Help with ISO info for my D5500

[EmzDad]

Evening,

I am reading through the Training library at the moment. Came across the section about ISO... (http://www.ausphotography.net.au/forum/showlibrary.php?title=New_To_Photography:Detailed_explanation_of_ISO)


Quote from training: "Q: So the "native ISOs" are taken care of by the amplifier, but the "other ISOs" are not?

A: Correct! All the non-native ISO settings are simply mathematical trickery. For example, on my 20D, if I set ISO 3200, the sensor system simply carries right on shooting at ISO 1600 (because that is as high as the amplifier can go) but the camera electronics set one stop of negative exposure compensation and double whatever number the A/D converter puts out."

So what are the "main" ISO settings on a Nikon D5500?

Is this generally the same across most DSLR's?

Buy shooting with "main" ISO am I reducing the "electrical noise" ?

Thanks
Shane

[Cage]

Shane, that's a very profound question for a 'beginner'. I like it, because I also need to know more than to be told 'how', I also need to know 'why' as well.

I'm guessing here, but I reckon the native ISO of most modern DSLR's is ISO100.

What modern DSLR's do with their adjustable ISO settings is to try, with computer algorithms, to mimic the different coatings on film to attract more light. I believe the jury may still be out on how successful they have been.

I hope one of the techno geeks with a better understanding of the subject drop in and set you straight.

[Mark L]

Well I'm not one of those techno geeks.:)
I wonder if how it's done it makes that much difference to the final image.
You can easily set something up to take the same photo and test how the various ISOs create noise (or not).
I'd suggest the main ISO setting is the one that gets the shutter speed high enough to get a sharp photo in any given light.
The above probably doesn't address you questions.

[EmzDad]

As I am reading through this library, me being me... (one of my strengths I suppose is trouble shooting, making things run as well as they can, I am a mechanic. Work with high speed packing machines in the sugar industry) so as I read this the brain starts formatting "what gives the best picture then"

If there are "main ISO" and then ones made as an electronic calculation my brain is thinking then if you know what the "main" ones are does that produce a less noise picture.

Sorry if this is irrelevant, usual if you don't know ask...

Thanks
Shane

[Cage]

IMHO, after ISO100 it is an ever increasing downward curve in image quality.

[EmzDad]

hmmm... decided to google "Nikon Native ISO"... the statement "Can of worms" comes to mind.

[farmmax]

There was a lot of discussion about this in the Magic Lantern forum, because Magic Lantern can allow a canon camera to run a much higher iso's than on the camera menu's. That is where I first read about what you are saying. Only some of the iso's are native, the others are interpolated. They suggested trying to stick to the native iso's on your menu. From memory it varied between camera's. Sorry, I wasn't interested at the time and tucked the information away in case I wanted to explore it later :D

[EmzDad]

Thanks Farmmax,

Reading around the net, I can not find a statement or info stating that for eg: 100 to 6400 is native than extended is to 25600...

But I can find a little bit in reviews that Nikon has stated that the D5500 is native all the way form 100 to 25600.

If I remember it is in the specs as :Native ISO: 100- 25,600 and Extended: ISO: 100- 25,600

So that doesn't make much sense.

[arthurking83]

Just had a look at the D5500's menu for ISO.

It's strange the way the specs blurb has been written, but from what I've seen the selection of ISO value on the 5500 seems to have changed from standard Nikon fare(I think)

With Nikon, it's simple: any pure integer value(eg. 100, 200, 1600, 6400) means native ISO value. In general this is a calibrated ISO value and Nikon can guarantee a specific SNR value for that setting.

If the ISO value was a Lo or Hi range type(ie. Lo0.3, Lo1 .. Hi0.7, Hi2 .. etc) then it's an extended ISO value and as already said this relies on an exposure with exposure compensation added to the image file during the internal processing. What's not guaranteed is SNR consistency, which is probably due to inconsistent exposure possibilities in this mode.

What Nikon seems to have done in the D5500 is to remove the Lo and Hi ranges fro ISO selection! :confused013

From what I'm gathering of this there are two possible conclusions/reasons:

1/. to simplify the choice of ISO sensitivity. Makes sense if a newbie is just getting into photography and doesn't understand the use of ISO for exposure, then maintaining a consistent value hierarchy makes more sense than a random and incoherent change in values at the extreme ends of the scale!
That is, going from ISO6400 to ISO12800 makes more sense than ISO6400 to Hi1! .. what the hell is Hi1 and how does it relate to the value below it.
Problem is, doing this makes it a bit more confusing if you upgrade to a higher end body where you have native ISOs and then the Lo-Hi system!

2/. The other possibility(although unlikely!!) is that Nikon software engineers have managed to eke out a bit more quality from the the cameras CPU and have managed to achieve a native ISO quality result at the upper end of the ISO scale.

I'm tending to think that the reason is more likely #2 .. and only because of the changes made between the D7100(older than D5500) and the D7200(newer than the D5500!)
If you look at the differences between the D7200 and D5500 ISO settings, the D7200 also has the same(as the D5500) ISO up to 25600, but they've also given the option of Hi1 and Hi2 but those Hi settings are only B&W versions. Once again this comes down to the uncalibrated nature of the extended ISO values.
(note too that it seems that the D7200's Hi ISO settings only allow jpg shooting too!)

So my guess is that the D5500 doesn't have extended ISO values as an option and only because Nikon are confident that the Expeed CPU is capable of a decent quality rendering compared to what the preceeding models were capable of.

I dunno about other DSLRs(or most other cameras actually) but in previous Nikon cameras the ISO choices were Lo to - native values - to Hi values.
Lo went down to Lo1(used to be Lo0.3, Lo0.7, and Lo1)
Lo was a value based on minimum native ISO, and changed with each sensor's ability, so for example if the lowest ISO was 100, then Lo was based on ISO100
Hence Lo0.3 was equivalent to ISO100 - 0.3Ev = 84ish. Lo0.7 = 66ish, and Lo1 was 1Ev below 100 = 50.
If the lowest native ISO on the camera was ISO200, then the above changes!
In that case, Lo0.3 = 167, Lo0.7 = 133, and Lo1 = 100

So what I reckon Nikon are doing(which makes sense!) .. is to create model separation in a clear manner between the D5500 and D7200 by offering a good set of ISO values, but obviously value adding the D7200 by having the extended Hi1 and Hi2 values as well(although they do seem quite limited and not of much real value).

So the D5500 doesn't have a set of extended ISO settings(as such) .. but still allows a very good range of sensitivities.
FWIW, Nikon have always produced very good noise handling capability in their cameras since the switch to CMOS sensors with the D3/D300(back in 2007!).
Only other camera that comes close is the Pentax. Even Sony who manufactures most of Nikon's and Pentax's sensors can't usually provide as good quality rendering at the same (high) ISO levels as Nikon and Pentax, for a given sensor.

The only ISO value I've stopped using for awhile now is the Lo setting. Can be handy for some instances, and I started using it after I read a review on how Lo0.3 on the D300 gave the best dynamic range from the sensor. So I shot with that for a while, but then found that the review I read must have been dependent on the software that guy used at the time.
It's didn't really translate the same way using Nikon's software. I did some tests and found that lowest native ISO(ISO 200 on the D3000 was the best option for 99.9% of situations).
But at the other end, I use ISO's all the way to the maximum(Hi2) on the D800E in AutoISO mode.
D300 only goes as far as Hi1(which I also set up in AutoISO mode).

So the overall summary of this reply is simple; don't worry about it, and that the info in the NTP section you were reading was crated before the D5500 was created.

[Cage]

Shane, you are spot on with your 'can of worms' comment.

I've been doing some online research to try to find out why my D800 has, IMHO anyway, unacceptable levels of noise at not very high ISO levels, ie anything above ISO800.

As you have discovered there seems to be a lot of conflicting ideas as to what "Native ISO' actually refers to. One school of thought believes that it is the 'normal' range, ie 100-25600 or whatever with maybe an extended range of 50-51200 or whatever. I'm not really sold on this idea because once you move away from the base ISO100 the camera starts to make 'adjustments'.

I'm leaning more toward the concept that Native ISO is in fact the basic in-camera ISO setting, in most cameras ISO100. In my internet wanderings I came across DXOMARK, a seemingly highly respected testing facility. Have a look at the link below (for your D5500, which came out of the test smelling like a rose :th3:) and particularly the ISO sensitivity graph where their testing methodology revealed that the D5500's indicated ISO100 was actually ISO83 and ISO800 in their test came in at ISO651.

http://www.dxomark.com/Cameras/Compare/Side-by-side/Nikon-D5500-versus-Nikon-D3300-versus-Nikon-D7100___998_928_865

What does it all mean? I'm blowed if I know, and wonder if I should really care. Maybe in a shooting situation where all the variables were fixed and the mandatory ISO setting was ISO800 you may have to raise your camera's ISO setting to ISO1000 to compensate, but I can't ever see myself in that situation.

I guess on a day to day basis the best scenario is to see how your camera reacts to different shooting situations and adjust your settings accordingly.

I do feel however that my D800 is well over par with it's ISO noise handling and I'll keep looking for an answer as to why. I've double checked all my in-camera settings so maybe it's an in-camera computer glitch. Time for that D810 methinks.

PS: And what Uncle Arthur said. :nod:

[arthurking83]

While DxO is respected, it's not as respected as many seem to think.
ie. all that means that it's not the definitive answer to photographic questions. I'ts just one resource which some people find totally accurate and others may not.

The issue is what software are they using, and does that software produce the definitive rendering of any file(raw or otherwise).

So lets take the not so accurate ISO values as noted by Cage.

The problem is that to create a jpg file from the camera when the camera is supposedly shot in a raw state, the raw file needs to be converted(to a jpg).

The ISO standard for digital cameras specifies a jpg file from the camera(not raw) .. and also note that the ISO standard does allow for some latitude/varaince in the exposure.

So 83ISO is probably a totally acceptable result in terms of accuracy for the chosen 100ISO setting in camera.
The other issue(and the major one I have with DxO's 'respectibility') is what lens did they use(if they used one) . and this is where their results get murky and pretty much become useless info!

Firstly, any image basically require a lens to create. While you can make images without lenses .. for most of us normal people .. we use lenses.
While DxO (may)may not use a lens and instead do some super paranormal extra terrestrial godlike process testing .. because we have different processes to them(gods!) .. their results are basically useless(to us mere mortal .. who may use simple lenses).
The problem is we don't know what process DxO use to test stuff.

So the issue is: if they use a lens, which lens? All lenses have different rending ability. Do they account for vignetting, aperture inaccuracies, transmission issues due to lens designs .. etc.

I mount a 50mm Sigma lens to my D300, and the exposure is different to the 50mm f/1.2 Nikon lens. Lets say(just for example!) the Sigma lens is brighter here.

But mount the Nikon 50 now to the D800 and use Dx mode in the D800 to roughly compare the same framing .. and the D800 may now be brighter.

D800 and D300 produce different exposure results(with the D800 in crop mode) most of thee time.
And the issue I've seen is that this difference changes depending on the lens used.
Note that the difference may be very small .. 1/3 or so .. but can be over 1Ev different .. in exposure .. in manual mode with clearly defined exposure variables.

The problem I think comes down to software(and obviously hardware to a high degree! .. eg. sensor tech changes massively over time).
But I think the major issue is software both in camera and externally.
That is, the tone curves applied to images change over time as sensors evolve.

So the only possible way to accurately test ISO variances is to shoot in jpg mode in camera and check the results. But then you have the issue of what picture style(in Nikon's world, this means Picture Control) .. which is simply the tone curve applied to this jpg. So either way, the image that is being used to check for ISO variance is processed .. no matter what the format used is.
This is why I have very little interest in DxO's sensor results(especially their stated ISO variance figures).

In the old days when your sensor was transportable from camera to camera .. ISO made a massive difference and NEEDED to be consistent.
You used film A in camera A and or camera B. You then used film B in camera .. etc., etc.
Now the 'film' is fixed to the camera so the old days of consistency are irrelevant to a degree.
As long as the quoted ISO works in the camera for a specific exposure, taking into account the lenses ability to transmit ... the DxO numbers above are meaningless!(especially if you shoot in raw mode!).

ps. Kev! Your quality standards are set way too high! .. I'm happy with anything nearing ISO25600 on the D800! .. above that .. I'm not particularly happy with tho! :p
I found that while the D300 was fantastic back in it's day .. I outgrew it's ISO3200 ability quicker than I thought.
D800 is better for sure, and while it's not uber in it's ability at ISO6400 .. It's well above acceptable quality, and acceptable at ISO Hi2(ISO25600).

In saying that tho .. I'm still keen on a D500, which should give better quality at higher ISOs I reckon.

I've read a lot of guff regarding the intermediate ISO values between the main 1Ev points too.. ie. ISO 640 as opposed to ISO 800, and so forth.
Again it probably comes down to software other's may have used/tried .. but again for my use, using my workflow .. I've found no reason not to use any integer value for ISO.
You do have issues with the extended(Lo and Hi) values tho.
But within the ISO range that is native to the camera(ie. any integer ISO) .. the camera is calibrated for it and should work well.

Mind you my experience(s) are limited to Nikon camera and predominantly Nikon software too!
I used to use Lr in fits of silliness(on my part) and found that it was more inconsistent with respect to noise and exposure .. but I stopped using Lr completely(as in haven't installed it on Win10 since Win10 was released)
And there a ton of discussion right there .. how ISO quality is inexorably tied to exposure!!

But what I'm reading here with the D5500, Nikon have done good in having rid the camera of the Lo/Hi ISO ranges and kept to the native (integer) values only! :th3:

[EmzDad]

Thanks Guys,

Have been reading some more this morning after having some sleep after night shift. Note: big cuppa coffee to my right... :nod:

Most reviews seem to state that the camera is usable in Jpeg all the way to 25600...

With noise starting some where around 3200 iso.

So with my reading I come to the conclusion that I need to learn what takes a "good photo" setting's wise on my camera, and not worry about what standard or generic measurements apply to some of the settings... as you stated cage, know your own camera.

As much as knowing some of this info may help, I can see as arthur has stated depends on a mix of other things as well. Like lens quality :lens:.

So I will leave this quest for knowledge in this area and move on to my next questions... Tripods, Raw and the Digital processing that it bypasses in camera... (noise reduction :confused013)

I will post these questions up later after more coffee and I reach the 100% awake on the wife's NSB scale... (NSB = NIGHT - SHIFT - BRAIN)



Thanks
Shane

[arthurking83]

I think(I'm sure) I once proposed that you have a look at Nikon's CaptureNX-D software .. in addition to getting to know VNX2.

This is what I do:
Reason is(I probably mentioned this too) .. CNX-D has some very useful and powerful tools in it that VNX2 either has but lacking in usefulness . or simply doesn't have at all.

NR is one of thems tools in CNX-D(no NR tools in VNX2 :()

While there are better NR tools out there, the one in CNX-D works very efficiently .. but note that this is only on raw files!
The tool also works on jpgs too, but in a much more limited capacity(more simple slider tool).


The other thing with ISO. It's better to get a noisy/grainy image of something that could be interesting, than to not get the image, or capturing it massively under exposed or way too blurry from camera movement due to insufficient shutter speed.
One trick that tends to work OK in many situations is to over expose a lil more than you'd otherwise shoot.
ISO noise is basically a factor of Signal to Noise Ratio .. that is, if there is more noise than signal, you see not so flattering image graininess. if there is a little bit more signal(ie. light/exposure) then the SNR ratio has been lessened and the visual outcome is that it's less grainy/noisy.
What you then do in PP, is recover any over exposure of the exposure and drop brightness a little to render the image the way you may have originally intended.