horshack

FYI, the NX1's H.265 may be DOA due to licensing royalties:

http://blog.streamingmedia.com/2015/07/new-patent-pool-wants-share-of-revenue-from-content-owners.html

http://yro.slashdot.org/story/15/07/26/0149234/hevc-advance-announces-h265-royalty-rates-raises-some-hackles

​There are other inconsistent fields as well. For example, the ACR-generated focal plane resolution fields are for a 36MP A7r:

From linked image:

Focal Plane X Resolution        : 2049.067291
Focal Plane Y Resolution        : 2049.067291

From an A7r image processed in ACR:

Focal Plane X Resolution        : 2049.067291
Focal Plane Y Resolution        : 2049.067291

From an A7II image processed in ACR:

Focal Plane X Resolution        : 1675.257385
Focal Plane Y Resolution        : 1675.257385

"The 15 stops is done by taking the raw sensor data and running it through dual image processors at two different ISOs (high and low) before making a composite image from the dual raw stream."

This sounds like the "Dual ISO" feature of previous Canon sensors that Magic Lantern unleashed for stills. Andrew, what is your source that the C300II is using this technique?

Has every serial killer spent a decade planning and exhibiting bad behavior and every common assault perpetrator only a few seconds exhibiting his? It could be argued that Clarkson's years of progressively worsening behavior toward others that ultimately escalated to violence is an imputed form of planning. Certainly Clarkson was aware that his behavior toward others was unacceptable yet he failed to stop its progression. That means he's either guilty of consciously planning his bad behavior or guilty of consciously not planning to correct it.

As for my intelligence, I would kindly ask we limit the debate to the topic at hand and not try to color the discussion with personal insults.

​How could we know that if we don't know interact with them on a regular basis? The same as how we can't know how normal Clarkson is for the 99.999% of the time he's not pummeling his producer.

​Serial Killers spend 99.999% of their time living normal lives. But the .001% of the time they spend murdering people is rather significant.

Nobody should be allowed to keep their job after physically assaulting a coworker. The rest of the discussion is just moral relativism gobbledygook. Clarkson  isn't a scientist inventing a cure for cancer - the world will go on without him, including the careers of the victimized parties.

Jeremy Clarkson 'to be sacked TODAY' after BBC probe finds he launched '30-second attack' on Top Gear producer during steak dinner 'fracas'

http://www.dailymail.co.uk/news/article-3010167/Top-Gear-presenter-Jeremy-Clarkson-sacked-BBC-internal-investigation-concludes-did-attack-producer-steak-dinner-fracas.html

Making cameras as seamless for online operation as Smartphones will make existing camera enthusiasts happy but it wont do anything to bring the P&S and DSLR market back. That ship has sailed. Most have no reason to buy a separate camera.

WIth LA-EA4 you'll get much better AF vs Metabones but you'll pay a 1/3 to 1/2 EV noise penalty due to the SLT.

The 1DC grabs look decidedly soft vs the A7s, as does nearly every other DSLR compared to the A7s. Any color issues can be corrected in post - acuity not so much. For IQ alone I would take the A7s over the 1DC.

​I'm going to redo this with a resolution chart. I made a poor choice of subject for evaluating resolution

Here's a base ISO comparison with the same cameras, including a comparison with the D800/D810 moved back to match the D750's wider crop. Not sure I picked the best subject for the comparison. All using Zeiss 35mm f/1.4 @ f/8, Cloudy WB, Standard Picture profile, 1/50 ISO 100.

https://www.transferbigfiles.com/2c0a7a0c-d7c5-4298-b728-ad49bab8bd1c/J1jQVSQY-eNa1eX5r5IWag2

Thanks I downloaded it. I don't know if it is the lighting, but they seem to be better than I thought they would. At first I thought that it was the crushed black, but using Gom player and lifting the lows the noise is still very nice. The D750 is cleaner and in this lighting even the 12800 looks very nice and 25600 usable. The D810 6400 iso still looks good with lots of resolution and very nice filmic noise and 12800 would be usable. The D800 is clearly a step below those two in terms of noise and resolution.

 

From what I have seen before they all look better by 1 stop from what I thought. In other footage the D750 seemed to have a sharp degradation of the quality between Iso 10 000 and 12 800, did you see the same.

 

I can also understand why the D810 was chosen for that big studio Australian Movie. It has a lot of resolution and it retains a lot of detail even at high ISO. You can easily shoot at 3200 ISO with a ton of detail. This is enough for any movie.

The D800's video IQ drops off a cliff between ISO 6400 -> 12800, whereas on the D810 and more so the D750 the decrease is more linear. Btw I'll try to get a base ISO video comparison done tomorrow.

Here is the original video file for download - the following link is good for 5 days or until the download quota has been exceeded:

https://www.transferbigfiles.com/e9270268-c766-48f3-b271-05c18076a3f9/WRxTxw2Cd9aocePN4nIvvg2

Thanks for the review Andrew. Regarding your High ISO comments about the A7s's ISO 12,800 being equivalent to the A7 at ISO 3,200, my tests indicate the A7s doesn't start pulling ahead until ISO 12,800, at least for stills (which is the context you made your comments in). Video of course a different matter. Here's a carefully-controlled High ISO stills comparison I did between the A7r/A7/A7s, all normalized to the same resolution (stills): http://***URL removed***/forums/post/54031579

This 5DM3 vs D750 comparison (

What I am not understanding from the article is it implies that at large apertures, the camera is automatically compensating by increasing the ISO, but the user is unaware of the ISO increase? 

 

 

So the camera says, for instance, ISO 1600, and the camera is really at ISO 3200?

 

Michael

Yes, on a noise basis that is effectively what happens. On an exposure basis it matches the user-indicated ISO.

I would think another significant problem would be the decreased efficiency of the micro-lenses in front of each pixel.  The larger the micro-lens the more efficient?  Or, the smaller the micro-lens, the less efficiency, especially in low light.  

One issue with the microlenses is that they have an associated max aperture, like normal lenses. Producing very large aperture microlenses is difficult and expensive apparently, so commercial sensors have to compromise a bit. The downside of this compromise is loss of light when using large aperture lenses, mostly at f/1.4 and larger. You can read it about it here: http://www.dxomark.com/Reviews/F-stop-blues

A lower resolution sensor holds a massive advantage for video. You can downscale a 36MP still to 2MP and say "look how clean" but pixel quality is pixel quality, signal to noise is signal to noise, there's far fewer ways to fudge the facts when it comes to video.

That's only because sensors and sensor procesisng ASICs aren't yet fast enough to process higher MP streams for video. It's not a pixel quality issue since those same high MP sensor produce equal or better IQ than their lower MP bretheren for stills, for everything except the very extreme High ISOs (+12,800 for FF).

HI horshack, I did read that thread but had difficulty understanding.  It seems misleading when you say, "cumulative read noise".  PLEASE correct me.  I would think that on a set of 4 pixels (pre de-bayering), you would get more sensitivity at high ISO, and less noise, then a similar block of 16 pixels fit into the same space.  I can see how you could say the cumulative noise is less on the 4 pixels, then 16 pixels, but isn't that obscured the prime difference between different size pixels?  I can understand that experimentally, it makes sense to look at cumulative read noise, but in explaining the difference to filmmakers, isn't it better that they think in pixels?

 

On the base ISO issue, it seems that comparing 4 pixels against 16, or 1 against 4, allows one to visualize the difference between say having a dish microphones vs an omnidirectional.   

The typical analogy used is buckets of water. Four small 8oz buckets placed side-by-side hold the same amount of water as a single 32oz bucket. Since the smaller buckets are side-by-side you would expect some loss of water when pouring into them for the gaps in between the buckets; this is where sensor microlenses come in. They act as a funnel to keep water from spilling around the sides of the extra boundaries/edges of the smaller buckets (ie, the funnel light into the photosensitive portion of each pixel, preventing the light from reflecting off the additional edges of smaller pixels). You'd be surprised to learn that the highest-efficiency sensors available right now for any commercial camera are tiny P&S cameras, where they convert 75% of the light they receive, vs 56% for the best full-frame sensors.

"Without compensating technologies, smaller pixels have lower dynamic range, lower fill factor, worse low light sensitivity, higher dark signal, and higher non-uniformity."

Source: Standford Research Paper

At the individual pixel level they do. But pixel-level metrics aren't relevant since images are rendered by area irrespective of the number of pixels that area contains. On a per-area basis the best technology high MP sensor (D800/A7r) has the same or better quantum efficiency as the best technology lower MP sensor (A7s/D4/D4s/Df/D3s/1DX), and have better base ISO dynamic range.

The question most others are interested in is the tradeoff the camera makes between low noise at high ISO and less DR at base ISO.  All sensors have a base ISO at which they perform optimally.  Everything after that is degraded.  Apparently, and I don't fully understand this myself, higher sensel count cameras improve DR at base ISO.  In other words, the a7S will be better at low-light than the a7, but the a7 will have better DR at base ISO (say 100).  

 

It is not the low megapixel count that makes the a7S more sensitive to light, it is the LARGER sensel/pixel size on the sensor.  Each sensel is like a little telescope/radio dish with a colored filter in front of it.  As in astronomy, you can collect radiation through lots of little dishes, or one big dish.  In picking up faint objects, the bigger the better.  In short, larger pixel, less noise, period.  There is nothing temporary in this area of physics.  I do not see TV stations replacing their satellite dishes with 50 little dishes.

 

Again, it is NOT about the low megapixel count.  It is about the increased pixel size (more sensitivity/less noise) of the a7S that makes it unique.    Here is someone's calculation of pixel width

 

Approximate pixel pitch  (in microns)

 

Refer to the reservations  here  about calculating the "true" width and area of an individual pixel.

 

Pixel pitch in microns  = width of sensor in millimetres  divided  by  image width in pixels  multiplied by 1000

 

A77   =   3.917    (23.5 / 6000  x 1000)

A7S =     8.443    (35.8 / 4240 x 1000)

 

Relationship: A7S is approximately 116% greater than A77

 

http://www.robsphotography.co.nz/Sony-A77-SonyA7S.html

 

Would you rather have a 4 inch telescope or 8 inch telescope when peering into the night sky? 

 

Larger pixels are not more sensitive to light - the A7s's sensitivity ("quantum efficiency") is about equal to that of the D800/A7 - this is why midtone noise on the A7s is the same as the D800/A7r when compared on a per-area basis (via downsampling). What larger pixels do provide, at least with current technology limits, is better Higher ISO dynamic range, which is due to the total lower cumulative read noise from fewer pixels having to be read over the same area vs a higher MP sensor. This translates to lower noise in the shadows. This larger pixel advantage turns into a disadvantage at base ISO because of the read noise penalty from holding a larger charge (full-well capacity). You can read more details at my dpreview thread here: http://***URL removed***/forums/post/53860364

Someone who had an early copy of the A7s posted a video to youtube showing no resolution loss in crop mode. That video has since been pulled but it was pretty convincing. In the meantime here's another video showing the relative noise between FF and crop mode - looks about the expected 1.x stops: