Jpg Vs Raw - Deadpixels

A

atufte1@mac.com

Alexander Tufte
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Hello fellow R-D1 shooters..

I was almost shocked to see the results from a wedding
i did yesterday...
I always shot raw, but for this job there were no time
for post processing, so i went on with a big smile on my
face with the camera set to JPG B&W...
On all of the pictures i took (over 500), there is 10 big heeps of
deadpixels with 4-5 more or less deadpixels tucked in together,
and their all noticable even without zooming....?!!
With raw i get maybe 1 or 2 hotpixels on high ISO's but they
move around, and did'nt really bother me much...
But this is a BIG problem, because it seem as if i cant use
JPG at all, and this is not something you suspect from a camera
in this pricerange...!!??

I really love the camera, and it's been almost perfect until i
discovered this, (it has slightly "off" framelines but i got
used to it)

After reading this forum i'm really afraid for the replacement
i hopefully get for this one, i heard of people on their 4'th one
still finding problems with it, is this a common problem or is
it only my bad luck...?

My R-D1 counts about 2500 expo's
And why dosent the 'faulty' pixels appear when i shoot raw, is
there some mapping of deadpixels in the Epson Converter?

Best Regards

Alexander Tufte
 
Alexander,
One possibility that springs to mind is that some dust has gotten on to the sensor,
Long shot I know... It would be good if you could re test shooting both JPG and Raw at
a dark and light background and at 200 and 800 and 1600.
If you get the same problems now it very well could be dust.
I have heard this going the otherway around.. As in no dead pixels visible in JPG but there in RAW. This is I think the first time I have heard it this way around..
Mike.
Can you post an example?
 
I'm guessing here, but...

As you've probably noticed in other images, a quirk of the JPEG compression algorithm is that it exaggerates edges around small details. You've probably noticed this in JPEG pictures that have lots of small, high-contrast details, such as leaves on trees against the sky -- if you look at such an area closely, you'll often see "ridges" around the edges of the leaves.

I'm attaching a couple of files I made in Photoshop to simulate this: the "HQ" one was saved with the maximum quality setting, and shows none of these "compression artifacts." The "LQ" one was saved at the minimum quality setting, and shows a lot of the artifacts.

Looking at the examples, you can see how JPEG compression artifacts could make a relatively mild crop of hot pixels look much worse! (This will happen with any digital camera that uses JPEG compression, not just the R-D 1.)


Is there anything you can do about it after the fact? Well, you might try this automated fix, if you've got the full version of Photoshop. (Warning: It only works on your original, uncropped JPEG files.) Here's how to do it:

1) Set your R-D 1 the way you had it when you shot the "problem" pictures, and shoot a frame with the lens cap on. This should give you a completely dark frame with your hot pixel clumps clearly showing.

2) Manipulate the black-frame image in Photoshop so that the background is completely black and the hottest pixel is completely white. Using the Image>Mode command, convert the black-frame image to grayscale. Now save it -- for example, call it hot pixels.psd

Leave this file open as you perform the next steps. Since the hot pixels in your pictures should be in the same locations as in this file (that's why you have to use original, uncropped files) you can use it as a "map" to locate the hot pixels automatically and fix them.

3) Open one of your "problem" images. Load the hot pixels image as a selection, by using the Select>Load Selection menu command. Choose hot pixels.psd as your source document, and 'gray' as the source channel. This converts your hot-pixel map to a selection that you'll see on your image.

4) Using Photoshop's Filter>Noise>Dust and Scratches command, find a filter setting that eliminates the hot pixels with as little degradation as possible to the image. You may want to apply a small amount of feathering first (Selection>Feather) to blend the repair into the image.

5) Once you have some settings that work, you can create an Action that will automatically apply these steps to all 500 "problem" images. I suggest saving new copies in another folder, rather than overwriting the originals; that way, if something goes wrong on a particular image, you can go back to the original and fix it manually.

This may sound like a lot of bother, but it isn't hard to set up, and it recently saved my bacon when I had several hundred high-ISO JPEG images that needed some hot pixels repaired.
 
Last edited:
The CS2 Photoshop Raw converter automatically patches for dead or hot pixels and makes these anomalies completely invisible.
 
Hello thanks for reply...

I just did a test shooting at f/16 against the blue summer sky, and
yes there are some dust , but at different locations then the deadpixels!
I also shot the exact same scene in RAW and JPG, with the same results
as i tought, deadpixels on the JPG and nothing on the RAW...?

I would gladly post an example but i couldnt figure out how, sorry...!!

I really think this camera is going back to its birthplace, EPSON, i really
does hope for a healty camera nr.2...

Wish me luck, hehee....

Best Regards

Alexander Tufte
 
Thanks JLW, i will try this in PS, for this pictures, but tomorrow the R-D1 goes back,
because there are way to many deadpixels, to make this into a habit...

Thanks for very useful tips...

Alex
 
vincenzo said:
The CS2 Photoshop Raw converter automatically patches for dead or hot pixels and makes these anomalies completely invisible.
Click to expand...

Yes, but he shot the original files in JPEG format, not raw.

If he had shot raw format, the problem wouldn't be as severe in the first place (hot pixels would not be exaggerated by JPEG compresson artifacts) and he would have a lot more options for solving it (CS2 hot-pixel patcher, similar function in Raw Developer, bad-pixel map in dcraw, etc.)

Yet another reason for only shooting in raw, all the time. If only it were always practical to do this in the real world! Unfortunately, sometimes it isn't, and then we need to be prepared to dip into our bag of tricks.
 
atufte1@mac.com said:
Thanks JLW, i will try this in PS, for this pictures, but tomorrow the R-D1 goes back,
because there are way to many deadpixels, to make this into a habit...Alex
Click to expand...

I hope that helps. But if you are seeing only one or two hot pixels in raw-format pictures (not at all an excessive number for any digital camera) then I suspect most of your problem stems from JPEG compression artifacts instead. If that's the case, your replacement camera may produce results that you find any better, although that's certainly worth trying.

Some digital cameras are more strongly afflicted by this than others, depending on the degree of JPEG compression that they apply -- but with any camera, JPEG compression will exaggerate the appearance of minor image flaws.
 
Would you like to post a full-size sample for us to look at? It doesn't sound normal at all.

Sean
 
10 Hot/Dead pixels in jpeg mode seems high to me and I think you are right to exchange the camera. I have 3 in jpeg mode at iso 400 and upwards but they only prove troublesome if they coiniside with a plain area. From earlier discussions on the topic here up to 3 or 4 hot pixels in jpeg mode seems about typical for the R-D1 so you should get a better example on exchange, at least in this respect.

Judging from what has been said here and from friends who have made exchanges, serial numbers above about 003400 seem to be showing better quality control on all counts. Hopefully this is the case.
 
I would like to post a fullsize image sample, but i get an error saying my image is to big when i try to upload to the image gallery....?

Anyone here who knows have to do this...?

Alex
 
Hi Jim

Judging from what has been said here and from friends who have made exchanges, serial numbers above about 003400 seem to be showing better quality control on all counts. Hopefully this is the case.[/QUOTE]


Hmmm, thats odd, it seem's mine is a 0036XX so maybe
there are flaws after this numbers aswell....?

Best Regards

Alexander Tufte
 
Alex,
Looks like I jumped to an assumption too soon. I know of two people who exchanged because of rangefinder alignment and frameline problems both had started with serial numbers below 003000 and were replaced with ones which seem O.K. above 3400. One friend's original was strange as he only brought it in the U.K. last month (and his dealer had to order from the distributer) yet he had a lower serial number than mine brought last December. This made me think that the distributer was recycling returns, but if this was the case you would have thought they would have fixed the rangefinder spot , which was cranked at an angle, before sending it back out.

Epson can't be doing themselves any favours if the QA issues still haven't been fixed for this fairly expensive camera.
 
Same here

Same here

My Rd1 now has about 8 dead/hot pixels in JPEG mode at any ISO. In RAW there are NO dead or hot pixels. WHy is this?

Just got mine today and noticed two right off the bat. Then after closer inspection I found 8 bad pixels. Kind of disapointing. Love the camera anyway. Crazy isnt it? Loving a $3k cam with bad pixels? I may exchange it though...

S
 
sgy1962 said:
Are dead pixels something present in all digital cameras?
Click to expand...

Pretty much. I just posted something about this in another R-D 1 thread. The dead-pixel-count on my R-D 1 is no worse than on any of the other digital cameras I've owned.

Imagine manufacturing six million of anything (pixels, potatoes, piccolos, whatever) and saying that if even one of them was defective, you'd throw the whole lot away. That would have to be a very expensive product! The manufacturers have to accept a certain minimal level of dead sites in order to get a product people can afford.

This is just as true with LCD screens, for example, as with digital camera imagers. If you looked critically at the image on an LCD monitor, or a flatscreen TV, or whatever, you'd almost certainly find a dead pixel or three. Most people don't notice them because they blend into details of the image and because we don't look that hard.

We do look hard at photographs, though, so we're more likely to notice them. And some of us shoot types of subject matter that make them more evident, and some of us are more tolerant than others of minor defects. IMO, these differences in expectation and tolerance, interacting with random camera-to-camera variations, account for the fact that some of us are delighted with our R-D 1s, others are satisfied but not thrilled, and others find their cameras unacceptable.

I do think Epson (or its sensor vendor) could have done a better job of mapping bad pixels so at least they'd be less obtrusive. But in terms of count, I don't think they've done any worse than anyone else.

It's also important to note that there are other causes for bad image pixels than bad sensor pixels -- random electrical noise and JPEG compression, for example. If your bad pixels move around rather than always appearing in the same place, they're probably from something other than sensor faults.
 
Ok, i have seen deadpixels on all of my DSLR's aswell, but not in a severe way like this, you dont need to zoom in on the pictures to see them, and they are WAY to many, i have 10 big heeps of dead pixel's, because the things you see here are not 10 dead pixels as it seems but rather 50+ if i zoom in on the deadpixel area....

See for your self:

http://www.alexandertufte.com/Oversikt_win.jpg

Best Regards

Alexander Tufte
 
That is about how mine is looking - I have about 8-9 clumps and if zoomed in, you see its a group of pixels making it appear to be one large pixel.

My E1 had one bad pixel but with the built in mapping it fixed itself with a push of a button. My D2h had NO bad pixels and neither did my old D70. When I had the 1ds it had ONE. The Epson at $3k has WAY WAY too many bad pixels. Epson could of mapped these out easily. Why they didnt I have no idea. This is the only problem I have with mine, otherwise it would be perfect.
 
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