Here you see another super high resolution image (20 MP), albeit with higher compression than normal in order to keep down the file size. Otherwise my homepage would slow down...
Nevertheless - it allows you to scrutinize the resolution in finer detail (with these Vertex method photos). In this example i used a light wide angle lens; the Pentax 67 SMC 75mm ƒ4.5 mounted via Vertex adapter onto the Fujifilm GFX 50sII camera; emulating a 70x70mm digital sensor, using the entire image circle of the 6x7 lenses.
the Pentax 75mm ƒ4.5 shows a lot better optical quality, especially in the corners - compared to the first gen. Pentax 6x7 Takumar 55mm ƒ3.5 lens.
Buying a better Pentax 55 mm wideangle lens ?
Pentax 6x7 provides three different version of their 55mm 6x7 lenses. (It's equivalent is like a 28mm wideangle lens on fullframe).
first generation Pentax 6x7 Takumar
55mm ƒ3.5 lens
Utmost beautiful on film (!!!)
- but pretty bad with digital sensor
The first generation Pentax 6x7 55mm lens, is the funny looking lens with HUGE front diameter of 10 cm. It contains yellowing glass, due to radioactive thorium glass. (Like first generation Pentax 6x7 Takumar 105mm ƒ2.4, also contains yellowing thorium glas. It can be cleared up by exposing it 1-2 days with a UV lamp).
Cinematic fingerprint !
This Takumar 55mm ƒ3.5 has a unique fingerprint - with a cinematic feel - because the ƒ 3.5 aperture gives beautiful bokeh despite being a wideangle mediumformat lens, with a beautifully ethetic look, i have rarely seem among other mediumformat lenses. That's also why i chose that one over the sharp third generation lens.
When used on a digital camera however - it isn't critically sharp (except in the very center). bBoth borders and corners are mushy to say the least (with the Vertex 70x70mm sensor emulating method) - and leaves a lot to be desired.
Even stopped down, the details often get mushy at the borders, still.
Here a few photos
i made with the Pentax 6x7 Takumar 55mm ƒ3.5 with the Pentax 67 II camera on Fuji ACROS 100 film, with Sal back in 2016 in Pedara, Sicily. Notice the enticing smoothness of the background, despite being a 28mm wideangle lens. You normally don't get this cinematic flair with wideangle lenses !
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