Luminous Landscape Forum
Equipment & Techniques => Mirrorless Cameras => Topic started by: Dan Wells on July 11, 2019, 07:53:15 pm
-
As is usual for Sigma, an odd design... It's extremely small and light, although most L-mount lenses aren't! If you like the 45mm f2.8, it's almost certainly the lightest FF camera/lens combo around. It's actually lighter than most lens options on an X-T3 - with the 45mm f2.8, it's very close in weight to an X-T3 with one of the f2 primes, since the Sigma body is almost exactly 100g lighter, but the lens is around 70g heavier.
Just about any other lens currently available, however, puts it in the realm of the heavier options available - any of the DSLR-conversion Sigma lenses, either of the new lenses today other than the 45mm, or any of the current Panasonic lenses are heavier than Sony, Nikon or Canon equivalents by enough to make up for the light body.
To get the very light body weight, Sigma left off two essential items, though - a viewfinder and a grip. When I first saw the pictures, I thought it had a small finder off to the side, which would have been an interesting tradeoff - give up the big finder in the "prism" bump on most FF mirrorless for a smaller finder in the old "rangefinder" position and a weight savings. No, it's viewfinderless. An accessory electronic viewfinder will weigh something between 30 grams (the tiny one for the Sony RX1) and 150 grams (the Leica Visoflex). A grip will weigh something, too - although perhaps not much, depending on what it's made of and how it attaches.
There are a couple of other tradeoffs. It uses a "small" battery (similar to what Fuji and Sony use in APS-C mirrorless and Sony used to use on FF as well until the A9 and the III generation) - according to B+H specs, it has slightly less power than a Fuji NP-W126S, slightly more than a Sony FW-50. The small-battery FF Sonys had lousy battery life, and Sigma has not historically done terribly well at power management. It has a single SD card slot - neither a more durable XQD card nor dual slots.
Is this really a still camera in the conventional sense at all? By the time it's ready to shoot with a viewfinder and a grip, it's probably no lighter than a "small-battery" FF Sony, and only 100 grams lighter (at most) than a Z or a "big-battery" Sony, half of which is given back by the weight of a spare battery. The most likely place to attach the grip precludes using a strap, unless there's a strap lug on the grip...
Thom Hogan thinks that it's more of a video camera that's meant to be mounted to things. It has a bunch of tripod sockets - what if it's meant to go on a drone, a gimbal or other forms of rigging? It's not only smaller and lighter than Sony, Nikon and Canon options, it's also nearly symmetrical, making balance easier with no heavy big battery on one side. It would still need light lenses to do its job, but it might well be the most convenient way yet to get the ubiquitous Sony 24 MP BSI sensor into odd places...
-
It's mostly meant at providing Sigma fans with a means to start mounting L mount Sigma lenses while they finalize the 20mp FF Foveon isn't it?
I find the Sigma 35mm f1.2 to be one the most appealing lens announced these past years. I am sure that many others agree.
I can see enough people buying this one as a stop gap solution that that they will keep for ISO situations and as a back up to the dream Foveon wonder.
Cheers,
Bernard
-
I don't get the point. Sigma's whole involvement in the camera body side of things seems to be nothing more than a show of pride, with no prospect of commercial success, and has been for years.
E-mount is an open design, and the biggest mirrorless mount out there in terms of market share by far. Sigma can make a killing producing lenses for E-mount. They have all the autofocus information. The current lineup, adapted from SLR lenses (including motors optimised for SLR rather than mirrorless AF systems) may be slower than native lenses designed for mirrorless from the ground up, but their dedicated mirrorless lenses won't be. And the image quality is impeccable. Add a customisable button to the lens (like all Sony lenses have) and provide lens correction information to Capture One, Adobe and others and they'd have a killer system thay could be easily adapted to Canon and Nikon once Sigma manages to crack the R and Z mount AF systems. No need to say 'me too' in a crowded mirrorless playing field - Sigma should play to its strengths, sell Foveon to someone who can make better use of it, get out of the camera business and stick to optics.
Even if they did want to make a camera body, for whatever reason, why use the L-mount, which has a very small audience that isn't likely to get much bigger? As said, E-mount is an open design - make a camera using that mount, that would then be compatible with every other E-mount lens out there, including Sigma's own. Concentrate on camera designs that Sony is unlikely to try to match - small, video-oriented designs designed to be attached to things rather than used in hand, high-resolution Foveon designs, monochrome or astrophotography cameras, etc. Sigma's not going to capture the centre of mass from Sony, but Sony's not going to bother pursuing fringe niches either. And using the E mount would allow Sigma to benefit from the large number of Sony shooters out there, who might use an A9 or A7r3 as their main camera, but who would be more than open to getting a Sigma body for drone work, astrophotography, micrography or other specialised, niche interest, provided they could use their regular lenses on it. Pursuing the L mount seems to be nothing more than an act of pride, allowing Sigma to say, 'Look, we have our own lens mount too!', while ensuring that practically no-one is going to actually buy the camera. Just look at the 'success' of Sigma's SLR line, using its own proprietary mount.
-
I believe that the spec of the E mount are accessible to bona fide third party lens manufacturers, but I don't believe that any company can use the mount in camera bodies without explicit authorization from Sony.
The mount is open in that sense, but not public domain.
Cheers,
Bernard
-
I believe that the spec of the E mount are accessible to bona fide third party lens manufacturers, but I don't believe that any company can use the mount in camera bodies without explicit authorization from Sony.
The mount is open in that sense, but not public domain.
Cheers,
Bernard
Then the logical thing would be to make E-mount lenses using a dual mount design, whereby it would attach to E-mount bodies using one set of connectors and Sigma mount cameras using a different set. That way, you'd have a huge pool of potential users for your cameras and lenses. Making it Sigma (and Leica) mount exclusive is a good way to ensure no-one buys your body in the first place, and would ensure you'd sell 50 E-mount lenses for every one L-mount lens in the same model.
Or just don't get involved in the camera business in the first place, and sell Foveon to someone who can make better use of it.
-
What if some of their engineers like making cameras?
What if making cameras helps them make better lenses?
Cheers,
Bernard
-
What if some of their engineers like making cameras?
What if making cameras helps them make better lenses?
Cheers,
Bernard
Then those engineers can go and make cameras for another company that actually makes a significant number of them. 'Our engineers like making cameras' is a dumb rationale for a corporate decision to produce them.
Sigma has been making good lenses for years, without being much of a player on the camera scene. Making cameras is a hugely expensive business - the production lines aren't interchangeable with lens production, the expertise required is completely different, and, at the higher end at least, it's lens sales that drive profit, not body sales - Canon makes much more money selling 70-200 and 24-70 lenses to 1Dx shooters than it makes from selling the bodies themselves, and Sigma makes far more from selling lenses to Canon/Nikon/Sony shooters than it could ever hope to make from selling its own bodies.
Not to mention Zeiss, Rodenstock and others have been making great lenses for decades, without ever having anything to do with making bodies, beyond slapping the occasional 'Zeiss' label on someone else's camera. So, plainly, the ability to make great lenses had little to do with making cameras.
Do you have any data or rationale to support these 'what ifs'? Or are you just throwing them in to argue?
-
As is usual for Sigma, an odd design... It's extremely small and light, although most L-mount lenses aren't! If you like the 45mm f2.8, it's almost certainly the lightest FF camera/lens combo around. It's actually lighter than most lens options on an X-T3 - with the 45mm f2.8, it's very close in weight to an X-T3 with one of the f2 primes, since the Sigma body is almost exactly 100g lighter, but the lens is around 70g heavier.
Just about any other lens currently available, however, puts it in the realm of the heavier options available - any of the DSLR-conversion Sigma lenses, either of the new lenses today other than the 45mm, or any of the current Panasonic lenses are heavier than Sony, Nikon or Canon equivalents by enough to make up for the light body.
To get the very light body weight, Sigma left off two essential items, though - a viewfinder and a grip. When I first saw the pictures, I thought it had a small finder off to the side, which would have been an interesting tradeoff - give up the big finder in the "prism" bump on most FF mirrorless for a smaller finder in the old "rangefinder" position and a weight savings. No, it's viewfinderless. An accessory electronic viewfinder will weigh something between 30 grams (the tiny one for the Sony RX1) and 150 grams (the Leica Visoflex). A grip will weigh something, too - although perhaps not much, depending on what it's made of and how it attaches.
There are a couple of other tradeoffs. It uses a "small" battery (similar to what Fuji and Sony use in APS-C mirrorless and Sony used to use on FF as well until the A9 and the III generation) - according to B+H specs, it has slightly less power than a Fuji NP-W126S, slightly more than a Sony FW-50. The small-battery FF Sonys had lousy battery life, and Sigma has not historically done terribly well at power management. It has a single SD card slot - neither a more durable XQD card nor dual slots.
Is this really a still camera in the conventional sense at all? By the time it's ready to shoot with a viewfinder and a grip, it's probably no lighter than a "small-battery" FF Sony, and only 100 grams lighter (at most) than a Z or a "big-battery" Sony, half of which is given back by the weight of a spare battery. The most likely place to attach the grip precludes using a strap, unless there's a strap lug on the grip...
Thom Hogan thinks that it's more of a video camera that's meant to be mounted to things. It has a bunch of tripod sockets - what if it's meant to go on a drone, a gimbal or other forms of rigging? It's not only smaller and lighter than Sony, Nikon and Canon options, it's also nearly symmetrical, making balance easier with no heavy big battery on one side. It would still need light lenses to do its job, but it might well be the most convenient way yet to get the ubiquitous Sony 24 MP BSI sensor into odd places...
To make the camera small, Sigma also eliminated the mechanical shutter and skipped on IBIS. Without those two, it was probably much easier and faster to design a camera. We’ll see how bad Sigma’s rolling shutter is.
-
Then those engineers can go and make cameras for another company that actually makes a significant number of them. 'Our engineers like making cameras' is a dumb rationale for a corporate decision to produce them.
Do you have any data or rationale to support these 'what ifs'? Or are you just throwing them in to argue?
None except 20+ years of corporate experience.
As if rationality had much to do with so many decisions taken by “companies”. Oh... I was forgetting... companies don’t take decisions, people do.
Cheers,
Bernard
-
I can get by without a viewfinder but I dont like it and I’m not comfortable with it. Could be a generational thing. I see loads of younger people not raising the camera to their eyes but looking at the LCD. I fear the day, if it comes, that cameras dispense with viewfinders entirely.
I will not be buying this camera.
-
Actually...didn’t Zeiss make lots of different camera bodies over the years? And they just announced a new camera body recently didn’t they? I feel they have entered a lot of different format markets. Some were really great too.
Then those engineers can go and make cameras for another company that actually makes a significant number of them. 'Our engineers like making cameras' is a dumb rationale for a corporate decision to produce them.
Sigma has been making good lenses for years, without being much of a player on the camera scene. Making cameras is a hugely expensive business - the production lines aren't interchangeable with lens production, the expertise required is completely different, and, at the higher end at least, it's lens sales that drive profit, not body sales - Canon makes much more money selling 70-200 and 24-70 lenses to 1Dx shooters than it makes from selling the bodies themselves, and Sigma makes far more from selling lenses to Canon/Nikon/Sony shooters than it could ever hope to make from selling its own bodies.
Not to mention Zeiss, Rodenstock and others have been making great lenses for decades, without ever having anything to do with making bodies, beyond slapping the occasional 'Zeiss' label on someone else's camera. So, plainly, the ability to make great lenses had little to do with making cameras.
Do you have any data or rationale to support these 'what ifs'? Or are you just throwing them in to argue?
-
I will post here some thoughts about this new camera's ISO6 I posted several hours before you did (https://forum.luminous-landscape.com/index.php?topic=131242.0) (definitively you get higher engagement than me Dan!):
Sigma has made an unexpected announcement: a new L mount FF Bayer mirrorless (and EVFless) camera.
Sigma announces ultra-compact 'fp' L-mount camera, teases full-frame Foveon sensor (https://www.dpreview.com/news/6719748669/sigma-announces-ultra-compact-fp-l-mount-camera-teases-full-frame-foveon-sensor)
I paid special attention to this:
"The camera has an ISO range of 100-25600, expandable to 6-102400. It has a fully electronic shutter and supports Eye AF and HDR. It can capture 14-bit DNG files and is fully compatible with Sigma's Photo Pro software. Its burst rate is an impressive 18 fps, though that's for only 12 shots."
I have a feeling that this ISO6 (and probably at a lower degree, the other ISOs in the ISO12-ISO50 range) can be quite interesting, much more than the fake "LOW ISO" found in most cameras. Let's put things together:
- ISO6 is 4 stops away from ISO100, too much to produce it by faking an ISO100 into ISO6 using metadata; highlights and even midlights would simply get blown away. So this ISO6 must be something REAL
- The shutter is fully electronic which means there can be no physical vibration, being this the natural shutter operation of the camera
- Finally, and contrarily to Sigma's usual slowness, it is aimed at being able to capture at a rate of 18fps, which means important readout and buffering capabilities
Putting all that together, I think this ISO6 is an averaging of 16 consecutive ISO100 shots with 1/16th the exposure time. Continuous vibration-free shooting means nearly having a real ISO6 (maybe moving light sources get a bit discontinued at times). What's this ISO6 useful for?
- Of course for long exposure photography (ISO6 means 16 times longer exposure time than ISO100)
- But also a Dynamic range enhancement of 2 entire stops for tripod applications (every x4 in captures means doubling SNR and hence gaining 1 stop of DR), which if you can afford the exposure time will basically mean nearly HDR RAW files
The procedure can be done with any camera, but probably with shutter vibrations and more importantly: not in a single output RAW file (I'm assuming the ISO6 setting will work on RAW here, but I see no reason why it shouldn't).
Regards
-
I am slightly mystified as to why Sigma has persisted with its side-line of cameras, but I won’t complain so long as they offer some quirky options that fill gaps in the market.
But given that they are making MILCs, I understand the choice of L mount (while also making lenses in E mount, and maybe soon in R and Z). It is the only 36x24mm format mirrorless mount and protocols fully open to them (Sony wants third party lenses that add value to its bodies, not competition for body sales; especially if Sigma bodies end up using non-Sony sensors) It is way better than the alternative of creating their own mount, like they did with its SA mount for SLRs (though that largely copied Canon’s EF).
The fp is definitely aimed in part at niches like drones and video rigs; see some of the photos at DPReview.
-
I agree with Guillermo - this ISO 6 is something new and interesting. We've seen ultra-low expanded ISOs like this before, but only on sensors where it's not as far from base ISO as one might think):
The old Kodak 14n/14c/SLRn complex went to ISO 6 (at least some of them did) - but Kodak was probably lying about the base ISO of their sensor - they said it was 80, but it was probably at least a stop lower than that and perhaps more. Those cameras had very poor high ISO performance (iffy at 200, generally considered unusable by 400), and pretty special image quality below base ISO. This suggests that their base ISO was wrong. Their real base ISO was probably somewhere between 15 and 40, meaning 6 wasn't a huge pull.
I'm not sure if any of the older Phase One backs went as low as ISO 6, but they got very, very low (and had exceptional long-exposure performance). Those had published base ISOs as low as 32 (and maybe even 25), though.
This is doing something different - it's a standard sensor (probably the ubiquitous Sony 24 MP FF) with a base ISO of 100 - exposing it conventionally at ISO 6 would blow not only the highlights, but some of the upper midtones as well! I suspect Guillermo is right that it's a built-in HDR function.
The ubiquitous Sony sensor has about 13 stops of dynamic range (without any multi-shot) at ISO 100. This will add between 2 stops (by Guillermo's calculation) and 4 stops (if the shot noise is low enough that the concern is picking up enough light to activate the pixel at all) of DR. The problem is that the raw file is only 14-bit. This is one of the rare cases where a 16-bit ra w file actually matters...
-
Dan, I agree that the unusual Fill Factory CMOS sensor in the Kodak 14N (with no microlenses, IIRC) had a base ISO SSat well below 80; it’s unusual design had very large well capacity. But do not confuse “lowest standard EI setting” with base ISO speed; for very good reasons, most ILCs are designed to provide more than the bare minimum highlight headroom embodied in the ISO SSat measure of base speed, and a stop or two of extra headroom puts the lowest normal EI setting a stop or two higher than base ISO speed.
One more time: base ISO speed is not even vaguely optimal; it is intended as a guideline for minimal acceptable highlight handling ability, aimed originally at low-end digicams of the last millennium.
-
Interesting - so there is an actual ISO measure of base speed... I had always considered base speed to be a number chosen by the sensor manufacturer (generally by "this is where our sensor performs best" unless they're trying to hide something, as in the case of the old Kodaks). Generally, the base speed I think of gives as much room in the shadows as possible without blowing highlights early (it puts the full well capacity somewhere high enough in the highlights that most non-specular highlights won't hit it in most images).
BJL is saying (and I have no reason to doubt it's true)that there's a technical definition from the International Standards Organization, the same people who rated film speed, that defines how much highlight room is "needed", and that that number is generally a stop or two lower than the manufacturers choose as their "base speed", giving significantly less room in the highlights. If ISO set their standard based on old digicams with 5-7 stops of dynamic range (which is very possible, ISO is notoriously slow to update anything), it certainly would be low on an 11-13 stop sensor. Any manufacturer would want to shift their sensor higher, adding room to the highlights...
At this point, sensors perform well enough quite a ways above their ideal (manufacturer's "base") ISO that there's no reason to "cheat" in the direction of advertising a lowest measured ISO higher than the ideal. I (and I suspect a lot of other photographers) would rather have a measured range of 64-25600 than 200-51200 (knowing that 3200 and even 6400 are likely to be pretty decent on both sensors).
When Kodak advertised that misleading ISO 80 , there was incentive to cheat, because not only was the ideal ISO of the sensor probably 25 or so, it had very high noise and performed poorly at any ISO much over 100. The misleading 80 was meant to make people think the camera was more sensitive than it was - an ISO range of 25-200, which was probably the honest range of those old Kodaks, would have struck people as unduly restrictive for anything except a medium format back (the Phase backs of that time and even somewhat later advertised ranges like that honestly, because they were mainly used with powerful lights).
Today's cameras are all extremely sensitive, and the competition, at least for my type of photography, is more about who has a low ISO setting with exceptional image quality. Nikon's ISO 64 is actually useful - I shoot my Z7 down there all the time, and am rewarded with images that look like 4x5" film in many ways - in a big print, the extra DR and utter lack of noise shows, even compared to ISO 100 from the same camera. One of the real drawbacks of many smaller than 24x36mm sensors is that they not only don't have 64 as a "real" setting, they even lack 100. A camera that starts at ISO 200 can't (with today's sensor technology) match the low noise and wide DR of one that starts at ISO 64.
One real problem Sigma faces, even if they do have a good way of getting to ISO 6 through multiple exposures, is sensors with twice the pixels and noiseless ISO 64 (and maybe 50 - I'm not clear on whether the S1r has a true ISO 50 that doesn't sacrifice highlights - I've seen it as 50 "base" and as 100 "base"). For landscape shots where the shadows are that important, the big pixel count can be, too. Even a single shot at ISO 64 from a Z7, D850 or S1r may very well print big better than the ISO 6 shot, let alone a 2 shot HDR merge at 46 MP and ISO 64?
-
This will add between 2 stops (by Guillermo's calculation) and 4 stops (if the shot noise is low enough that the concern is picking up enough light to activate the pixel at all) of DR. The problem is that the raw file is only 14-bit. This is one of the rare cases where a 16-bit ra w file actually matters...
Good point, I missed that. Being a somewhat cooked RAW file, a gamma lift could be applied (like the Leica M8 does on its 8-bit RAW files for instance) before the final encoding. With such gamma (informed in the metadata for proper RAW development) a 14-bit RAW file can hold a much higher DR than 14 stops.
It will be interesting to analyse this camera's ISO6 RAW files to find out the truth.
Regards
-
Dan, I suggest you read a bit about the relevant standard ISO 12232, because you suffer a common confusion about what the ISO setting on a camera means. The problem is that there are at least three different measurements of camera and light-metering function that get called “ISO”.
The setting on a camera sets the Exposure Index for both its light meter and the amplification used in producing default JPEG output; it is almost nothing to do with the sensitivity of the sensor itself, either in terms of highlight handling (ISO SSat, for minimum advisable EI to mostly avoid blown highlights) or noise and shadow handling (ISO Ssnr10 or Ssnr40, based on adequate SNR in mid tones).
So the minimum EI of 80 on the 14N is not the slightest bit misleading (let alone dishonest or cheating as some have claimed) once you know what it does and does not measure. One more time: it is standard and good practice for DSLRs and MILCs to offer more than the ISO-recommended bare minimum of highlight headroom (based on placing mid/tones at 18%) at even their lowest “normal” EI setting, and likewise to place metered mid tones significantly below 18% of maximum raw level.
-
Thanks for the reference to the standard... Is EI maybe the term we should be using for "the sensitivity value we set on our camera that tells it how to expose, and what amplification to use on JPEGs"? It sounds like the value we are setting is not actually aligned with the ISO standard?
Further confusion is added by the fact that many cameras today are "ISOless" or nearly so - the actual gain applied to the output of the sensor (which would be the closest thing to the old ISO film speed) either doesn't change or changes only in one or two steps. What happens when you set a higher "ISO" value is often that the camera applies a digital exposure modification to the (underexposed) sensor data after the image is captured.
This is more equivalent to what photojournalists used to call "push-processing" and Zone System devotees called "+1 or +2 development" than it is to using an inherently more sensitive film, no?
-
I don't get the point. Sigma's whole involvement in the camera body side of things seems to be nothing more than a show of pride, with no prospect of commercial success, and has been for years.
I am so glad they continue to create innovative cameras.
It inspires me to head out to shoot with my DPMs because they're just so cool and bring a smile to my face every time ;D
-
Thanks for the reference to the standard... Is EI maybe the term we should be using for "the sensitivity value we set on our camera that tells it how to expose, and what amplification to use on JPEGs"? It sounds like the value we are setting is not actually aligned with the ISO standard?
Further confusion is added by the fact that many cameras today are "ISOless" or nearly so - the actual gain applied to the output of the sensor (which would be the closest thing to the old ISO film speed) either doesn't change or changes only in one or two steps. What happens when you set a higher "ISO" value is often that the camera applies a digital exposure modification to the (underexposed) sensor data after the image is captured.
This is more equivalent to what photojournalists used to call "push-processing" and Zone System devotees called "+1 or +2 development" than it is to using an inherently more sensitive film, no?
Dan, I think the best way to view it is that digital cameras simply do not have a single “sensitivity” the way most films have a single ASA/ISO speed number; they are more like some special cases where the ASA speed of a film can truly vary with different development. And the dial on a digital camera genuinely varies that “Standard Output Sensitivity” or “Recommended Exposure Index”, to use the names from the ISO standard.
The ISO standard also explicitly tries to give measures for upper and lower limits on that range of “output sensitivity”, with an upper limit based on SNR of 10 or 40 in the mid-tones, and the lower limit (SSat) based on barely adequate roughly 2.5 stops of headroom between mid-tones and where highlights get blown due to overfilled photosites or such.
As far as I can see, cameras usually offer a range of “normal” output sensitivity settings on the “ISO” dial that lies within this ISO-defined exposure latitude, and then sometimes additional “High” and “Low” choices that fall outside it. However, the SNR-based upper limit is fuzzy and not so strictly followed; after all, resolution trade-offs like down-sampling or noise reduction can improve that mid-tone SNR, so it can often make sense to use a higher exposure index (outside the ISO-suggested latitude) to get a high enough shutter speed and deal with the noise later.
TL;DR I’d love to see a name like “output sensitivity” used for what the ISO setting does, but “exposure index” has more chance and is consistent with both traditional meaning and the language sometimes used in the ISO and Japanese CIPA standards.
-
Dan, I think the best way to view it is that digital cameras simply do not have a single “sensitivity” the way most films have a single ASA/ISO speed number; they are more like some special cases where the ASA speed of a film can truly vary with different development. And the dial on a digital camera genuinely varies that “Standard Output Sensitivity” or “Recommended Exposure Index”, to use the names from the ISO standard.
The ISO standard also explicitly tries to give measures for upper and lower limits on that range of “output sensitivity”, with an upper limit based on SNR of 10 or 40 in the mid-tones, and the lower limit (SSat) based on barely adequate roughly 2.5 stops of headroom between mid-tones and where highlights get blown due to overfilled photosites or such.
As far as I can see, cameras usually offer a range of “normal” output sensitivity settings on the “ISO” dial that lies within this ISO-defined exposure latitude, and then sometimes additional “High” and “Low” choices that fall outside it. However, the SNR-based upper limit is fuzzy and not so strictly followed; after all, resolution trade-offs like down-sampling or noise reduction can improve that mid-tone SNR, so it can often make sense to use a higher exposure index (outside the ISO-suggested latitude) to get a high enough shutter speed and deal with the noise later.
TL;DR I’d love to see a name like “output sensitivity” used for what the ISO setting does, but “exposure index” has more chance and is consistent with both traditional meaning and the language sometimes used in the ISO and Japanese CIPA standards.
IMO all the ISO story deserves much less attention than it receives. A good RAW shooter should simply study carefully how his camera responds to every amount of light, and forget about the ISO conventions. For me ISO values are just amplification gains, and I know I'll get the best overall DR and SNR captured if I can manage to do ETTR at the lowest real ISO. The ISO100, ISO200, ISO Low,... conventions are pretty useless, the only important thing is to know what's going on with the captured signal at every ISO setting.
For example: it's usually said (in the first place by the camera maker itself) that Olympus and Panasonic cameras lack ISO100, starting at ISO200. Well, I'd rather say Olympus cameras really HAVE ISO100 than saying they don't have it. When set at ISO200, a Olympus camera behaves closer to any other camera's ISO100 (specially old Canons) in terms of RAW highlight headroom, which in the end is what really matters. This means an Olympus RAW file from my E-P5 at ISO200 will have roughly the same RAW values than a RAW from my Canon 350D at ISO100 when both cameras receive the same amount of light per sensor surface unit (i.e. when the same aperture and shutter are set on both). If so, how the hell can you say the PEN doesn't have ISO100? or how can you say the Canon has ISO100?. When used with camera's suggested exposure at ISO200, Olympus cameras produce really bad SNR (an example of this is seen in so many users complaining at Olympus noisy skies), but the reason is not so much the M4/3 sensor performance, is that compared to other cameras you are sistematically underexposing by one stop!
Therefore I tend to ignore the "ISO100" naming convention, I just know what ISO setting I need to adjust to get the most DR of my captures and that's it.
Regards
-
IMO all the ISO story deserves much less attention than it receives. A good RAW shooter should simply study carefully how his camera responds to every amount of light, and forget about the ISO conventions. For me ISO values are just amplification gains, and I know I'll get the best overall DR and SNR captured if I can manage to do ETTR at the lowest real ISO. The ISO100, ISO200, ISO Low,... conventions are pretty useless, the only important thing is to know what's going on with the captured signal at every ISO setting.
For example: it's usually said (in the first place by the camera maker itself) that Olympus and Panasonic cameras lack ISO100, starting at ISO200. Well, I'd rather say Olympus cameras really HAVE ISO100 than saying they don't have it. When set at ISO200, a Olympus camera behaves closer to any other camera's ISO100 (specially old Canons) in terms of RAW highlight headroom, which in the end is what really matters. This means an Olympus RAW file from my E-P5 at ISO200 will have roughly the same RAW values than a RAW from my Canon 350D at ISO100 when both cameras receive the same amount of light per sensor surface unit (i.e. when the same aperture and shutter are set on both). If so, how the hell can you say the PEN doesn't have ISO100? or how can you say the Canon has ISO100?. When used with camera's suggested exposure at ISO200, Olympus cameras produce really bad SNR (an example of this is seen in so many users complaining at Olympus noisy skies), but the reason is not so much the M4/3 sensor performance, is that compared to other cameras you are sistematically underexposing by one stop!
Therefore I tend to ignore the "ISO100" naming convention, I just know what ISO setting I need to adjust to get the most DR of my captures and that's it.
Regards
Exactly. ISO-invariant sensors only have a few real ISO levels, with the rest being no different to pushing a lower-ISO shot in postprocessing. The Sony 42MP sensor only has ISO 100 and ISO 640. Nikon's D850 only has ISO 64 and 400.
Which leads to a particular quirk regarding the way non-base ISOs are treated. Basically, they're throwing away highlights. There's no disadvantage in shooting at USO 100/640 (Sony) or ISO 64/400 (Nikon), then pushing to a higher equivalent ISO, as opposed to shooting at a higher ISO in the first place. Conversely, many scenes where you'd want to shoot with a higher ISO are mostly dark, but with a few, small bright areas, which are captured well at ISO 100 (for argument's sake) but which are blown out at ISO 400. So it actually works out better to shoot at the base ISO and push, sparing the bright areas, rather than shooting at ISO 400, getting the rest of the image at the right exposure, but blowing the highlights. It would be great if there was a camera setting to only shoot at the base, 'real' ISO levels, only using the other levels for the purposes of exposure simulation in the viewfinder. For instance, on the Sony, if you shot a scene at ISO 2500, you would see the image at ISO 2500 in the viewfinder, but the actual exposure would be captured at ISO 640, allowing for selective pushing to bring the image back to proper exposure, while sparing the highlights. At this time, there's no option to do this - if you want ISO 640, you have to shoot at ISO 640, which results in a completely black viewfinder (if using exposure simulation) or you having no idea what ISO you actually need (if not using exposure simulation).
-
@Guillermo, agreed that makes sense for photographers like you who learn enough about sensors to then expose for an optimal raw file and adjust levels in raw conversion. On the other hand, the great number of photographers who aim for settings that make the in-camera preview informative and the default JPEG conversion useful much of the time, and then maybe use raw+JPEG so the hard cases can be improved by custom raw conversion, the cameras’ ISO “output sensitivity” settings do the job quite well. The extra stop or so of highlights in raw files vs default JPEGs is useful insurance.
(Do you all remember the bad old days when people criticised digital cameras for their very limited highlight headroom? Overcoming that is why the minimum “normal” ISO output sensitivity is so often a stop or so above ISO SSat “base ISO speed”.)
-
@shadowblade: indeed when sensors gain almost nothing in shadow handling and noise by using other than the two base ISO speeds, it might be best to not use intermediate degrees of analog amplification, but instead essentially give raw photoelectron counts in raw files, with metadata indicating the intended exposure index, to guide amplification used in raw conversion. (Some MF CCD cameras with good discrete ADCs did this, and it made sense, and some CCD cameras at least did it for their “High” output sensitivity settings.)
-
Today's cameras are all extremely sensitive, and the competition, at least for my type of photography, is more about who has a low ISO setting with exceptional image quality. Nikon's ISO 64 is actually useful - I shoot my Z7 down there all the time, and am rewarded with images that look like 4x5" film in many ways - in a big print, the extra DR and utter lack of noise shows, even compared to ISO 100 from the same camera. One of the real drawbacks of many smaller than 24x36mm sensors is that they not only don't have 64 as a "real" setting, they even lack 100. A camera that starts at ISO 200 can't (with today's sensor technology) match the low noise and wide DR of one that starts at ISO 64.
I would mostly argue the opposite. We need cameras with several stops more sensitivity - not for 19 stops of DR at ISO 100, but for 13-14 stops at ISO 3200-6400, with noise and image quality similar to what we currently get with ISO 100-200.
A lot of landscape and cityscape situations are taken in dim lighting and/or at narrow apertures. Exposure times of 1/4s to 4s are fairly typical. But landscapes and cityscapes aren't entirely still. Leaves flutter, branches sway, pedestrians and cars move. Exposures in this range don't freeze motion sufficiently. Shooting at a longer exposure can blur cars out if there's little traffic, but pedestrians have a nasty habit of standing in place and loitering, while the technique does nothing for moving leaves, grass or branches. If I could shoot the same scenes at 1/20-1/80s or so, it would eliminate this unwanted motion blur and make for far less frustrating shots and improved shooting opportunities, much more so than getting a bit less noise in an already-clean ISO 100 shot by being able to shoot at ISO 6.
If I really want ISO 6-25, I can get that simply by taking 4-16 ISO 100 exposures and averaging them. But I can't generate extra sensitivity that the camera doesn't already have.