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 1 
 on: Today at 02:35:01 AM 
Started by deejjjaaaa - Last post by BartvanderWolf
I believe that a 14 bit linear raw file can be lossy compressed at practically no loss of image information. I.e. some of the bandwidth is wasted on storing noise that has no image-information in it.

Hi,

While this forum/thread is perhaps not the best place to discuss this in depth, I'm not so sure about the 'waste' part of storing noise.

Afterall, the signal consists of (Poisson distributed) shot noise, with 'some' more noise added by the capture system. The shot-noise component in my mind adds a bit to the malleability of the image data when we get to post-processing it. That of course does depend on some additional factors, like well depth that allows a significant signal level in order to steer clear of the other (system generated) noise components, but also low levels of PRNU. Some of that system noise could in principle be reduced by averaging multiple-read-outs from CMOS devices and good calibration.

There is even information hidden in the higher levels of shot-noise (which is where Sony does most of its compression), which can be made more detectable by averaging the signal component of multiple captures (which requires mostly stationary subjects). Lossy (actually irreversible) compression of that hidden info will risk losing it.

Cheers,
Bart

 2 
 on: Today at 02:23:39 AM 
Started by sunshine1234 - Last post by Guillermo Luijk
I guess that I am more interested in Bernard's images than in the DXOMark ratings. As it should be.

Do you mean you'll decide the purchase of one or another camera system based in how good are the pictures produced by their owners?. Or you simply meant that you enjoy more looking at pictures than looking at graphs and numbers?. If this is the case I'll tell you enjoying pictures is totally compatible with the usefulness of DxO data in deciding a purchase.

 3 
 on: Today at 01:43:59 AM 
Started by deejjjaaaa - Last post by hjulenissen
Sony are doing some good stuff these days.

The A7/(A9?) is an interesting option once my Canon crop DSLR needs a replacement. I have a few worries, though:
*My Sony RX100M2 has very good IQ for its size. But ergonomy leaves something to be desired. Are Sony as good as Canikon on ergonomy in their bigger cameras?
*What is happening with lenses? Are Sony catching up? Sigma? Will converters for my Canon lenses do the job?
*I have really gotten into running my DSLR for 1 week on a single charge. When (if ever) will milfs get to that level?

In some ways, I am still hoping for Canon to wake up and offer a competitive 6D/EOS-M/A7 mashup once a sufficient number of customers start to leave. I guess I have invested time and money into flashes, lenses, ways of working...

-h

 4 
 on: Today at 01:37:16 AM 
Started by deejjjaaaa - Last post by hjulenissen

They both have pseudo 14-bit images and the raw files are lossy (as opposed to lossless) compressed - two very questionable (aka 'stupid' some might say, .. like me) decisions by Sony.
In order for the decision to be genuinely "stupid" we would have to know what is lost and what is gained. I believe that we (?) don't know.

I believe that a 14 bit linear raw file can be lossy compressed at practically no loss of image information. I.e. some of the bandwidth is wasted on storing noise that has no image-information in it.

I don't know if Sony does this a some pure software compression to save bandwidth/storage space (in that case it is strange that they don't offer the pure lossless as an option, if only to silence the critics), or if this is some physical feature of their ADC front end (as some has suggested). I.e. that the data is allready compressed once it reach their software for reasons unknown (ADC speed? Noise performance? Cost?)

-h

 5 
 on: Today at 01:33:22 AM 
Started by William Walker - Last post by William Walker

One option is to composite all three images into one image.

Great idea Lou! That will be my focus now.

Jeremy: the framing is a cock-up! I caught myself out with that by placing the flower too much to the right, not realising that it would open up like it did! I had to push the flower more to the centre with the next shot the following day. Lou's suggestion solves that problem nicely and I was concerned about large expanses of grey - a composite solves that problem too!

Now you know why I don't do too much without running it past you guys!
Thanks
William

 6 
 on: Today at 01:23:27 AM 
Started by deejjjaaaa - Last post by Guillermo Luijk
This is not the first 5-axis IBIS camera, and the existing ones (E-P5, E-M1) do fantastically well. I think metering or focusing is more reliable and easier for the camera engine once the image is stabilized. It makes sense to me.

I find much easier to check for perfect focus, framing or even exposure in manual mode when I half press the shutter on my E-P5 and get a wonderfully stabilished view on the EVF. Not different from the time I tried a 300mm with IS on my Canon APS.

 7 
 on: Today at 01:13:15 AM 
Started by Dave (Isle of Skye) - Last post by sdwilsonsct
I think this feature is useful for judging the attractiveness of thumbnails. Many of the 80% are probably following the discussion, having already enlarged the thumbnail on their first visit to the thread.

 8 
 on: Today at 01:06:43 AM 
Started by JV - Last post by synn
Sure. And how many times will you repeat yourself before you bore yourself out?

-h

At least as many times as people find the time to point it out.

 9 
 on: Today at 01:06:23 AM 
Started by JV - Last post by BernardLanguillier
Nobody is demanding anyone to do anything.
If the techies have a right to barge into every thread, tech related or otherwise and spill their infinite wisdom, the non techies have an equal right to say it bores the crap out of them.

Indeed. I think that this whole tech talk on the 007 results from the fact that people see a gap between the marketing sensor tech talk of Leica and their understanding of its actual merits relative to the competition. In other words, Leica marketing may have made a mistake by trying to further rationalize the value of the 007 in terms of sensor technological advance that may not be as clear cut as they claim.

My personal view remains that the S system is a fascinating offering, mostly thanks to is remarkable lenses.

In that context, the 007 has closed a lot of the gaps that existed relative to its DSLR competitors (645Z, D810, a7r) and that in itself means it is much better value than the previous S cameras. The system now has capabilities that make it universally appealing.

Whether the pricepoint makes sense or not depends on everyone's needs and situation. Not needing shutter leaf lenses, I personally think it is way over priced.

Cheers,
Bernard

 10 
 on: Today at 01:05:50 AM 
Started by JV - Last post by hjulenissen
... an equal right to say it bores the crap out of them.
You can tell me that I am boring. I can tell you that you are boring. And so forth. What good does it do to any of us? Please feel free to PM me.

-h

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