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2025-10-25

SunRace CSM901 WA1 12-speed 11-51T cassette

After deciding to switch to a 12-speed drivetrain, I began acquiring other components. In my opinion, the most important of these is the cassette.

My first choice was the SunRace CSM901 WA1 12-speed cassette (for [Shimano] HG freehub body of my rear wheel).




Its sprockets are 11-13-15-17-19-21-24-28-33-39-45-51 (teeth). 




The 51T sprocket is made of aluminum A7075.

According to my measurements, the cassette weighs 597g. This is about 110g heavier than the SunRace CSMX8 11-46T 11-speed cassette.

2025-10-23

Industar-26M 50/2.8: Samples [2] - FF - f/2.8

Camera: Sony a7c (FF, 24MP)
Lens: Industar-26M 50/2.8 at f/2.8

This is my second copy of the Industar-26M lens. I took it from the Zarya camera (1959). This copy is in better condition overall than the first one.








2025-10-21

Cannondale KP284: Derailleur hanger application (up to 2018)

According to the 2018 Cannondale TechBook, the KP284/ derailleur hanger is compatible with the following bikes:




Adventure - 2018-2017
Althea - 2018-2016
Bad Boy 2, 3, 4 - 2018-2016
Catalyst - 2018-2016
Contro - 2016-2015
Cujo - 2018-2017
Foray - 2018-2017
Kids Quicks - 2018
Kids Trail 20 & 24 - 2018
Kids Cujo 20 & 24 - 2018
Kids Race 24 - 2017-2014
Kids Trail 24 - 2017-2014
Kids Street 24 - 2017-2014
Law Enforcement - 2017-2016
Mavaro Neo 1, 3 - 2018
Quick - 2018-2016
Quick CX - 2018-2015
Quick Neo - 2018
Scarlet - 2018
Tango - 2018-2016
Tesoro Neo - 2018
Trail - 2018-2015

2025-10-19

Five Star 500/8 + Pentax Q: The Moon

The longest focal length lens that I have is the Five Star 500/8. It was interesting to test this cheap lens with the Pentax Q. The Pentax Q has a tiny 1/2.3" sensor with a crop factor of ~5.6x, so 500mm will be equivalent to ~2800mm!

As a subject, I chose the Moon.


f/11, 1/125, ISO 125 (Looney 11 rule)

This image has not been cropped, only resized. The result is not perfect due to noise and a lack of resolution, but it's still nice.



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2025-10-17

Shimano RD-M8100-SGS (Deore XT): 12-speed rear derailleur

This is a 12-speed rear derailleur.




It is the Shimano RD-M8100-SGS (Deore XT).




It can handle a maximum sprocket size of 51 teeth.




Unlike the Shimano RD-M8000-GS, the H/L adjustment screws are arranged in a more typical layout.




The Shimano RD-M8000-GS weighs 283g.

Initially, I wanted to use this 12-speed derailleur with the other 11-speed Shimano components on my Cujo 1 (they are unofficially compatible). I wanted to change the Shimano RD-M8000-GS (11-speed Deore XT) derailleur because there was a lot of play in its connection to the hanger.  However, then I changed my mind and decided to switch to a 12-speed drivetrain completely.



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2025-10-15

2025-10-13

My Pentax Q lenses

All my Pentax Q lenses (including "Unique Lenses"):




From left to right:

Pentax Q 02 5-15/2.8-4.5 Standard Zoom

The total number of Pentax Q lenses was eight:




Two of them are missing: 

Pentax Q 06 15-45/2.8 Telephoto Zoom. I don't like zooms. And I don't like telephoto lenses. Also this lens is rather unreliable.

Pentax Q 08 3.8-5.9/3.7-4 Wide Zoom. This lens is more interesting. However, it is too expensive and rare.

2025-10-11

Motorola Edge 50 Pro: Main camera DCP file for ART/RT (download)

The JPEGs produced by the Motorola Edge 50 Pro are terrible, so I mostly shot in DNG. I created a dual illuminant (StdA + D50) profile (DCP) for the ART and RT raw converters. It is based on my shots of the Calibrite ColorChecker Classic Mini. See details: ColorChecker, DCamProf, ART/RT

Download file (2025-10 version): edge50pro-main.dcp (64KB)

1. This DCP is for the main (wide angle) camera only. I don't use the other cameras due to their bad quality, so I even didn't try to create profiles for them.

2. The DCP contains the Base table only. I removed the Look table because it hinders highlight recovery.

3. There is no suitable JPEG preview in DNG files, so the Auto-Match Tone Curve doesn't produce anything. You should use a custom tone curve instead. Or, at least, choose the Smooth S-shaped base curve.

4. The colors may not be as saturated as you expect. You can adjust the Saturation/Vibrance to your liking.

Here are some samples with the default settings from the ART raw converter. The only exceptions are that the Custom (DCP) setting is used instead of the Camera standard setting, and the Smooth S-shaped base curve is chosen.




2025-10-09

Cannondale Cujo 1 (2018): New grips again

I have already replaced the handlebar grips on my Cujo 1 (2018), but they have worn out again, so it is time to replace them again.




These are some unknown lock-on grips that go by several names.

2025-10-07

Pentax Q 01 8.5/1.9 Standard Prime: Samples [1] - 1/2.3" - f/1.9

Camera: Pentax Q (1/2.3", 12MP)
Lens: Pentax Q 01 8.5/1.9 Standard Prime at f/1.9; The profiled lens (distortion/vignetting) correction is disabled.

I am slightly disappointed with this lens. I expected better resolution from a standard prime lens. However, the poor resolution may be due to the 1/2.3" sensor. There is also noticeable distortion and purple fringing.










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2025-10-05

ColorChecker, DCamProf, ART/RT

I have the Calibrite ColorChecker Classic Mini target. Using DCamProf, I created some color profiles for use with the ART (RT based) raw converter. I will share my experience.

The overall workflow is described here: How to create DCP color profiles


1. It is crucial to avoid overexposing the highlights in color checker pictures. That was my main problem. You can use the Raw Histogram of ART/RT to check the highlights. Take a lot of pictures with different exposures and then select the best one.

2. In real life, it is often sufficient to use a single D50 illuminant color profile.

3. On my Linux system, argyll-scanin is called scanin (installed from the argyll package).

4. The path to the ColorChecher.cht file is also different: /usr/share/color/argyll/ref/ColorChecker.cht

5. X-Rite/Calibrate changed their formula in ColorCheckers produced November 2014 and later. cc24_ref.cie (from DCamProf) is for targets produced before November 2014. While cc24_ref-new.cie is for targets produced November 2014 and later. Therefore, I use the cc24_ref-new.cie file.

6. You can try the -s option with make-profile to use an alternate optimization algorithm.

7. Pay attention to the DE values in the make-profile result report. In my experience, they should not exceed 5. If the values are too high (10+), take another picture of the color checker.

8. It is better not to use an embedded tone curve for ART/RT. So I use the -t none option with make-dcp, and disable the "Look table" in ART/RT.

9. I also prefer to completely remove the "Look table" from a dcp file. I use the dcp2json and json2dcp commands of DCamProg; in the intermediate JSON, I remove the "ProfileLookTable" field.

10. Do not use the HueSatMap 3D (the -D option with make-dcp). In some cases, it can worsen highlight recovery in ART/RT.

2025-10-03

Angarsk: 7 views from 1956 (and 2025)

This is a small postcard titled "Виды Ангарска" (Views of Angarsk, 7 photos) from 1956. Also, see the postcard (11 photos) and the postcard (10 photos) from 1956.




The views themselves are tiny, about the size of a postage stamp, so the resolution is low.

I've also included similar views that I took in September 2025.

Disclaimer: My photographs are nothing more than a documentation of reality.

1.




2. Дворец культуры (a palace of culture).
.




3. Проспект Ленина (Lenin avenue).





4. Гостиница "Саяны" (Sayan hotel).





5. Иркутский техникум жидкого топлива (Irkutsk liquid fuel technical college); кинотеатр "Победа" (Pobeda/Victory сinema).





6. Улица Олега Кошевого (Oleg Koshevoy street).





7. Центральный проспект (Central avenue).






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