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K5 High ISO banding?

vincechu
Posted 25/06/2011 - 14:31 Link
Hi guys,

I noticed some banding at high ISO on my k5 and started a thread at the other forums (link)

and just wondered if anyone noticed banding at high ISO here?

Here's what I said over there:

Quote:
Hi guys,

Just shot my K5 at high ISO for once and noticed 'banding' appearing at ISO 9000. I then took a few more shots to see if this was normal and it seemed to get progressively worse the higher the ISO, begins only faintly visible to obvious and is most obvious in darker scenes.

This occured regardless of the Noise reduction setting (it appeared at all strengths, on or off)

I did a google search and nothing came up, so thought I'd ask. I'd appreciate it if anyone else can test for this.

It looks similar to the 'Panasonic GH1 banding issue' (google it), and I can post images if necessary.

I'm just surprised that no one else has said anything about it so thought i would, could just be my k5 though

Thanks in advance for any help/suggestions/ideas

Quote:
Thanks guys, its harder to see around ISO9000-12800 I'd say

For now I've got jpegs - I dont know how to upload raws, but I can assure you its on RAWs too.

Heres ISO12800 from my k5

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12800 Banding 2 by VinceChu89, on Flickr

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12800 Banding 1 by VinceChu89, on Flickr

ISO 25600

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25600 Banding 2 by VinceChu89, on Flickr

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25600 Banding 1 by VinceChu89, on Flickr

ISO 51200

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51200 Banding2 by VinceChu89, on Flickr

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51200 Banding1 by VinceChu89, on Flickr

I know that I rarely use above ISO 6400, but still I'd like to know if this is normal I also have to say that this banding is more noticeable in different settings, mainly where there are darker colours or shadows.

Vince
Edited by vincechu: 25/06/2011 - 14:32
Pentaxophile
Posted 25/06/2011 - 14:47 Link
ISO 51200 banding? As a K-7 owner, my heart bleeds for you, Vince!
[link=https://500px.com/will_brealey/[/link]
johnriley
Posted 25/06/2011 - 15:14 - Helpful Comment Link
I haven't felt any need to go abouve ISI3200, so I can't say i've noticed anything. The K-5 I tested for EPZ had no banding issues.
Best regards, John
Blythman
Posted 25/06/2011 - 15:27 - Helpful Comment Link
Mine seems ok at ISO 25600

Comment Image

Nuthatch by Blythman1960, on Flickr
Alan


PPG
Flickr
Pentaxophile
Posted 25/06/2011 - 16:03 - Helpful Comment Link
The lighting/exposure makes a difference I expect. You wouldn't seriously be shooting at those sensitivities anyway would you? Unless you were going for black and white grainy
[link=https://500px.com/will_brealey/[/link]
Mannesty
Posted 25/06/2011 - 16:11 - Helpful Comment Link
I think your subject and lighting are bound to show any tiny flaw in the K5's sensor at these settings.

Here's a test shot at 1/200th, f4, and ISO 51200 I made a couple of nights ago. The light was from a low power energy saver bulb.

I'm quite happy that if I ever needed this extreme setting, I would get a shot I could use, where others will fail, unless they also use a K5 of course.

Comment Image
Peter E Smith - flickr Photostream
Edited by Mannesty: 25/06/2011 - 16:12
Chrism8
Posted 25/06/2011 - 16:28 Link
Thats darn good at those setting Peter.
Chris

www.chrismillsphotography.co.uk

" A Hangover is something that occupies the Head you neglected to use the night before".

-------------------------------------------------------------
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K3iii + K3ii + K5iis converted to IR, Sigma 17 - 70 F2.8, Pentax 55 - 300 F4.5 / F5.6 PLM
K10D
Posted 25/06/2011 - 16:42 Link
Mannesty wrote:
I think your subject and lighting are bound to show any tiny flaw in the K5's sensor at these settings.

Here's a test shot at 1/200th, f4, and ISO 51200 I made a couple of nights ago. The light was from a low power energy saver bulb.

I'm quite happy that if I ever needed this extreme setting, I would get a shot I could use, where others will fail, unless they also use a K5 of course.

Comment Image

Great example Peter.

Best regards
Inspiration is rarer than a plate glass camera.....
vincechu
Posted 25/06/2011 - 16:51 Link
thanks guys, my battery is on charge til tonight, so I'll do some testing later and I will look over the photos I've taken the past 6 months with the K5 and see if its occured before - could be I'm shooting conditions which highlight this banding and make it more obvious.

In the mean time its true that I rarely shoot high ISO (above 3200/6400) so it shouldn't be an issue (I've not noticed it for 4000 shots, but will check again later). Nevertheless if my k5 does have an issue, it's not right, and I'd like to know so I can get it addressed by Pentax.

Edit: probably is the 'subjects' in the above photos which make the banding obvious - couldnt resist and took my batteries off charge and snapped some more normal photos around the house (ie of actual things I'm likely to photograph) and at those high ISO's the banding is only visible in darker, under exposed areas, such as shadows.

The issue doesn't bug me and I can live with it, and if it does get worse I always have the 2year warranty to help me out

Nevertheless I'm going to swap RAWs with JohnBee at the other forums, and see if it is worse on my k-5. Will keep you all updated - perhaps this could serve as a useful reference in the future
Vince
Edited by vincechu: 25/06/2011 - 17:12
vincechu
Posted 26/06/2011 - 23:34 Link
haven't done the RAW swap yet, but as others on have said, the more I look into it, the more its looking just like chroma noise which at times takes the form of banding, whereas at other times its not visible.

Using the colour noise reduction in LR3 seems to get get rid of it easily enough though. So not much of a problem really and my k5 seems fine.
Vince
pentaxian450
Posted 27/06/2011 - 03:01 Link
You're more likely to see banding at high ISO and continuous tones like a sky than low ISO with varying tones. All digital cameras, without any exceptions, will show banding under some extreme conditions. Unlike films, digital cams can't record continuous tones. It records by "steps". If the subject is smoothly and slowly fading, the steps will sometimes show as banding.
Yves (another one of those crazy Canucks)
vincechu
Posted 02/07/2011 - 01:34 Link
Thanks guys for all the input

I sent some raws to JohnBee over at PF to check out and like others have said my k5 seems fine and they don't see the banding too - I just think it was a problem caused by my poor noise reduction (inexperience), and me over examining my photos and wanting to find a problem.

anyway for those interested, and so that this might possibly serve as a type of reference here's what JohnBee said:

Quote:

I think you've likely encoutered that artifacts such as banding can and are often times dealt with by the RAW developer. However in other cases, its not so easy or possible and so you may notice banding appearing in certain images, and not in others at the same sensitivity.

On the other hand, the ISO51200 sample didn't exhibit any banding on my end using both RAW Therapee and Adobe Camera Raw(without NR). Though I still wouldn't recommend ISO51200 for anything but extreme measures given that the limited amount of detail available at this level.

Having said that, I did notice a significant magenta case in your table DNG. And at first glance(without looking) I'd say this was most likely due to underexposure. To which I'd add, one helpful tip I've discovered, is to lean to the right as far as possible without blowing highlights when shooting at higher sensitivities. Which helps reduce overall artifacts and more importantly... the type of problems such as the ones seen here.

Other than that, I'm happy to report that your sensor seems pretty much identical to my own in terms of high ISO performance. And so I'd say you are safe! and that there is no need to send out your unit as far as this goes.

FRT. here's some RAW Therapee/Topaz Denoise output from your ISO51200 sample. And while its not the greatest! - I'd say its good enough for emergency use if/when needed



PS. I used to shoot at max sensitivities with my K20's on a regular bassis. However, with the K-5, I've gotten into the habit of limiting my output to ISO2000. And that's not because I'm afraid of max ISO, but because I don't like the low level noise reduction that the K-5 applies to RAW files. Which kicks-in at ISO2200. And therefore, by keeping the meter bellow 2200, you can push process in post(RAW developer) and avoid the detail loss that comes with the K-5 prime engine. The downside on the other hand is that you have more noise to deal with(so its a give and take).

Anyways, based on what I've seen here, I'd say you're K-5 is in good hands! - Take care and thanks for participating.

Sincerely,
JohnBee

Vince

Stop by my flickr and say hi here =)
Vince

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