Dxomark "measured" ISO vs Manufacturer ISO

Started Jan 7, 2013 | Discussions thread
Endos
Contributing MemberPosts: 763
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Re: Okay...
In reply to Cudacke, Jan 23, 2013

Cudacke wrote:

Endos wrote:

Cudacke wrote:

Endos wrote:

Cudacke wrote:

Endos wrote:

Cudacke wrote:

Endos wrote:

EinsteinsGhost wrote:

Endos wrote:

Cudacke wrote:

I did, but you didn't read. Sorry I cannot help on your reading problem. It is your job to read. I can only point it out you didn't do.

Well, when you find anything I wrote that is not true, feel free to quote them here. I will be happy to read your conclusions.

It is rather difficult to figure out where to start. If you don't mind, I chose this gem of yours:

Endos wrote:

ET2 wrote:

Let's see X100's F-Stop and Shutter speeds in imaging-resources studio shots

ISO 1600 - F8 - 1/250

ISO 3200- F8 - 1/500

ISO 6400 - F8 - 1 / 1000

So much for the "theory" that dxomark "measured" ISO mean anything in real life. They don't. Fuji X100 behaves perfectly. You get exactly one stop faster shutter speeds from ISO 1600 to 3200 and again from ISO 3200 to 6400.

Yes but with underexposed results. Exactly the same if you shoot with that speeds at ISO 1600.

Now two questions:

1-Why would image at ISO 6400 above be underexposed compared to ISO 1600? Is it because, per your belief, the real ISO is 1000?

The Fuji X100 sensor doesn't support ISO6400. His maximum ISO is 1600 (measured ISO 1000). Then in reality when you choose ISO 6400 - F8 - 1 / 1000 the camera uses ISO 1600 - F8 - 1 / 1000 ‚ÄčThe result is obviously 2 stops underexposed:

ISO 1600

ISO 6400. 2 stops underexposed compared with the ISO 1600 image.

You can download the RAW files from imaging-resource and with any RAW analyzer test it for yourself (don't use a RAW converter, they push the exposure to compensate).

2-A hypothetical question: If DXO measured ISO is higher than manufacturer ISO, is it a good thing, or bad? Either way, explain your choice.

That question has nothing to do with the discussion, but well, I think it's a bad thing because having clipped highlights with the "default exposure" is not a good idea.

Again... the lies....
A77 test result clearly shows that A77's measured ISO 50 is above its manufacturer ISO and also happened to has the highest DR and tonal range amount all other ISO setting.

Of course, because the measured ISO 50 is lower that the measured ISO in all other ISOs. What is uncommon here?

Exposure is about how you as a photographer learn how to use the equipment.
What default exposure! Auto mode?

Again... you tried to change topic when the hole in your lies pop.
"clipped highlights with the "default exposure" is not a good idea."

I quoted it because it's unclear what I mean. Talking about the A77 for example, if you has an ETTR exposure (of the RAW file as showed in a RAW analyzer) at ISO 100 for example, at a given aperture and shutter speed, if you changes to ISO 50 with the half shutter speed and the same aperture, as a result the image will have clipped highlights.

The problem is what you mean is nonsense a lot of the time.

Maybe is because you have not understood anything I've written.

The lie is that you just said you can learn from DXO's result.
"Maybe don't help you, or the OP, but it helps me a lot. My photos have the maximum DR and lower noise that my camera sensor can get. "
So learn from it. don't clip high when you use ISO 50 because it supposed to have better DR!
What "default exposure"? You as a photographer supposed to determine the exposure.

Of course, I shoot always in Manual Exposure mode. I never use extended ISOs, at least not the ones I'm aware that are extended. I don't like to change my exposure settings if I need to change the ISO, or get worse results for using extended ISOs.

for example from one of your pictures.
Its clipping highlights is because the default exposure failed? or you set the exposure to have the result?
http://500px.com/photo/15505077

The RAW file from this image has not clipped highlights, it has the shadows clipped by a insignificant 0.1% in the red channel. And of course I select the exposure, as always I do.

Too bad your final image clearly clipped a lot!
Please try harder next time!

The image has not clipped highlights at all. You need to calibrate your monitor.

come on do what you said.. learn from the DXO result. have better DR at ISO50 with your A77.... if you have one!

I don't have an A77, I don't like SLTs, they are a step backwards in image quality and I don't like EVFs in his current state, but that's another question. If I would have one, I would never use ISO 50.

Good. As you clearly showed you don't have the tool, not much useful thing you can say about it either as I can tell from all your false info.
Again, try harder next time.

I'm sorry for you, but all my info is correct.

BTW, if you did read the DXO's result, then you should use ISO 50 with A77 because it is better in pretty much all spec which DXO measures which makes your "would never use ISO 50 comment" on a camera you don't have just totally nonsense...(wow again.. the nonsense!!) But you don't have the camera so what do you know how to use it anyway!! Well, at this point we "ALL" know you actually likes to comments on the things you don't know and pretend you know and making non sense anyway.

try read more next time. please!

http://www.dxomark.com/index.php/en%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%82%C2%AF%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%82%C2%BF%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%AF%C2%BF%C2%BD%C3%82%C2%BD/Cameras/Camera-Sensor-Database/Sony/SLT-Alpha-77

The nonsense it's you saying me how I have to work.

In the same way I never use the ISO 100 in my A900, if I would have an A77, I would never use ISO 50. At lower ISOs both cameras are only a bit better, but as there is not a full stop difference in exposure from ISO 50 to ISO 100 in the A77, and from ISO 100 to ISO 200 in the A900, I will lose a lot of time archiving the correct exposure when I will need to raise/lower the ISO. And time is money.

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