ND4 filters

Even with modern digital cameras, neutral density (ND) filters are useful for recording video. Since I rarely record video, I mostly use ND filters with film cameras. This is because the maximum shutter speed of film cameras is usually [very] slow.

The ND4 filters I use most often have a M52x0.75 mm thread. I also use filter step-up adapters.

One of these is an old ND4 filter made in the USSR.

Another is a modern ND4 filter made in China.

Both filters have a slight color cast (they are not actually neutral). However, I shoot with B&W film, so the cast is not visible.

See also related notes:

• Filter thread: 40.5x0.5 vs 40.5x0.75 (2024-09-13)

Image albums:

• Lens accessories

Motorola Edge 50 Pro: Android 16

My Motorola Edge 50 Pro stuck on Android 15. When I checked for updates, it still showed that there were none available.

So, I decided to use Software Fix (for PC) to update the phone. Checking by IMEI showed the long-awaited update to Android 16.

Despite the warnings, the "Do not erase my data" option was available.

The update went well. Now, I can use Android 16.

Maybe SZ Viewer will be updated to target API level 36 (Android 16), while retaining the features of A1-2025-01-07 (I didn't make any changes).

See also related notes:

• Motorola Edge 50 Pro (2025-04-01)

Image albums:

• Android

Pentax K 50/1.4: Samples [3] - FF - f/1.4

Camera: Sony a7c (FF, 24MP)

Lens: Pentax K 50/1.4 at f/1.4

Image albums:

• Pentax K 50/1.4

Fillmore tubeless valves

This is the fifth type of tubeless value I want to try (1, 2, 3, and 4).

This valve is unusual. It is Presta-compatible, but has a different design without standard internal removable core.

Each valve weighs 6g with the cap.

See also related notes:

• Бескамерные покрышки на Cujo 1: вторая попытка (ободная лента и вентиль) (2019-09-13)
• Бескамерные покрышки на Cujo 1: первая попытка (2019-06-11)

Image albums:

• Bicycle

Kiev-6S: Two prism finders

I have two prism finders for the Kiev-6S camera.

The first is an earlier model, with no electronics (non-TTL). The second has a built-in light meter (TTL).

The earlier (non-TTL) model is smaller and lighter:

Non-TTL prism: 332 g

TTL prism: 424 g (without battery)

I expected the non-TTL model to make focusing easier. In practice, however, I see no difference. I have difficulty focusing with both prism finders.

See also related notes:

• Kiev-6S: TTL light meter (2025-07-13)
• Kiev-6S: Budget medium format film camera (2025-06-11)
• 3RTs53 battery (2025-04-13)

Image albums:

• Kiev-6S

Philips 9@9++ (2026)

This is my first own GSM mobile phone (before, it was D-AMPS phones).

It's the Philips 9@9++. I bought it in 2004 for $133. And it still works.

Although it wasn't as convenient as Nokia phones at the time, it was more power-efficient. The 9@9++ could go a week without needing a charge. The phone body is also sturdy.

I even made a cable to connect the phone to a PDA to access the Internet (via GPRS).

See also related notes:

• Эх, мобильные телефоны... (2014-03-07)
• Philips (2009-11-16)

Image albums:

• Mobile

Pentax K 28/3.5: Samples [2] - FF - f/3.5

Camera: Sony a7c (FF, 24MP)

Lens: Pentax K 28/3.5 at f/3.5

See also related notes:

• Pentax K 28/3.5, K 30/2.8, K 35/3.5: опять к старой теме (2022-05-22)

Image albums:

• Pentax K 28/3.5

RockShox SID SL Base 3P 110mm: Installed

I installed the RockShox SID SL fork instead of the RockShox Recon RL fork.

The SID SL is noticeably lighter. The SID SL weighs 1570 g (with the uncut steerer tube, and including the axle). The Recon RL weighs 2200 g (with the cut steerer tube, and including the axle).

At the same time, the Recon RL has longer travel (120mm vs 110mm) and also allows for larger tires.

For example, the Recon RL has a lot of space for the Vittoria e-Barzo Trail 29x2.6. The SID SL can also accommodate this tire, but there is rather little clearance between the fork and the tire (with the i27 rim).

Anyway, I will keep the Recon RL and use it in the winter.

See also related notes:

• RockShox SID SL Base 3P 110mm (2026-05-07)
• Cannondale Cujo 1: Vittoria e-Barzo Trail 29x2.6 mounted (2025-12-23)
• Vittoria e-Barzo Trail 29x2.6 (2025-12-19)
• Koozer XM1850 (622x27) wheelset (2024-06-29)
• Cannondale Cujo 1 (2018): компоненты и спецификация (2018-10-14)

Image albums:

• Bicycle

Viltrox AF 28/4.5 (FE): Embedded profile

Some time ago, I complained that there is no profile embedded in the metadata of images taken with the Viltrox AF 28/4.5 (FE) lens. Recently, however, I noticed an enabled embedded profile for such images in ART.

I thought this was related to an ART update, but old ARW images still open without an embedded profile.

The reason is the new v1.11 lens firmware. With this firmware, the Sony a7c camera embeds the working lens profile.

Here are some examples.

Without correction:

Geometric only (almost invisible):

Geometric + Vignetting:

Without correction:

Vignetting only (it looks overcorrected):

See also related notes:

• Viltrox AF 20/2.8 & AF 28/4.5: Firmware updates (a7V support) (2026-02-27)
• Viltrox AF 28/4.5: Samples [1] - FF - f/4.5 (2025-02-02)
• Viltrox AF 28/4.5 (FE): Wide-angle pancake lens (2025-01-24)
• RawTherapee (2022) и ART (2022-03-30)

Image albums:

• Viltrox AF 28/4.5 FE

FTP Practice (~1999)

Practice using the FTP protocol: FTP: File Transfer Protocol

As far as I know, it's a rather old publication, from around 1999. Some of the information is still interesting today.

ISCO Iscovitar 50/2.8: Samples [3] - FF - f/2.8 + close focus (helicoid) adapter

Camera: Sony a7c (FF, 24MP)

Lens: ISCO Iscovitar 50/2.8 at f/2.8 

The close focus (helicoid) adapter was used instead of the built-in focusing mechanism. This reveals the true nature of the triplet.

See also related notes:

• ISCO Iscovitar 50/2.8: Samples [2] - FF - f/2.8 - Two types of focusing (2026-04-23)
• ISCO Iscovitar 50/2.8 (M42x1/45.5): Triplet with simple focusing mechanism (2024-05-21)
• Noname Leica M-Sony FE/E close focus (helicoid) adapter (2023-07-30)

Image albums:

• ISCO-Göttingen Iscovitar 50/2.8

RockShox SID SL Base 3P 110mm

My new bike fork: RockShox SID SL Base 3P (FS-SIDS-BSE3-D1) with 110mm travel. It is the cheapest version in the SID SL series. And 110mm is the longest travel (axle to crown 516 mm with 44 mm offset).

Some details.

It weighs 1570 g with the uncut steerer tube.

See also related notes:

• RockShox SID SL Base 3P 110mm: Installed (2026-05-15)

Image albums:

• Bicycle

Pentax Q7: SR and Live View

In my opinion, the Pentax Q7 is much better than the Pentax Q. But unexpectedly, the Pentax Q has one important advantage.

The Pentax Q7 lacks the ability to perform shake reduction (SR) during Live View!

The Pentax Q has the related SR option.

(Pentax Q's option)

The Pentax Q7 has no such option. SR only works during capture time.

This is important for manual focusing (with so-called "Unique lenses", for example). Although the Q7 provides more magnification for accurate focusing, the shaking during Live View with a long focal length lens is disruptive.

Even half-pressing the shutter button doesn't stabilize Live View. The goal is probably power efficiency.

See also related notes:

• Pentax Q7: Better, but still too specific (2025-11-13)
• Pentax Q "Unique Lenses" (2025-09-19)
• Pentax Q: Non-electronic lens support (2025-04-07)
• Pentax Q: Useless mirrorless camera (2025-02-14)

Image albums:

• Pentax Q (series)

Socks5: Non-standard commands

The Socks5 protocol is defined by RFC 1928. It includes three commands:

0x01: CONNECT

0x02: BIND

0x03: UDP ASSOCIATE

Also, there are some proprietary extensions that introduce new commands:

0x05: UDP IN TCP (by HevSocks5)

0xF0: RESOLVE (by Tor)

0xF1: RESOLVE_PTR (by Tor)

Pentax M 50/4 Macro: Samples [2] - FF - f/4

Camera: Sony a7c (FF, 24MP)

Lens: Pentax M 50/4 Macro at f/4

See also related notes:

• Industar-61L/Z-MC 50/2.8 and Pentax M 50/4 Macro (2023-04-15)

Image albums:

• Pentax M 50/4 Macro