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Author Topic: Best ISO for IQ280  (Read 61410 times)

BJL

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Re: Best ISO for IQ280
« Reply #120 on: July 09, 2015, 01:40:27 pm »

OK I meant they are the same as that camera's ISO100, whatever the real ISO is. This is the only thing that matters IMO, answering the question: "can I get some advantage from those ISO35/50 as a RAW/JPEG shooter?".
Yes, this is the original, practical question!  And the answer seems to be:
(a) no, in that you can get the same results either way by choosing your aperture and shutter speed appropriately, but
(b) maybe yes if you rely on AE to chose exposure settings, in that they will favor more exposure at 35 or 50 than at 100 and so hopefully give less noise.
« Last Edit: July 09, 2015, 06:14:05 pm by BJL »
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Guillermo Luijk

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Re: Best ISO for IQ280
« Reply #121 on: July 09, 2015, 01:44:44 pm »

(b) maybe yes if you rely on AE to chose exposure settings, in that they will favor more exposure at 35 or 50 than at 100 and so hopefully give less noise.

Less noise and more blown highlights. As long as the RAW shooter knows the story behind these ISO values and acts accordingly, all three are equivalent to him.

voidshatter

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Re: Best ISO for IQ280
« Reply #122 on: July 09, 2015, 01:49:58 pm »

Less noise and more blown highlights. As long as the RAW shooter knows the story behind these ISO values and acts accordingly, all three are equivalent to him.

Exactly. 8)
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Paul2660

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Re: Best ISO for IQ280
« Reply #123 on: July 09, 2015, 03:21:48 pm »

Not to sound like the child that had their head in their desk during class, but I am still trying to get my head around this.

I don't have the 180, (have shot it 5 or 6 times), but instead have the 260.  That back is base iso of 50. 

So if I follow the information on this thread, it sound like the best overall iso setting on the 260 for highlight control would be iso 100 instead of 50.  50 might give a bit better shadow recovery, but 100 is going to give the best overall exposure? 

The other elephant in the room that no one has mentioned is heat.  The CCD backs do get hot, and in the summer outdoor pretty quick if you are shooting in the sun with no shade over the back.  In my home state of Arkansas (US), the 5 months of May through September are hard on the 260.   If the back is on for over 20 minutes, which is common with a tech camera you will feel that top plate get hot, sometimes really hot. That heat seems to have a direct reflection on the noise in the shots so most times in the summer I will try to stay in the iso 50 range as it just seem to be a bit cleaner in push areas of a shot, even over iso 100.  That's just from my experience.  If you use zero latency, then the back heats up almost too much to hold, yes it can get really hot.

The other issue is if you use a tech camera/copal shutter lens, you are robbed of the 1/2 and 1/3 shutter speeds that a DF+ or XF would allow you.  These in-between shutter speeds sometimes can make just enough difference to give you a clean shot/manageable noise. 

In my workflow, I work with water quite a bit, I prefer the slow shutter speeds for the blur effect.  Most times I am at iso 50 here, but I have often noticed that in areas of the greatest concentration of water, and where the light is the strongest, the Dalsa backs, seems to loose the fine details in the water.  I am not sure if this due to iso 50, and a bit of loss in overall highlight retention or something else.  But I will work with iso 100 next time out and see if I notice any differences.

Paul Caldwell


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voidshatter

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Re: Best ISO for IQ280
« Reply #124 on: July 09, 2015, 04:25:22 pm »

Paul, base ISO for the IQ260 is 100 for normal mode and 200 for long exposure mode. ISO 50 in normal mode is indeed working at ISO 100, and ISO 140 is indeed working at ISO 200. ISO 50 and ISO 140 are just affecting your metering suggesting you to do more ETTR. If you are familiar with the highlight recoverability of the back you could use anything up to ISO 100 in normal mode, and anything up to ISO 200 in long exposure mode and still achieve the best results with a proper ETTR; otherwise just use the lowest possible ISO and check the highlight warnings.
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BJL

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Re: Best ISO for IQ280
« Reply #125 on: July 09, 2015, 06:16:00 pm »

Less noise and more blown highlights. As long as the RAW shooter knows the story behind these ISO values and acts accordingly, all three are equivalent to him.
Yes: less noise and more risk of blown highlights.
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ErikKaffehr

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Re: Best ISO for IQ280
« Reply #126 on: July 09, 2015, 06:45:06 pm »

Hi,

So what you say is that as long as exposure, that is f-stop, shutter speed and illumination is the same all the three low ISO settings give identical results, except the possibility that the raw converter applies different defaults or biases?

That would make a lot of sense.

Best regards
Erik



Less noise and more blown highlights. As long as the RAW shooter knows the story behind these ISO values and acts accordingly, all three are equivalent to him.
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Guillermo Luijk

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Re: Best ISO for IQ280
« Reply #127 on: July 09, 2015, 08:57:07 pm »

So what you say is that as long as exposure, that is f-stop, shutter speed and illumination is the same all the three low ISO settings give identical results, except the possibility that the raw converter applies different defaults or biases?

That would make a lot of sense.

That is exactly what happens: the RAW data will be indistinguisable (this can easily be checked with DCRAW for instance), while the RAW metadata will inform the RAW developer about the needed clandestine exposure correction down (Baseline exposure metatag in DNG format) to create the illussion of ISO35/ISO50 being something different to ISO100.

Regards
« Last Edit: July 09, 2015, 08:58:55 pm by Guillermo Luijk »
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voidshatter

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Re: Best ISO for IQ280
« Reply #128 on: July 09, 2015, 09:11:49 pm »

That is exactly what happens: the RAW data will be indistinguisable (this can easily be checked with DCRAW for instance), while the RAW metadata will inform the RAW developer about the needed clandestine exposure correction down (Baseline exposure metatag in DNG format) to create the illussion of ISO35/ISO50 being something different to ISO100.

Regards


I have explained this for pages here and at getdpi but people just won't listen but instead defend their superiority of ISO 35 hard...
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BJL

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IQ280 and A99 have minimum EI within ISO recommended limits, D810 no
« Reply #129 on: July 10, 2015, 05:43:27 am »

But I still don't understand why ISO 35 can be base setting for ISO 29 measured (IQ180), while ISO 50 cannot be base setting for ISO 48 measured (A99). Please explain? The standard you describe requires a headroom of just over ln(50/48)/ln(2) and less than ln(35/29)/ln(2) stops?
I skipped any debate about the Sony A99, or whether the IQ180 or A99 can use certain ISO EI settings, but since you ask: I see nothing wrong with the EI=50 on the A99.  What I am reporting on is a guideline on exposure latitude in the ISO 12232 standard that the SSat value is the minimum suggested exposure index setting (based roughly on giving three stops of highlight headroom: placing the metered luminance level at a raw level three stops below maximum.) Since 35>29 and 50>48, both are within that guideline.  It is the Nikon D810 minimum EI of 32 that falls outside it, with 32 being less that its SSat of 47 (as measured by DXO), so that EI setting gives about 1/2 stop less highlight headroom than the ISO suggested minimum.
« Last Edit: July 10, 2015, 08:11:47 am by BJL »
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dchew

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Re: Best ISO for IQ280
« Reply #130 on: July 10, 2015, 07:45:40 am »

I have explained this for pages here and at getdpi but people just won't listen but instead defend their superiority of ISO 35 hard...

Yunli,
I don't think anyone is really arguing the point that the raw data is the same for ISO 35, 50 and 100. As is so often the case with these debates, it seems to be one about semantics and tact. I happen to be in the BJL camp here. I don't see ISO 35 as a "fake" ISO. I see it as the only ISO that is "real". All the other ones are "fake." Therefore, I think of ISO 35 as the base ISO, and 50/100 (and all the others) as some sort of push. I think this is supported by the DXO graph. It is the ISO standard that leads me to this view. You may choose to look at it differently, which is fine by me. Just please don't bother trying to convince me that your perspective is the only one that is correct.

This is an interesting position for me to take because I've owned an IQ180 since they were first released (ordered Apr-2011 delivered Aug-2011). Some may remember when this back was first announced the base ISO was not 35. It was an early firmware release that provided the option for 35 ISO.

I do not agree with your position that this is some conspiracy on the part of PhaseOne. As Bernard stated, all this isn't rocket science; learn how the camera / back / histogram / metering works and shoot accordingly. I don't see this any differently than the old Velvia debate. Was it really ISO 50, or was it ISO 35 film?? Those who loved the saturated colors used it at 50. Those who wanted a more neutral result used it (carefully) at 35. Was 50 a conspiracy on the part of Fuji? Not to me, but think what you want.

You state your definition of proper exposure is to check with RawDigger. While I understand and appreciate that, as a landscape photographer I find it particularly difficult to do that in the field. What I do is use both ISO 35 and ISO 100. In order to be efficient for me I use ISO 35 when I am worried about shadow detail, and ISO 100 when worried about blowing highlights. I'm sure that sounds ridiculous to you, but that keeps me moving when the light is changing fast. I don't have a light meter in the field at all so I rely on my head and the histogram, which needs to be interpreted (especially my head).

What I find amusing about all this is the two photos below. I took these while backpacking in the Wind Rivers. Although I've posted them in other threads, I think they are useful in getting a point across. The first image was taken at sunset with IQ180/Alpa STC/90hrsw ISO 35. The second image was taken the next morning with Sony a7r/Leica 90 summicron ISO 100. Why did I use the Sony in the morning? Was it because I was worried about the wide dynamic range of this shot? No, it was because it was cold, I was in a hurry and I had a miserable sleepless night because of a nasty headache and buffeting winds against the tent all night. I figured I would drop half of the Alpa gear in my state at the time.

The point is at the end of the day it is the Sony image that has blown highlights and struggles with the dynamic range of the scene. So all of this debate pales in comparison to what subjects you like to shoot and what conditions you have to deal with.

To the OP I would offer this: If you are worried about highlights, use ISO 100. If you are worried about shadows use ISO 35. But most of all, do what gives you the best results given your workflow.

Dave



« Last Edit: July 10, 2015, 07:49:45 am by dchew »
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Paul2660

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Re: Best ISO for IQ280
« Reply #131 on: July 10, 2015, 08:17:15 am »

Dave

Great shots. Love the top shot.

Paul
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Re: Best ISO for IQ280
« Reply #132 on: July 10, 2015, 11:17:05 am »

+1

Love your work, Dave!

Alvin
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ErikKaffehr

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Re: Best ISO for IQ280
« Reply #133 on: July 10, 2015, 11:54:01 am »

Hi Dave,

Great pictures…

I would essentially share your opinion. I am not shoot any IQ-backs, P45+ is the closest I get. My ISO setting is almost glued to base ISO. On the cameras I have, that is the P45+ and the Sony the histograms work pretty well. With the P45+ I don't use a light meter, just take a shot and adjust exposure until I have ETTR on the histogram and no blinkies. That works well for me mostly. I use RawDigger quite a lot, but it is a learning experience, just to learn about my exposures.

On the Sonys I use aperture priority and use compensation to get ETTR exposure.

Best regards
Erik

Yunli,
I don't think anyone is really arguing the point that the raw data is the same for ISO 35, 50 and 100. As is so often the case with these debates, it seems to be one about semantics and tact. I happen to be in the BJL camp here. I don't see ISO 35 as a "fake" ISO. I see it as the only ISO that is "real". All the other ones are "fake." Therefore, I think of ISO 35 as the base ISO, and 50/100 (and all the others) as some sort of push. I think this is supported by the DXO graph. It is the ISO standard that leads me to this view. You may choose to look at it differently, which is fine by me. Just please don't bother trying to convince me that your perspective is the only one that is correct.

This is an interesting position for me to take because I've owned an IQ180 since they were first released (ordered Apr-2011 delivered Aug-2011). Some may remember when this back was first announced the base ISO was not 35. It was an early firmware release that provided the option for 35 ISO.

I do not agree with your position that this is some conspiracy on the part of PhaseOne. As Bernard stated, all this isn't rocket science; learn how the camera / back / histogram / metering works and shoot accordingly. I don't see this any differently than the old Velvia debate. Was it really ISO 50, or was it ISO 35 film?? Those who loved the saturated colors used it at 50. Those who wanted a more neutral result used it (carefully) at 35. Was 50 a conspiracy on the part of Fuji? Not to me, but think what you want.

You state your definition of proper exposure is to check with RawDigger. While I understand and appreciate that, as a landscape photographer I find it particularly difficult to do that in the field. What I do is use both ISO 35 and ISO 100. In order to be efficient for me I use ISO 35 when I am worried about shadow detail, and ISO 100 when worried about blowing highlights. I'm sure that sounds ridiculous to you, but that keeps me moving when the light is changing fast. I don't have a light meter in the field at all so I rely on my head and the histogram, which needs to be interpreted (especially my head).

What I find amusing about all this is the two photos below. I took these while backpacking in the Wind Rivers. Although I've posted them in other threads, I think they are useful in getting a point across. The first image was taken at sunset with IQ180/Alpa STC/90hrsw ISO 35. The second image was taken the next morning with Sony a7r/Leica 90 summicron ISO 100. Why did I use the Sony in the morning? Was it because I was worried about the wide dynamic range of this shot? No, it was because it was cold, I was in a hurry and I had a miserable sleepless night because of a nasty headache and buffeting winds against the tent all night. I figured I would drop half of the Alpa gear in my state at the time.

The point is at the end of the day it is the Sony image that has blown highlights and struggles with the dynamic range of the scene. So all of this debate pales in comparison to what subjects you like to shoot and what conditions you have to deal with.

To the OP I would offer this: If you are worried about highlights, use ISO 100. If you are worried about shadows use ISO 35. But most of all, do what gives you the best results given your workflow.

Dave




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dchew

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Re: Best ISO for IQ280
« Reply #134 on: July 10, 2015, 12:46:47 pm »

Thanks Paul, Alvin and Erik. I still do the "be there" part better than the "f/8" part or the creative part. But some day I will master this craft!

I don't often get involved in these debates, but it occurred to me that this back is four years old. About a year after using it I stopped carrying ND grads. Sure there are times when I wish I had them but they are few and far between. The new Sony sensors have wonderful dynamic range (and yes I will be getting the new a7rII). Do the IQ backs have poor dynamic range? Well, the answer is compared to what? I still jump for joy at how much they have compared to what I used to shoot (Velvia and Canon DSLR's), so I'm still slaphappy. It's kinda like saying a McLaren P1 has poor acceleration because a Porsche 918 gets to 60 mph in 2.4 seconds vs. 2.7 seconds (and of course the Porsche is cheaper too). But either one is an awful lot better than my Jeep! Unless of course I can get one of those cars to follow me through the Rubicon Trail.

Everything is relative.

Dave
« Last Edit: July 10, 2015, 02:11:53 pm by dchew »
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Paul2660

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Re: Best ISO for IQ280
« Reply #135 on: July 10, 2015, 01:31:57 pm »

Dave,

You bring up a good point, and after reading over this thread, I found myself going back to some of early 2008/2009 P45+ work, with the AFD III, non DF even and 35mm Mamiya lens.  I have been a bit negative on the old P45+, however after working some old files in both latest versions of LR and C1 vr 8, I have to say, I was impressed.  I have thousands and thousands of images from those years as I worked the hardest with the P45+, but had written off a lot of those trips thinking the DR of the P45+ was just not there.

However,, it is there as long as you follow pretty much the same rules that have been stated in this thread, and the P45+ does have an amazing look to the files, a bit refreshing. 

Never thought I would find myself saying that either, but the old 35mm AF Mamiya F3.5 (at least the one I have) was darn good, better than I remembered. 

Sincerely
Paul
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Steve Hendrix

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Re: Best ISO for IQ280
« Reply #136 on: July 10, 2015, 03:21:16 pm »

Yunli,
I don't think anyone is really arguing the point that the raw data is the same for ISO 35, 50 and 100. As is so often the case with these debates, it seems to be one about semantics and tact. I happen to be in the BJL camp here. I don't see ISO 35 as a "fake" ISO. I see it as the only ISO that is "real". All the other ones are "fake." Therefore, I think of ISO 35 as the base ISO, and 50/100 (and all the others) as some sort of push. I think this is supported by the DXO graph. It is the ISO standard that leads me to this view. You may choose to look at it differently, which is fine by me. Just please don't bother trying to convince me that your perspective is the only one that is correct.

This is an interesting position for me to take because I've owned an IQ180 since they were first released (ordered Apr-2011 delivered Aug-2011). Some may remember when this back was first announced the base ISO was not 35. It was an early firmware release that provided the option for 35 ISO.

I do not agree with your position that this is some conspiracy on the part of PhaseOne. As Bernard stated, all this isn't rocket science; learn how the camera / back / histogram / metering works and shoot accordingly. I don't see this any differently than the old Velvia debate. Was it really ISO 50, or was it ISO 35 film?? Those who loved the saturated colors used it at 50. Those who wanted a more neutral result used it (carefully) at 35. Was 50 a conspiracy on the part of Fuji? Not to me, but think what you want.

You state your definition of proper exposure is to check with RawDigger. While I understand and appreciate that, as a landscape photographer I find it particularly difficult to do that in the field. What I do is use both ISO 35 and ISO 100. In order to be efficient for me I use ISO 35 when I am worried about shadow detail, and ISO 100 when worried about blowing highlights. I'm sure that sounds ridiculous to you, but that keeps me moving when the light is changing fast. I don't have a light meter in the field at all so I rely on my head and the histogram, which needs to be interpreted (especially my head).

What I find amusing about all this is the two photos below. I took these while backpacking in the Wind Rivers. Although I've posted them in other threads, I think they are useful in getting a point across. The first image was taken at sunset with IQ180/Alpa STC/90hrsw ISO 35. The second image was taken the next morning with Sony a7r/Leica 90 summicron ISO 100. Why did I use the Sony in the morning? Was it because I was worried about the wide dynamic range of this shot? No, it was because it was cold, I was in a hurry and I had a miserable sleepless night because of a nasty headache and buffeting winds against the tent all night. I figured I would drop half of the Alpa gear in my state at the time.

The point is at the end of the day it is the Sony image that has blown highlights and struggles with the dynamic range of the scene. So all of this debate pales in comparison to what subjects you like to shoot and what conditions you have to deal with.

To the OP I would offer this: If you are worried about highlights, use ISO 100. If you are worried about shadows use ISO 35. But most of all, do what gives you the best results given your workflow.

Dave






Dave - I think that is really well said. At the end of the day, we're all photographers, or people with cameras in their hands at least, and what you wrote makes total sense and is what matters.

I don't understand why some (yes, Yunli, I'm looking at you) continue to hammer home insignificant points, page after page. Why the war, why the conflict, why the need to make some sort of point of very infinitesimal value and present others as engaging in and extending your conflict? Is it so important to be right on whatever single, non critical point you're trying to make, rather than have some spirit of photography, and of people who are engaged in it and passionate about it? Why not talk about that? Why not come from that perspective - at least once in a while.

I'm not trying to be grouchy - really, I'm not! - I just don't understand this pursuit and I'm asking for a reconsideration of this (and similar) pursuit(s).

Some really good information was brought out by this thread - why not focus on expanding on that as valuable information for the readers rather than driving home pissing match points?


Steve Hendrix
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« Last Edit: July 10, 2015, 03:36:01 pm by Steve Hendrix »
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eronald

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Re: Best ISO for IQ280
« Reply #137 on: July 10, 2015, 03:33:21 pm »

of course it is the Sony which will blow the highlights at the earliest opportunity if rated normally BECAUSE THE PHASE UNDEREXPOSES BY 1.5 STOPS @ ISO 100 BY DESIGN. It's not rocket science: Overexpose at a standard rating on a dLSR, goodbye data, hello burnout. Overexpose on a Phase back and you have padding, by design, because the ISO is fake. Of course this will then allow Dealer Doug to crow about the better behavior of the back. It is true, they are more foolproof.

Anyway, anyone with a Sony should just shoot the ISO 100 as ISO 400 and enjoy the added highlight protection, with shadows protected by the superior DR.

Edmund

Yunli,
I don't think anyone is really arguing the point that the raw data is the same for ISO 35, 50 and 100. As is so often the case with these debates, it seems to be one about semantics and tact. I happen to be in the BJL camp here. I don't see ISO 35 as a "fake" ISO. I see it as the only ISO that is "real". All the other ones are "fake." Therefore, I think of ISO 35 as the base ISO, and 50/100 (and all the others) as some sort of push. I think this is supported by the DXO graph. It is the ISO standard that leads me to this view. You may choose to look at it differently, which is fine by me. Just please don't bother trying to convince me that your perspective is the only one that is correct.

This is an interesting position for me to take because I've owned an IQ180 since they were first released (ordered Apr-2011 delivered Aug-2011). Some may remember when this back was first announced the base ISO was not 35. It was an early firmware release that provided the option for 35 ISO.

I do not agree with your position that this is some conspiracy on the part of PhaseOne. As Bernard stated, all this isn't rocket science; learn how the camera / back / histogram / metering works and shoot accordingly. I don't see this any differently than the old Velvia debate. Was it really ISO 50, or was it ISO 35 film?? Those who loved the saturated colors used it at 50. Those who wanted a more neutral result used it (carefully) at 35. Was 50 a conspiracy on the part of Fuji? Not to me, but think what you want.

You state your definition of proper exposure is to check with RawDigger. While I understand and appreciate that, as a landscape photographer I find it particularly difficult to do that in the field. What I do is use both ISO 35 and ISO 100. In order to be efficient for me I use ISO 35 when I am worried about shadow detail, and ISO 100 when worried about blowing highlights. I'm sure that sounds ridiculous to you, but that keeps me moving when the light is changing fast. I don't have a light meter in the field at all so I rely on my head and the histogram, which needs to be interpreted (especially my head).

What I find amusing about all this is the two photos below. I took these while backpacking in the Wind Rivers. Although I've posted them in other threads, I think they are useful in getting a point across. The first image was taken at sunset with IQ180/Alpa STC/90hrsw ISO 35. The second image was taken the next morning with Sony a7r/Leica 90 summicron ISO 100. Why did I use the Sony in the morning? Was it because I was worried about the wide dynamic range of this shot? No, it was because it was cold, I was in a hurry and I had a miserable sleepless night because of a nasty headache and buffeting winds against the tent all night. I figured I would drop half of the Alpa gear in my state at the time.

The point is at the end of the day it is the Sony image that has blown highlights and struggles with the dynamic range of the scene. So all of this debate pales in comparison to what subjects you like to shoot and what conditions you have to deal with.

To the OP I would offer this: If you are worried about highlights, use ISO 100. If you are worried about shadows use ISO 35. But most of all, do what gives you the best results given your workflow.

Dave




« Last Edit: July 10, 2015, 03:54:32 pm by eronald »
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voidshatter

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Re: IQ280 and A99 have minimum EI within ISO recommended limits, D810 no
« Reply #138 on: July 10, 2015, 03:50:10 pm »

I skipped any debate about the Sony A99, or whether the IQ180 or A99 can use certain ISO EI settings, but since you ask: I see nothing wrong with the EI=50 on the A99.  What I am reporting on is a guideline on exposure latitude in the ISO 12232 standard that the SSat value is the minimum suggested exposure index setting (based roughly on giving three stops of highlight headroom: placing the metered luminance level at a raw level three stops below maximum.) Since 35>29 and 50>48, both are within that guideline.  It is the Nikon D810 minimum EI of 32 that falls outside it, with 32 being less that its SSat of 47 (as measured by DXO), so that EI setting gives about 1/2 stop less highlight headroom than the ISO suggested minimum.

So you've reached a conclusion that Sony is falsely advertising the native base ISO for the A99? They advertise for 100 but apparently they are deceiving and they should modify it to 50, is this correct?
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voidshatter

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Re: Best ISO for IQ280
« Reply #139 on: July 10, 2015, 04:11:51 pm »

Yunli,
I don't think anyone is really arguing the point that the raw data is the same for ISO 35, 50 and 100. As is so often the case with these debates, it seems to be one about semantics and tact. I happen to be in the BJL camp here. I don't see ISO 35 as a "fake" ISO. I see it as the only ISO that is "real". All the other ones are "fake." Therefore, I think of ISO 35 as the base ISO, and 50/100 (and all the others) as some sort of push. I think this is supported by the DXO graph. It is the ISO standard that leads me to this view. You may choose to look at it differently, which is fine by me. Just please don't bother trying to convince me that your perspective is the only one that is correct.

This is an interesting position for me to take because I've owned an IQ180 since they were first released (ordered Apr-2011 delivered Aug-2011). Some may remember when this back was first announced the base ISO was not 35. It was an early firmware release that provided the option for 35 ISO.

I do not agree with your position that this is some conspiracy on the part of PhaseOne. As Bernard stated, all this isn't rocket science; learn how the camera / back / histogram / metering works and shoot accordingly. I don't see this any differently than the old Velvia debate. Was it really ISO 50, or was it ISO 35 film?? Those who loved the saturated colors used it at 50. Those who wanted a more neutral result used it (carefully) at 35. Was 50 a conspiracy on the part of Fuji? Not to me, but think what you want.

You state your definition of proper exposure is to check with RawDigger. While I understand and appreciate that, as a landscape photographer I find it particularly difficult to do that in the field. What I do is use both ISO 35 and ISO 100. In order to be efficient for me I use ISO 35 when I am worried about shadow detail, and ISO 100 when worried about blowing highlights. I'm sure that sounds ridiculous to you, but that keeps me moving when the light is changing fast. I don't have a light meter in the field at all so I rely on my head and the histogram, which needs to be interpreted (especially my head).

What I find amusing about all this is the two photos below. I took these while backpacking in the Wind Rivers. Although I've posted them in other threads, I think they are useful in getting a point across. The first image was taken at sunset with IQ180/Alpa STC/90hrsw ISO 35. The second image was taken the next morning with Sony a7r/Leica 90 summicron ISO 100. Why did I use the Sony in the morning? Was it because I was worried about the wide dynamic range of this shot? No, it was because it was cold, I was in a hurry and I had a miserable sleepless night because of a nasty headache and buffeting winds against the tent all night. I figured I would drop half of the Alpa gear in my state at the time.

The point is at the end of the day it is the Sony image that has blown highlights and struggles with the dynamic range of the scene. So all of this debate pales in comparison to what subjects you like to shoot and what conditions you have to deal with.

To the OP I would offer this: If you are worried about highlights, use ISO 100. If you are worried about shadows use ISO 35. But most of all, do what gives you the best results given your workflow.

Dave





Nice pictures Dave :) Of course we can stop using the word "fake" but it doesn't change the fact that ISO 35 of IQ180 is essentially the same as ISO 50 on Sony A99, i.e. extended ISO. It is one way or the other as below:

a) The IQ180 is accurately advertised for ISO 35 as base but falsely advertised for anything above ISO 35 (for underexposed images not up to the standard), possibly trying to hide its poor low-light performance;
b) The IQ180 is indeed an ISO 100 camera but is not explicitly specified with ISO 35 as extended ISO, giving the user the false impression that using ISO 35 can gain more DR than using ISO 100, and increasing the self-satisfaction of the user.

I would say that either way Phase One is clever and this is all about marketing. If Phase One follows Canon/Nikon/Sony's specification rules then the IQ180 would either look poor in low-light or look less awesome for the low ISO number.

As for the correct exposure for landscape without tethering, I have already shown by actual experiments that no matter whatever ISO you choose, you won't be able to get accurate highlight clip warning out of IQ260 or Nikon. Actually ISO 50 for IQ260 and ISO 50 for D4S are both best for playback purposes as the highlight clip warnings are most close to RawDigger results. You might end up using the extended ISO settings for Canon/Nikon/Sony for a more accurate playback. The IQ3 series is advertised for the ability to report true histogram for RAW but I haven't tested it yet.

As for your examples, if you shoot the same picture with IQ180 and A7R side by side, both with correct ETTR without bracketing, then the IQ180 would have less recoverable shadow details. However you don't do long exposure shots so I see no problem bracketing and DR will not be of an issue in such scene for the IQ180.
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