Shadow detail obsession bla bla bla

Great Bustard · Jun 1, 2011

Chato said:
Chato said:

...they know what they're talking about. The D2x is an "ISOless" camera. That is, the read noise is flat throughout the ISO range:

http://www.sensorgen.info/NikonD2X.html

Click to expand...

I don't doubt it...

Chato said:

This means that changing the ISO does not have any effect on noise for a fixed aperture and shutter speed , but it may result in blown highlights, if you use higher ISOs.

Click to expand...

And is there an advantage to doing this?

I will explain that directly and simply in just a few moments.

Chato said:
Can I keep a high speed? Can I keep a larger aperture.

Absolutely.

Chato said:
Essentially, the argument is, (pardon the quotes) "You can completely blow the picture, and then restore the image and get almost as good a result. "

You're almost there, but you got it exactly backwards. OK, here we go. Let's say you take a pic of a scene at 1/100 ISO 1600 and it comes out just perfect. There's no advantage to shooting it at 1/100 ISO 100 and using +4 EC in conversion.

But let's say you shot the scene at 1/100 ISO 1600, and you blew a few highlights you wish you hadn't. Well, tough -- blown is blown (trust me on this -- the massage parlor I go to is a wonderful example of that).

However, if you had instead shot the scene at 1/100 ISO 100, then you could have used a different tone curve in the conversion (pseudo HDR, if you will) that would preserve the highlights and give the apparent exposure on everything else the way you like.

The reason, of course, is that the flat read noise of an ISOless sensor gives no penalty for EC pushing in conversion, and the limited bit-depth of the camera makes for in-camera gain (either analog or digital) subject to oversaturation (blown highlights).

Does this make sense to you? I billed my explanation as "simple and direct", so I hope I succeeded.

Chato said:
After all is said and done, this is strictly an intellectual exercise with no practical benefits.

Hopefully, the explanation above explains the "practical benefit" of using only base ISO on an "ISOless" camera.

Chato said:
How's it going to help the dynamic range on this image?

Well that looks like it was taken at base ISO, so same difference. However, let's say it was taken at ISO 400. If there were blown highlights in the pic, then they would have been recoverable had you taken it at base ISO (or, at least, "more" recoverable), and the photo could have been converted with a tone curve that gave the apparent exposure you desired without the blown highlights.

So, if you never blow highlights, or simply don't care about blown highlights, then, no, there is no reason to do as we suggest. But if you occasionally blow highlights, and would like more recovering them, then shooting at base ISO on an ISOless camera is the way to go.

bobn2 · Jun 1, 2011

Chato said:
bobn2 said:

Chato said:

I shoot with a fixed aperture 'Scope. All I can do to change the light is increase or decrease the speed. This shot was taken at f10, the speed was most likely 1/1600 at ISO 800. Since I'm now shooting ISO 400, I would probably use 1/800. Either way, there's nothing you're telling me that will improve the photography.

Click to expand...

Click to expand...

Chato said:

If you can shoot at 1/800, why didn't you just select 1/800?

Click to expand...

I'm going to find out if I can get away with 1/800, I'm not sure yet...

Good, maybe you can't, but you can get away with 1/1000. Then, that's the speed.

Chato said:
Chato said:

Why do you need to choose an ISO to shoot at in order to select your shutter speed?

Click to expand...

The shutter speed is determined by the expected maximum action. You think that Egret was staring into the water for his health(Well I suppose feeding yourself can be defined as acting for your health)?

Exactly so. My question was, why do you need to choose an ISO to shoot at in order to select your shutter speed. It isn't a trick question, just a straightforward one.

Chato said:
Chato said:

The advice is, determine the slowest shutter speed that you can choose without unacceptable shake or subject movement and use that. That will always be the lowest noise. Choosing 800 ISO made you chose a shorter shutter speed than you needed. Instead of thinking about the ISO, think about the shutter speed, and get it as long as you can.

So, using the method I advocate would have improved the DR in this shot, and if you follow the advice, you'll improve your photography.
Simples.

Click to expand...

If I followed your advice I wouldn't get any shots at all. Wildlife refuses to act in a predetermined manner. While it's true that I change speeds on the fly, I don't change them in 1/10 of a second intervals

Well, you probably do, if you are setting an ISO and the setting the exposure according to that ISO. All I'm saying is instead of adjusting the shutter speed to get the exposure 'right', you should be adjusting the shutter speed to get the motion blur 'right'. It's a question of why you select the shutter speed you do, and what is the simplest way of selecting that shutter speed.

What I'm suggesting is that you choose the shutter speed as the maximum in accordance with your motion blur (both shake and subject movement) requirements and you set it by setting it.

What you seem to be saying is that you choose a shutter speed to get exposure 'right' according to some ISO you've decided is right. You seem to be selecting ISO according to the shutter speed you think it will give you. That means when you make a different judgement about the shutter speed you want, you need to change the ISO to get that shutter speed. So far as I know, to change the ISO on a D2X you have to:

take your eye from the finder
look at the settings screen
press a button
turn the back wheel.

Now you need to find if you're getting the speed you want so you:

put your eye back to the finder
meter
letting the shutter speed adjust if in A mode or adjust it yourself until the meter its centered in M
check the shutter speed is what you want - if not go back to changing the ISO
shoot.

What I am saying is that you decide what shutter speed you want and set it, the procedure is

set the shutter speed you want.

Can you see that one is likely to lose you less shots than the other?

Chato said:
For a Little Blue Heron, I would have chosen 1/800 at the same ISO. But whatever the chosen speed, it's chosen to capture the action.

SInce I can't change the aperture, what good is this information? Shoot the Egret at the same speed as the Heron? Sorry, no, no more highlights.

Well, if you set the camera to 100, and choose the shutter speed you want, you get the highlights, probably less blown than all this fuffing about with the ISO, that is what we're saying.

--
Bob

Chato · Jun 1, 2011

Great Bustard said:
Well that looks like it was taken at base ISO, so same difference. However, let's say it was taken at ISO 400. If there were blown highlights in the pic, then they would have been recoverable had you taken it at base ISO (or, at least, "more" recoverable), and the photo could have been converted with a tone curve that gave the apparent exposure you desired without the blown highlights.

Alright. For the entire time I've had this camera, I've been shooting at ISO 800 except for some tests. This shot was probably taken at 1/1600, since it was strong direct light, well past dawn, and that's what I use on all white birds in that light.

Great Bustard said:
So, if you never blow highlights, or simply don't care about blown highlights, then, no, there is no reason to do as we suggest. But if you occasionally blow highlights, and would like more recovering them, then shooting at base ISO on an ISOless camera is the way to go.

I care very much about highlights. However there have been times when shooting similar scenes I forgot to change the speed. Highlights blown, and ACR is useless in recovering them. While not a common mistake on my part, when you take 60,000 wildlife images a year, it happens often enough to notice.

So how do I recover these blown highlights? How should I be set up?

Dave

Bobo Hodls · Jun 1, 2011

Ben_Egbert said:
Bob Tullis said:

Ben_Egbert said:

Or perhaps that was emulsion grain peeper.

And he tried for maximum shadow detail. Those who like dirty, nosiy, low quality artsy images probably dont like Adams either. But I do.

Click to expand...

LOL! Sounds like reverse transference to me, Ben. I wouldn't bet any serious money on that notion.

Click to expand...

Not sure what you mean here Bob, but I do get tired of people dissing a search for quality. Quality is not everything, but it is an integral part of the process.

I just can't stop thinking like an engineer who knows technical progress never stops.

Quality serves a purpose, but not all purposes/objectives require the full frame sensor fidelity that's possible to exhibit. Those eschewing either speak of a limited perspective on the realm of photography. One needs not enjoy / pursue either end of that spectrum, or all potential subject matter, but to dismiss either afaic is rather narrow.

The reverse-transference relates to your own self-imposed limits (maybe "transference" alone covers that). You'd lose that wager, that those who enjoy gritty / dramatic expressions don't appreciate other styles as well - or all manner of renowned practitioners and contributors to the craft such as Ansel.

bobn2 · Jun 1, 2011

Chato said:
So how do I recover these blown highlights? How should I be set up?

Dave, we've all told you, several times. Joe's told you exactly how to do it.
'Shooting at base ISO on an ISOless camera is the way to go'

You have an ISOless camera. Set it to 100. Set it to M. Set the shutter speed you want. Shoot.

Joe's going to tell you that again, probably better. Read what he says and forget about ISO .

--
Bob

Steen Bay · Jun 1, 2011

Chato said:
Chato said:

Well that looks like it was taken at base ISO, so same difference. However, let's say it was taken at ISO 400. If there were blown highlights in the pic, then they would have been recoverable had you taken it at base ISO (or, at least, "more" recoverable), and the photo could have been converted with a tone curve that gave the apparent exposure you desired without the blown highlights.

Click to expand...

Alright. For the entire time I've had this camera, I've been shooting at ISO 800 except for some tests. This shot was probably taken at 1/1600, since it was strong direct light, well past dawn, and that's what I use on all white birds in that light.

Chato said:

So, if you never blow highlights, or simply don't care about blown highlights, then, no, there is no reason to do as we suggest. But if you occasionally blow highlights, and would like more recovering them, then shooting at base ISO on an ISOless camera is the way to go.

Click to expand...

I care very much about highlights. However there have been times when shooting similar scenes I forgot to change the speed. Highlights blown, and ACR is useless in recovering them. While not a common mistake on my part, when you take 60,000 wildlife images a year, it happens often enough to notice.

So how do I recover these blown highlights? How should I be set up?

Blown is blown and can't be recovered, but if you instead had shot at a lower ISO (maybe even at base ISO) with your chosen shutterspeed, then the highlights wouldn't have been blown, and you could have chosen whatever tone curve (output brightness) you wantet afterwards in ACR. So, in this particular case I'll have to admit that it makes good sense to do it like Bob and others are suggesting.

Chato · Jun 1, 2011

Steen Bay said:
Chato said:

Steen Bay said:

Well that looks like it was taken at base ISO, so same difference. However, let's say it was taken at ISO 400. If there were blown highlights in the pic, then they would have been recoverable had you taken it at base ISO (or, at least, "more" recoverable), and the photo could have been converted with a tone curve that gave the apparent exposure you desired without the blown highlights.

Click to expand...

Alright. For the entire time I've had this camera, I've been shooting at ISO 800 except for some tests. This shot was probably taken at 1/1600, since it was strong direct light, well past dawn, and that's what I use on all white birds in that light.

Steen Bay said:

So, if you never blow highlights, or simply don't care about blown highlights, then, no, there is no reason to do as we suggest. But if you occasionally blow highlights, and would like more recovering them, then shooting at base ISO on an ISOless camera is the way to go.

Click to expand...

I care very much about highlights. However there have been times when shooting similar scenes I forgot to change the speed. Highlights blown, and ACR is useless in recovering them. While not a common mistake on my part, when you take 60,000 wildlife images a year, it happens often enough to notice.

So how do I recover these blown highlights? How should I be set up?

Click to expand...

Blown is blown and can't be recovered, but if you instead had shot at a lower ISO (maybe even at base ISO) with your chosen shutterspeed, then the highlights wouldn't have been blown, and you could have chosen whatever tone curve (output brightness) you wantet afterwards in ACR. So, in this particular case I'll have to admit that it makes good sense to do it like Bob and others are suggesting.

I'd blow the shadows...

Dave

bobn2 · Jun 1, 2011

Chato said:
I'd blow the shadows...

No you wouldn't, with a D2X, that is one of the things we've been trying to get across to you. Doesn't seem like we've done a very good job.

--
Bob

bobn2 · Jun 1, 2011

Steen Bay said:
So, in this particular case I'll have to admit that it makes good sense to do it like Bob and others are suggesting.

You forgot the word 'grudgingly'
--
Bob

Bobo Hodls · Jun 1, 2011

. . . go out and take an exposure, and then make a photograph out of it.

I only charge a quarter for such sage advice - so don't throw out that invoice when it arrives.

--
...Bob, NYC

'Well, sometimes the magic works. . . Sometimes, it doesn't.' - Little Big Man

http://www.bobtullis.com

jonikon · Jun 1, 2011

Kopend05 said:
Sick of it , as digital marches on, we have tech nerds getting excited beyond belief about PP potential of the newer sensors, am i the only one who is thinking proper photography is dying ?

The new DSLRs are so dam good now technicaly speaking that we now have a hobby that has been hijacked by tech nerds taking pics of lowlight brickwalls etc etc and displaying it on forums where fellow techs comment on there great shots ?!!
These camera's are spawing really crappy but technically perfect pictures .

Do you mean like photos of a candy tin like I saw in your photo gallery?

--
Best regards,
Jon

John Sheehy · Jun 1, 2011

Steen Bay said:
If important highlights are blown when shooting at a high ISO, then the ISO is to high and should therefore be reduced! (which will maintain the exposure and prevent clipping)

Why not have that done automatically, if it has no cost at all in those times where you don't need the highlight headroom, and makes the losslessly-compressed RAW files smaller?

Steen Bay said:
Well, my new SX30 'superzoom' can't shoot RAW (and I'm not even sure that I'd bother if it could), but still it's capable (in the right hands) of getting both a 'correct' exposure and reasonably good results : http://forums.dpreview.com/forums/read.asp?forum=1010&message=38219962

RAW is worthwhile with any camera. The shadows are more recoverable on my Canon G9 and my Casio EX-FH25 than they are on my Canon 5D2! You'd never know this from the JPEGs of the compacts.

As I said in another post, anyway, all cameras capture RAW, whether they give it to the user or not. A cheap camera without RAW could use a negative film type of tone curve for keeping the highlights, if the user sets the contrast to lower than "normal".

--
John

mattr · Jun 1, 2011

bobn2 said:
Read what he says and forget about ISO .

There is one reason why it makes sense not to completely forget about ISO, even with an "ISO less" camera: You might want to check focus and composition on the camera's LCD screen.

John Sheehy · Jun 1, 2011

bobn2 said:
You have an ISOless camera. Set it to 100. Set it to M. Set the shutter speed you want. Shoot.

Joe's going to tell you that again, probably better. Read what he says and forget about ISO .

Unless, of course, your f-stop and shutter speed allow too rich an exposure for base ISO.

Of course, if you need to review your images in the field, it might help to work with just enough headroom safety, until manufacturers facilitate use of base gain more intelligently.

--
John

Steen Bay · Jun 1, 2011

John Sheehy said:
Steen Bay said:

If important highlights are blown when shooting at a high ISO, then the ISO is to high and should therefore be reduced! (which will maintain the exposure and prevent clipping)

Click to expand...

Why not have that done automatically, if it has no cost at all in those times where you don't need the highlight headroom, and makes the losslessly-compressed RAW files smaller?

Sure, I agree that a real 'ISO-less' camera is a good idea. It's just that for my kind of shooting I don't think it would really change anything, because I normally have all the time needed to 'optimize' the exposure, but for other shooting scenarios (like in Dave's below) it could probably be helpful.

John Sheehy said:
John Sheehy said:

Well, my new SX30 'superzoom' can't shoot RAW (and I'm not even sure that I'd bother if it could), but still it's capable (in the right hands) of getting both a 'correct' exposure and reasonably good results : http://forums.dpreview.com/forums/read.asp?forum=1010&message=38219962

Click to expand...

RAW is worthwhile with any camera. The shadows are more recoverable on my Canon G9 and my Casio EX-FH25 than they are on my Canon 5D2! You'd never know this from the JPEGs of the compacts.

Yes, there's no doubt that shooting RAW is the best solution, but much can be done with JPEGs also, and I've always used the lowest in-camera settings for sharpening and contrast on my compacts, in order to get the best possible (next to shooting RAW) starting point for PP.

John Sheehy said:
As I said in another post, anyway, all cameras capture RAW, whether they give it to the user or not. A cheap camera without RAW could use a negative film type of tone curve for keeping the highlights, if the user sets the contrast to lower than "normal".

Yes, why shouldn't it be possible also for JPEG shooters to take advantage of the increased headroom at higher ISOs with an 'ISO-less' camera. That would certainly be a good thing.

John Sheehy · Jun 1, 2011

mattr said:
bobn2 said:

Read what he says and forget about ISO .

Click to expand...

There is one reason why it makes sense not to completely forget about ISO, even with an "ISO less" camera: You might want to check focus and composition on the camera's LCD screen.

True, but I don't think anyone is claiming that the cameras already have it right, firmware-wise. Iif you need the camera review, for the time being you can try to stick to only a couple of stops of so-called "under-exposure". Sometimes two stops of extra headroom is all you need.

Of course, there is no reason why manufacturers, in the future, can't give you embedded-JPEG re-conversion on the fly, or "auto-ISO" after capture (metering the RAW data).

Of course, for flash fill, the camera has to have some idea of what the mean exposure is, so it would have to determine something like intended ISO at flash time.

--
John

John Sheehy · Jun 1, 2011

bobn2 said:
Chato said:

I'd blow the shadows...

Click to expand...

No you wouldn't, with a D2X, that is one of the things we've been trying to get across to you. Doesn't seem like we've done a very good job.

This guy is taking a very, very long time to even realize what it is that he's disagreeing with, with numerous hints.

We'll have to wrestle the camera out of his hands and show him its properties.

--
John

Iliah Borg · Jun 1, 2011

--
http://www.libraw.org/

Chato · Jun 1, 2011

John Sheehy said:
bobn2 said:

Chato said:

I'd blow the shadows...

Click to expand...

No you wouldn't, with a D2X, that is one of the things we've been trying to get across to you. Doesn't seem like we've done a very good job.

Click to expand...

This guy is taking a very, very long time to even realize what it is that he's disagreeing with, with numerous hints.

We'll have to wrestle the camera out of his hands and show him its properties.

He speaks English.

Dave

John Sheehy said:
John

mattr · Jun 1, 2011

John Sheehy said:
True, but I don't think anyone is claiming that the cameras already have it right, firmware-wise. Iif you need the camera review, for the time being you can try to stick to only a couple of stops of so-called "under-exposure". Sometimes two stops of extra headroom is all you need.

Yes, that's what I would do regularly if I had one of the new Sony sensor cameras.

John Sheehy said:
Of course, there is no reason why manufacturers, in the future, can't give you embedded-JPEG re-conversion on the fly, or "auto-ISO" after capture (metering the RAW data).

Of course, but I'm not holding my breath. The whole "ISO-less" concept appears to be difficult to sell to a lot of people. The manufacturers of cameras that have already pretty much the dynamic range for ISO-less, don't seem to view it yet as a big selling point for marketing.

John Sheehy said:
Of course, for flash fill, the camera has to have some idea of what the mean exposure is, so it would have to determine something like intended ISO at flash time.

Good point. Perhaps fill flash could be dialed in not as an absolute intensity but relative to the brightness of the scene.

Shadow detail obsession bla bla bla

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