bclaff

Lives in United States Metro-West Boston, MA, United States
Joined on Nov 4, 2006

Comments

Total: 33, showing: 1 – 20
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In reply to:

windplr: Is it possible that the test camera has some early pre-release firmware that is causing such poor performance? In any case will be interesting to see if production units are the same.

A common question but the answer is "no".

Link | Posted on Jul 21, 2017 at 05:42 UTC
In reply to:

matthew saville: To be fair, I don't think *ANY* Canon FF sensor, to date, has *EVER* surpassed the half-dozen top-ranked Nikon DX sensors for ISO 100 dynamic range.

The DxOMark numbers are not a good measure (for example they put the D7200 ahead of several Nikon FF cameras!).
Naturally, I use my own numbers.
By those I see only the D7200 and D7500 ahead, not a "half dozen".
In any case, we're wandering off topic I think :-)

Link | Posted on Jul 20, 2017 at 06:15 UTC
In reply to:

matthew saville: To be fair, I don't think *ANY* Canon FF sensor, to date, has *EVER* surpassed the half-dozen top-ranked Nikon DX sensors for ISO 100 dynamic range.

I think you'll find the Canon EOS 5D Mark IV and the Canon EOS 1D X Mark II meet that criteria.

Link | Posted on Jul 20, 2017 at 06:04 UTC
On article Should I buy a Canon EOS 6D Mark II? (443 comments in total)
In reply to:

Pavel Matousek: regarding Dynamic range (the most important factor in my opinion) - today DxO data
http://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%205D%20Mark%20IV,Canon%20EOS%206D%20Mark%20II,Canon%20EOS%2080D,Nikon%20D610,Nikon%20D750

OTOH, although I'm slightly biased, I think it's better than DxOMark data :-)

Link | Posted on Jul 20, 2017 at 04:42 UTC
On article Should I buy a Canon EOS 6D Mark II? (443 comments in total)
In reply to:

Pavel Matousek: regarding Dynamic range (the most important factor in my opinion) - today DxO data
http://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%205D%20Mark%20IV,Canon%20EOS%206D%20Mark%20II,Canon%20EOS%2080D,Nikon%20D610,Nikon%20D750

FWIW & FYI: DxOMark has not published any Canon EOS 6D Mark II measurements; that's from PhotonsToPhotos :-)

Link | Posted on Jul 20, 2017 at 03:31 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)
In reply to:

noirdesir: Lloyd Chambers of diglloyd nicely shows a regular pattern noise (repeated every 12 rows) in the red channel: https://diglloyd.com/blog/2017/20170525_2056-Sony_A9-PatternNoise-at-ISO100.html

@noirdesir, he claims 12 pixels high not every 12. But in any case I see it in every channel pretty much equally, not just in the red.
http://www.photonstophotos.net/Charts/Sensor_Heatmaps.htm#mode=46,camera=Sony%20ILCE-9,suffix=14

Link | Posted on May 31, 2017 at 13:06 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)
In reply to:

noirdesir: Lloyd Chambers of diglloyd nicely shows a regular pattern noise (repeated every 12 rows) in the red channel: https://diglloyd.com/blog/2017/20170525_2056-Sony_A9-PatternNoise-at-ISO100.html

Jim Kasson and I have both confirmed Fixed Pattern Noise (FPN) for the ILCE-9 (A9) particularly at low ISO.
You may want to visit:
https://www.dpreview.com/forums/thread/4162649
as well as Jim's blog (links in the thread)

Link | Posted on May 31, 2017 at 04:07 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)
In reply to:

solarider: Nice info!
I'd like to compare with Pentax K-1, but don't see K-1 in the drop down menus.
Thanks.

Really ?
http://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%201D%20X%20Mark%20II,Nikon%20D4S,Pentax%20K-1,Sony%20ILCE-9

Link | Posted on May 30, 2017 at 20:10 UTC
On article Sony a9 Full Review: Mirrorless Redefined (2726 comments in total)
In reply to:

solarider: Nice info!
I'd like to compare with Pentax K-1, but don't see K-1 in the drop down menus.
Thanks.

You can see a comparison of Photographic Dynamic Range at PhotonsToPhotos:
www.photonstophotos.net/Charts/PDR.htm#Pentax%20K-1,Sony%20ILCE-9

Link | Posted on May 30, 2017 at 18:46 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)
In reply to:

bclaff: For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

Well, the article does say "We've taken an initial look" and my PDR values are estimates so it's hard to say for sure and we'll know better when more data is available.
FWIW, I'd say that even the existing numbers I have put the cameras pretty close together down to ISO 200 or 250.

Link | Posted on May 19, 2017 at 22:41 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)
In reply to:

bclaff: For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

Rishi,
Regarding the semantics of "about the same" and "won't reach A7RM2 levels". "About the same" could mean "less than but not by much".
I see no inconsistency.

Note that PDR is not a function of EDR (unlike DxOMark); so that reasoning does not apply.

Note that based on the estimated value the A9 is no more than 0.8 EV below the A7RM2 and that gap is likely to shrink with final numbers.

Regards,

Link | Posted on May 19, 2017 at 19:38 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)
In reply to:

bclaff: For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

That doesn't relate directly to dynamic range. It's a visual test for ISO Invariance that is largely affected by whether the noise sources are upstream or downstream of the amplifier.
On my site the best tool for determining ISO Invariance is:
Shadow Improvement of Photographic Dynamic Range versus ISO Setting
http://www.photonstophotos.net/Charts/PDR_Shadow.htm
(The A9 curve is a bit lumpy right now with the estimated values.)
and PDR is best for dynamic range.

Link | Posted on May 19, 2017 at 19:03 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)
In reply to:

bclaff: For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

Not sure what you're trying to accomplish. My PDR estimates don't relate directly to ISO Invariance.

Link | Posted on May 19, 2017 at 18:17 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)
In reply to:

bclaff: For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

Rishi, not exactly sure what you're asking. The A9 is pretty close to the A7RM2 at all ISO settings estimated except at ISO 100 where it's currently 0.80 lower. My experience is that my estimates tend to be low, especially at low ISO settings; so I expect that gap to narrow. But my initial impression is that below ISO 640 the A9 won't reach A7RM2 levels.

Link | Posted on May 19, 2017 at 17:51 UTC
On article Sony a9: more speed, less dynamic range (666 comments in total)

For those who may be curious I have revised the estimated Photographic Dynamic Range (PDR) available at http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D5,Sony%20ILCE-7RM2,Sony%20ILCE-9(estimate)
Still looks like the A9 is on track for having about the same PDR as the A7RM2.

Link | Posted on May 19, 2017 at 12:25 UTC as 46th comment | 11 replies
On article Canon EOS-D30 Review (10 comments in total)

Would be fun to do a sensor test on this for historical reasons
(I have Nikon tests back to the D1).
If you still have a D30 and are willing to collaborate, get in touch.

Link | Posted on May 5, 2017 at 15:24 UTC as 1st comment
On article Hasselblad X1D-50c First Impressions Review (316 comments in total)
In reply to:

bobn2: If the GFX50S and X1D have the same sensors then they have the same ADCs, because it's a Sony Exmor design with the ADCs on the sensor. I'm wondering whether the innards of the two might not be very similar, and possibly also the lenses - the H cameras have a lot of Fulifilm in them and Hasselblad's lenses are Fujifilm.

I has been demonstrated by mathematical modeling as well as by read noise measurements on many other cameras that quantization is not a measurement issue until read noise in Digital Numbers (DNs) drops well below 1 DN. (This includes the Nikon D810)

At 14-bits the X1D the read noise would still be about 1.6 DN, below the 1.9 DN figure for the GFX 50S but still well above 1 DN. 14-bits would be enough for the X1D and it's unclear to me why they went with 16-bits.
Your conjecture that the improved read noise for the X1D is better than the GFX 50S due to ADC bit depth is unfounded.

I'm not an EE but I know there are many other factors in the external circuitry and firmware that could affect read noise.
My conjecture would be slower read-out on the X1D versus the GFX 50S; we have measured this effect before on some cameras that support both 12-bit and 14-bit read-out.

Link | Posted on Apr 5, 2017 at 14:13 UTC
On article Hasselblad X1D-50c First Impressions Review (316 comments in total)
In reply to:

dbateman: A 0.08EV advantage sounds to me like you need to look at 10 cameras from Fuji and 10 cameras from Hasselblad. I bet with in the brand you would see a 0.08 EV difference. Ie your within your error for looking at the exact same thing!

Yes, 0.08 is barely within the accuracy of the Photographic Dynamic Range (PDR) test. A slight variation on data collection or sample variation could explain such a small difference. Certainly there is no photographic consequence.

Link | Posted on Apr 4, 2017 at 15:46 UTC
On article Hasselblad X1D-50c First Impressions Review (316 comments in total)
In reply to:

bobn2: If the GFX50S and X1D have the same sensors then they have the same ADCs, because it's a Sony Exmor design with the ADCs on the sensor. I'm wondering whether the innards of the two might not be very similar, and possibly also the lenses - the H cameras have a lot of Fulifilm in them and Hasselblad's lenses are Fujifilm.

Bob, you're very knowledgeable about these things.
Are we sure that all the ADC is on chip and none is external?
Could bit-depth be select-able via firmware?
In any case, 14-bits would be sufficient to capture read noise at even the lowest ISO setting so I wonder if the 16-bit choice was just convenient.

Link | Posted on Apr 4, 2017 at 05:18 UTC
On article Hasselblad X1D-50c First Impressions Review (316 comments in total)
In reply to:

Class A: Your comment about not losing dynamic range when increasing ISO does not make sense at all.

Please look up the definition of ISO. Please look at dynamic range charts published by DxOMark.

The only way to not lose dynamic range would be to not push in post-processing, meaning that you don't effectively increase the ISO value.

The same effect can be achieved by just using any other camera with an "ISO-less" sensor and shooting it at base ISO or at least below the intended final ISO. This gives one highlight protection if needed and all the effective ISO required (up to blowing out highlights).

You are creating a difference between a "traditional camera" and this Hassy, which simply does not exist. I'm sure not even Hasselblad would support your very strange statement.

Regarding dynamic range; here we are tripped up by semantics.
The ISO setting controls two things, exposure and the downstream processing of the sensor.
Above the ISO 1600 setting the downstream processing remains at ISO 1600 while exposure respects the ISO setting.
So no dynamic range is lost, you simple underexpose more and more.
This is what many people do manually when they have an ISO Invariant sensor; so it's nice to see the camera taking care of it for us.

Link | Posted on Apr 4, 2017 at 05:15 UTC
Total: 33, showing: 1 – 20
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