HELP Please! D600 and ISO equivalent 50

[hark]

Last week when I shot the waterfalls photos, I switched my ISO to the lowest setting possible--whatever is equivalent to ISO 50. The photos turned out fine as far as I can tell.

I have 2 questions:

1. Since the equivalent ISO technically isn't ISO 50 but is listed something like ISO LO 1.0 (just going off of memory without pulling out the camera), what disadvantages are there with using this ISO if it specifically isn't listed as ISO 50? I remember reading something about its not being exactly the same as ISO 50 but cannot remember why. I used a Circular Polarizer but don't own a Neutral Density filter at this moment in time and needed a slower shutter speed for the water. Do any of you see something (other than the speed of the water) that would make me NOT use this ISO for shooting in certain conditions. If I get a Neutral Density filter, then of course I can shoot at ISO 100.

2. While getting ready to write this post, I noticed something odd--the ISO isn't listed in the EXIF data. None of the original jpegs or RAW files show the ISO on the ones shot at ISO LO 1.0. That said, the first photo was edited strictly in PSE10 and contains no ISO; however, the second photo I opened as a RAW file in Lightroom 4 then exported as a jpeg and worked some more in PSE10. This one lists ISO 50 (no, I did not insert that info myself), but the original jpegs and RAW files of this shot do NOT show the ISO in the EXIF. Would a D600 owner please shoot something at the ISO LO 1 equivalent and let me know if the ISO shows up in the EXIF data of the original files? I'm wondering if it has anything to do with the 3 Nikon services the camera has endured since the beginning of September or if all D600s don't show ISO LO 1 (equivalent of ISO 50) in the EXIF. Thanks!

EDIT: All my files shot at ISO 100 and above DO list the ISO in the EXIF data. I'd just like to know if anyone else has problems with the ISO displaying if it is set to its lowest ISO setting.

 

[PapaST]

My exif shot at L1.0

 

[480sparky]

ISO is an international standard, a product of an outfit called International Organization for Standards. The reason it's Low 1.0 is that the speed doesn't meet ISO's requirement for ISO 50. It's created internally by the camera based on an ISO 100 shot. The software is able to alter the exposure by 1 stop.

The disadvantage is the process can generate noise.

 

[hark]

My exif shot at L1.0

View attachment 58527

Many thanks. PapaST! I added a question to my Nikon service to see if it might be a problem due to its service. Greatly appreciated!

ISO is an international standard, a product of an outfit called International Organization for Standards. The reason it's Low 1.0 is that the speed doesn't meet ISO's requirement for ISO 50. It's created internally by the camera based on an ISO 100 shot. The software is able to alter the exposure by 1 stop.

The disadvantage is the process can generate noise.

Ahh...I knew there was something that made it not as nice as an original ISO 50 would be but couldn't remember why. Thanks! So perhaps I will use the rewards $ accumulated via B&H to order a neutral density filter. Now I need to decide whether to go with one that has a variable stop or one set to a specific amount. Hmmm.... Any suggestions are certainly welcome!

 

[WayneF]

Ahh...I knew there was something that made it not as nice as an original ISO 50 would be but couldn't remember why. Thanks! So perhaps I will use the rewards $ accumulated via B&H to order a neutral density filter. Now I need to decide whether to go with one that has a variable stop or one set to a specific amount. Hmmm.... Any suggestions are certainly welcome!

The LO ISO method does not meet ISO standards, in this way:

The sensor has only one designed ISO value, that is to say, the sensor can only do whatever it can do.

Higher ISO is simply a math operation afterwards. ISO 200 multiplies all pixel data by 2, and ISO 400 by 4. etc. This shifts all data right in the histogram. including the noise near zero has been shifted higher too. This simulates more exposure (but the sensor only has one exposure possibility).

LO ISO simply divides, and shifts data left in the histogram. That simulates less sensitivity (does not change what is captured, but simply shows it differently - like you would do in a later editor). This left shift (LO 1.0) also leaves the top half of sensor range blank, unused, which is a stop less dynamic range. The final histogram you see is not blank, because the scale is changed so what you see appears to be a full exposure, but it is not, in that the top half of the sensor dynamic range was not used. It is basically a contrast reduction.

A ND filter will change what the sensor actually captures, and does not suffer the same loss of dynamic range.

 

[hark]

Thank you for taking the time to explain this, Wayne! I learned something new today!

 

[Mfrankfort]

Great shots!

 

[nmccamy]

I read somewhere that ISO 50 may not give the most accurate exposure or color rendition. But your examples are great!

​Has anyone encountered any problems with ISO 50?

 

[mguffin]

All ISO settings, that are not the native ISO, have the possibility of creating negative results, regardless if the setting is above or below the native. The native ISO of the D600/D610 is 100-6400, and I may be wrong, but I thought I read somewhere that the native ISO range is full stops, anything in between is non-native...

 

[WayneF]

The Native ISO is 100, period. That is simply what the sensor does. Its pixels are "buckets" which collect and count photons. After design and manufacture, there is no way to make it count more or less photons (other than exposure, aperture and shutter speed).

Higher ISO is simple math multiplications, increasing the counted number by math, but not increasing the photons. Downside is increased noise, due to raising the noise floor by multiplication of numbers (which might not be very important in some cases).

Lower ISO is simple math division, discarding the top end of range, losing dynamic range, which is reduced image contrast. It is not about color or image exposure accuracy. Contrast is the range between darkest and brightest tones, and the range is reduced (which might not be very important in some cases).

 

[nmccamy]

Bottom line. Experiment with ISO 50 and ISO 100 and see what works best for you. I will try that out when I eventually purchase a Nikon camera and post the results if it is notable.

 

[aroy]

This brings up an interesting question. If changing the ISO to a higher ISO is just shifting the histogram (and this is corroborated by DXO DR readings - higher the ISO lower the DR), then why bother at all using the higher ISO capability, just shoot RAW and shift the levels by required amount.

Similarly if ISO 50 just shifts the histogram lower, it is in effect clipping the highest bit of data, and one might just as well do it in computer.

 

[hark]

This brings up an interesting question. If changing the ISO to a higher ISO is just shifting the histogram (and this is corroborated by DXO DR readings - higher the ISO lower the DR), then why bother at all using the higher ISO capability, just shoot RAW and shift the levels by required amount.

Similarly if ISO 50 just shifts the histogram lower, it is in effect clipping the highest bit of data, and one might just as well do it in computer.

Well, I certainly don't know the answer, but the reason why I used the ISO LO1 was to slow down my shutter speed while capturing the waterfalls. I wanted smoother water. I used a Circular Polarizer because I don't own a Neutral Density filter yet, and the lower ISO slowed down my shutter speed. I don't see how changing the histogram after the fact will smooth out the water if the images are shot at ISO 100.

 

[WayneF]

This brings up an interesting question. If changing the ISO to a higher ISO is just shifting the histogram (and this is corroborated by DXO DR readings - higher the ISO lower the DR), then why bother at all using the higher ISO capability, just shoot RAW and shift the levels by required amount.

Similarly if ISO 50 just shifts the histogram lower, it is in effect clipping the highest bit of data, and one might just as well do it in computer.

It is not quite the same thing afterwards. The camera chips do much of it with analog amplification before the A/D digital conversion. After A/D, it is much more locked in. Sure, we can do a certain limited amount after, a stop or two if Raw (with more than 8 bits), but noise becomes a much bigger problem after, I suppose because digital has definite "ends" on the data range.

But the idea of what's happening is about the same thing, before or after.

 

[aroy]

Well, I certainly don't know the answer, but the reason why I used the ISO LO1 was to slow down my shutter speed while capturing the waterfalls. I wanted smoother water. I used a Circular Polarizer because I don't own a Neutral Density filter yet, and the lower ISO slowed down my shutter speed. I don't see how changing the histogram after the fact will smooth out the water if the images are shot at ISO 100.

What I meant is, that you set the camera ISO at 100 and the other exposure parameters for ISO 50 - over expose by a stop. You thus get lower shutter speed and during processing just get rid of the left most bit data.

From what I know of image sensors, the native ISO is the one where the full well capacity is achieved at the stated exposure. The camera manufacturers in general leave a margin for over exposure (1/2 stop or so), which is why you can recover a bit of highlight. Higher ISO is achieved by analog amplification prior to A-D conversion, but the noise remains the same with respect to the signal, hence higher noise at higher ISO.

My original question was that, if the signal is amplified (along with the noise) by the camera, is the resultant signal and noise as much as you would get by just shifting the histogram by those many bits, or is it better. In case the noise if same or at the most marginally better, in my opinion it would be easier to underexpose the image by using the native ISO and shifting the histogram in post processing.