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2025-05-21

Carl Zeiss Jena Biometar MC 80/2.8: Samples [1] - FF - f/2.8

Camera: Sony a7c (FF, 24MP)

This version of the Biometar was made to mount on cameras with the MF 6x6 frame (56mm x 56mm, with a diagonal of ~79mm) as a normal prime lens. However, I use it on an FF camera as a short telephoto lens.








2025-05-19

Zarya: Details of the rare 1959 version

The Zarya film camera itself is rather uncommon, and my copy is even rarer.




The first digit of the serial number indicates the year of manufacture. I only saw two options: 9 for 1959 and 0 for 1960. Mine is from 1959.

My Zarya has details that differ from those of later versions.

It has a larger front viewfinder window.




There is no knurling around the viewfinder eyepiece.




The film speed memo on the shutter shutter winding/cocking knob is also different.




For comparison, the film speed memo of a FED-2, which is the same as on later Zarya models:



It has a differently shaped cold shoe.




It also has a rare type of pressure plate.





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2025-05-17

Mosler Photoguard 35/2.8: T2-M42 adapter modification

The Mosler Photoguard (Tokina) 35/2.8 lens is incompatible with ordinary T[2]-Mount-M42 adapters. The lens cannot be fully screwed into these adapters.

I took one of these adapters and modified it.

Here is the M42 part of the adapter after filing:




Then, after painting:




The assembled adapter:




Finally, the adapter mounted to the Photoguard lens.




The lens screws in fully, so focusing to infinity is possible.

2025-05-16

Carl Zeiss Jena Biometar MC 80/2.8 (P6): Medium format lens

I acquired the Carl Zeiss Jena Biometar MC 80/2.8 lens for some work.




It is a medium format lens with the Pentacon Six (P6) mount (also known as B-Mount).

The lens has 5 elements in 4 groups and 8 aperture blades.





I was surprised by the image quality (even at f/2.8), when I mounted the lens to the Sony a7c (FF). So, I started using the lens as an 85mm alternative. One drawback is that the lens with an adapter is quite large (for an f/2.8 FF lens).

2025-05-15

Samyang AF 35/2.8: Lens station

A drawback of the Samyang AF 35/2.8 is that a lens station is required to update the firmware.

I found the Samyang Lens Station.






The firmware of my Samyang AF 35/2.8 was version 04 out of the box.




Now, version 08 is available.




I successfully updated the firmware using the Lens Station.






One thing I was wondering. I bought the new lens in a sealed box, however, the AF correction (so called "AF Pint") was already set to -4 (instead of the expected 0). I decided not to change the settings since I had no complaints about AF accuracy.

Anyway, I don't want to buy any more lenses that require a lens station. I would prefer a lens that can be upgraded with a camera or a lens with a USB connection for firmware upgrades (like the Viltrox AF 20/2.8).

2025-05-13

Motorola Edge 50 Pro: JPEG vs DNG

JPEG images from the Motorola Edge 50 Pro are poor quality. They are overprocessed: oversaturated, oversharpened, and excessively noise-reduced.

Fortunately, the Pro mode (in the Camera app) offers the option to shoot in raw (DNG). 

The ultra wide angle and long focus cameras produce poor results due to their tiny sensors (1/3" and 1/3.94"), even in DNG. I rarely use them. The ultra wide angle camera also exhibits significant "mustache" distortion (in DNG/JPEG).

Also note that the macro mode uses the ultra wide angle camera. The resulting DNG contains the entire image without cropping and resampling.

However, the main (wide angle) camera (1/1.55") is quite good in DNG. The resolution and detail are adequate for 12.5MP (raw 50MP data is unavailable).

The image in DNG is obviously noise-reduced by software. However, the noise reduction is rather coarse at high ISO. Additionally, noise remains visible when processing at low ISO (boosting shadows).

Both the DNG and JPEG images taken with the main camera show visible barrel distortion.

Another issue is the slight green tint that is visible under certain conditions. This may be due to ART (raw processor). I now fix this issue by adjusting the white balance during processing.



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2025-05-11

Pentax A 35-70/4: Samples [1] - FF - 35mm - f/4

Camera: Sony a7c (FF, 24MP)
Lens: Pentax A 35-70/4 at 35mm and f/4

There is noticeable barrel distortion at 35mm. The minimum focusing distance is too long for wide-angle close-ups.










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2025-05-09

API SQ/ILSAC GF-7

New API Service Category SQ/ILSAC GF-7 (GF-7A/7B) oils are available from 31 March 2025 (first permitted use).

2025-05-07

Slik Sprint Mini II: Tripod mounting plate adapter

The Slik Sprint Mini II tripod uses a proprietary mounting plate. Normally this doesn't bother me, but sometimes I want to switch between cameras quickly.

In this case, I attach an Arca Swiss mount adapter.





2025-05-05

Industar-50 lenses

I have several Industar-50 50/3.5 lenses.




From left to right:

SLR M39 1958
RF M39 1958
SLR M39 1964
RF M39 1965
SLR M42 1980 (Industar-50-2)

None is optically perfect. Some are better, some are worse. But all are decentered. I see it clearly when I try to use them.

2025-05-03

Mitakon [Zhongyi] Creator 35/2 (Pentax K): The lens that can break your film camera

This is one of the Mitakon [Zhongyi] Creator lenses. The Mitakon [Zhongyi] Creator 1:2/35mm.




The lens has 7 elements in 5 groups and 9 aperture blades.




The lens does not offer outstanding image quality, but its characteristic is a rather smooth background blur (especially for a retrofocus lens).

The Mitakon 35/2 has several mount options. My copy has a Pentax K mount. I chose this mount to be able to use it with a film camera (I have several suitable ones). But when I tried to mount the lens on my Vivitar V3800, I broke the camera.




The stop-down coupler broke off after I tried to mount the lens.




The stop-down indicator is made of plastic and fell off because of the Mitakon lens.

The reason is the incompetence of Zhongyi Optics. They do not have enough knowledge and understanding to design a Pentax K mount lens.

In contrast to all Pentax K digital cameras, almost all Pentax K film cameras have the stop-down coupler (except cameras with "crippled" Pentax K mount). The stop-down coupler is used to mechanically transmit of the position of the aperture ring to the camera for proper metering with automatic diaphragm.

For example, one of the Pentax lenses has a stop-down indicator:




Even if a lens does not have an automatic aperture (as in the case of the Mitakon lens) there should be a groove for the stop-down indicator. 

For example, a T[2]-mount to Pentax K adapter:








Now look at the flange of the Mitakon lens:




There is no a groove, so mounting the lens on a Pentax K film camera can break or bend the stop-down coupler.

Unfortunately, my Vivitar V3800 cannot measure the exposure correctly after such a break. Even with an M42-Pentax K adapter the camera now assumes that the aperture is fully closed, so the metering is incorrect. I should use a dedicated light meter.

2025-05-01

Rodinal: Back to 1:50 from 1:100

I really liked the lazy style of [semi]stand B&W film development with 1:100 Rodinal. But there was uneven development (and repetitive streaks originating from the sprocket holes) on some film.

I tried pre-soaking a film and a little more agitation, but it didn't help much. Perhaps I should use a very aggressive agitation (for an hour!), which goes against the spirit of [semi]stand development.

So I went back to the 1:50 solution: developing in about 10 minutes with moderate agitation. In this case, the uneven development was gone.



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2025-04-29

Staeble-Lineogon 35/3.5: Samples [2] - FF - f/3.5

Camera: Sony a7c (FF, 24MP)

The minimum focusing distance of the lens is about 1m, which is very long for practical use. It makes sense to try the lens with the macro helicoid next time.









2025-04-27

Pentax A 35-70/4: Manual focus zoom lens

I had the Pentax A 35-105/3.5. This lens surprised me when I tested it on APS-C (crop 1.5x) digital cameras. But it is quite unhandy to use. Too big and too heavy for a small camera.

I sold it before I bought the Sony a7c, so I didn't test it on a full frame sensor.

Now I have the Pentax A 35-70/4.




This lens is more comfortable to use. I tested it a bit with the Sony a7c. And it looks pretty good. Also it is possible to test the lens on a film camera: the Pentax Super A. This camera even supports program modes (P, Tv), since the Pentax A has the A position of the aperture ring.

An unusual (for me) thing I found on the Pentax A 35-70/4 is how the minimum focusing distance (MFD) depends on the focal length.

70mm: 0.247m
50mm: 0.275m
35mm: 0.575m

The shorter the focal length, the longer the MFD.

2025-04-25

Motorola Edge 50 Pro: Cameras

Rear cameras of the Motorola Edge 50 Pro.

1. Main (wide angle) camera (so called 1x)

Sensor: 1/1.55" 50MP (12.5MP after binding) OmniVision OV50E, crop factor 4.2x
Lens: 5.89mm (25mm equiv) f/1.4 OIS


2. Ultra wide angle camera (so called 0.5x)

Sensor: 1/3.00" 13MP Hynix Hi-1336, crop factor 7.5x
Lens: 2.13mm (16mm equiv) f/2.2


3. Long focus camera (so called 3x)

Sensor: 1/3.94" 10MP Samsung ISOCELL 3K1, crop factor 9.5x
Lens: 7.06mm (67mm equiv) f/2





There is a macro mode in the Camera application, in this mode the ultra wide angle camera is used with cropping and upsampling up to 13MP (in JPEG).



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