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01-21-2010, 02:53 AM   #1
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Question - Sensitivity Steps

Why wouldn't you want the extra sensitivity steps in between 200-400-800-1600? In other words, why would you take a picture at 1600 ISO if the shutter speed would have been fine to handhold at 1300 ISO? Any reason for not leaving on extra sensitivity steps?

Thanks

01-21-2010, 03:47 AM   #2
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These standard ISO steps are doubled, each one being twice as sensitive as the previous and were the traditional film sensitivity ratings, makes it easy for calculations (which would have been done when sensitivity ratings were originally created in relation to aperture and shutter speed).
There maybe other reasons, I'm just thinking logically here.


On K20 you can also have 140, 280, 560, 1100 and 2200.
I believe if auto ISO is set the camera will choose other increments.
01-21-2010, 04:03 AM   #3
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If you have a K-7, try setting the Customs menu item 1 to 1 (use of 1/3 LW steps instead of 1/2 LW steps), and item 2 to 2 (ISO sensitivity step as LW steps).

- Bert
01-21-2010, 06:39 AM   #4
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QuoteOriginally posted by joodiespost Quote
Why wouldn't you want the extra sensitivity steps in between 200-400-800-1600? In other words, why would you take a picture at 1600 ISO if the shutter speed would have been fine to handhold at 1300 ISO? Any reason for not leaving on extra sensitivity steps?

Thanks
I don't know what camera you have, but my cameras can be set to 1/3 stop ISO increments.

01-21-2010, 07:32 AM   #5
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QuoteOriginally posted by joodiespost Quote
Why wouldn't you want the extra sensitivity steps in between 200-400-800-1600? In other words, why would you take a picture at 1600 ISO if the shutter speed would have been fine to handhold at 1300 ISO? Any reason for not leaving on extra sensitivity steps?

Thanks
Canon at one time used digital gain for it's in-between steps ie like 150. It was found that it was better to underexpose at the lower "normal" iso ie 100 then to shift to the "intermediate" iso. These "normal" iso's just used the amp gain where the intermediate were amp and digital gain causing loss of DR or more noise.... more than was expected in going from 100 to 200.
You may want to consider this though I have no way of knowing IF that is true for Pentax...... even if Pentax has in between steps (which apparently they do) I personally would probably not use them for any "good stuff". I may just be overcautious though.
01-21-2010, 07:53 AM   #6
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I think the OP is asking why one would leave that setting to 1 stop over 1/3 or 1/2, and jeffkrol provided a good answer.

Probably all DSLRs do it this way, but technology is good enough such that there isn't really a loss with digital gain anymore (everything over 1600 ISO is digital gain btw)
01-21-2010, 02:41 PM   #7
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QuoteOriginally posted by joodiespost Quote
Why wouldn't you want the extra sensitivity steps in between 200-400-800-1600? In other words, why would you take a picture at 1600 ISO if the shutter speed would have been fine to handhold at 1300 ISO? Any reason for not leaving on extra sensitivity steps?
I've got one, and it might seem lame to some, but I've found it matters to me: the marginal improvement I might get by shooting at ISO 1300 instead of 1600 is not worth the fact that this means it takes 2 or 3 times as many clicks to get from, say, 400 to 1600 when I'm actually changing ISO.
01-21-2010, 02:49 PM   #8
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QuoteOriginally posted by Marc Sabatella Quote
I've got one, and it might seem lame to some, but I've found it matters to me: the marginal improvement I might get by shooting at ISO 1300 instead of 1600 is not worth the fact that this means it takes 2 or 3 times as many clicks to get from, say, 400 to 1600 when I'm actually changing ISO.
I'll agree with Marc, about the only reason to decrease the steps would be for speed/convenience, I would think. If you need to change ISO a lot during a shoot because of drastically different lighting conditions, the few extra clicks can be bothersome.

Scott

01-21-2010, 06:16 PM   #9
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thanks for all the input. i think i now prefer the regular steps. ^^
01-21-2010, 06:27 PM   #10
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QuoteOriginally posted by Marc Sabatella Quote
I've got one, and it might seem lame to some, but I've found it matters to me: the marginal improvement I might get by shooting at ISO 1300 instead of 1600 is not worth the fact that this means it takes 2 or 3 times as many clicks to get from, say, 400 to 1600 when I'm actually changing ISO.
I feel the same way. I used to have ISO steps configured at 1/3EV intervals, but I was generally using only the "full" stops, and so several weeks ago I switched to 1EV interval and haven't looked back.
01-22-2010, 08:02 AM   #11
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I do use the "in between" sensitivity steps. Having 140 between 100 and 200 isn't a big deal, and I almost never shoot at anything except for the old standard values when I'm shooting at 400 or below. But above 400, I do start using the half steps: 560, 1100 and occasionally even 2200, as well as the standard 800 and 1600. When I'm shooting in low light, I don't want to increase the sensitivity more than absolutely necessary to allow me to get the aperture and shutter speed that I require. If 800 won't do the job, but 1100 will, I'd rather take 1100 than go all the way to 1600.

I would mention that I have my cameras (K10D/K20D) set to use sensitivity steps that are the same as the EV steps. And I have the EV set to use 1/2 steps rather than 1/3. I do this because I've been using hyperprogram (P) a lot, which means adjusting the EC (+/-) frequently. If the EV setting in the menu (custom setting menu #2 on the K20D) is 1/3 steps, the EC dial on the top of the camera will only allow me two stops of latitude +/-. But if I set the EV menu to use 1/2 steps, then the EC dial lets me get 3 full stops +/-. I have occasionally needed that 3 stop latitude.

Will
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