XF56 f1.2 released and specs

Started Jan 6, 2014 | Discussions
New MemberPosts: 15
any more info on the lens?
In reply to a l b e r t, Jan 8, 2014

any links somewhere?

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Contributing MemberPosts: 509
Re: XF56 f1.2 released and specs
In reply to malcolml1, Jan 8, 2014

malcolml1 wrote:

Now I've thought a bit more, I think there is another source of confusion....I have convinced myself again that, whilst I accept that noise levels would be different, if I took a photo with my Fuji and the 56/1.2 at ISO200 and did the same with my (now sold) 5D mk2 with the 85/1.2 at ISO 200, both in aperture priority mode, they would both select much the same shutter speed (I assumed that both Canon and Fuji agree on definition of ISO).

At the same ISO, yes. But why would you select the same ISO in the first place?If your shot requires (for your artistic or technical purposes) certain DOF, or certain shutter speed, or certain noise level -- you are free to play with remaining parameters at will.

In case of equivalent apertures (say f/1.2 on APS-C and f/1.8 on FF) selecting ISO 1 1/3 stops higher for an FF would result in the _same_ DOF, noise and shutter speed. The only reason to avoid raising the ISO are either noise concerns (not a concern, the noise is the same in both  cases) or shutter speed (say if you want to avoid to fast a shutter to allow some motion blur) -- again not a concern for the shutter speed is the same in both cases.

But then the actual number of electron-hole pairs is not used to form the image - rather the signal is digitized when it is read. If both the APS and FF sensor are 14 bit, then in underlying analog signal is converted into one of 2 ** 14 levels. Further, I assume that the levels (at base ISO or amplification) are spread (non-linearly, I know) between 0 and 'full' (max electron-hole pair capacity for that pixel).

I am not sure what you are trying to say here. Let's consider the example of the same pixel count again. FF photosites 2.25 times bigger. Apertures 1.2 and 1.8 for APS-C and FF respectively. Same illumination of the scene, same shutter speed.

Result: Same number of electron-hole pairs in both cases -- ergo the same signal and shot noise levels. The same amplifier gain is required (though the ISO convention would assign 1 1/3 stop higher ISO rating to the FF case -- but the amplifier and analog-to-digital converters do not know anything about ISO convention -- nor would they care if they did).

At what point of recording, reading or digitization process would the results (signal, noise, bit resolution, dynamic range -- whatever comes to your mind) become any different in these two cases?

To me, a given exposure would result in of the same output level regardless of sensor format - I think this is because the supposedly common definition of ISO.

I really don't understand this passage. Electronics knows nothing about ISO, and any sane manufacturer would squeeze as much signal-to-noise ratio as possible at every setting, whether it is base ISO, elevated or however it's defined. ISO is an empty number assigned to real settings (such as amplifier gain) afterwards.

The advantage of a larger pixel size is the confidence level you have in the level you measure after conversion. More exactly (I work with statistics...),

Great. If you work with statistics you know what Shot noise is, and why it's the same in both cases.

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a l b e r t
Senior MemberPosts: 1,339Gear list
Re: XF56 f1.2 released and specs
In reply to malcolml1, Jan 9, 2014

malcolml1 wrote:

Yes - exactly - that's what I believe too. but some others argue differently.....and I am trying to understand why!

As bigpigpig has stated, the shutter speed would be the same, assuming they have the same metering.  Personally, I found that Fuji's metering is different than Canon, it tends to expose the scene brighter, perhaps due to having more DR in the sensor.

As a side note: people said Fuji's ISO is inflated.  But that is due to the metering.  Fuji exposes brighter, so higher ISO is used.  They should check the histogram before they declare Fuji having inflated ISO.

People are confused by the FF lens gathering more light because it covers a larger image circle.  Yes it gathers more light, BUT the light also needs to be spread out in a larger surface area.  So the amount of light intensity per unit area on FF is the same as APS-C.  This is why the same aperture on FF = APS-C = camera phone.

However, lens FOV is different with different sensor size.  This is why manufacturers use 85mm on FF, but 56mm on APS-C.  This conversion is correct.  But you don't see them converting f-stop from a FF lens to a different value on an APS-C lens, right?  This already tells you f-stop is the same (exposure OR light intensity per unit area), regardless of sensor size.

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Martin Datzinger
Senior MemberPosts: 2,220
Re: Aperture ring
In reply to Ross Kennedy, Jan 9, 2014

Well and exactly that is absolutely against my shooting habbits and my idea of something being "manual". I already hate all of my Nikons' back wheels for that reason: They are far too easily turned by accident because they are too close to the tumb. Camera orientation change -> wheel barely touched -> camera went from x-synch to Bulb -> shot ruined. Happend all too often to me. So I do want dedication and a little bit of concentration necessary to change aperture. I don't know anyone who changes aperture between each and every shot and the choice of the aperture alone is something that requires a thought process, so why make accoding dial that easy to operate (note: I still believe this is the more intuitive place to do it, rather than a thumb wheel).

I'm certain they changed the force needed to turn the aperture because of feedback, they are known to take user opinions seriously. Hence my hope they retrofit the older ones (quietly).

Best regards,

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Regular MemberPosts: 140
Re: XF56 f1.2 released and specs
In reply to a l b e r t, Jan 9, 2014

Totally agree. Some people extend the idea of equivalence to include the noise characteristics of the resultant image. FF has a slight advantage here, so similar noise characteristics are achieved by increasing the ISO (which means you need to stop the lens down accordingly).

However, I personally believe that this argument more theoretical than practical with modern sensors, since noise levels are so low. I'd be surprised if anyone can tell the difference between two properly exposed prints - one shot at 200 and one at 800 or even 1600 ISO.

So for all practical purposes I would say that the new Fuji 56/1.2 on APS is 'equivalent' to an 85/1.8 on FF as far as DoF and angle of view are concerned, and equivalent to an 85/1.2 on FF as far as shutter speed at a fixed ISO are concerned. As the end user that's all I care about.

Within reason, I do not care about noise now - different story 10 years ago. I remember accidentally leaving my Canon 10D set on ISO 800 whilst shooting a car blaze in the middle of a busy London street. In broad daylight and the images were horrible. With my Xe-2 or X-Pro1 it doesn't matter (to me).



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The Davinator
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Re: XF56 f1.2 released and specs
In reply to Bernie Ess, Jan 18, 2014

Bernie Ess wrote:

I shoot only RAW and without a single doubt Nikon is the better system for this IMO with the Fuji being the worst, skin tones are inconsistant and often horrid from the Fuji X, now if Fuji dropped the X sensor then things might well be different.

Then you may do something wrong. Do you have some "horrid samples" from the Fuji X online somewhere? I'd be curious to see them.

Colour engine of the d800 is a bit less unpleasant than older Nikon models, but still not up to Canon or Fuji.

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'All the technique in the world doesn’t compensate for the inability to notice.' (Elliot Erwitt)

Bernie....he just trolls the Fuji forums complaining Bout color, bokeh, etc.  Just ignore him....he's looking for an audience to support his bitter pill.

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Veteran MemberPosts: 8,015
Re: XF56 f1.2 released and specs
In reply to dark13star, Jan 18, 2014

dark13star wrote:

Krich13 wrote:

No, you can use the same shutter speed, adjusting ISO accordingly for the same Image quality results.

Maybe on a Nikon FF, but have you seen how many Canon shooters here say they get better high-ISO results out of their Fujis? ISO must remain the same for the the comparison.

Raw files from my 5D Mark II produce less total noise than the raw files from my Fujifilm X-E1 and X-E2, and the 5D Mark II is more than 5 years old.

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