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Messages - x-vision

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31
EOS Bodies / Re: New Sensor Tech in EOS 7D Mark II [CR2]
« on: June 19, 2014, 11:46:05 AM »
Wouldn't you be worried about that approach messing up the phase detection?
Yes  ;D.

32
EOS Bodies / Re: New Sensor Tech in EOS 7D Mark II [CR2]
« on: June 19, 2014, 11:24:58 AM »
Assuming it's a Bayer sensor with multiple pixels under each microlens (like the 70D), there's not a lot they can do to improve sensor performance that's outside the realm of read noise.  There are several ways to attack that one, and some of them involve doing clever things with the multiple pixels per microlens, such as reading out each one at a different ISO and then combining them, sort of like what Magic Lantern has done to increase DR.


Either that - or, it might not be a Bayer sensor in the first place.

By the look of things, the so called dual-pixel tech is actually quad-pixel already.
See my previous post on the topic here.

With a quad-pixel design, rather than having a single color filter per pixel, it's theoretically possible to have individual color filters for each of the four sub-pixels.
These color filters don't need to be monochromatic R/G/B filters anymore.
Instead, these could be a combination of di/poly-chromatic filters, from which the full color of a pixel can be derived.
That's better than a Bayer sensor, where two of the pixel colors need to be interpolated from neighboring pixels. 

So, you never know. The 7DII could have the first non-Bayer sensor in a DSLR.
If they use a combination of dichromatic filters for each sub-pixel, they could achieve maybe 1 stop of ISO improvement vs a Bayer sensor.
I think Canon will inevitably implement this sooner or later, given that they have gone the quad-pixel route already.
The question is, will the 7DII be the first camera to have it - or will we have to wait more for that.

33
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 03, 2014, 04:53:34 PM »
I've been through every free Chipworks article they have ever published.

Hmm. Obviously not, because Chipworks has a free partial die photo of the 70D sensor:
https://chipworks.secure.force.com/catalog/ProductDetails?sku=CAN-EOS-70D_Pri-Camera&viewState=DetailView

Take a careful look and consider the geometry of a dual-photodiode pixel:
- you can have two rectangular photodiodes that form a square pixel
- or, you can have two square photodiodes that form a rectangular pixel
- finally, you can have two square photodiodes plus wasted space on the die that form a square pixel

Now, as I said, take a careful look at the partial sensor die and tell me if you see:
a) anything rectangular features on this photo
b) any apparently wasted space

A partial die photo is certainly not a definitive proof.
It's a very good clue, though, that the 70D sensor is in fact using a quad photodiode design, not  a dual one.
Again, just think of the geometry of a dual pixel design and make your own conclusions.

As for the resolution of a non-bayer filter: I should have been more clear.
The 70D sensor is a bayer sensor, where each pixel has a monochromatic R/G/B color filer.
Thus, each of the four constituent photodiodes of that pixel lies under a single, common monochromatic filter - that happens to throw away 2/3 of the incoming light.

Now, imagine if each of the photodiodes had their own, individual color filters.
You still have a single pixel with a single microlens.
Underneath,  however, there are four individual color filters - one for each photodiode.
Here's the thing about the individual color filters: they don't have to be monochromatic R/G/B filters anymore.
Instead, you can use a combination of di/poly-chromatic filters, from which you can derive the overall pixel color.
And instead of deriving a single R/G/B color, as in a bayer sensor, you derive all three primary colors.

In summary, if you have a single, monochromatic filter for the entire pixel, you can only get one color per pixel (either R, G, or B).
But if you use individual di/poly-chromatic filters for each photodiode, you can derive all three primary colors per pixel (R+B+G).
Plus, you have a more sensitive/efficient pixel, as di/poly-chromatic filters by definition are filtering-in more light than a monochromatic filter.

Hopefully I'm able to communicate the point.

Back to the topic of extra resolution:
The increase in resolution comes from the fact that you have all three primary colors per pixel vs the single color per pixel in a beyer sensor.
Admittedly, the resolution increase is not all that big - but it's still an increase.
(Sigma/Foveon fans will tell you that it is a significant increase 8) ).

Think about all those things.
You seem to be dismissing the quad-photodiode tech - seemingly without fully realizing its potential.
If you believe that Foveon is better than Bayer, just consider that a quad-photodiode design with individual non-bayer color-filters (one per photodiode) is a better solution that Foveon.

Finally, even if you are still not convinced that the 70D sensor is a quad-photodiode sensor, consider that going from dual-photodiode to quad-photodiode is the next evolutionary step of this design - for all the reasons outlined above.

The simple fact is that a bayer sensor throws away 2/3 of the incoming light.
And the seemingly low-hanging fruit for improving sensor efficiency is to throw away less light.
Foveon is just one solution to the problem. There will be others soon.

Regards

34
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 02, 2014, 08:58:49 PM »
We’re told by a few other people that Canon is working on a “foveon like” sensor for their next generation of full frame cameras.

Any sensor expert can testify that Foveon is an impractical technology.

At the same time, Canon's has its own 'dual pixel' tech, which has a lot of potential and room to improve. 
So, why would Canon go chasing Foven when they already have a new, promising technology in-house ?? 

This Foveon rumor is totally fake. 

35
EOS Bodies / Re: New DSLR and PowerShots in May [CR2]
« on: April 02, 2014, 10:43:44 PM »

36
EOS Bodies / Re: New DSLR and PowerShots in May [CR2]
« on: April 02, 2014, 12:04:22 PM »
I really hope that Canon doesn't release another rebel series dslr.. I still see t3i being sold and don't even see the t4i much and even less of the t5i.  the price differences are so minimal now too.  Just stop.  lol 

Heh. That's precisely why a new Rebel makes sense.

Canon now has two entry-level Rebels - the new T5 and the SL1. Both are $500 models, basically.
To charge a premium for the higher-end Rebel, Canon needs to better differentiate it from the entry level models.
Hence, it makes the most sense for Canon to update the 700D/T5i next. Probably with the 70D sensor and video features.

37
EOS Bodies / Re: Suggestions of a NAB 2014 DSLR Announcement [CR1]
« on: March 03, 2014, 09:39:31 PM »
The most likely candidate for a NAB announcement is a C100 successor, IMO.

Canon will put the 70D's dual-pixel AF in some of their camcorders eventually - and the first one will most likely be the C100 successor.
The C300 and C500 are higher-end models, where AF is arguably less valuable.

It doesn't seem likely that a new DSLR will be announced at NAB.


38
EOS Bodies / Re: Is Dual Pixel Tech Coming to the EOS 5D Mark III?
« on: March 01, 2014, 01:36:02 AM »
Didn't Chipworks or someone already do an analysis on the 5D Mk III CMOS? I feel like they would have noticed something like this.

Edit: Yeah, they did. Here's a link: http://www.chipworks.com/en/technical-competitive-analysis/resources/blog/full-frame-dslr-cameras-canon-stays-the-course/


Yup. The 5DIII sensor has been under the microscope (literally) - and no, no dual pixels under the hood.

The poor guys at Planet5D should have done their homework rather than daydreaming.
Ignorance is bliss, indeed.

39
Canon General / Re: $4 Million Photograph
« on: February 24, 2014, 09:12:45 PM »
What makes this photograph worth $4,338,500 (other than the obvious fact someone was prepared to pay that amount for it)?





It's valuable because it's a piece of (art) history.


For the same reason, this Jasper Johns painting has sold for $110 million:




Source: http://www.theartwolf.com/10_expensive.htm

40
EOS Bodies / Re: Patent: Canon Curved Aperture Diaphragm
« on: January 27, 2014, 11:11:50 AM »
If I’m reading this correctly, if the aperture follows the curvature of the glass you end up by saving some space ...

Yup. Presumably for pancake lenses.

41
Pricewatch Deals / Re: Deal: EOS 70D Body $949 at B&H Photo
« on: December 10, 2013, 11:01:30 PM »
Deal: EOS 70D Body $949 at B&H Photo

Same for Amazon.

Going forward, the price will surely get even lower.
$950 is already a good price, though.

The DSLR market has become a buyer's market.
So, the prices, they will fall  8).

42
Next year is a Photokina year and it would be very surprising if Canon doesn't have anything to announce for the show.

By the look of things, the 5DIII/6D split of the 5D-series was somewhat rushed - without a unified vision/strategy behind it.
So, my expectation is that Canon will be working to address that.

The most likely candidate for Photokina announcement is the 5DIV, IMO.
Probably with more megapixels (~30?) and modern amenities like WiFi and dual-pixel AF.

Canon needs this update in order to keep charging $3500 for the 5D series - while leaving room for better specs in the 6D successor, which should arrive sometime in 2015.
With a properly differentiated 5DIV, the 6DII won't need to be crippled, like the 6D is.
So, it should be a pretty compelling offering, without stepping on the 5DIV's toes.

In parallel, Canon will be definitely developing a high-resolution sensor that will be used for 4K video and high-resolution stills.
I can't tell which camera will have this sensor, though.

I don't see the 1DX/1DC getting updated at lest until 2016.
At the same time, I don't see Canon waiting that long without a high-resolution camera either.
So, not sure what they will do at the end.

43
I just don't want to spend a significant amount of money and be disappointed by a quirky AF behavior.

Well, the 6D has what is effectively a 1-point AF system.

I haven't heard about any quirks related to the center AF point, which is supposed to be very good.
Lots of quirks, OTOH, when using the outer AF points (e.g. not able to focus).

So, get the 6D and use it in single-AF-point mode only. You surely won't be disappointed. 
Well, except that the 6D doesn't have more AF points like the center one  8).
Good luck.

44
EOS Bodies / Re: EOS 7D Mark II Spec List Surfaces [CR1]
« on: October 27, 2013, 10:12:42 PM »
Scepticism aside, I wonder how Canon will be able to place a 7D MkII in its current product line?

+1

With FF cameras now selling for $1700-2000, I just don't see Canon coming up with a 7DII.
There's just no place in the lineup for it.

45
EOS Bodies / Re: 6D Mark II
« on: September 20, 2013, 01:30:22 PM »
the 6Dmk2 would be built close to 5D3 while retaining its small size and multi-directional dial (whatever you call it).

The problem with the 6D is that it was apparently conceived when the 5DIII specs were frozen.
So, not much breathing room for Canon to give it proper specs.

Going forward, I'm not sure that the 6DII will be build close to the 5DIII.
I do expect, though, that the 6DII will be properly differentiated from the 5DIV - without having to be crippled.

We'll see what happens.
Body size (form factor in general) will surely remain a key differentiator between the two.

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