Comparing FF & Fuji high ISO & shadow pushing

[Phil1]

I'm a died-in-the-wool Fuji fan, having invested more in the X system than my car so please don't take this as knocking Fuji! It is what it is & I love it!

I do mainly event photography in low light conditions and I'm fairly happy with using ISO 1,600 max with the 2.8 zooms at full bore with SS in the range 1/30- 1/125 (the OIS of my X-H1s is invaluable here - in my slightly shaky hands!).

However, I'm often pushed to more extreme low light conditions where I begin to run into problems so I thought it would be interesting to compare the low light noise performance of the X-H1 with the current crop of FF rivals (Z6 & Z7, 7III & 7RIII) on the DPR camera review website. All things being equal, the 24MP FFs should be better, having larger sensors, but by how much?

In terms of low light ISO it looks to me (& I'm no expert, so I'm seeking comments from those with more experience) that the x-H1 is around 0.5 stops worse noise-wise at say ISO 6,400 than the FFs which is not too significant.

However, there seems to be a much greater difference if you look at the 'pushability' of these cameras, where the X-H1 (the X-T2 & X-T3 would be the same or very similar) seems to be several stops worse off - maybe as much as 2-3 stops perhaps - than the FFs and I’m guessing this is much more serious.

I'd love to hear your comments on the practical implications (if any) of these figures for very low light work.

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

 

[Erik Baumgartner]

I'm a died-in-the-wool Fuji fan, having invested more in the X system than my car so please don't take this as knocking Fuji! It is what it is & I love it!

I do mainly event photography in low light conditions and I'm fairly happy with using ISO 1,600 max with the 2.8 zooms at full bore with SS in the range 1/30- 1/125 (the OIS of my X-H1s is invaluable here - in my slightly shaky hands!).

However, I'm often pushed to more extreme low light conditions where I begin to run into problems so I thought it would be interesting to compare the low light noise performance of the X-H1 with the current crop of FF rivals (Z6 & Z7, 7III & 7RIII) on the DPR camera review website. All things being equal, the 24MP FFs should be better, having larger sensors, but by how much?

In terms of low light ISO it looks to me (& I'm no expert, so I'm seeking comments from those with more experience) that the x-H1 is around 0.5 stops worse noise-wise at say ISO 6,400 than the FFs which is not too significant.

However, there seems to be a much greater difference if you look at the 'pushability' of these cameras, where the X-H1 (the X-T2 & X-T3 would be the same or very similar) seems to be several stops worse off - maybe as much as 2-3 stops perhaps - than the FFs and I’m guessing this is much more serious.

I'd love to hear your comments on the practical implications (if any) of these figures for very low light work.

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

There's no question that a state of the art 24MP FF camera will have an edge in low light, but the fact that you can get the same DOF with the Fuji at wider apertures negates that in some situations where you NEED a certain amount of DOF. I find that with careful post processing, ISO 6400 or 12,800+ are absolutely usable with the Fujis. Here is the X-H1 and the A7III (currently among the very best FF cameras in low light and significantly better than older FFs). Is it better than the Fuji? Yes, without question it is, but Fuji still puts in a good showing, The Fuji loses here, but is every bit as good or better than an A7II. If you want the ultimate low light camera, it's a current FF, but I find my X-T2 still gets the job done just fine in most situations. Can you see a big difference between these images without looking at 100%?

And before people start going on about how Fuji cheats with their ISO numbers, please note that the exposure is exactly the same between these two images.


Fuji X-H1 ISO 12,800


Sony A7III ISO 12,800

As far as pushing goes, again, FF will be better, but I find the Fuji files work just fine too. This is a 3 1/3 stop push, from ISO 1250 up to ISO 12800(ish) equivalent:

 

[Waldemar]

I´m not shooting high ISO much. With my A7 Mark I I get loads of pushability, at least at the low ISOs I use. I often shoot against the sun with -2 or even -3 EVs to retain color in the sky (see shot below; ISO 100 at 1/100 and F22, a much underexposed raw file).

If I lift the shadows, there is certainly more tolerance to do that in the A7 shots compared my Fuji X-T20.

This said, in practical use this only shows in very extreme situations, probably if I go for that HDR look.

But this is, as I said, for low ISOs. With higher ISOs noise creeps up much faster with pushing. Basically, if the A7 allows only for a 1 stop push with an ISO 3200 shot (before the shadows get too noisy), you couldn´t do it at all with an APS-C sensor.

What matter more for me in practical use: in my impression the Fuji APS-C sensor has a tendency for harsh highlight clipping and the picture can become ugly, if you try to get blown highlights back. I´ve used the old Canon 6D Mark I this week and was surprised, how much highlight information was hiding in the raw file.


---------------------------------------------
Wald

 

[lélé777004]

I'm a died-in-the-wool Fuji fan, having invested more in the X system than my car so please don't take this as knocking Fuji! It is what it is & I love it!

I do mainly event photography in low light conditions and I'm fairly happy with using ISO 1,600 max with the 2.8 zooms at full bore with SS in the range 1/30- 1/125 (the OIS of my X-H1s is invaluable here - in my slightly shaky hands!).

However, I'm often pushed to more extreme low light conditions where I begin to run into problems so I thought it would be interesting to compare the low light noise performance of the X-H1 with the current crop of FF rivals (Z6 & Z7, 7III & 7RIII) on the DPR camera review website. All things being equal, the 24MP FFs should be better, having larger sensors, but by how much?

In terms of low light ISO it looks to me (& I'm no expert, so I'm seeking comments from those with more experience) that the x-H1 is around 0.5 stops worse noise-wise at say ISO 6,400 than the FFs which is not too significant.

However, there seems to be a much greater difference if you look at the 'pushability' of these cameras, where the X-H1 (the X-T2 & X-T3 would be the same or very similar) seems to be several stops worse off - maybe as much as 2-3 stops perhaps - than the FFs and I’m guessing this is much more serious.

I'd love to hear your comments on the practical implications (if any) of these figures for very low light work.

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

I do own both a Sony Alpha 7 III and a Fujifilm X-T3.

I think comparing the cameras at the same (claimed) ISO is 'a false good idea'. Here is why:

• The ISO standard ISO 12232:2006 gives the manufacturers five different methods to determine their ISO rating. In addition, some of these methods can give the manufacturer some freedom. Hence, 'ISO3200' on let's say a Fujifilm X-H1 a Nikon Z6 might not give the same relationship between exposure (amount of light per unit of surface) and final image brightness. That's why some companies like DXO Mark measure the actual camera sensitivity with a consistent method across all cameras, so comparisons can be done in proper conditions.
• At the same (measured) ISO, it's very likely that the FF camera will give you more dynamic range/less noise than the APS-C camera. But is this telling you the whole story? Certainly not! In practice, you may encounter several cases :
  • You may have plenty of light and be able to set both cameras to their 'base ISO'. In such a case, the FF can have a double advantage: it has better DR/less noise at the same (measured ISO) and it may offer a lower (measured) base ISO. Will this make a real world difference? it depends on the scene (the more contrasty it is, the more advantage), the color grading (the more you lift shwadows, the more advantage) and your requirements.
  • You don't have plenty of light and have to crank up the ISO. Then, you can - at least - study three scenarios:
    • You need the same depth of field on both camera (e.g. because your photographing a group) and in such a case you will have to close the lens by about one stop more on the FF and compensate by increase the ISO by about one stop more. And the end, the APS-C and the FF cameras will give you very similar results.
    • You have two 'equivalent' lenses, for exemple a 85mm f/1.8 on the FF and a 56mm F/1.2 on the APS-C, then you will end up to a similar scenario than the first case and similar DR/noise level.
      I would add that from my experience (with a focus on prime lenses), 'equivalent' lenses are often of similar price and weight.
    • You have two lenses with similar relative aperture on both the FF and the APS-C (e.g. a 50mm f/1.4 on the FF and a 35mm f/1.4), the you will set the two cameras to the same (measured) ISO and the FF will have more or less one stop of advantage in terms of DR/noise. It will also show shorter depth of field.
      I would add that from my experience a FF lenses of same relative aperture, with all the rest similar (correction, build quality, etc.) is usually more expensive and heavier.

All that to say that solely comparing cameras at the same claimed ISO might be a pure waste of time§ You should consider the lens and use case into the equation.

 

[Erik Baumgartner]

I´m not shooting high ISO much. With my A7 Mark I I get loads of pushability, at least at the low ISOs I use. I often shoot against the sun with -2 or even -3 EVs to retain color in the sky (see shot below; ISO 100 at 1/100 and F22, a much underexposed raw file).

If I lift the shadows, there is certainly more tolerance to do that in the A7 shots compared my Fuji X-T20.

I've shot with an A7II alongside my X-T2 and saw no real noise advantage whatsoever over the APS-C Fuji, The A7III, yes, but the A7 or A7II, no.

This said, in practical use this only shows in very extreme situations, probably if I go for that HDR look.

But this is, as I said, for low ISOs. With higher ISOs noise creeps up much faster with pushing. Basically, if the A7 allows only for a 1 stop push with an ISO 3200 shot (before the shadows get too noisy), you couldn´t do it at all with an APS-C sensor.

I totally disagree, this was shot with an X-T20 at ISO 12,800 and pushed more than a full stop (to ISO 25,600+). Looks pretty good to me.


X-T20 at ISO 12,800 pushed to ISO 25,600 in post. Lightroom/IXT

What matter more for me in practical use: in my impression the Fuji APS-C sensor has a tendency for harsh highlight clipping and the picture can become ugly,

Only if you blow the highlights with incorrect settings. A Canon sensor and an ISO invariant Fuji sensor (Sony) will require different techniques to get the best out of each in low light. They are very different animals.

if you try to get blown highlights back. I´ve used the old Canon 6D Mark I this week and was surprised, how much highlight information was hiding in the raw file.

...and horrible noise hiding in the unrecoverable shadows.

 

[biza43]

The lack of enough DR for me in 2013 was what caused me to go from Fuji to Sony A7 system when I fully transitioned to MILC. Back then, for my landscape work, recovering highlights and shadows was not good enough for me.

Today, for my needs, Fuji can do it, and that is why I went back to them. However, the Sony FF sensors are class leading in that regard.

 

[Waldemar]

if you try to get blown highlights back. I´ve used the old Canon 6D Mark I this week and was surprised, how much highlight information was hiding in the raw file.

...and horrible noise hiding in the unrecoverable shadows.

While it´s nowhere near an A7 or D750, its´not quite that bad. You have to pay more attention to the exposure, getting as close to clipping the highlights as possible, by paying attention to the zebras, for example. You can also go behind that a bit, as highlights are very recoverable. If you do that, you usually need only a modest shadow push in raw, which the 6D I can handle. With low ISO shots there´s not much noise. The larger caveat is, that there is just not much detail in the darker areas of the raw file, so the result of a stronger push resembels applying curves to a TIFF file. So, basically, for most practical purposes the DR of Canon raw files is enough, but you have to go different about it. That´s not in defence of Canon, I got the 6D I (basically only as a cheap carrier for my EF 16.35 II) much later than my A7 and that are my findings from using it recently.


---------------------------------------------
Wald

 

[lélé777004]

if you try to get blown highlights back. I´ve used the old Canon 6D Mark I this week and was surprised, how much highlight information was hiding in the raw file.

...and horrible noise hiding in the unrecoverable shadows.

While it´s nowhere near an A7 or D750, its´not quite that bad. You have to pay more attention to the exposure, getting as close to clipping the highlights as possible, by paying attention to the zebras, for example.

I agree that exposure is very important.

Increasing exposure decrease shot noise and provide you with cleaner pictures.

You can also go behind that a bit, as highlights are very recoverable.

Highlight are not recoverable. When they're clipped, they clipped, period.

The ability to recover highliths is a pure illusion that relies on the fact that the camera zebras, the camera histogram, what you see in the EVF, what you see in Lightroom/Capture One Pro/whatsoever does not represent faithfully the RAW data. It's based on a highly processed image.

When people test 'highlight recovery' they're in fact just assessing how much the image processing clips in the highlights...

If you do that, you usually need only a modest shadow push in raw, which the 6D I can handle. With low ISO shots there´s not much noise. The larger caveat is, that there is just not much detail in the darker areas of the raw file, so the result of a stronger push resembels applying curves to a TIFF file. So, basically, for most practical purposes the DR of Canon raw files is enough, but you have to go different about it. That´s not in defence of Canon, I got the 6D I (basically only as a cheap carrier for my EF 16.35 II) much later than my A7 and that are my findings from using it recently.

 

[Phil1]

Hi Erik

Many thanks! I take your point about FF needing to be stopped down where some DoF is required and, for me, this can even up the game by around a stop. I'm to know that delighted the difference between FF & APSC is not hugely significant!

Looking at images I took yesterday I think that some of my problems are due to having to under-expose in order to minimise subject movement, e.g. 1/30 @ ISO 3,200 & f1.4. I guess the images are underexposed by 2-3 stops (it was a lightshow event where I was photographing the audience which was in virtual darkness!). I'll try some at ISO 6,400 & 12,800 next time as an experiment.

Thanks also for your posts on LR sharpening and noise reduction which have proved very useful!

Phil

 

[Erik Baumgartner]

Hi Erik

Many thanks! I take your point about FF needing to be stopped down where some DoF is required and, for me, this can even up the game by around a stop. I'm to know that delighted the difference between FF & APSC is not hugely significant!

Looking at images I took yesterday I think that some of my problems are due to having to under-expose in order to minimise subject movement, e.g. 1/30 @ ISO 3,200 & f1.4. I guess the images are underexposed by 2-3 stops (it was a lightshow event where I was photographing the audience which was in virtual darkness!). I'll try some at ISO 6,400 & 12,800 next time as an experiment.

Thanks also for your posts on LR sharpening and noise reduction which have proved very useful!

Phil

Remember, the “exposure” is determined entirely by the shutter speed and aperture setting, the ISO setting is only in-camera brightness gain added after the exposure, it doesn’t actually do anything to change the sensitivity of the sensor. In low light, if you’ve set the minimum shutter speed to prevent motion blur and your aperture is as wide as possible while maintaining the necessary DOF, that’s all you can do to maximize the exposure.

If you are at ISO 800 or above (I always set my minimum Auto-ISO setting to 800 in low light situations), your camera is ISO invariant and so long as you aren’t clipping the highlights it doesn’t really matter where you set the ISO in-camera, you can easily increase the exposure (brightness, actually) after the fact in post with no real penalties, but with the big upside of retaining all the important highlight information that can easily be lost if you’d set the ISO too high.

Set your exposure as described above, turn on the highlight warning blinkies on in your EVF, set your minimum AUTO-ISO to ISO 800, adjust the ISO (brightness) as needed for a decent image in the EVF on the fly with the EC dial (“C” mode), but with only specular highlights or direct light sources allowed to blink. In low light, if your exposure is maxed out, your is at ISO 800 or above, and no important highlights are blinking in the EVF, you’ve done about all you can to produce the best RAW file for post processing.

Erik

 

[mike lix]

I'm a died-in-the-wool Fuji fan, having invested more in the X system than my car so please don't take this as knocking Fuji! It is what it is & I love it!

I do mainly event photography in low light conditions and I'm fairly happy with using ISO 1,600 max with the 2.8 zooms at full bore with SS in the range 1/30- 1/125 (the OIS of my X-H1s is invaluable here - in my slightly shaky hands!).

However, I'm often pushed to more extreme low light conditions where I begin to run into problems so I thought it would be interesting to compare the low light noise performance of the X-H1 with the current crop of FF rivals (Z6 & Z7, 7III & 7RIII) on the DPR camera review website. All things being equal, the 24MP FFs should be better, having larger sensors, but by how much?

In terms of low light ISO it looks to me (& I'm no expert, so I'm seeking comments from those with more experience) that the x-H1 is around 0.5 stops worse noise-wise at say ISO 6,400 than the FFs which is not too significant.

However, there seems to be a much greater difference if you look at the 'pushability' of these cameras, where the X-H1 (the X-T2 & X-T3 would be the same or very similar) seems to be several stops worse off - maybe as much as 2-3 stops perhaps - than the FFs and I’m guessing this is much more serious.

I'd love to hear your comments on the practical implications (if any) of these figures for very low light work.

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

Try this (I have done it already) - download RAWs from the cameras and ISO values that you are insterested in, lets say 3200, 6400. They will have different brightness, colours, contrast, sharpness etc. Do your best to match them - in terms of exposure, colours (you can apply colour profiles), contrast, sharpen the less sharp, apply noise reduction where needed. Then export the photos like you are used to. Then compare them.

It´s the only way how to remain unbiased.

--
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www.facebook.com/michal.placek.fotograf
500px.com/mikepl500px

 

[Phil1]

Thank you for your very detailed and helpful reply. I have no problems in decent light conditions i.e. the results from my X-H1s are more than satisfactory (for my needs) especially with the better Fuji lenses.

However, most of my images fall into your 'low-light' category where some of my colleagues are using F4 FF zooms while I am using Fuji’s F2.8 APSC zooms, so your point is well taken.

Many thanks again!

Phil

 

[Erik Baumgartner]

I'm a died-in-the-wool Fuji fan, having invested more in the X system than my car so please don't take this as knocking Fuji! It is what it is & I love it!

I do mainly event photography in low light conditions and I'm fairly happy with using ISO 1,600 max with the 2.8 zooms at full bore with SS in the range 1/30- 1/125 (the OIS of my X-H1s is invaluable here - in my slightly shaky hands!).

However, I'm often pushed to more extreme low light conditions where I begin to run into problems so I thought it would be interesting to compare the low light noise performance of the X-H1 with the current crop of FF rivals (Z6 & Z7, 7III & 7RIII) on the DPR camera review website. All things being equal, the 24MP FFs should be better, having larger sensors, but by how much?

In terms of low light ISO it looks to me (& I'm no expert, so I'm seeking comments from those with more experience) that the x-H1 is around 0.5 stops worse noise-wise at say ISO 6,400 than the FFs which is not too significant.

However, there seems to be a much greater difference if you look at the 'pushability' of these cameras, where the X-H1 (the X-T2 & X-T3 would be the same or very similar) seems to be several stops worse off - maybe as much as 2-3 stops perhaps - than the FFs and I’m guessing this is much more serious.

I'd love to hear your comments on the practical implications (if any) of these figures for very low light work.

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

Try this (I have done it already) - download RAWs from the cameras and ISO values that you are insterested in, lets say 3200, 6400. They will have different brightness, colours, contrast, sharpness etc. Do your best to match them - in terms of exposure, colours (you can apply colour profiles), contrast, sharpen the less sharp, apply noise reduction where needed. Then export the photos like you are used to. Then compare them.

It´s the only way how to remain unbiased.

I totally agree, it’s not what the RAW files look like at default processing values on DPReview that matters, it’s what can you get out of them with your own processing, more importantly, is what you can do with them good enough? I know that an A7III with the best (and very pricey) glass can outperform a Fuji in low light, but I also know that in most situations, even very dark ones, that with optimal post processing I can produce images that look nearly indistinguishable compared to what most people can get out of their FFs, but at considerably less cost to both my wallet and my skeleton, not to mention that I just really like shooting with Fuji in general and genuinely enjoy trying to wring every last bit of quality out of the files they produce. I don’t really have much choice as I can’t afford the cutting-edge FF stuff anyway.

 

[SkvLTD]

So from my Nikon experience, noise was green and red pixels in the blacks as I'm sure is the case with everything BUT Fuji due to the sensor array. Good old X-Pro 1 was almost entirely lacked color noise, and simple grain looks completely usable in high ISOs.

That said, Fuji is still a complete beast in terms of high-iso noise thanks to its sensor array more than anything else.

 

[sebiruns]

So from my Nikon experience, noise was green and red pixels in the blacks as I'm sure is the case with everything BUT Fuji due to the sensor array. Good old X-Pro 1 was almost entirely lacked color noise, and simple grain looks completely usable in high ISOs.

That said, Fuji is still a complete beast in terms of high-iso noise thanks to its sensor array more than anything else.

 

[Truman Prevatt]

By the way, please don't take my interpretation of the DPR data as gospel but do have a look the appropriate DPR web pages and see if you agree: https://www.dpreview.com/reviews/nikon-z6/6. I was looking at the RAW files and you’ll have to change the ISOs and cameras on the web page.

Now I’m scared & waiting for the flack(!), but if you do feel aggrieved please read the opening para again & the section in italics before shooting me down and please be patient and explain where I’ve gone wrong in my interpretation of the DPR data.

Cheers

Phil

Of course the hordes will come to the defense of Fuji - on a Fuji forum. What were you thinking :-D. Of course FF will be better. The Fuji uses the same sensor technology as the Sony and Nikon so more size and larger aperture for the same field of view weighs in for the FF will result in better DR. Less magnification of the final image will accentuate that advantage For no other reason but f1.4 on a APS-C at a given field of view is over f2 on an FF - yep more light at the same aperture.

However, that is not the question you should be asking. Shooting APS-C you give up DR and the ability to recover shadows - well duh you give up DR because of less light at equivalent aperture and there is no equivalent aperture in Fuji now to a f1.4 in a FF. The questions you should be asking are a) do the other trade offs (size and weight difference skew the trade and b) is what you get out of the Fuji good enough. Of course they are connected.

If what you are getting out of the Fuji is not good enough (a 1.2 stops difference more or less) then you need to dump Fuji and go FF. If the Fuji is "good enough" you need to forget this nonsense and get the most our of you're Fuji. Only you can answer that.

The best is the enemy of good and if that is the case you need to stop whining ;-) . On the other hand if it is not good enough then it is not good enough - you need a change.

 

[SkvLTD]

Of course the hordes will come to the defense of Fuji - on a Fuji forum. What were you thinking :-D. Of course FF will be better. The Fuji uses the same sensor technology as the Sony and Nikon so more size and larger aperture for the same field of view weighs in for the FF will result in better DR.

Surprising lack of noise I defended even in my primarily Nikon days because to get decent results from a standard Sony sensor array you pretty much NEEDED FF, and not an entry-level one at that. Ancient X-Pro 1 avoided color noise like a magical beast, but it did lack just about every other important feature to shoot in low light.

Nowadays, T3 is a swiss army knife unless things come down to extremely low light AF or needing a decent ultra-wide with AF (for a reasonable price).

Absolutely agree. I used to be a Nikon shooter and i can only second what you wrote. Totally under appreciated what Fuji achieved in the high ISO noise department.

Plus the said natural colors and skin tones. I never figured that better sensitivity to green would yield better magenta and orange.

 

[rlx]

I agree with others and especially with télé who mentions that there are a number of different standards to set the camera ISO (someone had a very informative post on the few ISO definitions used by Canon, Fuji and others). However all those methods basically target the JPEG format. Apparently Fuji will position the 18% gray level as expected on the JPEG file(if using average metering. smart metering is something else).

However when shooting RAW there is apparently no standard. Our best bet is to collect a few test shots (more on this later), get the DN number from the raw file and convert to the number of electrons captured per pixel. One needs the Bill Claff data to convert from RAW DN numbers to electrons. Then the square root of the number of electrons is the signal to noise ratio. The way to do this is to set the camera to average metering auto exposure and shoot a uniformly lit sheet of white paper. The data recorded on the center of the raw file should be about the average gray (18%). One can use dcraw to extract the raw data (DN numbers. Beware there is a bias (around 255 if I remember well).

The above method really amounts to comparing apples with apples if you are shooting raw. Sorry I cant provide the data myself since I have no FF camera around. As far as the Fuji's are concerned the gray level falls about 3.2 stops below the raw saturation level. An older Powershot camera I have sets the gray level about 2.5 stops below the raw saturation level and that is the minimum needed to make a jpeg out of that raw data.

Sorry if that sounds confusing initially but it is quite straightforward if you do some homework like looking for DN numbers in test raw files and look at the right graph in Bill's data.

To keep things simple I would think that comparing the two DPR shots above should be a good enough test of how much pushing can be done on the pictures, if the amount of lighting stays the same and it most likely does.

 

[Phil1]

Many thanks Erik - excellent, helpful and useful points - as usual!

Phil

 

[Phil1]

Hi Truman

Good, pragmatic advice - many thanks!

It was because the differences on paper didn’t seem large (ca.1.2 stops, as you mentioned) that I was seeking the views of folk who had both FF & APSC systems on whether in practice the differences in IQ were worth the extra size & cost (whatever they might be) of FF.

I take your point that only I can decide what is good enough for my requirements.

In view of the many replies I’ve received – and I’m very relieved to say all were very helpful and pleasant – that I’ve decided the way forward, for reasons of cost and weight, is to make more use of my fast primes rather than the more versatile 2.8 zooms when the light levels get tough.

Nevertheless, it will be interesting - and no doubt tempting – to see what the next incarnations of the A7 series, the Z6/7 & X-H2 bring to the table.

Phil