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10-24-2009, 11:35 AM   #1
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K20D at higher ISO

Hi All,

Heading into town (Cork city!) for a look around the jazz festival and maybe a few scoops
I'm bringing my faithful K20D and a K55 f.18 and a Super Tak 85 f1.9.
Bearing in mind low light conditions, no flash and a total ignorance of the higher ISOs, what should I limit myself to? 800 max or perhaps a little higher.
And all photos will be of the handheld variety as they happen ;-)

Tks
Robbie

10-24-2009, 12:08 PM   #2
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On the K20D, I would say ISO 1600 is perfectly fine for 8x10 prints. ISO 3200 and 6400 are probably only worth web-sized photos.

Of course, if you don't mind grain and just want to remember the moments, who cares about some noise?
10-24-2009, 12:17 PM   #3
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QuoteOriginally posted by wallyb Quote
On the K20D, I would say ISO 1600 is perfectly fine for 8x10 prints. ISO 3200 and 6400 are probably only worth web-sized photos.

Of course, if you don't mind grain and just want to remember the moments, who cares about some noise?
thanks for the reply Wally. 1600 it is then. On the bus in so shooting starts in 10 mins or so! As a side note the mobile version of pentax forums works very well :-)
10-24-2009, 12:57 PM   #4
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Let us know how you go with it.
I've had OK results come from ISO 3200 (as long as the shots are exposed well and not needing to be 'pushed' in PP).

10-24-2009, 01:01 PM   #5
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QuoteOriginally posted by Ash Quote
Let us know how you go with it.
I've had OK results come from ISO 3200 (as long as the shots are exposed well and not needing to be 'pushed' in PP).
Likewise - I'd probably limit to ISO 2000, shoot RAW and push +.3 or +.7 EV compensation.

This was at ISO 2000 (but it lacks the dark areas where you'd expect noise to really show up)...
10-24-2009, 01:27 PM   #6
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ISO 2000 works great, and I've had success with 3200 in most situations. Practice a bit before the real deal with exposing to the right in lower light and, absolutely, shoot RAW.
10-24-2009, 06:54 PM   #7
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Iso 2000 is my upper end and that is using some fairly significant noise reduction. The thing about high ISO is that it really diminishes dynamic range. If you shoot really high, you are almost better off planning to turn the photos into black and white, they just look better.

10-24-2009, 09:05 PM   #8
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Well I always shoot in raw format. A digital negative as it were.
Only issue was that I was in a pub for most of the night with mosly red light which blew the colours a bit.

a couple from this evening then:







Seems the noise is quite noticable...

Last edited by robbiec; 10-25-2009 at 03:22 AM.
10-24-2009, 09:43 PM   #9
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Yes, but acceptable.
Now adjust WB to neutralise the colours in those heavily casted ones and you may find more pleasing results all round.
10-26-2009, 11:50 AM   #10
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I am surprised at the recommendation to shoot at a lower ISO and then "Push" the exposure as a way to control noise. As I understand Signal to Noise (SN) ratios, this is the opposite approach you should take if you can avoid it at all. You're far better off exposing to the right (ETTR) and then pull the exposure down by .5 to .75 stops. This prevents the shadows from exhibiting that serious noise signature. One of my complaints about Pentax exposure has been that it tries to avoid clipped highlights at the expense of shadow noise. If the sensors were near the top of the pack in terms of noise performance, this would be fine, but the K-7 is middle- to lower-pack in terms of high ISO performance and exposing to the left only compounds the issue. I understand the K20D is better in terms of noise performance but you're not going to help matters by exposing to the left and upping the exposure.
10-26-2009, 01:11 PM   #11
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Thanks all for your comments and recommendations. Now I'll be the first to admit that I am not nearly as talented, experienced or frankly speaking as good as most on here and it was as such an experiment in some really horrible lighting. I did use the full gamut of the K20s ISO range and the 2 lenses I used (Super Tak 85 f1.9 and K55 f1.8) were never above f2.4
So some examples with some colour tuning:

K 55 @ f2 ISO 3200 (noise visable but nothing as bad as I expected)


ST 85 @ f2.4 ISO 1600 (clearly less noise compared to above but I wonder if the 85 is helping the sensor resolve more!)


ST 85 @ f2.4 ISO 1000 (you have to look for the noise to be honest)


K 55 @ f2 ISO 800 (I was really wary of moving up the ISO ladder at first, this really should have been at 1600 or 2000)


Just to confuse matters I used 2 lenses and both had UV filters on to protect from splashing drink! (it was one of those nights). I don't know if lens quality has come into it, I would consider the Super Tak as a lens needing to be stopped down exposure wise more often than the K but I was at +0.3 EV in all my shots. All said and done, I was happily surprised at what I got at ISO 3200, and in hindsight I should have been between 1600 and 2000 all night especially with the band. Lessons learned? Go high ISO wise, and learn to focus in the dark. Dunno how well the AF would have coped.
Oh and I met a fellow Pentax shooter at the start of the night out and about doing some street shots. Small world! :-)

Last edited by robbiec; 10-26-2009 at 01:23 PM.
10-26-2009, 01:48 PM   #12
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Decent result for such high ISO - do watch your manual focusing, it's a little off in some images here.
As for AF in the dark, the best technique is to focus on something reasonably well lit very close to or right on your subject matter, and direct your focus point to focus on that high contrast area. Then you've locked focus reasonably quickly and can take the shot.
10-26-2009, 02:04 PM   #13
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Hi Ash,

Taking the last shot as an example. If I had say a FA77 or say DA55 , I would put the focus point on the guitar as that would be high contrast and take it from there?

Tks,
Robbie

ps another lesson learned, stay off the sauce while manual focusing
10-26-2009, 02:55 PM   #14
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robbiec, don't know much from ISO, but I know a good portrait when I see one and this is a good one. Evocative and mysterious, that's what portraiture, in my opinion, is all about. With a subject like that, and a capture to match her strength and beauty, technology and technique become secondary. As somebody once said, The average photograph captures the things in that moment in time, the good ones capture the mood of those things in that moment... but the very best ones are forever a window into who and what the photographer was in that moment and offers that moment to anyone who cares to see. Good work,
Brian

Last edited by FHPhotographer; 10-26-2009 at 03:07 PM.
10-26-2009, 02:59 PM   #15
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QuoteOriginally posted by Rich_A Quote
I am surprised at the recommendation to shoot at a lower ISO and then "Push" the exposure as a way to control noise. As I understand Signal to Noise (SN) ratios, this is the opposite approach you should take if you can avoid it at all. You're far better off exposing to the right (ETTR) and then pull the exposure down by .5 to .75 stops. This prevents the shadows from exhibiting that serious noise signature. One of my complaints about Pentax exposure has been that it tries to avoid clipped highlights at the expense of shadow noise. If the sensors were near the top of the pack in terms of noise performance, this would be fine, but the K-7 is middle- to lower-pack in terms of high ISO performance and exposing to the left only compounds the issue. I understand the K20D is better in terms of noise performance but you're not going to help matters by exposing to the left and upping the exposure.
I think you are responding to my earlier post, and you are correct - I should not (I think) have used the word "push" as I really meant, use + EV compensation (ETTR) and then pull the shadows in post - sorry for the confusion.
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