Friday, June 22, 2018

Sigma 30mm f/1.4 EX DC HSM lens sample photos without pp.


A few days ago, I wrote about this lens - Sigma 30mm f/1.4 Nikon mount APS-C lens on full frame camera--Sony A7 @ May 29, 2018
And I talked about second-hand price which was inexpensive. So I will quote that part:
Quite cheaper way to get the f/1.4 lens.

In Korea, secondhand Sigma 30mm f/1.4 EX DC HSM lens was not expensive--about $106 to $130 US dollars, especially Nikon mount. And others like Canon, Alpha mount were more--but not so much.
And secondhand Sigma 30mm f/1.4 for Sony E mount costs around $280.

Other cheap way to get the 1.4 lens is old lens like Takumar 50mm f1.4 or Nikon/Canon 50mm f1.4 which is slightly cheaper than Sigma.
But when put this lens on APS-C camera, it became 75mm lens. Because of crop factor.


According to the Sigma 30mm f/1.4 EX DC HSM lens - Wikipedia web page, on APS-C sensor cameras, its filed of view equivalent to a 46mm lens. Or slightly more for other camera like Canon, older Sigma bodies.



Sigma 30mm f/1.4 EX DC HSM lens technical details:

type: Prime lens
mount type: Canon EF-S, Micro four thrids, Nikon F (DX), Pentax KAF, Sigma SA, Sony/Minolta Alpha
optical design: 7 elements in 7 group
aperture range: f/1.4~f/16
aperture blade: 8
minimum focus: 40 cm
filter thread size: 62mm
weight: 430g
length: 59mm


I don't much care about this technical details of lens. But sometimes it can be useful.
For example, if I already have 62mm uv filter or hood, I can use with this lens.
And I'm walking long hours when I do photo-walks. So if lens wasn't heavy, it was very suitable for me. That is the reason that I mostly shoot with prime lens.
So I do check those things from the technical details.


You can read more about the lens from here:



Sigma 30mm f/1.4 lens with cameras:

Sigma 30mm f/1.4 lens on Nikon D7000
Sigma 30mm f/1.4 lens on Sony Nex-5R
Sigma 30mm f/1.4 lens on Olympus E-P3


Photos of the lens that I used.
Sigma 30mm f/1.4 EX DC HSM for Nikon mount lens
Sigma 30mm f/1.4 EX DC HSM for Nikon mount lens



Technical notes:

These photos were all taken with handheld and I used Nikon G lens to Sony E mount or Micro four thirds adapter so I have no idea about aperture number for the photo.

When I am taking photos, I do use Raw file format. So I need to convert raw file to jpg file and during that time, I do some post-processing--this is kind of darkroom process in developing film.
And when I do this, I don't use any default setting from Rawtherapee--open source software because there has some image modification settings like sharpening, micro-contrast and among other things.
I don't use Adobe Photoshop but this also has same kind of default setting with sharpening.
This isn't important for photography. But this is about the lens--what kind of photo I can take with this lens. So sharpening won't help to know about the lens.


So when I do use Rawtherapee, I removed all the default setting.
I will do these adajustments, if necessary:
 - click the auto button in exposure tab--automatically calculate the exposure value,
 - adjust exposure value, if overall image was still dark or too bright,
 - adjust contrast(between 3 and 18) in L*a*b* adjustments tab,
 - if there have some areas were too dark or too bright which makes me feel unbalance the overall look, adjust the shadow/highlight value.
 - Sometimes, white balance set to auto or slightly reduce the temperature value. Because Sony A7's white balance value was quite terrible when I do use other brand lens--not Sony E mount lens.



Sample photos:

Nikon D90 with Sigma 30mm f/1.4 EX DC HSM for Nikon mount lens:
at the Bongeunsa (sa means Buddhist temple)


Solution for auto focus problem in Nikon DSLR camera.
If you have a Nikon D90 or D7000 and problem with auto focus, you can probably fix with adjust 'Fine tune' in lens setting.
quoted from Autofocus is useless with Nikon D7000 body? | Sigma 30mm f/1.4 EX DC HSM | Flickr
einsteinsmonster said:
I had the same problem with my D7000.
Works perfect on D90.
Fine tuned the lens to -8 and now it's spot on.
Fine tune + or - till your happy with it.



Nex-5R with Sigma 30mm f/1.4 EX DC HSM for Nikon mount lens:

at Seongnae 2 dong--Bukseongro, Daegu
It was 45mm so slightly wider than 50mm. I felt quite wider than 50mm lens.

near Dongsingyo, Daegu
near Dongsingyo, Daegu
at the Sincheongyo, Daegu






Olympus E-P3 with Sigma 30mm f/1.4 EX DC HSM for Nikon mount lens - Olympus E-P3 has crop factor of x2 so lens became 60mm lens.

Magpies in a tree.
near Sinseonggyo, Daegu




at the Sincheongyo, Daegu




P.S. If you'd like to read in Korean, you can read it from here--this is my Korean blog.

Sunday, June 17, 2018

answer--not physically destroy hdd, for erase data from a hard disk so no one can ever recover it.


Thinking about selling used hard drives.

Recently I bought external 2.5" hard disk drive because my external 2.5" hard drivers have low on free space. Copied all the data to new hard drive from old hard drives.
Now I have number of hard drivers--external 2.5" 500GB, 750GB and a few desktop PC 3.5" hard disks that no use. So I'm thinking about to sell it.

Before I'm selling, I needed to clean up the hard disk so no one can recover my personal data. I don't much have important data though--I have a lot of piece of writings and ideas. But I don't think people will understand what those a pieces of writing is for.
I know this because some of those ideas, I already wrote in my twitter or blogs but no one seems to understand what I am saying. So I don't much care about those.
But I have been learning photography so I have tons of photos which I'd like to erase it.

So I did googling and came across this--in Quora:
How do I erase data from a hard disk so no one can ever recover it? 


Why would you like to physically destroy hard disk which you spend a lot of money for?

Quite surprise to see so many answered with physically destroy the hard drive.

I thought -
Wow...wows!
Nowadays, everyone is sooo rich that everyone suggest to physically drilling, shredding the hard disk.
I'm not rich so I had to completely erase the data before selling.


I know the simple solution without physically destroying it.

I know how software works--because I was a programmer. So I know very easy and simple way. Download some software--bigger size will be better, useless documents or anything from the internet or your not important things like Netflix movie files. And delete all your data. And then copy the downloaded software, documents and all. And kept copy it(same files over and over--make folder to more easier--Windows will make new name for it like below screenshot) until hard disk became zero-ish byte of free space.
screenshot: overwrite files for make unrecoverable

So when the recovery software or professional try to store data from my hard drive, they will only recover those useless data.
It's THAT simple to permanently erase data.
Yes, it takes time. But it perfectly works.


Yes, someone answered what I suggested--overwrite data to remove personal data.
And someone saying that forensic analyse(or something) still can find a bit of information from there. Sure. That might be true.

That's why my solution makes more sense.

Because my personal data was already replaced by thousands, thousands and thousands of files.
That means forensic analyse take more, more and more time to figure out which bit of information connected to the which part of information. It's like thousands, thousands and thousands of jigsaw puzzles to figure out.
And it will be almost impossible because a lot of pieces were missing.

Loren Forslund answered very interesting one and I think it's very good method, too:
My method is using Ubuntu disks utility to break all partitions down and formatting the drive into one “FAT” partition. Now make 2 equal partitions and format them in EXT4 writing over the drive. Now break these partitions back to one NTFS partition over writing the disk. I’m sure if you had one million dollars worth of DOD equipment and 3 months of time you may get a scrap of something, but I doubt anything useful.


People watched way too much TV shows--CSI kind of TV shows.

Especially this part:
I'm sure if you had one million dollars worth of DOD equipment and 3 months of time you may get a scrap of something, but I doubt anything useful.
 - People were watched way too much TV shows
 - and they were way too much talk about this theoretical ideas.

Let's talk about reality.
I told you that I bought a external 2.5" hard disk which has 4TB space--actual size is 3.63TB.
So I put all my old data to this new hard disk..
screenshot: my external hard disk drive's files and folders

Last time, I had a lot of software and documents from the internet. But when I started taking photos, I had to delete those files because nowadays DSLR or mirrorless camera need bigger space to backup.
And other reason is I can always go online to get those software again.  So I don't need to kept in my hard drive.

So in my case, 50% of files(153,598 / 2 = 76,799 files) were probably personal data. But each photo was like 7 to 24 mega bytes only. I have software, downloaded documents, audiobook from Librivox and games and those were far more bigger size than photos.

So even if I have 50 to 70% of files were personal data(because photos I took), 40 to 80% of space were filled with not personal data. That means 40 to 80% of 0.98 tera byte.

That means if forensic analyse find a bit of information, it will quite likely not my personal data. For example, 70% of space were not personal data means:
other not important things - 1,003.52 giga byte * 70% = 702.464 giga byte
my personal data - 1,003.52 giga byte * 30% = 301.056 giga byte
Because my personal data was only 30% chance to picked up by forensic analyse.


And there has more. I have thousands of photos but do you think all of my photos were all very important photos--which I probably use it in my blog.
Photography is my hobby so technically it wasn't very important data.

Even if so, reality is this:
How many professional photographers really use all of their photos they took, do you think?

And how many people do you think they use their hard drive only for their important data?
Even if that's the case, why do they need 1 to 4 tera bytes of hard disk?

I have important documents but most of my documents(which I kept it in text file format--smaller than Word file format.) takes only a few kilo byte.
So I'm sure that a few giga bytes of hard disk should be enough for their personal--important data.



Reality of un-delete kind of software.

How I know this? Because about 10 or 15 years ago, I tried to recover my important data from un-delete kind of software with no success.
I can see the files with so many other files. But I can't recover it because it was already half destroyed--some new files already overwritten some part of those files.

You've known this, too. Good example is 'corrupted file'. Did you recover that corrupted file?


Reality is this:
Even if that forensic analyse find a bit of byte, what can you do with that part of byte?


It was 10 or 15 years ago experience so I have to check. And found this:
Recovering Deleted Files After Formatting: Is it Possible? | Deleted File RecoveryThere are many debates regarding the possibilities of recovering deleted files among computer scientists. All evidence points to the fact that in order to recover files deleted from recycle bin, or any other part of the operating system, they must not have been written over.

In order to recover a deleted file every sector that included data for that file must be in it’s original condition. Overwriting any part of this file with new data will cause corruption.


As you can see, this professional(??) data recovery company saying things were far different than what many people answered in Quora.
Professional data recovery company saying that they can't recover if it's already written over.
But many people in Quora saying that you can recover it--because you can find a piece of information with forensic analyse(or something). So you must do physically destroy hard drive--drilling, shredding, burning and among other physical way.

See the difference.


Even if you recover the part of file, you probably can't read--because of corrupted. But what many people in Quora saying is it can read--recover it.
* If you seen CSI kind of TV show, they can always recover it, don't they?
Yes, you can recover the random data. But do you think that random data is worth a million dollars with spent a few months or a year of work?



That's why I completely agree with what Loren Forslund said:
I'm sure if you had one million dollars worth of DOD equipment and 3 months of time you may get a scrap of something, but I doubt anything useful.


Reality is extremely different than what people were saying in internet, unfortunately.
This is how people kept getting more wrong ideas.



P.S. I found permanent file delete software:
They also explain same thing--overwrite to make unrecoverable.




Tuesday, June 12, 2018

No longer work on metered network to stop Windows 10 auto--force update!


Extremely forceful auto update in Windows 10 Home edition.

- Windows 10 Pro (and Enterprise) edition can easily block the auto update with group policy setting.


I was very irritated by Windows 10 update because it kept bugging me for restart.
So I had to find how to stop Windows 10's auto-update--I did this before about two years ago.

And I found two options:
One is set on metered network in wifi setting--turn on the "Set as metered connection".
Other one is change group policy settings. But this option is available for Windows 10 Pro and Enterprise edition. Mine is Windows 10 Home edition so I can't use this option.
* About two years ago, it wasn't possible to disable Windows 10 update service but now it might possible.

And luckily, I'm using wifi to connect internet so I did use first option.
You can see the screenshot for how I set the metered network:

screenshot - set the metered network in wifi setting

So I didn't get the update for quite while. About a month ago or a few months ago, I thought I needed update Windows Defender so I did use Windows update.

After that, at first I didn't notice much about this red circle with cross mark in Windows Defender Security Centre icon.
But about a month or two months ago, it kept showing the icon in taskbar like this:
screenshot - Windows Defender Security Centre icon

And then I just realise it that suddenly my mouse--actually, I'm using wacom tablet as mouse though, sometimes stuck--not responding like 5 to 30 seconds.
I thought this is because my computer--almost 10 years old laptop computer, was quite old so that is the reason that my mouse was not responding.

But it looks like actual reason is Windows 10 kept trying to update in metered network.
screenshot - auto update in metered network
It said:
Update settings
We'll automatically download and install updates, except on metered connections (where charges may apply). In that case, we'll automatically download only those updates required to keep Windows running smoothly.

So it will automatically download and updates in metered connections, too.

screenshot - awaiting restart in metered connections


I haven't try the disable windows update service yet. I have no other choice--I have to do that to stop auto update.


You can try some of things from here:





Stuck in a Windows 10 update loop - KB4088776

When I'm writing this, I realised that my problem is not only because of that reason. Those update numbers were very familiar--KB4088776.
It kept trying to install the update and then it kept failed like this:
screenshot - couldn't finish installing updates

I think I found solution for looping update of '2018-03 Cumulative Update for Windows 10 Version 1709 for x64-based Systems (KB4088776)' from here:



I'm not sure whether it will fix the problem but there have number of possible solutions so I think I might find a way.




P.S. Additional info. wrote at September 10, 2018:
My laptop computer's wifi network driver not working time to time, if I don't do the update for Windows 10--because metered network--partly blocked update.
Very strange happening--when it happened first time, I thought my laptop computer was too old because it's 8 to 10 years old. But it kept happening again. So I did update Windows 10 and it was okay. But three(or two?) month later it happened again. And just a few days--or a week ago, Windows 10 start showing warning of update. Very similar behaviour like first time.
Now I'm trying to update Windows 10 again. And I will write it again, whether wifi-issue was gone or not.

Additional info. wrote at September 14, 2018:
My guess was right. After update Windows 10, I am not getting wifi-network issues anymore.
So if I don't do Windows 10 update, I can't use internet.