Pentax SMC 85mm f1.8

[peterm1]

I am progressively working through my manual lenses now that I have a digital camera that can accommodate them. I took this picture this morning in my front courtyard. I am very happy with it. The focus point is the furthest pillar and you can all of the texture in it. I gave it only the smallest amount of sharpening (which I do with all digital shots.) The color is really nice too. I really must use this fella more often.

The one problem is focusing when shooting wide open. My old eyes are not up to it. But if you nail it the image really pops. It has nice bokeh too wide open. I will try to find some shots taken with it set this way.

[Attila]

I have this lens with broken !? front lens at edge , takes great captures as well like new

[LucisPictor]

Very nice! I love these parameters: 85mm f1.8!

[peterm1]

I wonder what it is about 85s, 105s and 135s? These focal lengths all tended to have particularly good lenses from the big name designers and manufacturers.

Is it that these were the "signature" focal lengths so they went all out to design good lenses for them, knowing that these would make or break their name in the market place. Or is it because there is something about these short to medium telephotos optically that made them easier to design? Perhaps a bit of both.

Even if they had features that allowed an "easier" design, the designer had choices to make. I have read that the earlier (pre-AI) Nikkor 105s were designed as true telephotos ie they were optimized for medium to long distances based upon the earlier still rangefinder design and lens usages. Later when these were redesigned they realized that many of these were now more likely to be used for portraits so optimized them for shorter ranges.

[Abbazz]

[Orio]

[peterm1]

Thanks Abbazz. I should have thought about that. When stated that way its obvious. (As most good ideas are.) Cheers.

Certainly I was going to add that I had noticed that longer focal lengths like this often have fewer elements and of course, your explanation is the reason. It is part of the reason too why I respect what I call lenses with "modest" design specs. It seems to be exponentially harder to design a lens with just that extra half a stop or a stop of coverage while retaining image quality. Part of the reason no doubt that Leica glass is so damn expensive, together with the build quality is that these are amongst the lenses that you can shoot wide open without serious degradation.

But it remains that so often the slower lens (ie with a simpler lens element layout) is the substantially better lens when it comes to image making - Not always; there are some excellent faster lenses - the 50mm Nikkor 1.4 and the 50mm Takumar 1.4 being cases in point where they approach the resolution of the 1.8 versions. (Which themselves are regarded as being exceptional.)

[LucisPictor]

That's the main reason why wide angle lenses for rangefinder cams can be so amazingly good: no mirror.

[peterm1]

I said I would try to find some wide open shots. Here is one. I did not quite nail the focus correctly (on the glass) but this shot demonstrates the lovely soft bokeh of this lens when shot wide open (the box behind the glass.)

On reflection, the DOF of this lens at this distance, wide open is so small that it may be impossible to get the whole glass in focus. Note that the front lip of the top of the glass is reasonable but the stem is well out of focus.

[Abbazz]