Should I use expanded low ISO (80) on a Pentax K-5?
Asked 4/26/2011
1 views
2 answers
0
My Pentax K-5 offers a standard minimum ISO of 100, but with expanded ISO enabled I can set it to ISO 80. In general, lower ISO usually means lower noise, but does that also apply to this expanded setting? If I’m shooting in bright light and ISO 80 works without forcing an awkward shutter speed or aperture, is it worth using, or is ISO 100 still the better choice? I’m asking about normal shooting, not special cases where a very low ISO is needed to avoid maxing out shutter speed.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
15y ago
2 Answers
7
True, lower ISO does typically bring lower noise, but all digital cameras adjust ISO by altering internal exposure sensitivity, and any change from the 'native' ISO typically introduces some noise, or other trade-off, such as dynamic range. This includes setting ISO below the 'native' ISO.
This 'native' ISO is that for which the sensor and electronics are optimized. Other ISOs are achieved by pushing (or pulling) exposure internally.
Since your camera offers this 'expanded ISO" that provides for 80 ISO, you can assume that this ISO is sub-optimal, and could exhibit more noise or a loss of dynamic range than the 'native' ISO. Unfortunately, few camera manufactures publish what the 'native" ISO is, but for the most part it is assumed to be the lowest ISO in normal settings. Some suggest Canon cameras are 'native' for ISO 100, and full stop ISO are best (100,200,400 etc.), but I haven't seen such results for Pentax.
Google for "native ISO" and you likely will find some interesting discussion and even sample images.
Originally by user4880. Source · Licensed CC BY-SA 4.0
user4880
15y ago
0
Generated from our catalog & community — verify before relying on it.
Usually, an expanded ISO below the normal range is not automatically “better” than the camera’s standard low ISO. On many cameras, expanded low ISO is achieved by pulling exposure and can reduce highlight headroom or dynamic range.
For the Pentax K-5 specifically, community experience suggests the difference between ISO 80 and 100 is very small. In JPEG, you’re unlikely to see much difference at all. In RAW, ISO 80 may give a slight dynamic-range benefit on the K-5, especially if you heavily lift shadows, but it’s only a fraction of a stop.
So: yes, you can use ISO 80, but don’t expect a dramatic improvement over ISO 100. If you want the safest general-purpose setting, ISO 100 is fine. If you shoot RAW and want every bit of shadow recovery, ISO 80 can be worth trying.
If your real goal is using slower shutter speeds in bright light, an ND filter is a better solution than relying on expanded low ISO.
Recommended products
UniqueBot
AI15y ago
Your Answer
Related Questions
Why won't my Pentax K-5 IIs let me select ISO 100?
Why do some DSLRs offer ISO settings below 100?
Why can Pentax P-TTL flash underexpose, especially with bounce flash or at longer distances?
Why don't most digital cameras offer ISO settings below about 80 or 100?
Does ISO 50 on a Canon 6D Mark II give cleaner images than ISO 100 or 160?