Sony Alpha A99 Field Test Report

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bakubo
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Re: Sony Alpha A99 Field Test Report

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bakubo wrote:
bfitzgerald wrote:Also some makers are overstating the ISO ratings more than others (OM-D is off by a stop which is way more than most) so I'd be cautious about DxO ratings on sensors (for some reason they give the 24mp CMOS a better rating on the SLT models v the 16mp for high ISO, which is odd real world doesn't support that)
These are interesting articles for people who want to understand this stuff better:

RAW is not Raw

http://theonlinephotographer.typepad.co ... t-raw.html

Why ISO Isn't ISO

http://theonlinephotographer.typepad.co ... t-iso.html

Sense and Sensitivity

http://www.dpreview.com/articles/424180 ... ensitivity

Sensitivity (ISO) in digital imaging seems to be the subject of quite a lot of confusion - it's becoming common to hear talk of manufacturers 'cheating with ISO.' So we thought it made sense look at why sensitivity appears hard to pin down, why we use the definition we do and how it's actually not as complicated as it can sometimes seem.
Good stuff that is worth reading. Self education never ends. :)
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bfitzgerald
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Re: Sony Alpha A99 Field Test Report

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If only I took articles written by Ctein seriously unfortunately I don't. I can only comment real world with Fuji and they were over stating their ISO by a large margin which was obvious when using the cameras ie the actual exposure. Did it matter? Well it did actually because Fuji seemed to be promoting their super low light capability thing is when ISO 6400 is looking not too bad it's was less than ISO 3200 so it was misleading. A bit of variation I can understand a stop off is unacceptable

It's like those lithium cells that state 8000mAh on the label but even the best cells are barely 3600mAh. It's called marketing/sales
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Re: Sony Alpha A99 Field Test Report

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Yes, Fuji actually meters and gives a different and more exposure for a given ISO than what is standard and expected. That has a real, practical affect on the photographer. That is not the case with Olympus, Sony, etc. That is why it is worth understanding the digital ISO stuff reported by DxO. Easy to jump to wrong conclusions otherwise.
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bfitzgerald
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Re: Sony Alpha A99 Field Test Report

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DxO have not tested the Fuji X cameras or sensors as far as I can see no idea why that is. They are reporting Olympus are overstating ISO in excess of a stop. I don't hang on every word DxO say but there must be a reason for that difference. They are also suggesting the A99II and A99 is a stop off of set ISO. Other Alpha models are a bit off including the E mount ones but not as much (A77II less accurate than A77 A68 also off and the A58) seems a trend in lately though they are not a full stop off. Looking over their data it might explain real world why the A77 gives more exposure real world (a bit) at a given ISO setting v the A57 and I tested both extensively and saw that identical lenses

That means you cannot make direct high ISO comparisons between some models say cameras set to ISO 1600/3200/6400 etc and get any accurate idea of performance. That makes browsing sample images pretty dangerous unless you factor that in. I'm not suggesting it's just Olympus other makers are also doing it but not quite as much. If ISO 12800 looks pretty damn good on the A99II and it's really ISO 6400 that's something I think would concern buyers. Just as I found with Fuji the ISO values are fudged shooting side by side it was quite obvious.

As a buyer it is something that bothers me I think it's done to over inflate real world performance
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Re: Sony Alpha A99 Field Test Report

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bfitzgerald wrote:DxO have not tested the Fuji X cameras or sensors as far as I can see no idea why that is. They are reporting Olympus are overstating ISO in excess of a stop. I don't hang on every word DxO say but there must be a reason for that difference. They are also suggesting the A99II and A99 is a stop off of set ISO. Other Alpha models are a bit off including the E mount ones but not as much (A77II less accurate than A77 A68 also off and the A58) seems a trend in lately though they are not a full stop off. Looking over their data it might explain real world why the A77 gives more exposure real world (a bit) at a given ISO setting v the A57 and I tested both extensively and saw that identical lenses

That means you cannot make direct high ISO comparisons between some models say cameras set to ISO 1600/3200/6400 etc and get any accurate idea of performance. That makes browsing sample images pretty dangerous unless you factor that in. I'm not suggesting it's just Olympus other makers are also doing it but not quite as much. If ISO 12800 looks pretty damn good on the A99II and it's really ISO 6400 that's something I think would concern buyers. Just as I found with Fuji the ISO values are fudged shooting side by side it was quite obvious.

As a buyer it is something that bothers me I think it's done to over inflate real world performance
Going back several years I have posted good info about digital ISO so you could start to understand it. I guess at this point I realize you are not interested in reading it and trying to understand though so I will no longer bother. :)
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Re: Sony Alpha A99 Field Test Report

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If it's linking to an ex film shooter who has IMO written some pretty weird articles over the years completely ignoring real world conditions and blowing off about technical qualifications then no don't bother there is nothing to support his odd article. ISO is ISO in the real world be it emulsion or sensor ISO
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Re: Sony Alpha A99 Field Test Report

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bfitzgerald wrote: ISO is ISO in the real world be it emulsion or sensor ISO
Exactly. Sony, Olympus, etc. do it right. ISO is ISO. They meter and expose properly for the light and ISO. They match each other or a handheld meter. Fuji seems to be doing something strange though since their ISO does not match. Anyway, if you prefer not to understand digital ISO then that is okay. Lots of people prefer not to know about things that they use. :)
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Re: Sony Alpha A99 Field Test Report

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It's not about not understanding digital ISO (you can use various methods as I did read) it's about the cameras being tested with a level playing field and real world use too. I'm sure if I got an Olympus I would find the ISO is being over stated to conclude that properly I'd use an adapter and fit an identical lens thus the transmission is the same. That's exactly what happened with Fuji they fudged the ISO values to give the impression their real world high ISO is superior to other makers when it's not really (there were some DR advantages I already noted and some drawbacks such as native ISO 200)

Metering has nothing at all to do with it that varies from models and makers it's about the light that enters the camera. Sony seem to be overstating their ISO values too with some models. DxO indicates the KM5d is pretty accurate for ISO they seem to be testing cameras in a consistent manner even though I'm not a fan of the site (I think the ratings can sometimes indicate larger differences than is obvious in person using the sensors). I'd put a bit more weight on their findings than Ctein
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Re: Sony Alpha A99 Field Test Report

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bfitzgerald wrote:It's not about not understanding digital ISO (you can use various methods as I did read) it's about the cameras being tested with a level playing field and real world use too. I'm sure if I got an Olympus I would find the ISO is being over stated to conclude that properly I'd use an adapter and fit an identical lens thus the transmission is the same. That's exactly what happened with Fuji they fudged the ISO values to give the impression their real world high ISO is superior to other makers when it's not really (there were some DR advantages I already noted and some drawbacks such as native ISO 200)
Please do that and report back here the results. Thank you.
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bfitzgerald
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Re: Sony Alpha A99 Field Test Report

Unread post by bfitzgerald »

Send me an Olympus and I will it's quite easy. The Fuji X models I used all fudged the ISO values by a stop or so it was very obvious shooting them next to my other cameras.
https://photographylife.com/does-fuji-c ... ts-sensors
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Re: Sony Alpha A99 Field Test Report

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You probably don't know what ISO means – and that's a problem

https://www.dpreview.com/articles/89245 ... -a-problem
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bfitzgerald
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Re: Sony Alpha A99 Field Test Report

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IMO a pretty silly article
"In short, ISO is an increasingly shaky metaphor that promotes misunderstanding, obscures what your camera is doing and robs us of the tools we need to get the most out of our cameras. Isn’t it time for something better?"

Most people with an interest in photography know what ISO is and I think it's working just fine. To me on a practical level there is no difference digital/film I know what both do and why they are used. Unless you're a millennial intent on trying to be different (but ending up the same anyway), I don't see the point
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Re: Sony Alpha A99 Field Test Report

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Good new article about ISO with digital cameras.

Is ISO Fake?

https://dslrbodies.com/cameras/camera-a ... -fake.html
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bfitzgerald
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Re: Sony Alpha A99 Field Test Report

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Assume all this comes from the Tony Northrup video about this which as per usual is over simplified though makes some reasonable points. I can only go on my own experience when I tested the Fuji and Sony's with the same lens and I revisited that with the raw files no tone curve straight out of the sensor and it's about a stop off the Sony's identical exposure and that's with an SLT mirror sucking some of the light away.
So based off that yes some makers are fudging the ISO values to give the impression of better low light performance. We've known this for a while, he just cites Fuji (correctly in my experience) and Olympus (not used any recent bodies can't confirm but widely reported) as being the "worst" offenders.

The ISO invariance applies to some sensors and not others. Either way I wouldn't see any real practical reason to use low ISO values and massively underexpose to get the same effect as setting the ISO. I understand some underexpose a bit to hold onto highlights, not really the same extreme example and I've done that in the past (less so now as the DR is pretty good on sensor even the older cameras I have ie A77/57)

It's one of those nerdy type things Tony often does - and whilst he can be entertaining it was clearly made to bag some extra views, and a bunch of others followed it like sheep! It does cover a point worth talking about, sadly most get sidetracked into the variance part which is far less important than the dodgy ISO figures thrown around.
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Re: Sony Alpha A99 Field Test Report

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The ins and outs of ISO: What is ISO?

https://www.dpreview.com/articles/96983 ... hat-is-iso

Raw is often talked about as being like a 'digital negative' but as we've seen, unlike the film standard, the digital version of ISO doesn't specify what should happen in your Raw file.

The latest update to the ISO standard makes it explicit that it does not apply to Raw files. Until a tone curve is applied, a Raw file doesn't have a 'middle grey': it's up to the manufacturer to decide which Raw value should be used. Consequently, there isn’t a specific Raw value you can measure or check for correct lightness, so you can't measure the ISO (or ISO accuracy) of a Raw file.

If you’re ever seen graphs plotting ‘Measured ISO’ against ‘Manufacturer ISO,’ then you risk being misled.

If you’re ever seen graphs of ‘Measured ISO’ plotted against ‘Manufacturer ISO,’ then you risk being misled. What they show is how a camera’s ISO settings are delivered, relative to an arbitrary system that assumes Raw files will saturate at a certain exposure. You can often work out how amplification is being applied using these graphs, but they do not show ISO accuracy, since the ISO standard doesn’t define a relationship between exposure and Raw saturation.
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