Due to loss of dynamic range.
Buying a neutral density filter is the rigth thing to do. For some kinds of pictures, a filter is the only solution I can think of (for instance, waterfalls shots with day light).
What about lowering the base ISO value on later sensor designs. With the 1D 3 you have native ISO 3200 and a base of 100 so why not have a base of 50 (with the low expansion value dropping to 25) and the high ISO going to 1600 (with expansion to 3200 ala last generation cameras).
Personally I'de find a native ISO50 VERY useful -- moreso then ISO 3200 or 6400.
Da Photoz wrote:
What about lowering the base ISO value on later sensor designs. With the 1D 3 you have native ISO 3200 and a base of 100 so why not have a base of 50 (with the low expansion value dropping to 25) and the high ISO going to 1600 (with expansion to 3200 ala last generation cameras).
Personally I'de find a native ISO50 VERY useful -- moreso then ISO 3200 or 6400.
Because it's easy to put a filter on there's no need to make the "buckets" smaller and correspondingly noisier! What is it that ISO50 would give you that's so desirable, other than longer shutterspeeds?
The technology development effort is going to reduce the noise from the high ISO settings - for folks who want reasonable shutterspeeds either in darker scenes or with slower (read lighter weight) lenses.
AJSJones wrote:
Because it's easy to put a filter on there's no need to make the "buckets" smaller and correspondingly noisier! What is it that ISO50 would give you that's so desirable, other than longer shutterspeeds?
The technology development effort is going to reduce the noise from the high ISO settings - for folks who want reasonable shutterspeeds either in darker scenes or with slower (read lighter weight) lenses.
I agree, even though I'd be more likely to use an ISO 50 setting than anything above 800 in my day to day use.Slapping on a ND filter isn't much of a hassle. There are no filters that add light.
"slapping on an ND" is a hassle, depending on how many filter sizes you have and how often you actually need this capability (ie. $$$ per shot for filters). I agree that it's a frustrating feature gap when other brands of gear have this ability.
Most of the comments about "buckets" are correct, but most are tailored towards CCD sensors. Remember that Canon uses CMOS sensors, which means there is/can be processing on board the sensor (unlike CCD). This means that the sensor could "divide by 2/4/8/16" in realtime during the exposure acquisition to prevent blowing highlights if this feature was _chosen_ to be implemented.
I agree that high-ISO is more useful to more people, but I would certainly love an ISO 50 and 25 option without buying (and carrying) hundreds of dollars in extra filters. ISO6 might be a bit of a stretch.
calemon wrote:
Most of the comments about "buckets" are correct, but most are tailored towards CCD sensors. Remember that Canon uses CMOS sensors, which means there is/can be processing on board the sensor (unlike CCD). This means that the sensor could "divide by 2/4/8/16" in realtime during the exposure acquisition to prevent blowing highlights if this feature was _chosen_ to be implemented.
While it is theoretically possible to put on electronics to reset or divide the well on a CMOS imager this would have a major impact on the sensor design and dramatically degrade the noise performance across all ISOs. CMOS sensor design involves extremely difficult trades in the number and size of transistors in each pixel cell, adding a entire extra transistor just for a low ISO option would be a very bad trade. Case in point, you can implement an electronic shutter easily onto a CMOS imager, no more mechanical shutters to break down, shutter speeds way up at 1/50,000, no flash-sync problems ever again. This would obviously be a huge feature improvement everyone would love, and it has been demonstrated numerous times over the past few years in R&D sensors, but no one has put it into a product because the addition of the one transistor per cell to implement the electronic shutter kills the sensor performance. A low ISO option on sensor would have a similar or worse impact. So yeah, it could be done, but it won't (or at least not anytime soon).
As someone else already suggested, take as many images as it takes and average them digitally (i.e. in Photoshop). Would work fine for things like waterfalls, but for some images the gaps in between the images would cause problems (i.e. moving lights, etc.). Otherwise, sadly, it means breaking out the ND filters.
Ken
P.S. Actually electronic shutters are used in imagers for machine vision systems all the time, just not in many megapixel photo quality sensors because of the noise impact.
