"Finger point" on Pentax lenses

Pentax K, M, A, F (and some FA) series lenses may have a "finger point" ("ball mark" as a small protrusion).

(K, M, A lenses)

This is obviously for "blind" mounting a lens on a camera, but this mark doesn't seem to match anything on modern Pentax cameras.

The reason is that this point mark is from the days when the lens unlock/release button was located near the lens locking pin.

(Pentax K1000, source)

The same can be seen now on the Pentax K-Sony FE/E adapter, for example.

The idea is that this mark should be aligned with the unlock/release button, the lens is inserted into the mount, and then turned clockwise:

But over time, the button and the pin have moved to different locations on cameras:

(Pentax K10D, source)

So the "finger point" became meaningless (it doesn't correspond to the unlock button placement) and disappeared on almost all lenses back in the days of the FA series.

See also related notes:

• K&F Concept: Адаптер Pentax K (DA) - Sony FE/E (2022-03-28)

Image albums:

• Lens accessories
• Pentax
• Pentax K10D

SZ Viewer A1-2023-10-18 (Android)

SZ Viewer (Android) changes:

1. The information output in the DTC tab is technically limited. I didn't like the previous version, so I changed the formatting.

2. A workaround for the "lacks permission android.permission.BLUETOOTH" bug of Chinese devices running on Android 12+.

See also related notes:

• SZ Viewer: общая информация (2014-02-15)

Image albums:

• On-board diagnostics

Anastigmat Victar 50/2.9: With close focus (helicoid) adapter [2/2]

(see part 1)

More results from the Sony a7c (FF, 24MP), the Victar 50/2.9 at f/2.9, and close focus (helicoid) adapter:

It's important to choose the background and the lighting.

That's when those soap bubbles of a triplet will appear.

And here is an example of flare (remember, this lens is uncoated) :

When the palm of a hand is used as a hood replacement:

See also related notes:

• Staeble-Werk Choro R 35/4.5: My experience [2/3] (2023-12-11)
• Riconar/Rikenon 55/2.2: Two types of focusing and background blur (2023-11-27)
• Staeble-Telexon E 85/5.6: My experience [2/3] (2023-11-09)
• Anastigmat Victar 50/2.9: With close focus (helicoid) adapter [1/2] (2023-10-14)

Image albums:

• Victar 50/2.9

Anastigmat Victar 50/2.9: With close focus (helicoid) adapter [1/2]

The Victar 50/2.9 shows triplet traits (see 1 and 2), but the limitation is that the minimum focusing distance is too long.

So I had to build an assembly: the lens, the M40x1-M42x1 ring, the M42x1-M39x1 adapter, two M39x1 5mm extension tubes, the M39x1-Leica M adapter, and the close focus (helicod) Leica M-Sony FE/E adapter.

It allows the minimum focusing distance to be shortened if necessary.

On the Sony a7c (FF, 24MP) I got the following result at f/2.9:

See part 2.

See also related notes:

• Riconar/Rikenon 55/2.2: Two types of focusing and background blur (2023-11-27)
• Anastigmat Victar 50/2.9: With close focus (helicoid) adapter [2/2] (2023-10-16)

Image albums:

• Lens accessories
• Victar 50/2.9

Panoramas of Bolshiye Koty (July 2006)

Lake Baikal, panoramas of Bolshiye Koty settlement. July 2006.

Pentax *ist Ds (1.5x crop factor, 6MP) + K 35/3.5 (53mm equiv.), as far as I remember.

Image albums:

• Baikal

Lenses without cemented elements (2023)

There are lenses where there are no cemented (grouped) elements, i.e. the number of elements is equal to the number of groups.

Some people believe that such lenses produce a more interesting image. I don't think so, but from a practical point of view, the lack of cemented elements makes it impossible to de-cement. And there will be no haze between the cemented groups. This is important for (very) old lenses.

I have such lenses:

Revue 24mm f/4 (M42x1): 7 elements in 7 groups

Holga 29mm f/8 (NX): 1 element in 1 group

<probably meniscus lens>

Samsung NX 30mm f/2 (NX): 5 elements in 5 groups

Pentax K 30mm f/2.8 (K): 7 elements in 7 groups

Pentacon 30mm f/3.5 (M42x1): 5 elements in 5 groups

Staeble-Werk Choro R 35mm f/4.5 (M39x1/44): 3 elements in 3 groups

(optical design like this)

Victar 50mm f/2.9 (M40x1): 3 elements in 3 groups

(optical design like this)

Riconar/Rikenon 55mm f/2.2 (K): 4 elements in 4 groups

<unknown optical design>

Vivitar 85mm f/1.8 (F): 6 elements in 6 groups

(Information about 10 elements in 7 groups is incorrect)

Mitakon 85mm f/2 (F) : 6 elements in 6 groups

Pentax M 135mm f/3.5 (K) - 5 elements in 5 groups

I used to have such lenses:

Brightin Star 23mm f/5.6 (FE): 5 elements in 5 groups

Вариозенитар/Variozenitar-К 25-45mm f/2.8-3.5 (K): 10 elements in 10 groups

Carl Zeiss Jena DDR Flektogon 35mm f/2.4 (M42x1): 6 elements in 6 groups

Таир-3С/Tair-3S 300mm f/4.5 (M42x1): 3 elements in 3 groups

Five Star 500mm f/8 (T/K): probably 4 elements in 4 groups (or 4 elements in 3 groups - I am not sure).

I wanted to buy such lenses (but I didn't get them, I have too many 50mm lenses):

Pentax M/A 50mm f/2 (K): 5 elements in 5 groups

Prakticar 50mm f/2.4 (Praktica B): 4 elements in 4 groups

See also related notes:

• Staeble-Werk Choro R 35/4.5 (M39x1/44): Very rare wide-angle triplet (2023-10-05)
• Pentax K 30/2.8: ad (2023-09-15)
• My lenses by focal length (2023) (2023-09-12)
• Revue 24/4 lens (M42x1) (2023-08-18)
• Anastigmat Victar 50/2.9 (M40x1): Uncoated triplet from 1940s (2023-07-24)
• Riconar/Rikenon 55/2.2 (K): It's not a triplet (2023-06-21)
• Pentacon 30/3.5 (M42x1) (2023-05-01)
• Mitakon [Zhongyi] Creator 85/2 (Second Version) (2023-03-31)
• Вариозенитар 25-45/2.8-3.5 (2022-12-23)
• Таир-3C и Five Star 500/8 (2022-05-26)
• Vivitar 85/1.8: дополнительная информация (2022-05-08)
• Brightin Star 23/5.6: странный китайский объектив для Sony FE/E (2022-03-19)
• 35 vs 35: два старых объектива (и о важности субъективных впечатлений) (2016-10-02)
• Holga HL(W)-SSN 29/8: объектив-спецэффект за $16 (2014-05-04)
• Объектив Samsung NX 30/2 (S30NB) (2010-11-16)

Image albums:

• ISCO-Göttingen Iscovitar 50/2.8
• Mitakon [Zhongyi] Creator 85/2 (II)
• Pentacon 30/3.5
• Pentax
• Pentax K 30/2.8
• Pentax M 135/3.5
• Photo
• Revue 24/4
• Samsung NX 30/2
• Staeble-Werk Choro R 35/4.5
• Staeble-Kata E 45/2.8
• Victar 50/2.9
• Vivitar 85/1.8

Noname [OEM] 50/1.1 FF: Cap replacement

The Noname [OEM ] 50/1.1 full-frame lens (for Sony FE/E) came with a screw-on cap, which is inconvenient for regular use:

If replacing the cap, you have to consider the front element, which is strongly curved forward. The cap should not touch it.

A push-on lens cap cannot be used because of the hood mount.

I had to find a suitable snap-on 52mm lens cap.

A Sigma cap fit:

It has nothing in the center part on the lens side.

That's what I need.

See also related notes:

• Noname [OEM] 50/1.1 (Sony FE/E): Full-frame lens (2023-08-23)

Image albums:

• Lens accessories
• Noname [OEM] 50/1.1 FF

Pentax K 30/2.8 vs Pentacon 30/3.5

This is my comparison of the Pentax K 30/2.8 at f/2.8 and the Pentacon 30/3.5 at f/3.5 on the Sony a7c camera (FF, 24MP).

The scenes changed a bit because of the wind.

1.

(Pentax 30/2.8)

(Pentacon 30/3.5)

2.

(Pentax 30/2.8)

(Pentacon 30/3.5)

3.

(Pentax 30/2.8)

(Pentacon 30/3.5)

4.

(Pentax 30/2.8)

(Pentacon 30/3.5)

The Pentax K 30/2.8 gives a wider field of view.

The difference between f/2.8 of the Pentax K 30/2.8 and f/3.5 of the Pentacon 30/3.5 is about 2/3EV (as expected).

See also related notes:

• Pentax K 30/2.8: ad (2023-09-15)
• Pentacon 30/3.5 (M42x1) (2023-05-01)

Image albums:

• Pentacon 30/3.5
• Pentax K 30/2.8

Baykal Port (August 2004)

Lake Baikal, the source of the Angara River, Baykal Port. August 2004 (see also 2006). The panorama:

Higher resolution: 7100x3594 5830.0KB

Pentax Optio 450 (4MP, 1/1.8") @ 39mm (187mm equiv.)

See also related notes:

• Baykal Port (2006) (2023-03-13)

Image albums:

• Baikal

Samsung NX2000 + Holga 29/8: "No Lens" error

I have used the Holga 29/8 lens on the Samsung NX300M and NX500. It works fine the same way on my current NX10 and NX300 cameras.

But when I tried the Holga on the NX2000, I got the famous "No Lens" error:

The cause is known. One of the lens bayonet tabs is supposed to push a special camera switch that detects the presence of a lens when it is mounted.

Yes, this tab is not made correctly on the Holga (it is too short and too thin), but for some reason this switch is more picky on the NX2000 than on the NX10 or NX300.

Of course, there is no problem with native NX lenses.

See also related notes:

• Samsung NX2000: cheap 20MP camera, welcome (2023-07-05)
• Holga HL(W)-SSN 29/8: объектив-спецэффект за $16 (2014-05-04)

Image albums:

• Samsung NX