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07-14-2016, 11:33 AM   #1
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is my k3 faulty?? newbie question regards performance

Hi chaps. I am not sure if it a performance issue or a fault on my k3. When I set iso to auto within the range 100-400 even in the brightest outdoor light and camera set to Av with the lens set to f4.5 and the zoom set to 70mm the iso does not seem to drop below 400. and the shutter speed was still coming out at approx 1/60th sec

To test if there was a problem I reset the camera to factory default settings and tried again Lens set to 70mm f4.5 and focused onto a lightbulb and the iso was still coming in at 320 and shutter speed was still not really going faster than 1/100sec.

so is this usual

lens is a tamron 70-210

07-14-2016, 12:02 PM   #2
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Oldstoad

please pictures with exif intact.

There are a number of variable parameters for ISO
07-14-2016, 12:17 PM   #3
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07-14-2016, 12:31 PM   #4
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What if you force exposure compensation to be darker?

07-14-2016, 12:55 PM   #5
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QuoteOriginally posted by oldstoat Quote
Hi chaps. I am not sure if it a performance issue or a fault on my k3. When I set iso to auto within the range 100-400 even in the brightest outdoor light and camera set to Av with the lens set to f4.5 and the zoom set to 70mm the iso does not seem to drop below 400. and the shutter speed was still coming out at approx 1/60th sec

To test if there was a problem I reset the camera to factory default settings and tried again Lens set to 70mm f4.5 and focused onto a lightbulb and the iso was still coming in at 320 and shutter speed was still not really going faster than 1/100sec.

so is this usual

lens is a tamron 70-210
Do you have highlight correction enabled? This will always double your ISO unless you manually select ISO 100. Highlight correction is set to "auto" but default and it certainly would have triggered in this case (since you were shooting straight at a lamp).

1/100s and 1/125 seem to be appropriate shutter speeds given the conditions.

You can otherwise control how the camera behaves using the "program line" option in the record menu, and you can also configure the auto ISO range and speed preference under "iso auto parameters" under "auto iso setting".

Adam
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07-14-2016, 01:05 PM   #6
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surely pointing the camera at a light would have made the iso lower ie down towards 50 etc
07-14-2016, 01:35 PM   #7
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The image looks overexposed to what I would normally expect an auto-exposure to produce with that ..... normally such large bright highlights produce underexposure. I would expect the lampshade to be almost black.

I don't think the issue is the auto-ISO ..... the ISO is being held higher in order to keep the shutter speed up for a steady shot. The problem seems to be with the calculated exposure value, which is surely too high for such a scene? Is there any exposure compensation dialed in?
07-14-2016, 01:37 PM   #8
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QuoteOriginally posted by oldstoat Quote
surely pointing the camera at a light would have made the iso lower ie down towards 50 etc
No, not necessarily. Auto-ISO is independent of the program line and for some configurations may take a fair amount of effort to coerce up or down. Configuration is done using capture menu (camera icon) 2/ISO AUTO Setting. The choices (slow, standard, and fast) are detailed on p39 of the user manual. The rub is that two of those three words do not mean what you think they mean.
  • Slow has nothing to do with ISO speed, shutter speed, or program lines. What it means is that the ISO will change only when there is no other way to get correct exposure
  • Standard (default) is Ricoh's best guess as to how auto-ISO should work. I strongly suggest leaving it on this setting unless you have a specific use case.
  • Fast has nothing to do with ISO speed, shutter speed, or Hi-speed priority program line. What it means is that the ISO will change more readily than if set to Standard.
Edit: The three points above reflect conventional wisdom from other discussions on the subject over several years, but are not consistently true (not true at all?) on the K-3. I did some additional look-see and am having to adjust my thinking.

I will admit to not being a huge fan of auto-ISO,* though I do use it on occasion, but never when I want to have fine control. My personal rules:
  • Generally use fixed ISO
  • If one wants ISO to float while controlling aperture and shutter, use TAv mode
  • Use auto-ISO when light is expected to be variable and when it is inconvenient to have to think about it
  • Set the auto-ISO limits to reasonable numbers that reflect quality expectations and style of shooting. Edit: This is particularly important in Tv and Av modes.
I almost added "Avoid using features such as Highlight Correction", but that is a personal choice that reflects my style of shooting.


Steve

* I am famous for stating that "auto-ISO is evil" with my prejudice being based on the tendency for new users to get tangled in a Web of conflicting configuration choices.


Last edited by stevebrot; 07-14-2016 at 11:01 PM.
07-14-2016, 01:43 PM   #9
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the camera was reset to factory defaults before that photo was taken and no changes where made to any settings whatsoever
07-14-2016, 01:49 PM   #10
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Yes .... and limits have been reached, as in the aperture is fixed (because its Av mode), and the ISO is at its highest possible by the range set. The shutter speed also is surely at its lower limits for a steady shot....

So if the calculated exposure value was to be lower than we see (which i'd expect given the bright highlights), then we would natuarlly expect that it would be the ISO that would reduce in order to bring the brightness down. So something is holding the exposure value high like that and preventing both the ISO and shutter speeds from changing and reducing the brightness.

With a zoom like that it may be preferable actually to have the shutter speed increase reather than the ISO reduce ..... ISO 400 is haardly high anyway for such a camera.
07-14-2016, 01:56 PM   #11
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QuoteOriginally posted by stevebrot Quote
Auto-ISO is independent of the program line and for some configurations may take a fair amount of effort to coerce up or down.
It occurred to me that this point should be reinforced along with something that @mcgregni touched on. The ISO setting does not affect the EV (light measurement) returned by the meter. If the meter indicates a poor exposure, a poor exposure is what you will get unless overridden.


Steve
07-14-2016, 02:14 PM   #12
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QuoteOriginally posted by oldstoat Quote
Hi chaps. I am not sure if it a performance issue or a fault on my k3. When I set iso to auto within the range 100-400 even in the brightest outdoor light and camera set to Av with the lens set to f4.5 and the zoom set to 70mm the iso does not seem to drop below 400. and the shutter speed was still coming out at approx 1/60th sec

To test if there was a problem I reset the camera to factory default settings and tried again Lens set to 70mm f4.5 and focused onto a lightbulb and the iso was still coming in at 320 and shutter speed was still not really going faster than 1/100sec.

so is this usual

lens is a tamron 70-210
Try using TAV mode instead of AV you dial in the aperture and shutter speed the ISO will be metered in for the exposure, it is manual mode with benefits. I generally put ISO at 800 on the K3 and rarely go above due to noise. The ISO range will suit most situations of daytime available light.
07-14-2016, 04:39 PM   #13
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The subject having the differing bright light/dark shadow combination does not make it easy for the camera to interpret it as a whole. If testing is what you are looking for, testing in natural light (as was mentioned in an earlier post) and avoiding extremely backlit (sun behind) subjects will tell you if the camera is behaving normally. TAV mode is what I use most of the time, along with Manual mode in cases where I want complete control over settings. Happy shooting.
07-14-2016, 05:15 PM   #14
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QuoteOriginally posted by stevebrot Quote
No, not necessarily. Auto-ISO is independent of the program line and for some configurations may take a fair amount of effort to coerce up or down. Configuration is done using capture menu (camera icon) 2/ISO AUTO Setting. The choices (slow, standard, and fast) are detailed on p39 of the user manual. The rub is that two of those three words do not mean what you think they mean.
  • Slow has nothing to do with ISO speed, shutter speed, or program lines. What it means is that the ISO will change only when there is no other way to get correct exposure
  • Standard (default) is Ricoh's best guess as to how auto-ISO should work. I strongly suggest leaving it on this setting unless you have a specific use case.
  • Fast has nothing to do with ISO speed, shutter speed, or Hi-speed priority program line. What it means is that the ISO will change more readily than if set to Standard.
I will admit to not being a huge fan of auto-ISO,* though I do use it on occasion, but never when I want to have fine control. My personal rules:
  • Generally use fixed ISO
  • If one wants ISO to float while controlling aperture and shutter, use TAv mode
  • Use auto-ISO when light is expected to be variable and when it is inconvenient to have to think about it
  • Set the auto-ISO limits to reasonable numbers that reflect quality expectations and style of shooting
I almost added "Avoid using features such as Highlight Correction", but that is a personal choice that reflects my style of shooting.


Steve

* I am famous for stating that "auto-ISO is evil" with my prejudice being based on the tendency for new users to get tangled in a Web of conflicting configuration choices.
My finding of that the Slow, Normal and Fast relates to the slowest shutter speed choosen for a certain focal length and is offset by a factor of one stop for the different choises.

I.e if I have the 77 on it will choose 1/50 for slow, 1/100 for normal and 1/200 for Fast as slowest shutter speed as long as the upper ISO limit is not reached. If it is to dark for ISO100 and 1/50 with Slow it starts to increase the ISO above 100 if the lowest range is 100. If it gets bright it will go to ISO100 and then increase the shutter speed and so on.
07-14-2016, 09:09 PM   #15
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QuoteOriginally posted by Tjompen1968 Quote
My finding of that the Slow, Normal and Fast relates to the slowest shutter speed choosen for a certain focal length and is offset by a factor of one stop for the different choises.
How does the Swedish user manual translation read? The English, it says we are setting "the manner in which sensitivity is increased":
  • Low - "Increases the sensitivity as little as possible"
  • Fast - "Actively increases the sensitivity"
It is quite possible that focal length figures into the equation as might S/N ratio and raw meter output, though the English appears to be pretty explicit that we are choosing a conservative vs. more dynamic strategy.

Edit: See following comments. While the English manual is explicit, I don't believe it is consistently accurate as written.


Steve

Last edited by stevebrot; 07-14-2016 at 10:54 PM.
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