking at noise more due to the imager or heat build up. I am hoping that for exposures between 10" and 5 minutes, the noise build up on the Nex-7 will compare to what Canon has, which is nominal as long as you keep the camera between ISO 100 to ISO 400. I realize you that there will be some stuck pixels, there always seem to be some but these are overall easy to remove, whereas overall image noise can get harsh enough to make the images really not useable.

Paul
 
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