Initially, I did not plan to buy this lens, although its bokeh is deemed a gold standard for Pentax 67 and medium format cameras in general. I was quite satisfied (and am still satisfied) with my remarkable compact 90mm f/2.8, which I had been using for many years by that time. It has become truly universal for me, a go-to during all my trips, with which I shoot literally everything, from portraits and street photography to landscapes and architecture.
However, I eventually decided to buy a replacement for my old and worn-out second camera body which I used as a backup. So, I found a very good offer but that camera was equipped with the 105mm f/2.4 late edition. It was out of my budget but I decided to buy this kit hoping to sell the lens after playing with it for some time. The reasons were (a) to earn some money and lower the overall price for the body by $300; (b) I did not need two standard lenses which would compete for the place in my backpack.
Thus, this lens became the fourth to come to hand. In practice, everything turned out a little different and I will keep it forever, I reckon.
Size and weight
The lens weighs 600g, just 110g heavier than its 90mm f/2.8 fellow, which allows it to remain in the class of relatively light lenses in the Pentax 67 system. It’s also worth noting that medium-format lenses are generally quite heavy, and this difference in weight may seem insignificant. But during trips I have to be practical and mostly opt for the 90mm f/2.8 lens because of its compactness. It is smaller than the 105mm lens by 15mm. But in the sense of usability, you won’t notice much difference while shooting with each of these two lenses, although the outcome will certainly differ.
It is very difficult and odd to describe this lens from the “image quality” viewpoint, as it implies a certain quantitative measurement of the parameters that I do not take note of, and it is not necessary in this case. But, in terms of image sharpness, when being stopped down to f/8-11, it takes a picture that is very similar to the one shot with the 90mm lens at the same f/8-11. You can hardly distinguish the resulting images after some time. This lens is valued for other features – its f/2.4 fast aperture and bokeh effect it helps to create. But let’s describe one thing at a time.
Its close focusing distance is just 100cm, as compared to 65mm in a 90mm lens. It gives 0.13× magnification ratio and the image area around 53×41cm, which is exactly the same as for 165mm f/2.8. It is necessary to use extension tube #1 to get more magnification when shooting close-up portraits.
Field of view
It covers 46° which is nearly equal to the FOV of a classic 50mm lens on the 35mm format. So, 105mm f/2.4 is a classic standard lens.
It has a 9-blade aperture, identical to the one used in the old Takumar/6X7 150mm f/2.8, which was meant to complement the 105mm lens. Such aperture configuration is really great for a smoother bokeh effect when the lens is stopped down. But I rarely use it stopped down below f/4.5, so I will show several photographs shot with aperture opening up to f/8.
The lens has a 67mm filter thread which works fine with both screw-in and special bayonet mount filters.
The original clip-on plastic hood PH-SB 67mm costs around $50. But in real life I prefer to use the PH-SA 67mm from the 135mm f/4 Macro lens which doesn’t vignette the corners. Sometimes I use the Mamiya G2 bellows lens hood mounted with a special adapter.
At the fully open aperture this lens creates a light, hardly noticeable swirl of the background, which I like very much. It adds a bit of “magic” to the bokeh effect making the 105mm lens stand out from its analogues even in other medium format systems.
This lens has a smooth and very pleasant bokeh effect.
It is difficult to give this lens an objective assessment after it received so many, mostly positive, reviews on the web. The lens has a f/2.4 aperture, and that’s probably says it all. It was an absolutely unique feature at the time of the lens’s release in 1969, and it remains so now, since no other lens with such maximum aperture has been released for the 6×7 frame size. Unless, of course, we consider different uncommon lenses such as Schneider Cinelux and others, which are not designed for Pentax 67, but can be adapted to it. It’s also worth mentioning that when Asahi entered the medium-format market, it simply had to create a lens with unique characteristics in order to gain a foothold on this market.
When I had only one lens, I had nothing to compare it with. Now that I have two standard lenses, it seems possible to make a direct comparison. But in fact, there is no need for this. For me, these are completely different lenses with clearly defined areas of application, which, in my view, do not really overlap. Although, you can certainly buy any of them, and just use it without going into much detail.
I mostly use this lens at the open aperture and occasionally at f/3.5-4 when I have an even-coloured background, so that the stopping down does not make it more “pronounced”. Although its constant comparison with 90mm f/2.8 cannot be avoided, but I have defined for myself that I always shoot portraits of a large and medium-sized (medium shot or waist shot), at a distance of up to 4m with 105mm lens, and all the rest, with 90mm lens. It certainly does not mean that I always carry both of them with me, and that when the distance is more than 4m, I immediately change the lenses. But I usually know what I am going to shoot in advance so I choose the lens accordingly. If I want to snap a street photo, I take 90mm lens, if I have a portrait session, I will certainly take 105mm lens. And if I go on a trip, I’ll certainly take 90mm lens for its versatility.
It is 105mm which became a real “portrait” lens for me. And not 165mm f/2.8, despite officially being labelled as such. And I would even dare say that 105mm is a lens for the sake of which one can change the entire system.
- Focal length: 105mm
- 35mm equivalent: 54mm
- Optical formula: 6 elements, 5 groups
- Field of view: 46°/37° (Diagonal/Horizontal)
- Aperture: 2.4 ~ 22 (9 blades)
- Close distance: 100cm
- Magnification: 0.13×
- Picture area: 53×41cm
- Exposure factor: ×1.28 (+0.36EV)
- Effective lens speed: 2.7 ~ 24.9
- Filter: 67mm, screw-in and bayonet
- Hood: PH-SB 67mm
- Case: S90-100
- Dimensions: 92×60mm
- Weight: 0.6kg