Issues with banding.

akv

Well-Known Member
Hi all,
I've been noticing that I've been getting banding on some images from time to time.
The major part of it is across the lower half of the frame when holding the camera normally.
I first noticed it when I used my Sigma EF 500 DG Flash wirelessly. There was very obvious banding on the lower half. In some other images I notice it but it's very faint.
In the test image I used to look for dust spots you can see it across the whole image.
And in the chipmunk image the camera was set at 1600Iso and I used the built in flash.
I sent an email to Sigma USA but they didn't say much, they didn't think it was an issue with using the wireless flash. And said I could send it in if I wanted.
Anyone else have these issues? I've got a Square Trade Warranty on the camera and I was wondering if I should send it in or not? Recently it only seems to show up in the high ISO shots and not always.

Thanks for any input!
 

Attachments

tc95

Well-Known Member
Akv,

Unfortunatly...the Sigma's that are out are really bad over ISO 800....I have had issues with them unless it is in a concert enviroment...where there is not a lot of information that has to be transfered from the sensor to the memory card...I am not technical...but it seems to progressively get worse from ISO 400

ISO 400 OK
ISO 800 1/2 I get are bad
ISO 1600 1/5 of the shots are keepers...

I don't use my flash at anything over ISO 400 and really keep it to ISO 200 when using it....the images and colors seem to come out better...at ISO 800 I usually use the manual mode and play with the f-stop and exposure times....most of the shots are dark..but I let the Sigma software help me pull them back to where they need to be before I use PS or NX2 to edit them further...

Uwe or Klaus can give a better explination on why there is issues at ISO 800 and 1600...you might want to PM them...

Tony C.
 

akv

Well-Known Member
Thanks Tony,
I knew about the higher ISO issues that the SD14 has. But I've noticed the banding in shots where I used the flash in lower ISO settings. And the banding on 1600 seems to be a lot worse than some of the examples I've seen.
I hardly ever shoot above 400, unless I'm going to take the color out.
 

Robert.4507

Well-Known Member
Hi AKV,

Sorry to hear about the problems with your camera. Personally I have not seen banding like these two shots in the pictures from my SD14, and I have taken about 9000 pics with it.

good luck,

Robert
 

Steaphany

Well-Known Member
I have not seen this either, and you know my diverse SD14 uses, medium and long night and astronomical exposures do have noise, but no banding. One thing to keep in mind is I try to stay with ISO 100.
 

akv

Well-Known Member
thanks for the info guys,
It's not a permanent issue, it only comes along once in a while. Usually when I use the flash. I'm guessing it might be a battery issue too. I've got a CTA battery I bought from Cameta Camera, and I think that as it gets low on power maybe there's fluctuation in the charge or some other engineering based answer that I haven't the slightest clue about.
I think if it gets worse I can always send it in to Sigma, but really nothing major, more just an annoyance when it does happen.
 

notalent

Active Member
I have seen this once with my SD14. I have just purchased the camera and taken only a couple dozen pictures so far. Here is the EXIF from the original picture.

Camera Model: SIGMA SD14
Image Date: 2009:04:18 09:37:06
Flash Used: Yes
Focal Length: 18.0mm (35mm equivalent: 30mm)
Exposure Time: 0.017 s (1/60)
Aperture: f/3.5
ISO equiv: 100
Exposure Bias: -0.70
White Balance: Auto
Metering Mode: Center Weight
Exposure: program (Auto)
Exposure Mode: Auto Bracketing

Sigma 18-50mm f3.5-5.6 DC Lens

Here is a crop:
banding.jpg
 

akv

Well-Known Member
Thanks notalent!
I was starting to think it was something I was doing.
When I noticed it in the lower ISO settings for me I was using a 500 dg flash remotely. So I did trigger the in camera flash, that might be something we did in common. I get it mostly on the high ISO though but it doesn't happen very often at all, so I'm thinking it might be a battery issue.
My lines go horizontally when I hold the camera in landscape, and I notice that it's more visible in the lower half of the image (if you divide the image directly in half it becomes more prominent right at the middle).
 

akv

Well-Known Member
notalent,
Were you using the PG-21 battery grip when you took that shot?
 

akv

Well-Known Member
Thanks notalent,
I had a pg-21 on mine. Do you remember if it was in RAW or JPEG mode?
Steaphany suggested that it might be from the in camera processing the RAW info to fit it into the Medium RAW format as opposed to the Hi RAW.
 

notalent

Active Member
Thanks notalent,
I had a pg-21 on mine. Do you remember if it was in RAW or JPEG mode?
Steaphany suggested that it might be from the in camera processing the RAW info to fit it into the Medium RAW format as opposed to the Hi RAW.
I only use RAW mode. I had to recharge the battery that night, and this was one of the last shots before the recharge.
 

notalent

Active Member
I only use RAW mode. I had to recharge the battery that night, and this was one of the last shots before the recharge.
Sorry, I meant to say HI RAW mode.

However, I tend to doubt the low power issue, unless there is some analog component in the chain somewhere. A computer will either execute instructions correctly or not at all. So this may be some kind of bug (or feature) in software/firmware that only manifests itself under specific combination of variables that are not encountered very often.

Unless, of course, you are encountering it very often. :z04_pc2:

Regards
 

akv

Well-Known Member
Thanks notalent,
So I guess it's not just the MED RAW that gets it. Although it might be a matter of degrees cause the banding in your image doesn't look as bad as in mine.

I figured it was a power issue more for the sensor itself rather than part of the image processing. Where the sensor isn't getting as much energy as it needs, but that's just a voodoo mumbo jumbo guess on my part.

And it doesn't happen too often with me. So I haven't bothered sending it in to Sigma or anything... yet.
 

Robert.4507

Well-Known Member
Hi AKV,

This week-end my counter passed 30,000. but the important part is that I saw the first banding problem. I usually only shoot in Raw. Somtimes lo or med depending on the sustained burst rate that I want to achieve. This instance was shooting HI-Raw spot metering, and was birding, so the shutter was continue pressing. I am probably not saying this correctly. I am trying to say that I was pressing the shutter while the images where still processing through the buffer.

Usually I replace the battery as soon as the blink starts. I have noticed that it can remain steady, but when you press half-way, the demand is enough that the battery icon may blink. On this day, I was shooting a lot in succession with the DB-DP400 1500mAh (which historically has not performed well for me, the weakest of 4, and this one is a warranty replacement for the first). When finished pressing the shutter button and let the buffer clear, the icon never stopped blinking.

Impression: the battery was depleted much farther than I previously use it. I often shoot many shots in succession when birding, but always change the batt's, as soon as they blink, even if they start blinking when under continuous processing.

Looking back at the time of exposure, I am estimating that the banding exposure was taken during this low charge period, because I can roughly remember the time of day and subject I was shooting when the battery needed changed. I also shoot 800 pics over the week-end and looked at them all for banding after I found the first. Only one existed.

good luck with your pictures,


Robert
 

Robert.4507

Well-Known Member
I see the banding at at rhe reflection at the neck of the bird. The ripples in the water are a circular pattern radiating from bird. These in the reflection are clearly horizontal. When first looking at it, it can almost pass for ripples.

Also, when in college, I have seen Texas Instruments handheld calculators that perform calculations incorrectly, because the batteries where low, but students continued to use the calculators because they were getting an answer. Consequently the calculations became correct when the batteries where replaced. The student I reference had the formulas programmed in the calculator, and the batteries went low during a test, so because she was getting an answer, she continued to use the calc because it was returning an answer and she did not have replacement batteries and wanted to continue the test. Albeit with errors. When critiquing the test, the programs where still in the calculator, batteries replaced, and derived the correct answers.

This student shared her story because she correctly assumed that other students would incorrectly draw the same conclusion about their calculators. Coincidentally, other students related having similar experiences with low battery calcs themselves when they heard the story about the wrong answers on the final test. I have in my own experience with an HP statistical and HP financial calc derived wrong solutions due to battery low.


I am not claiming to *know* what is going on with this banding thing, however, I will say that for my own use, based on my life's experiences with tech, when I first see the icon battery low blinking, I will change to a fresh battery.

The banding example:

SDIM1603_Banding_1.jpg


good luck with your pictures,

Robert


ps. because I don't want to get this thread off topic, I am going to start a fresh thread for the purpose of discussing *FOCUS* and it can be found here
Please, Log in or Register to view URLs content!
 

akv

Well-Known Member
Thanks Robert,
I've noticed that my blinking battery icon goes on and off sometimes. It'll blink, I'll take an image, then it'll stop blinking and I can continue shooting.
I use the original BP-21 battery that came with the camera as well as a CTA replacement I got from Cameta Camera.

I've also noticed in my banding issues that I get a "fine banding" as well as a "rough banding". Sometimes both in an image, like yours has. The "fine banding" is the tight clear horizontal (in landscape) lines across the image. The "rough banding" is also evident in your image up near the top. It's not as clearly defined or as tightly packed for lack of a better term.

I've only assumed that it's a battery issue (from the limited input I've gathered) because I've seen other technology perform the same way when it's low on energy. Tvs, monitors, hand held screens. And I think we can put the image processing as a lesser possibility of it being the cause since we have limited examples of banding in both HI RAW and MED RAW. Though no examples in Low RAW or Jpeg as yet.

And I think the connection to using the flash can be ruled out too, from your image, although it could be connected to the low power issue in that it is a drain on the battery at the time of shooting.

It's not a major issue as of yet for me because I'm not a pro selling images and tend to get lots of images rather than just that one "golden" shot.
 

Steaphany

Well-Known Member
Just a quick aside...

akv,

I'm sure the pro's here will concur, No one just shoots a golden shot.

Depending on the subject and setting, the one golden shot, which you may see in a gallery, exhibit, or published, may have been the culmination of tens to hundreds of exposures and many hours of work.
 

notalent

Active Member
I see the banding at at rhe reflection at the neck of the bird. The ripples in the water are a circular pattern radiating from bird. These in the reflection are clearly horizontal. When first looking at it, it can almost pass for ripples.

Also, when in college, I have seen Texas Instruments handheld calculators that perform calculations incorrectly, because the batteries where low, but students continued to use the calculators because they were getting an answer. Consequently the calculations became correct when the batteries where replaced. The student I reference had the formulas programmed in the calculator, and the batteries went low during a test, so because she was getting an answer, she continued to use the calc because it was returning an answer and she did not have replacement batteries and wanted to continue the test. Albeit with errors. When critiquing the test, the programs where still in the calculator, batteries replaced, and derived the correct answers.

This student shared her story because she correctly assumed that other students would incorrectly draw the same conclusion about their calculators. Coincidentally, other students related having similar experiences with low battery calcs themselves when they heard the story about the wrong answers on the final test. I have in my own experience with an HP statistical and HP financial calc derived wrong solutions due to battery low.
Hello Robert,

I could be wrong of course, but the problem with those calculators might have been in the analog elements in the LED display, not properly displaying the otherwise correct number.

But your low battery situation does seem rather coincident with your banding example.

Thanks for your input!

Regards
 

akv

Well-Known Member
Steaphany,
I stand corrected!
Even shooting film, I'm sure it took rolls just for that one perfect shot.
Even in the large format films! lol

I guess I meant having banding ruin a shot for me isn't that big a deal since I don't sell my images or in that "golden" shot situation or scenario.

I think right now my ratio is something like 20 shots for 1 keeper on average.
 
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