Hot Pixels

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Gary Nelson

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I just received the RD-1 first photos looked great. But upon closer examination found hot pixels. Looking at a few photos the hot pixels seem to move. The Raw file yielded different results than the JPEGs. Am I seeing things? How can the hot pixels move from photo to photo?
The camera looks and feels great, solid build love the analog gauges. First photos were taken with Konica 50mm f/2 lens.
 
Some pixels may be hot all the time; others are OK until they get exposed beyond a threshold, then they go hot. ISO settings also affect this; at low ISOs the signal from the sensor isn't boosted as much, so a pixel that is fine at 200 may go hot at 1600.

JPEG interpolation also can affect the appearance of a hot pixel (this was explained to me in an email by Dave Coffin, author of the dcraw conversion code used in many raw-file-conversion programs.) Also, some of us suspect that the R-D 1's JPEG compression algorithm itself may produce occasional artifacts that look like hot pixels -- I know I've got several that appear in JPEG files but not raw files.

Just to make things even more confusing, random electrical noise could cause sporadic hot pixels that appear at some times but not others.

With all the things that can go wrong, sometimes I'm surprised that photography works at all...
 
Gary,
Of the digital cameras I've owned, the R-D1 is the first where I've become aware of visible hot pixels. There are several threads on hot pixels in this forum, and it seems to be something you get to live with.

I get a bit frustrated with things about the R-D1 (rangefinder precision, etc) but the actual picture taking experience is so nice that I happily put up with it.

Phil

By the way, off topic, I've also got a Hexanon 50/2. Have you ever compared it to a late Summicron?
 
All sensors have some hot and/or stuck pixels. My R-D1 has a few that often show up at ISO 1600. With most cameras they're mapped out via firmware. But it seems Epson didn't do this...or didn't do it aggressively enough. If you shoot in RAW format and have a Windows PC the RSE (RAW Shooter Essentials) converter does a good job of detecting and cleaning up errant pixels.

-Dave-
 
If you shoot in RAW format and have a Windows PC the RSE (RAW Shooter Essentials) converter does a good job of detecting and cleaning up errant pixels.
Click to expand...

And if you use a Mac, RAW Developer has a function for detecting hot (and dead) pixels that seemed to work well in my limited testing. The dcraw command-line raw file converter (available for Windows, Mac and Linux) lets you map out bad pixels by manually entering their coordinates in a '.badpixels' file.

For hot pixels in JPEG images, see my other thread about fixing these automatically in Photoshop using a hot-pixel map image (which you make by shooting a dark frame with the lens cap on) and a Photoshop action that calls the Dust and Scratches filter to retouch them. Since my initial posting, I've been through several hundred ISO 1600 images previously afflicted with hot pixels, and this gambit seems to have been very effective at fixing them.
 
I am having similar hot pixel issues in my new R-D1s.

I read somewhere that the R-D1s (but not the R-D1) has an on-camera menu option for getting rid of hot pixels. Is this true? If so, what is this menu option called?

EDIT: Nevermind, I found it. Will try and see if it works later today.
 
Last edited:
trias10 said:
I am having similar hot pixel issues in my new R-D1s.

I read somewhere that the R-D1s (but not the R-D1) has an on-camera menu option for getting rid of hot pixels. Is this true? If so, what is this menu option called?

EDIT: Nevermind, I found it. Will try and see if it works later today.
Click to expand...

for those who haven't found it, it's on the second "page" of the Basic Settings menu.

it's worked quite nicely for me.
 
Sometimes the "hot pixel" mapping option of the R-D1s requires several activations to completely eliminate the hot/dead pixels. I have found that using it only once did nothing, but reactivating it about four times eventually eliminated the troublesome pixels. Don't know why this should be so.

/T
P.S. They eventually return, and you have to do the whole procedure over again.
 
Tuolumne said:
Sometimes the "hot pixel" mapping option of the R-D1s requires several activations to completely eliminate the hot/dead pixels. I have found that using it only once did nothing, but reactivating it about four times eventually eliminated the troublesome pixels. Don't know why this should be so.

/T
P.S. They eventually return, and you have to do the whole procedure over again.
Click to expand...
Exactly. In my case, hot pixels basically only appear at ISO1600 and lightroom takes care of most of them. I use the clean dust function to remove them one by one which is a bit cumbersome.
 
In order to run the dead pixel mapping most effectively, should you set the ISO to 1600?

Also, do you need to take the lens off (and put on the dust cover), or you can you keep the lens on and just put on the lens cap?
 
trias10 said:
In order to run the dead pixel mapping most effectively, should you set the ISO to 1600?

Also, do you need to take the lens off (and put on the dust cover), or you can you keep the lens on and just put on the lens cap?
Click to expand...

Those are good questions. I've never paid attention to any of that when I do the dead pixel menu option. Here is a chance for you to experiment and let us know. 🙂

/T
 
I am sorry to bring up a dead thread but I think my experience (below) should be useful for other R-D1 users.

Since I get my used R-D1 a couple of days ago I run a dead/hot pixel test software to find out that I have no dead pixels but many hot. There were 28 consistent hot pixels 1/30s shots with lens cap on. 3 of them are clusters (3 to 6 neighboring pixels) so if I count clusters as one, the number of hot pixels & spots was 18. When I shoot at ISO 200 at AE, the exposure was around 4 seconds and hot pixels were around 120, and ISO 1600 the exposure was around 10 seconds and it caused around 300 hot pixels. (and I did the test after not using the camera for several hours), obviously noise kicked in as well.

What I did was using the dead pixel correction feature in the camera menu. I set the ISO at 1600 (no such instruction and I believe ISO setting has nothing to do with it but in case it happens to be related, by logic I choose top ISO) and run it. It took a couple of seconds and after it ended I took another set of lens-cap-on shots at 1/30s and at AE which causes 8-10 seconds long exposure). Even though the correction is for dead pixels it amazingly worked at my first try and all hot pixels are gone for 1/30s shot, however long exposure shots still had many hot pixels so I went back to the manu and turned on the long exposure noise correction. Took another set of lens-cap-on shots at ISO 200 and 1600 at AE and analysed the image. There were only 3 in ISO 200 shot (ard. 4 second exposure) and only 18 at 1600 (ard. 10 second exposure) which are quite acceptable to me.

I feel as if I hit the jackpot ! Well, almost 🙂 Hope this serves to other R-D1 users as well.
 
there was a time when i examined sensors of my cameras and counted every hot/dead pixel (it was terrible if i found some). now i do not care about pixels any longer. i am free
 
I never checked or cared much about them either until now. This time though, it was because two clusters of 5-6 pixels showing up as light pink dots in my images that were too obvious against dark backgrounds.
 
nik software has also released a great plugin for photoshop, lightroom, and aperture for fixing dead pixels in an image (among other things). It's called dfine 2.0. I love it!
 
I view hot pixels much the same as dust on sensor. You will have them, but only worry if you start seeing something in your photos. So far I have had issues only with sensor dust. All my cameras obviously must have several hot pixels, but they don't appear in the final photos consistently.

My Leica M8 sometimes gives me hot pixels in the chimp mode. The LCD is fine and the hot pixels disappear when you browse or magnify the images. I don't really know what's going on there. Perhaps there's something wrong with the JPEG/resize algorithm on the camera.
 
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