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The Pentacon 30/3.5 and Pentax M42-K Adapter

The Pentacon 30/3.5 has M42x1 mount, but mounting it on a Pentax K camera with a standard adapter is problematic.

This lens has a very narrow flange that touches the adapter only.

The lens on the adapter does not rest on the K-mount flange of a camera. This causes play (backlash) of the lens on the camera.

I encountered this when trying to use the Pentacon 30/3.5 on a Samsung NX camera. I didn't have any M42x1 to NX adapters left, so I combined M42x1-K and K-NX adapters. Because of the lens play, it was noticeable that the focus plane moved. This may be the reason for the complaints about the image quality of the Pentacon 30/3.5 on Pentax cameras.

Of course, it is possible to use the Pentacon 30/3.5 with a flanged Pentax K adapter, but it won't focus to infinity.

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Yaesu VHF radio stations

For off-road competitions and team trips I needed a VHF radio station, so in 2010 I bought a Yaesu VX-170.

Then I had the idea to use a stationary station instead of the VX-170, so I bought a Yaesu FT-1900:

But the FT-1900 was not installed stationary [in the Suzuki Jimny], it was rarely used as a "portable" station with external power supply (through a connector).

It has been a long time since I have taken part in an off-road competition. And now I do not participate in team trips and do not plan to join any. So I have sold both Yaesu radios. Only simple LPD radio stations are left for local communication.

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Holga HL(W)-SSN 29/8: Samsung NX10 and springtime

I remembered the Holga 29/8 lens. And I photographed spring nature, but not with the full-frame Sony a7c (which makes no sense), but with the native Samsung NX10.

The Samsung NX10 is not good for manual focus. Only a 2x magnification on the low resolution screen/viewfinder. I practiced first and then used "scale" (symbol) focusing.

As mentioned, the Holga aperture is slower/darker than the claimed f/8. I think it's about f/20. But it is possible to remove the aperture plates and get close to f/8: Modifying a Holga DSLR lens to really be f/8

But then the specific vignetting would be lost. I haven't decided yet.

By the way, I've been trying to find a Holga 25/8 for the Sony E on sale, but it's hard. Although versions for the NX and 60mm for Canon/Nikon/Olympus DSLRs are still available. Holga cameras, lenses and other accessories have not been produced since 2015.


Febi 31942: application for lenses

I tried Febi 31942 as a lens grease.

1. Febi feels more viscous.

2. But the backlash of the focusing mechanism is the same as with GM.

3. The rotation of the focus mechanism is slightly uneven.

4. There is a smell, specific but weaker than with GM.

5.  I have not tested the operation in cold weather.

Overall, I don't like it very much, but it can be used if you have nothing else.


Angarsk: 8 photo card set from 1974 (and 2023)

Angarsk photos from 1974: 8 cards and 2 covers. I added my 7 photos of the same places taken in early spring 2023 (no leaves on the trees yet for better visibility).

Cover-1: Ангарск. Первые высотные (Angarsk. The first high-rises)

Cover-2: Дворец пионеров (A young pioneer palace)

1. Проспект К.Маркса (Karl Marx Prospect)

2. Политехнический институт (Polytechnic Institute)

3. Спортивный дворец (A palace of sports)

4. Старинный Московский тракт сегодня (The old Moskovsky Trakt today)

(I know the road, but I can't locate the exact viewpoint)

5. Дом культуры "Современник" (House of culture Sovremennik/Contemporary)

(2023 photo will be soon, I hope)

6. Из школы в морозный день (Out of school on a frosty day)

7. Городской сад. Встреча (A town garden. Meeting)

8. Окрестности города (Surroundings of the town)

(The hill and a small river? I don't know where it is)

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Samsung NX by megapixels

Samsung NX mirrorless cameras (2010-2015) grouped by the number of megapixels.

14.6MP APS-C

Samsung NX10 (2010)
Samsung NX5 (2010)
Samsung NX100 (2010)
Samsung NX11 (2010)


Samsung NX200 (2011)
Samsung NX20 (2012)
Samsung NX210 (2012)
Samsung NX1000 (2012)
Samsung NX300/NX310 (2013)
Samsung NX300M (2013)
Samsung NX1100 (2013)
Samsung NX2000/NX2020/NX2030 (2013)
Samsung Galaxy NX (2013)
Samsung NX30 (2014)
Samsung NX3000 (2014)
Samsung NX3300 (2015)

20MP 1"

Samsung NX Mini (2014)


Samsung NX1 (2014)
Samsung NX500 (2015)


TrendVision TDR-719S: date-time and GPS module

I have been using the TrendVision TDR-719S dash cam since 2016. Not so long ago, it started erasing the settings. And now it occasionally resets the date and time.

The TDR-719S was supplied with a dedicated GPS module:

It should be connected between the power cable (microUSB) and the dash cam itself. I initially did not install it because I did not need the GPS features (speed/location on video, speed cameras alert). Now I had to install it, but only for the automatic date and time synchronization.

There is no problem with Week Number Rollover (WNRO), the date is correct.

This dash cam is very problematic, I only put up with it because of the good video quality.


Noname Pentax K (A) - Sony NEX adapter with the aperture control

I use the K&F Concept adapter to mount Pentax K lenses on the Sony a7c. It's not bad, but it has two drawbacks: self-disassembling construction (I tightened the connection screws several times) and a mounted lens is rotated relative to the camera (but very small).

But I also have a [Chinese] noname Pentax K (A) - Sony NEX adapter as a spare:

Unlike other nonames, this adapter has aperture control (important to me):

Unlike the K&F Concept adapter, the lens is positioned without rotation relative to the camera. This is a good thing.

The aperture control ring is clickless. Sometimes that's good, but I'm not used to it.

But I noticed two bad things.

First, the aperture control has too short a travel:

As a result,  you can't close the aperture to f/22 or even f/16 with many lenses. Yes, with full-frame digital cameras this is very rarely necessary (because of diffraction), but still.

Compare the maximum travel with the K&F Concept:

And with the Samsung MA9NXK adapter (for NX cameras):

Second, the adapter is too thick. I think it's 0.1mm thicker than it needs to be. This is really bad. It is impossible to focus to infinity with the adapter.

That's why I don't use this adapter.


Fixing the rubber grip of the Ricoh GR

On my Ricoh GR, the rubber grip (under the thumb) came loose and started to detach. Gluing it on didn't help, because the grip was expanded and wouldn't fit.

To fix I had to completely remove it from the camera:

And removed glue residues.

Next I put the grip in "Галоша" (Нефрас C2-80/120, some kind of petroleum solvent).

First for 1 hour, then dried. Not enough, still too big. Then another 30 minutes, dried. Now the right size of the grip.

I used 0.17mm 3M (300LSE 9495LE) double-sided adhesive sheet to attach the grip to the camera.

It's been a while, the grip sticks well to the camera.


Philips 160 (2005): pseudo-color display

There was a time when a color display was a sign of a good mobile phone. But there were also tricks for very cheap models.

This is the Philips 160 (2005, not to be confused with the E160) in the middle. On the left is my old practical Philips Xenium 9@9++, and on the right is the very elegant Nokia 6100.

The special thing about the Philips 160 is that it has a black and white screen.

But when the backlight is on you can see the colored background, giving the illusion of a color screen.

I would like to point out that this trick worked and this phone looked more interesting than the usual cheap monochrome models.


Pentax M 200/4: on the full-frame sensor

I have the Pentax M 100/4 (a manual focus lens pictured on the right):

It's relatively small.

I tried it on my Samsung NX500 (1.5 crop, 28Mp). When focused accurately, the Pentax M 100/4 was better than the Samsung NX 50-200/4-5.6 III.

Although I don't like long focal lengths,  I also tried the M 100/4 on a Sony a7c (FF, 24Mp). And it turned out pretty good for its age.

A birdie:

Cropped 1:1.

Out of focus:

The main problem, of course, is the manual focusing, which must be accurate to get a good result.

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IBIS focal length for zoom lenses

To use In-Body Image Stabilization (IBIS) with non-electronic lenses, the focal length must be specified in the settings. What about zoom lenses? It is difficult to adjust the setting after the focal length changes.

So it's easier to set a focal length once, but what is the best? An attempt to calculate the optimal focal length: Selecting IBIS Zoom Focal Length

It gives an optimal focal length of 32-35mm. Previously, I chose 35mm (on the Sony a7c) without these calculations.


Ricoh GR: Continuous mode and raw (DNG) shooting

The continuous shooting mode of the Ricoh GR is quite strange when shooting in raw (DNG).

1. It only takes 4 shots in a burst when you hold down the shutter button. To repeat, you have to wait for processing and recording (quite a long time!) and press the button again. I sometimes take at least 10 shots for stacking, and this behavior is very inconvenient, and also increases the probability of significant camera movement between series of shots.

2. This series of 4 images is shot at about 8 frames per second.

3. In the ISO Auto and Auto-Hi modes, the minimum value is ISO400 instead of ISO100.

4. Although you can manually select ISO100.

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Sony a7c: readout speed (video mode)

I measured the sensor readout time of the Sony a7c in photo mode when using Silent Shooting (full electronic shutter). Now it's time to explore the video modes.

The methodology is the same: a fast blinking (500Hz) LED is recorded. One pair of lines (dark line and light line) is 2 ms of the sensor reading.

1. Full-frame width, 4K 25/24 fps [PAL/NTSC]

About 12.4 pairs, 24.8ms.

2. x1.2 crop width, 4K 30 fps [NTSC]

About 8.6 pairs, 17.2ms.

3. Full-frame width, Full HD 25/50/100 fps [PAL]

About 4 pairs, 8ms.

4. Full-frame width, Full HD 24/30/60/120 fps [NTSC]

About 3.6 pairs, 7.2ms

5. APS-C, 4K 25 fps [PAL]

About 7.9 pairs, 15.8ms

6. APS-C, 4K 24/30 fps [NTSC]

About 6.9 pairs, 13.8ms.

7. APS-C, Full HD 25/50/100 fps [PAL]

About 3.9 pairs, 7.8ms.

8. APS-C, Full HD 24/30/60/120 fps [NTSC]

About 3.4 pairs, 6.8ms.

Reading in 4K modes is rather slow.

You can see that Full HD modes do not use the same sensor area as 4K, it skips lines. This causes a lot of aliasing, so I find Full HD on the Sony a7c useless.

The value of sensor readout speed is very important for software stabilization with Gyroflow (at least in 4K). It is necessary to always enable "Rolling shutter correction" and set "Frame readout time".

An inaccurate value or a deactivated correction will not allow to achieve a good stabilization.

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