Does anyone else have issues of hot pixels on their D800? I just shot a few night shots at ISO 100, with anywhere from 6-30 second expsosure. At 15 seconds they become noticeable and by 30 seconds, they're bright enough to make you wonder if they are city lights (need to mention these are viewed at 100% in ACR).

I have found a couple on mine, if I look for them.

These will not show up on a photo and I am not bothered by a few hot pixels out of 36 million.

Visit my Nikonians gallery.

Visit my Nikonians gallery.

I just took three 30 second exposures of a lens cap at ISO 100 and no hot pixels. In my earlier situation, I was shooting 6-30 second exposures at ISO 100 for about 15-20 minutes (cityscape). My guess is the length of time shooting and length of each exposure all added up to increase sensor temperature, thus increase hot pixel visibility. I would guess that once the sensor cooled down, the hot pixel issue seems to have gone away.

So, my next question would be how long does it take the sensor to cool down so hot pixels don't crop up at 15 seconds exposure? Does increasing ISO increase the sensor temperature?

I just did the same thing. I took 3 - 30 second exposures in a row and did not find one hot pixel... Good findings I guess.

Michael Kaplan
http://www.pbase.com/mkaplan

Do you have Long Exposure Noise Reduction turned on?

Rick Walker

My photos:
GeoVista Photography

Download from our library of Image Doctor podcasts here

>Do you have Long Exposure Noise Reduction turned on?

Nope... Wanted to see the images without any significant in-camera processing.

Using long exposure noise reduction is the normal way of making exposures of that length. You'll see all sorts of artifacts with most any camera without it enabled.

Rick Walker

My photos:
GeoVista Photography

Download from our library of Image Doctor podcasts here

>Using long exposure noise reduction is the normal way of
>making exposures of that length. You'll see all sorts of
>artifacts with most any camera without it enabled.

I understand that but LENR is not a sensor cooler and I wanted to see how the sensor performs without LENR and whether or not hot pixels would affect my pictures. In yesterday's scenario it did. Just wanted know about other's experience.

>Using long exposure noise reduction is the normal way of
>making exposures of that length. You'll see all sorts of
>artifacts with most any camera without it enabled.


I think the noise you're referring to on your LE pictures are digital artifact noise where as what I am seeing are actual "hot" pixels that are brighter and sometimes in different colors than what the surrounding colors seem to be. Please correct me if I am wrong.

Long exposure noise reduction fixed both problems. If you don't have it enabled for long exposures, you'll almost always see hot pixels in my experience.

Rick Walker

My photos:
GeoVista Photography

Download from our library of Image Doctor podcasts here

I see way more hot pixels than I would expect on 100% views of very long exposure images. It is not unusual for me to shoot long exposures that last several minutes. Even with LENR on the hot pixels will show up in quantities that would easily take an hour to clean up (I print large format images so I will have to clean up the images that are selected for printing)

I have experimented LENR in ON and OFF settings. When turned off the noise increase during long exposures at low ISO settings is minimal and easily dealt with in post up until exposures of approximately 4 minutes. That is just the noise, the hot pixels are a different and annoying story.

Maybe this discussion could be of any help?

As for running LENR - when your exposure gets into minutes or longer, your NR will take just as long, doubling your frame capturing time, making you miss other possible shots and drain your battery faster. Am I wrong?

You're absolutely right AAY. On my previous cameras the LENR would be on because I could see a big difference and it would take a lot of PP to get rid of some kinds of noise. On the D800 it does not make sense to me unless the LE runs into 4+ minutes. And yes I have lost shots waiting for LENR to do its job. (You know how fast the light changes here during sunset / sunrise. 5 Minutes in between frames is enough time to lose the best light of the day)