It so happened that when I got my first Pentax 67 many years ago it was equipped with this lens. Eventually this led to a decade-long “love affair” with the Pentax 67 system.

And now I think that it is for the best that I started shooting with this particular lens which turned out to be truly universal. And still remains such.

It is worth mentioning that this is not the first prime lens that Asahi released for its Pentax 67 system. It was preceded by other normal primes: well-regarded 105mm with an exceptionally beautiful bokeh, and 90mm with a leaf shutter. In 1979-80 Asahi revamped its line-up of lenses, having rebranded “TAKUMAR/6X7” as “PENTAX-6X7”, and started to produce a series of completely new lenses designed from scratch. A new 90mm f/2.8 became one of the first in this line-up.

And despite the fact that the 90mm f/2.8 is about half f-stop darker than the 105mm f/2.4, it has some apparent advantages, which subsequently became very important for me.

Size and weight

Pentax 67 90mm f/2.8 compared with 105mm, 135mm Macro and 165mm

Pentax 67 90mm f/2.8 compared with other lenses

It is lighter and more compact compared to the 105mm lens – by 143g and 15mm respectively. It may seem at first that this difference is pretty small, but in fact the Pentax 67 camera rather resembles a brick with a lens attached to it, both in terms of its size and weight. And lenses that go with this system are quite big, with most of them weighing above 0.5kg. That is why for travel and outdoor shooting every 100g on top of the set, as well as the size of the camera and the lens, are essential.

Image quality

It is sharp and contrast throughout the entire aperture range, even when it is wide open. A majority of lenses are manufactured in such way as to achieve optimum performance at medium apertures. This is also fair for 90mm f/2.8. In fact I do not do technical tests, but comparing printed images I can say that the sharpness of images shot with the aperture of f/2.8–f/4 is almost equal to that of f/5.6–f/11 and is almost brilliant.

Field of view

It covers 53° which is wider than 105mm lens by 7°. It seems to be not that much but this makes it closer to a 75mm lens, which is wider than 90mm lens on 8° and places it exactly between 75mm and 105mm lenses. So, you can shorten a gap in focal lengthes between the 105mm standard lens and the 75mm wide-angle lens — just make a couple of steps with your feet and you will get a wider angle closer to a 75mm lens. This will allow you not to carry an additional lens and thus make your system set minimum 0.5kg lighter!

There is another good feature — the lens can be used on Pentax 645 cameras via a special lens adapter, working similar to the normal 645 lens. So, you may keep the 645 body as a backup camera without any native 645 lenses.

Close focusing

Pentax 67 90mm f/2.8: helicoid extension at infinity and closest distances

Pentax 67 90mm f/2.8 helicoid extension

It has a close focusing distance of just 65cm, which makes it unnecessary to use extension tube #1. The close distance is ~7.2× of the focal length while its typical value is 9-10×, such as 1m for 105mm. It gives 0.2× magnification ratio and image area around 35×28cm, which makes it comparable to a close-up lens near 135mm f/4 Macro. But this comes at a price; in particular it leads to a fall in the aperture by 1/2 EV at a minimum focusing distance. But it can be easily compensated by opening the aperture by half a step.

Aperture

Pentax 67 90mm f/2.8 aperture opening

Pentax 67 90mm f/2.8 aperture opening

The lens has 8 aperture blades, which is typical for most of the Pentax 67 lenses. I rarely stop it down below f/11, so I will show several photographs of aperture opening up to this value.

Filters

The lens has a 67mm filter thread which works fine with both screw-in and special bayonet mount filters.

Hood

Original clip-on plastic hood PH-SB 67mm costs around $50. While travelling I use a cheap compact metal round hood for $3 and during the staged photo shoots I prefer to use the Mamiya G2 bellows lens hood mounted with a special adapter.

Bokeh effect

This lens has been very smooth bokeh effect.

© Sasha Krasnov, 2012
© Sasha Krasnov, 2014
© Sasha Krasnov, 2016
© Sasha Krasnov, 2016
© Sasha Krasnov, 2012

Summary

So, it is completely different from 105mm f/2.4 – a great all-around standard lens for everyday use, truly versatile, compact and light weight with the great image quality. So, which one to choose? I’ve got both of them. Why? Well, I will describe it in the further article.

Lens data

Pentax 67 90mm f/28 - optical formula

Pentax 67 90mm f/28 – optical formula

  • Focal length: 90mm
  • 35mm equivalent: 46mm
  • Optical formula: 7 elements, 6 groups
  • Field of view: 53°/42.5° (Diagonal/Horizontal)
  • Aperture: 2.8 ~ 22 (8 blades)
  • Close distance: 65cm
    • Magnification: 0.2×
    • Picture area: 35×28cm
    • Exposure factor: ×1.44 (+0.53EV)
    • Effective lens speed: 3.4 ~ 26.4
  • Filter: 67mm, screw-in and bayonet
  • Hood: PH-SB 67mm
  • Case: S90-100
  • Dimensions: 92×45mm
  • Weight: 0.49kg
Sasha Krasnov