Svarichevsky Mikhail - RSS feed http://3.14.by/ Svarichevsky Mikhail - RSS feed en-us Tue, 10 Jun 2006 04:00:00 GMT Sat, 22 Sep 18 07:09:03 +0300 3@14.by 120 10 <![CDATA[Sony a7III: Time for Full Frame 2 (and some PDAF striping/fake RAW)]]> http://3.14.by/en/read/ff-time-Sony-a7iii-a77ii-a7riii-fake-raw-pdaf-striping

6 months ago I ebayed Sony A7II and thought that It will be with me for a while. But life is full of surprises - seller did not sent me few missing parts, I returned the camera... and by that time A7III was already released. There are quite a few nice features - BSI sensor with higher sensitivity, very pleasant high-ISO noise reduction, flexible autoISO settings... Some like larger battery and dual SD slot.

For me personally flexible autoISO is what gave me largest increase of good shoots yield. Also, now camera allows one to see the photos in the buffer while buffer is flushing to SD card.



After I was spoiled by zooms during ancient A-mount era ( I had Sony 16-50 F2.8 lens - it was quite sharp in the center and versatile) - here I bought loved by many Sony 24-105 F4. It was well worth it - even sharper and obviously slightly wider zoom range. Size and weight is probably maximum suitable for casual travel. F2.8 full-frame zooms in my view are only for professionals who used to lug a lot of equipment.

Fake RAW/star eater issue is still there. You can read more here, and sign a petition to Sony here. I was also able to reproduce PDAF striping issue under very exotic lightening conditions - but this is a topic for a separate article.

At the end, I really like the camera. It will definitely stay with me until 60+ megapixel full-frame cameras with 4K/60P full sensor readout are available. We might have to wait until 2022 for that...]]>
Sun, 01 Jul 18 23:12:56 +0300
<![CDATA[Soldering practice KIT - HKT002]]> http://3.14.by/en/read/soldering-practice-HKT002-johnson-counter-CD4017-decoupling
There is an 555 which frequency is set by long chains of capacitors and resistors. CD4017 johnson counter to drive 10 LEDs.
These 10 LEDs are driven by BJT's with high hFE and diodes in the base circuit, so any surface contamination from flux would not allow them to turn off LEDs.

Highly recommend to anyone who needs to solder from time to time. If you're just starting learning - you will need at least 2 set and lots of spare parts.

Here is last glitch: You can see 3 LEDs could be lit at the same time by CD4017. Why could that be?


One cannot use CMOS digital IC without decoupling. After adding decoupling it is rock solid:
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Sun, 10 Jun 18 15:24:31 +0300
<![CDATA[Analog Devices AD9361 — when microelectronics is more profitalbe than drugs]]> http://3.14.by/en/read/AD9361-SDR-Analog-Devices-DAC-ADC-65nm still often an FPGA), external filters and PA if your task requires it.

Finally I was able to take a look inside and peek at manufacturing cost of a microelectronic device with such an exceptional added value.

After decapsulation we see 4336x4730 µm 65nm die. On top metal you can notice PLL's inductors and datecode - chip was somewhat ready 2 years before introduction:
Read more on zeptobars.ru →]]>
Fri, 25 May 18 10:33:02 +0300
<![CDATA[Weekend laser galvoscanner fun]]> http://3.14.by/en/read/weekend-laser-scanner





I exposed many cameras to direct laser beam many times in the past, but only now I got image sensor of my smartphone damaged (only color one, B&W sensor intact). That was quite puzzling at first, and probably I will need to write a short article later on on why some cameras are damaged by laser and some other (color) cameras are not.

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Mon, 07 May 18 03:27:09 +0300
<![CDATA[PaperBack - proper way of storing information on paper]]> http://3.14.by/en/read/paperback-paper-backup-timecapsule PaperBack made by Oleh Yuschuk.

While playing with it I was able to store ~500 KiB of data on a single side of A4, which could already have some practical use. This density is achieved at 300dpi data density, 80% dot scale (recommended value of 70% gave higher error rate) and 20% for ECC correction. For reliable recovery scanned image had to be slightly sharpened using Gimp2/unsharp mask, but it feels like this is the limit (ECC had to recover ~10% of errors). On 200/240dpi data density everything is much more reliable.

One can for example take a photo of the sheet using film camera and get data microfilms at home ))) Also, this data is easy to read even in distant future and does not depend on spefic reading hardware, so even aliens or humans 1000 years in the future who find a timecapsure with it would be able to read it...

Here is how data looks at 80dpi:


Closer:


Now data at 300dpi, maximum for 600dpi printer:


Even closer (square side is 2.97мм). One can see that using less than 2*2 pixels for 1 bit of data would require different recovery approach due to very high rate of errors which will be pattern-dependent. Paper fibers would also cause some issues as higher data densities.

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Mon, 18 Dec 17 00:19:42 +0300
<![CDATA[Olympus UPlanApo 10x0.4 WI - ultimate fun microscope lens]]> http://3.14.by/en/read/Olympus-UPlanApo-10x0.4-WI-water-immersion
Apparently I am a fan of water immersion. Last time when I've got 10x0.3WI lens I thought I am set for life. But recently I've spotted even more interesting lens on ebay: Olympus UPlanApo 10x0.4 WI. That would be my first apochromatic microscope lens. It's very large field of view and 0.4 aperture makes it ~1.8x harder to achieve uniform focus over the field comparing to 10x0.3 WI. But the information density is again ~1.8 times higher.

In the center of the frame new lens (on the left) is sharper due to higher aperture (0.4 vs 0.3):


At the edge we can see that lateral chromatic aberations are lower for APO lens (who knew?). Remainng lateral CA is probably caused by microscope's tube lens. I surely correct lateral chromatic aberration in software, but this lens makes it easier and cleaner.
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Mon, 11 Dec 17 03:46:03 +0300
<![CDATA[Sony a7II: Time for Full Frame (and some fake RAW controversy)]]> http://3.14.by/en/read/ff-time-Sony-a7ii-a77ii-a7riii-fake-raw
Finally I've bought my first full-frame digital camera - Sony A7II, on ebay as usual. While everybody were excited about A7RIII - I was quite disappointed: same sensor as in A7RII and still not solved fake RAW issue (it's there for all Sony camera's though). Why it is called fake RAW? Sony cameras has noise reduction algorithm which you cannot disable. It kicks in at long exposures and is applied even in RAW(!!!!), which completely ruins whole idea of RAW files (=direct stream of data from the imaging sensor for further advanced processing). The most obvious effect of this forced "noise reduction" is erasing 2/3 of the stars at the photos of night sky. You can read very detailed research of the problem here and you can also sign petition to Sony to finally fix it.

As my personal punishment to Sony I've decided to skip few camera generations: I will have fun in full frame with A7II for a while, just like 2 years ago I've started to get experience in E-mount with Sony NEX-5, which was ebayed for 110$. Hopefully some day they will release something like A9RII with 60mpix sensor and fixed fake RAW issue - this camera will be worth to buy new :-)

Glad that I did not ever bought full-frame A-mount camera (A900/A99 - it would have wasted much more money after re-sale), and a little bit sad that 3 years ago I've blindly bought Sony A77II instead of some E-mount camera (like a6000) which was already available at the time...

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Sun, 10 Dec 17 07:32:10 +0300
<![CDATA[Slicing ruby like butter]]> http://3.14.by/en/read/Slicing-ruby-like-butter-diamond-saw
Photo cannot show incredible fluorescence of Ruby at 692nm - longest red wavelength, almost infrared... Deepest and most intense red that human eye can see...


Ruby rod has to be glued to glass holder with expoxy/UV glue:


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Mon, 06 Nov 17 06:14:12 +0300
<![CDATA[Blade Runner 2049]]> http://3.14.by/en/read/blade-runner-2049 ]]> Fri, 06 Oct 17 10:58:40 +0300 <![CDATA[Is 16 terabytes Enough For Anyone?]]> http://3.14.by/en/read/ext4-16tb-raid6-resize2fs-64-bit
After routinely adding yet another 4Tb disk to RAID6 array and trying to resize ext4 partition I was puzzled by the message:
root@lbox2:/var$ resize2fs /dev/md1
resize2fs 1.43.4 (31-Jan-2017)
resize2fs: New size too large to be expressed in 32 bits
That was totally unexpected. EXT4 does not support partitions larger than 16Tb? It appeared that it did not up until somewhat recent time. 5 years ago that would have been a brick wall, 2 years ago I would have to wrestle a little with bleeding edge resize2fs/kernel and now it all works on-the-fly out of the box. One just need to convert this ext4 partition to 64-bit format:
root@lbox2:/var$ resize2fs -b /dev/md1
resize2fs 1.43.4 (31-Jan-2017)
Converting the filesystem to 64-bit.
The filesystem on /dev/md1 is now 3907015424 (4k) blocks long.

root@lbox2:/var$ resize2fs /dev/md1
resize2fs 1.43.4 (31-Jan-2017)
Resizing the filesystem on /dev/md1 to 4883769280 (4k) blocks.
The filesystem on /dev/md1 is now 4883769280 (4k) blocks long.

root@lbox2:/var$ mount /var/bigfatdisk

root@lbox2:/var/bigfatdisk$ df . -H
Filesystem      Size  Used Avail Use% Mounted on
/dev/md1         20T   14T  5.9T  71% /var/bigfatdisk

xy@lbox2:~$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md1 : active raid6 sdf1[0] sdg1[7] sdh1[6] sdc1[5] sdb1[3] sde1[2] sda1[1]
      19535077120 blocks super 1.2 level 6, 128k chunk, algorithm 2 [7/7] [UUUUUUU]
      bitmap: 1/466 pages [4KB], 4096KB chunk, file: /var/md1_intent.bin

unused devices: <none>



I remember in the late 90's i've been to ftp.cdrom.com - it had enormous 0.5Tb array: it felt like absolutely insane volume of data (I had 850Mb HDD at the time). Probably readers of this article in 2037 would have 1024-layer 3D phase-change memory with 64Tb in 2.5" drive. Good for you, readers from the future... Although it is also possible that popularization of online-content, streaming and cloud apps will make it almost obsolete to have large local storage (with a few exceptions).

BTW since I went for softraid at home about 8 years ago - I had not a single HDD failure (about 50 hdd-years). Still pays off - much less worries about at least 1 thing... ]]>
Tue, 26 Sep 17 23:47:54 +0300