P45 Hasselblad 503 CW Manual ISO settings unclear

Questions, comments and suggestions regarding Phase One P+ series and P series digital camera backs.

P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Sat Sep 30, 2017 6:44 pm

I read in manual following:

ISO Settings.
Depending on the conditions, you can choose between ISO 50 and ISO 800 in the ISO settings, but in general, the higher the ISO value, the more disturbances you have to deal with. This is also the reason why the ISO settings are only processed with half resolution in the C1 application...


I use a digiback P45 on my Hasselblad 503 CW.
I measure the light with a seperate exposure meter.
I don’t understand the info in manual.
Different ISO settings are only relevant for exposure.
Maybe the time.
When I must use ISO 50 f 8.0 time 1/60.
Then:
With ISO 100 then I must use f 8.0 time 1/125
With ISO 200 then I must use f 8.0 time 1/250 and so on.
Or is the setting ISO 50 to ISO 800 a relevant for working digiback?
I use also C1.
Can someone give feedback?

Regards

Jochen
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby PhaseoneUser55657 » Sun Oct 01, 2017 2:04 pm

Not sure what question you want.

ISO is one corner of the exposure triangle. The others being Aperture and shutter speed.

On MF cameras most of the time the ISO is only available in full stops, (50,100,200,400,800). Now also with Higher ISOs come more noise, (Looks like their manual calls it disturbances).

Now, it is possible that the back always records at IS50 and just notes what the requested ISO was in the Raw file, and the raw converter does the exposure compensation, and for C1 only does it in ½ stops.

I would shoot just as you would normally and see what results you get.

Robert
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Sun Oct 01, 2017 2:32 pm

Hello Robert
Thanks for feedback.
PhaseoneUser55657 wrote:ISO is one corner of the exposure triangle. The others being Aperture and shutter speed.

You are right. That is clear and I know it. :D
PhaseoneUser55657 wrote:On MF cameras most of the time the ISO is only available in full stops, (50,100,200,400,800). Now also with Higher ISOs come more noise, (Looks like their manual calls it disturbances).

My back P45 has only ISO 50, 100, 200, 400, but this is not relevant in this case.
I read the statement with more noise in the manual.
And I know that by dark light we normally use higher ISO.
PhaseoneUser55657 wrote:Now, it is possible that the back always records at IS50 and just notes what the requested ISO was in the Raw file, and the raw converter does the exposure compensation, and for C1 only does it in ½ stops.

I would shoot just as you would normally and see what results you get.

Robert

I shoot four tests f11 with 1/30 ISO 50, 1/60 ISO 100, 1/125 ISO 200, 1/250 ISO 400 and don't see a different.
Later I will upload the examples maybe.
The reason why I post this was that I read in the past following statement.

„Don't use higher ISO 100, because that create high noise."

Jochen
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Sun Oct 01, 2017 2:56 pm

Hello

Lights and shadows ISO 50 to ISO 400

Jochen


Image

Image
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby PhaseoneUser55657 » Mon Oct 02, 2017 10:39 pm

The other thing to remember on all digital cameras, is you loose dynamic range as the ISO changes from the native ISO. On CCDs it is usually 50.

In all cameras, as you raise the ISO you get more noise, it is just the law of physics. Now CMOS sensors with on chip A2D converters produce less noise as the ISO goes up, then CCD sensors.

Still, not sure what you are asking?

Robert
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Tue Oct 03, 2017 6:59 am

PhaseoneUser55657 wrote:
In all cameras, as you raise the ISO you get more noise,

Robert


Did You see noise in my foto with ISO 400?
Maybe my eyes not so good?
What would be helpful to answer the question?

If there isn't noise I could use ISO 400 in some situation.
Maybe using camera with back by hand and not with tripod.

Jochen
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby PhaseoneUser55657 » Wed Oct 04, 2017 2:16 am

If you like the images at ISO400 go for it, all I am saying is that there will be more noise at ISO400 then ISO50.
If the noise at ISO400 is above what you find acceptable, then don't use it. Otherwise go for ISO400.

You also remember that MAX ISO is what the camera company feels is the max noise they will accept. Look at some of the 50Mpix CMOS MF cameras, I believe that PhaseOne stops at ISO6400, but using (I believe) the same sensor Pentax allow you to go up to ISO204800, and Fuji up to ISO12800. Will there be more noise at ISO204800 on the Pentax, you can bet on it.

It comes down to, do you find the images acceptable at ISO400. Only YOU can answer that question.

IF you want to really test the noise of a sensor, shoot something neutral gray and under expose it by -3 stops, at ISO50 and ISO400. Take the images into your favorite RAW convert, and change the exposure to +3. Then see what the noise looks like.

Look, PhaseOne just released a new Back which they allow to go down to ISO35, for even less noise then the ISO50 had.

Robert
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Sat Oct 07, 2017 12:15 pm

@Robert
Your answers was helpful for me.
I read some additionally explanations in www.
Now I know that higher ISO turns in back the boost of the signal.
(Simple statement).

Jochen
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby C-M-B » Tue Oct 17, 2017 10:43 am

I hope everyone who doesn't speak german can forgive me for replying in german:

Ich arbeite manchmal auch mit ISO800, obwohl das eigentlich schon sehr grenzwertig ist - allerdings beherrscht CaptureOne die Rauschreduktion so großartig, dass es durchaus machbar ist. Leider geht da auf Kosten der Details, deswegen schalte ich normalerweise die Rauschreduktion fast vollständig ab (nur die Reduktion des Farbrauschens stelle ich auf 50). Aber mit ISO400 zu arbeiten ist - auch dank der hohen Auflösung - echt kein Problem.
Wenn du die Rauschreduktion auf 0 stellst, wirst den Unterschied zwischen ISO50 und ISO400 aber schon deutlich sehen.

Zudem macht das Rückteil auch bei längeren Belichtungen eine eigene Rausch- und Hotpixel-Entfernung; es macht kurz nach dem eigentlichen Bild noch ein zweites Foto mit derselben Belichtungszeit aber mit geschlossenem Verschluss. Dann rechnet es das Rauschen und die Hotpixel des einen Bildes aus dem anderen heraus und produziert damit ziemlich saubere Ergebnisse.
Der Nachteil dabei ist, dass das Rückteil für ein Foto, das 3 Sekunden belichtet wird, 7-8 Sekunden braucht. Denn er macht danach ja noch eins mit derselben Belichtungszeit und rechnet das dann weg.

Ich persönlich hab lieber ein leichtes Rauschen, das sowohl beim Print als auch bei kleinen Ansichten im Internet kein Problem darstellt, als Detailverlust durch Rauschentfernung...aber ist ja reine Geschmacksache.
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Re: P45 Hasselblad 503 CW Manual ISO settings unclear

Postby spassig » Tue Oct 17, 2017 12:05 pm

Hello
C-M-B wrote:I hope everyone who doesn't speak german can forgive me for replying in german:


I use for some days this translator:
http://www.deepl.com

C-M-B wrote:Ich arbeite manchmal auch mit ISO800, usw.


Ich teste ISO Invariant, Rauschen, ETTR etc. momentan mit meiner Sony A7M2.
Wenn ich das verinnerlich habe, werde ich mein PO Digiback dahingehend mal testen.

Jochen
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