Why Not a lower ISO than ISO 200?

[MikeAusA200]

"I know P&S cameras have lower ISO's "

P+S Cameras have much smaller sensors than DSLRs so they inherently have a lower sensitivity.
--
Mike Sydney Australia

 

[keithallenlaw]

what about auto mode? i have enough to do as it is with the other
options on my camera. OR should i put those options on auto and worry
about my iso settings? im getting dizzzzzy...... like i said in another thread,
its all about robbing peter to pay paul.

 

[echelon2004]

isn't a valid option for me.

I'm one of those oldies that use a lens cap for protection, not some cheapo UV filter=)

Nd filters are great when needed, gradient ND's are wonderful, but if I don't have to use them I'm happy.

I can't see any technical reasons not to include lower ISOs?
--
Anders

http://www.teamexcalibur.se/iview/index.htm

 

[PalmsWestPhoto]

Other people already mentioned that a sensor just like film has a given base ISO.

But as it looks Nikon seems to overstating their sensitivty by almost a stop

So the ISO 200 is actually almost ISO 100 and their ISO 1600 is almost only ISO 800

Looking at it this way it allows you to have a higher published ISO value then what you really have. So instead of 'downgrading' an ISO 120 or so to ISO 100 Nikon 'upgrades' it to 200. Standard marketing ploy similar to overstating things such as MPixels (remember the days when the camera manufacturers published all pixels instead of only the active ones).

--
Michael Salzlechner
http://www.PalmsWestPhoto.com

 

[David Goodwin]

NOT TRUE !!!

There may indeed be manufacturing tolarences; (as there also was
with film); but the INTENTION is indeed for ISO to equal film
equivalents; so a handheld meter can be used if desired.

This is true ONLY for exposure times, other factors of slow-film speed are not present in equivalent slow-digital ISO speed, such as the 'rich' appearance the OP described.

 

[win39]

That is just not true. All you have to do is read a few of Phil's reviews to discover that Nikon's ISO ratings are very close to standard along with most digital camera manufacturers. Exceptions are Canon and Fuji which pretty consistently under rate their ISO.

Other people already mentioned that a sensor just like film has a
given base ISO.

But as it looks Nikon seems to overstating their sensitivty by
almost a stop

So the ISO 200 is actually almost ISO 100 and their ISO 1600 is
almost only ISO 800

Looking at it this way it allows you to have a higher published ISO
value then what you really have. So instead of 'downgrading' an ISO
120 or so to ISO 100 Nikon 'upgrades' it to 200. Standard marketing
ploy similar to overstating things such as MPixels (remember the
days when the camera manufacturers published all pixels instead of
only the active ones).

--
Michael Salzlechner
http://www.PalmsWestPhoto.com

 

[win39]

Why does the Nikon dSLR cameras "only" go down to 200?

Back in high school when I was taking photo workshops, my
instructor loved for me to use Kodachrome ISO 64 slide film. He
said that ISO 64 was even richer than ISO 100.

Many of the "point and shoot" cams even go down to ISO 50, but the
Nikon dSLR cams only go down to 200.

Should this be an issue with me when looking at cameras? I will be
taking general everyday photos of kids, etc., but I do really want
the flexibility of a dSLR.

As someone has already pointed out there are other base ISOs in Nikons than ISO 200.

The standard for base ISO is supposed to be the lowest ISO for which a further reduction will provide no measurable gain in noise reduction. Low ISO is no camera maker's goal or for that matter film makers. There is no gain in going below base ISO with any camera. Some sensor designs have been able to have their noise lowered to a lower ISO than others.

 

[Ron Parr]

The standard for base ISO is supposed to be the lowest ISO for
which a further reduction will provide no measurable gain in noise
reduction.

That's not the standard.

If you use the s_noise technique, the ISO is tied directly to SNR standards. The technique you have described appears to be tied to the derivative of the SNR, and that is not part of the standard.

If you use the s_sat technique, then noise reduction doesn't enter into it all.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/

 

[Bartman01]

CCD's are more sensitive to light than CMOS sensors:
http://www.siliconimaging.com/cmos_fundamentals.htm

 

[Ilkka Nissilä]

Well, the thing is that iso 200 is the native sensitivity of the sensor. This means that going for a lower sensitivity would not improve image quality.

In a point-and-shoot digital camera, the pixels are so small that they need iso 50 to get results which are still probably noisier than Nikon's iso 200 results.

As for today's films, the iso 100 ones are the best, the slower ones are old emulsions left behind in technological development and they're used by people who have strong experience with the characteristics of the film type, and they're typically not less grainy or sharper than the iso 100 films.

 

[Ron Parr]

CCD's are more sensitive to light than CMOS sensors:
http://www.siliconimaging.com/cmos_fundamentals.htm

A CMOS sensor may have a lower fill rate than a CCD sensor, but this depends upon many factors. CCDs such as those used by Nikon are interline transfer CCDs, which means that they can sacrifice up to half the area of each pixel for charge transfer. Even full frame CCDs such as those used by Olympus sacrifice a chunk of their area to an anti-blooming gate, which is not needed for CMOS sensors.

CMOS sensors sacrifice area to transistors. The amount sacrificed depends upon the pixel design and the pixel size. For large pixels, it may not be more than the area sacrificed by, say, the charge transfer area of an interline CCD. (I don't know for sure; I'm just saying that it's possible.)

CMOS sensors are also known for having more dark current, which can increase noise and potentially force the lowering of ISO. Manufacturers have been making a lot of progress reducing this, so it's hard to say how much of a factor it is in the best modern CMOS sensors.

--
Ron Parr
FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/

 

[SoftD100]

go back to your cave troll ,
your only comments since joining are to bag nikon
you probally have a big white lens to fill your other short comings