Pages: 1 2 [3] 4 5 ... 10   Go Down

Author Topic: Best ISO for IQ280  (Read 52709 times)

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter
Re: Best ISO for IQ280
« Reply #40 on: July 06, 2015, 12:51:57 pm »

I made a simple test with my IQ180: 3 exposures

- at ISO 35
- at ISO 35 1.5 stops underexposed (= exposed like ISO 100)
- at ISO 100

If I open the files in ACR and add 1,5 stops exposure to the second picture, I see the following:

- the three pictures look very similar, but
- the second and third are more grainy in medium and dark areas

so my conclusion would be that the IQ180 is

- ISO 35 native* (not ISO 100 like Void suggests)
- up to ISO 100 in reality also ISO 35, just underexposed and already compensated by Phase RAW firmware (which means the picture looks correct exposed if opened in ACR or C1, just raw digger and similar raw programs can detect), but has reduced DR compared to shot at ISO 35
- above ISO 100 basically the same like below, means the real sensitivity is 1,5 stops lower than read on the back and internally compensated (which of course reduces the DR)

End of the story: Shoot ISO 35 wherever possible to get the 13.5 steps DXO-DR (acc. my experience up to 8s exposure time, then degration of file quality), then maybe still stay at ISO 35, underexpose and push in RAW conversion .

* I also read the enclosed DXO measurement of ISO sensitivity that way

Hi, please supply RAW files for same aperture, same shutter speed, same light for ISO 35 and ISO 100.

DXO measured 13.5 stops of DR at ISO 100. If you believe ISO 35 give better DR than ISO 100, then DXO has made a serious mistake underestimating the true performance of the IQ180.
« Last Edit: July 06, 2015, 01:21:19 pm by voidshatter »
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter
Re: Best ISO for IQ280
« Reply #41 on: July 06, 2015, 12:57:07 pm »

Man, you do not give up. Gotta give you mad points for being persistent. You will not be happy until "the truth" about PhaseOne is known to all and PhaseOne is gone and buried forever (and maybe you won't be happy until they give some of their profits back to those who bought into the system). You make them sound like they are scammers. That anything but the exmor is junk. Meanwhile amazing photographs and prints are being made with lots of different gear worldwide right now.

Here some real world samples of a snap I mad while scouting a location a while back. I usd a IQ160 on a H1 with 80mm H lens handheld at 1/160 sec f2.8 iso 200. Processed in Lightroom which is not ideal, with just some quick and basic adjustments.

First is the whole frame then a 100% crop.

Looks good enough to me. Iso 200 is very very far from "worhtless" on the newer dalsa ccd sensors.

Could I have gotten the same result by using iso 50 and the same exposure and just increasing exposure in post? Of course, but I did not want to have a dark preview image in the rear lcd of the back.


Hi, in your IQ160 case you need same condition to compare ISO 50 and ISO 100, that is, same aperture, same shutter speed, same light, same condition. Upload the RAW files and I'll be able to show you ISO 50 is the same as ISO 100, but better than ISO 200.
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

I would say that base ISO as measured by DxO is 29 ISO, pretty close to 35, BTW.

Best regards
Erik



Base ISO for Nikon D810 as measured by DxO is ISO 47. It is closer to ISO 32. Do you think Nikon gave false information saying that ISO 32 is extended ISO?
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

I am not able to follow his logic and he is not able to follow mine.
He is insisting on the "same light different ISO" test, which makes no sense to me.
It must be my Credo ownership that limits my intellect.
As he said - I have "no clue about what is called native ISO" - must be my 20 years as computer engineer followed by my 10 years as a professional photographer that hinder my technical understanding abilities.

ISO 35 has more information for pushing shadows - that is the main thing I need to know when deciding on my ISO, since I can make the light to whatever I want.
Note that by my tests, it is not correct that in general ISO 35 has more dynamic range - for recovering highlights it is worse than ISO 100.
Both make perfect sense, if you consider the number of photons hitting the sensor for each ISO.
BTW now I remember that when I got my camera I also did a long exposure test and ISO 35 was cleaner.

Hi, all I said is that you won't get better dynamic range with ISO 35 over ISO 100. If you don't agree, then supply RAW files to disprove me (same aperture, same shutter speed, same flash - you do know what is called comparison under same condition don't you?).
Logged

JoeKitchen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4026

But why?  Why would anyone shoot like that.  It makes no sense.  Most photographers, when dropping the ISO, would not think twice about using more light.  

Some of these tests mean nothing to us who actually concentrate on making images.  I don't care how similar files will look after pushing lower ISOs harder then higher ISOs.  I care about light, and properly exposing the image, so I can assess the light in the image.  
« Last Edit: July 06, 2015, 02:25:47 pm by JoeKitchen »
Logged
Joe Kitchen
www.josephmkitchen.com

"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
“Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.”  William Faulkner

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

But why?  Why would anyone shoot like that.  It makes no sense.  Most photographers, when dropping the ISO, would not think twice about using more light.  

Some of these tests mean nothing to us who actually concentrate on making images.  I don't care how similar files will look after pushing lower ISOs harder then higher ISOs.  I care about light, and properly exposing the image, so I can assess the light in the image.  

Then in your logic you would shoot a Nikon D810 at ISO 32. You are saying that most Nikon / Canon users are not using their gear correctly.
Logged

sbernthal

  • Full Member
  • ***
  • Offline Offline
  • Posts: 215

Hi, all I said is that you won't get better dynamic range

You said a couple more things that you shouldn't have.
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

You said a couple more things that you shouldn't have.

Look into my original first reply. What do you think is wrong there?  ;)
Logged

JoeKitchen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4026

Then in your logic you would shoot a Nikon D810 at ISO 32. You are saying that most Nikon / Canon users are not using their gear correctly.

Ahhh ... no!

I said you expose correctly for the ISO you are shooting at, or you pick the ISO that allows you to expose correctly.  If a Nikon user is shooting at ISO 100 and exposing correctly for that ISO, then they are doing it right.  

If they decided to shoot at ISO 100, underexposing the image so they get the same results as if they exposed at ISO 200 after pushing in post one stop, then they have workflow issues.  Why?  Because unless you are shooting tethered and have the push automatically applied, it would be impossible to assess your exposure and whether or not you got the exposure correct.  But even so, it still is not the best way to work.  
« Last Edit: July 06, 2015, 02:45:58 pm by JoeKitchen »
Logged
Joe Kitchen
www.josephmkitchen.com

"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
“Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.”  William Faulkner

sbernthal

  • Full Member
  • ***
  • Offline Offline
  • Posts: 215

But why?  Why would anyone shoot like that.  It makes no sense.  Most photographers, when dropping the ISO, would not think twice about using more light.  

I think I figured out what he wants.
He's a guy that holds his camera and runs around town.
That explains why a digital back was not very useful for him.

For an available light situation without tripod, there isn't much difference between ISO 100 and 35, and indeed I would shoot 100 unless there was very much light or I wanted to open aperture more than the light allowed. BTW this is an important advantage of the ISO 35 capability, which is again not a marketing trick.

A studio shooter sees light completely differently. You make your own light according to what you need. So for me the question is, assuming a balanced exposure, what ISO is best to start from, taking into account future post. BTW not always 35. If your problem is shadows then 35, if your problem is highlights then 100, even in studio.
Logged

sbernthal

  • Full Member
  • ***
  • Offline Offline
  • Posts: 215

Look into my original first reply. What do you think is wrong there?  ;)

If after all this explaining you still can't figure out why your initial statement is completely erroneous,
and why you shouldn't offer advice based on speculation,
and why it's not cool to call people stupid on internet forums,

the there's not much else I can do for you.
Logged

ErikKaffehr

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 11284
    • Echophoto

Hi,

That guy has an IQ-250, which I think he cross graded from an IQ-260. Absolutely positive about the IQ-250, I even got a lot of raw samples from him. I am not sure he is coming from the IQ-260.

He likes very long exposures and finds that the IQ-250 and the Nikons work for him and the CCD backs don't.

Best regards
Erik

I think I figured out what he wants.
He's a guy that holds his camera and runs around town.
That explains why a digital back was not very useful for him.

For an available light situation without tripod, there isn't much difference between ISO 100 and 35, and indeed I would shoot 100 unless there was very much light or I wanted to open aperture more than the light allowed. BTW this is an important advantage of the ISO 35 capability, which is again not a marketing trick.

A studio shooter sees light completely differently. You make your own light according to what you need. So for me the question is, assuming a balanced exposure, what ISO is best to start from, taking into account future post. BTW not always 35. If your problem is shadows then 35, if your problem is highlights then 100, even in studio.
Logged
Erik Kaffehr
 

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

Ahhh ... no!

I said you expose correctly for the ISO you are shooting at, or you pick the ISO that allows you to expose correctly.  If a Nikon user is shooting at ISO 100 and exposing correctly for that ISO, then they are doing it right.

Your definition of "correct exposure" is vague. If you mean to ETTR to the edge of blown highlight in the RAW file, then you would lose 0.4 stops of dynamic range if you shoot a Nikon D810 at ISO 100 instead of shooting at ISO 64 or ISO 32. If you mean to make the histogram of in-body playback look right then ISO 32 would cause more blown highlight and ISO 100 would give you more noise in shadow.

If they decided to shoot at ISO 100, underexposing the image so they get the same results as if they exposed at ISO 200 after pushing in post one stop, then they have workflow issues.  Why?  Because unless you are shooting tethered and have the push automatically applied, it would be impossible to assess your exposure and whether or not you got the exposure correct.  But even so, it still is not the best way to work.  

You are getting it upside down. Shooting an IQ280 at ISO 100 with ETTR would require you to pull down exposure in post-processing, not pushing up exposure in post-processing. It would give you the same result as of ISO 35. If you disagree, then provide evidence by means of RAW files.
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

I think I figured out what he wants.
He's a guy that holds his camera and runs around town.
That explains why a digital back was not very useful for him.

No, I don't do any street photography.

For an available light situation without tripod, there isn't much difference between ISO 100 and 35, and indeed I would shoot 100 unless there was very much light or I wanted to open aperture more than the light allowed. BTW this is an important advantage of the ISO 35 capability, which is again not a marketing trick.

There is no advantage of the ISO 35 capability when you know how to shoot at ISO 100 (i.e. with +1.5EV EC for your metering and flash).

A studio shooter sees light completely differently. You make your own light according to what you need. So for me the question is, assuming a balanced exposure, what ISO is best to start from, taking into account future post. BTW not always 35. If your problem is shadows then 35, if your problem is highlights then 100, even in studio.

There is no difference between ISO 35 and ISO 100 if you know how to make reference to blown highlight according to the playback. Just stick to your habit.
Logged

ErikKaffehr

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 11284
    • Echophoto
Re: Best ISO for IQ280
« Reply #54 on: July 06, 2015, 03:01:18 pm »

Hi,

For the best result, you always try to get as many photons (particles of light) on the sensor as possible. So you want to have maximum exposure, without clipping any highlights. I am pretty sure that using minimum ISO will give the best results. Going up in ISO will reduce exposure. This may in a sense protect highlights.

On the cameras I have I essentially always use minimum ISO and check the histogram carefully. I also use "RawDigger" to check out the real histograms. Histograms in raw processors seldom show correct values. Worst offender may be Lightroom, doing intensive highlight recovery before indicating clipping. C1 has also ideas of it's own.

Best regards
Erik

I was just wondering what base ISO most use for there IQ280 (even the IQ260).  I've always been use to shooting at ISO 100 but I now the IQ280 goes to ISO 35.  Do you lose any dynamic range when you get that low (I know with the Leica systems you can if you shoot below there "normal" ISO).

gage
Logged
Erik Kaffehr
 

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

If after all this explaining you still can't figure out why your initial statement is completely erroneous,
and why you shouldn't offer advice based on speculation,
and why it's not cool to call people stupid on internet forums,

the there's not much else I can do for you.


I did not offer advice base on speculation. Instead, I made these conclusions by careful and repeated experiments. You are the one who did not do proper tests before you made your own imagination.
Logged

JoeKitchen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4026

Your definition of "correct exposure" is vague. If you mean to ETTR to the edge of blown highlight in the RAW file, then you would lose 0.4 stops of dynamic range if you shoot a Nikon D810 at ISO 100 instead of shooting at ISO 64 or ISO 32. If you mean to make the histogram of in-body playback look right then ISO 32 would cause more blown highlight and ISO 100 would give you more noise in shadow.

You are getting it upside down. Shooting an IQ280 at ISO 100 with ETTR would require you to pull down exposure in post-processing, not pushing up exposure in post-processing. It would give you the same result as of ISO 35. If you disagree, then provide evidence by means of RAW files.

Man you really have a heard time understanding what is being said here.  

My definition of correct exposure is the exposure that makes the image look the way you want it to look.

Photography, for me, or at least when I am being paid good money to create images, first begins with an idea of what I want.  I think it through and by the time I am ready to leave for the location, I already know how I want it to look like.  I know how I am going to compose it, how I will style it, and how I will light it.  I pick an ISO that will allow me to get the image I am thinking about with as little steps as possible and as little tech thinking as possible, which mean picking an ISO that exposes the images correctly, for how I want it to look.  

Under or over exposing only to correct that in post is kind of working against yourself.  You are increasing your workflow and decreasing your ability to assess your work on location with a client looking over your shoulder and you having to manage or worrying about a dozen other things.  

The test you are describing, when it comes to working like I mentioned above, which many working pros do, means absolutely nothing.  

There is no point in it. 

Not to mention if you can shoot at ISO 35 and get what you are thinking about, why would you not?  You always get better shadow recovery at lower ISOs.  Of course Sbernthal's observation about highlights and shooting at ISO 100 is very valid too. 
« Last Edit: July 06, 2015, 03:08:27 pm by JoeKitchen »
Logged
Joe Kitchen
www.josephmkitchen.com

"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
“Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.”  William Faulkner

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter
Re: Best ISO for IQ280
« Reply #57 on: July 06, 2015, 03:06:51 pm »

Hi,

For the best result, you always try to get as many photons (particles of light) on the sensor as possible. So you want to have maximum exposure, without clipping any highlights. I am pretty sure that using minimum ISO will give the best results. Going up in ISO will reduce exposure. This may in a sense protect highlights.

On the cameras I have I essentially always use minimum ISO and check the histogram carefully. I also use "RawDigger" to check out the real histograms. Histograms in raw processors seldom show correct values. Worst offender may be Lightroom, doing intensive highlight recovery before indicating clipping. C1 has also ideas of it's own.

Best regards
Erik


+1 for RawDigger to check the real histogram. In-camera playback is not reliable. Your advice could also apply to Nikon D810 users - you could suggest them to shoot at ISO 32.
Logged

sbernthal

  • Full Member
  • ***
  • Offline Offline
  • Posts: 215
Re: Best ISO for IQ280
« Reply #58 on: July 06, 2015, 03:09:04 pm »

For the best result, you always try to get as many photons (particles of light) on the sensor as possible.

If the counter attached to the pixel reaches 100% of what it can count, then you do have too many photons, and then this area has no detail.
More photons is always best, but only if you calibrate the counter (ISO) not to multiply so much it reaches 100%.
Logged

voidshatter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 400
    • www.500px.com/voidshatter

Man you really have a heard time understanding what is being said here.  

My definition of correct exposure is the exposure that makes the image look the way you want it to look.

Photography, for me, or at least when I am being paid good money to create images, first begins with an idea of what I want.  I think it through and by the time I am ready to leave for the location, I already know how I want it to look like.  I know how I am going to compose it, how I will style it, and how I will light it.  I pick an ISO that will allow me to get the image I am thinking about with as little steps as possible and as little tech thinking as possible, which mean picking an ISO that exposes the images correctly, for how I want it to look.  

Under or over exposing only to correct that in post is kind of working against yourself.  You are increasing your workflow and decreasing your ability to assess your work on location with a client looking over your shoulder and you having to manage or worrying about a dozen other things.  

The test you are describing, when it comes to working like I mentioned above, which many working pros do, means absolutely nothing.  

There is no point in it.  

Not to mention if you can shoot at ISO 35 and get what you are thinking about, why would you not?  You always get better shadow recovery at lower ISOs.  Of course Sbernthal's observation about highlights and shooting at ISO 100 is very valid too.  

If you do landscape photography of a high contrast scene for which you cannot bracket, then there is little chance that you could make it "look right" in the in-camera playback. You would need to carefully prevent highlight details being blown out. Without the use of RawDigger it is pretty difficult to accurately tell the actual area of blown highlight. You would have to rely on your own experience with the in-camera playback. Of course ISO 100 would give you a more overexposed look in the playback but you still retain the same amount of information as ISO 35.



« Last Edit: July 06, 2015, 03:18:46 pm by voidshatter »
Logged
Pages: 1 2 [3] 4 5 ... 10   Go Up