Soft focus lens or soft focus filter

Hello,
I am getting interested in portraits. At this moment, I am unable to afford a soft focus lens, like the Pentax 85mm.
How good are the various soft focus filters? If they are any good, what strength soft focus would be good for portraiture? Or should I just try a bot of vaseline on an UV filter?
My Camera is a K5.

Horst

I wouldn't advise vaseline. I tried that once and it's just too messy.

You can buy soft focus filters from most filter manufacturers, or even use one of the Cokin type filters. Have a look on eBay and experiment. You couyld also use a sheet of glass to shoot through, perhaps glass that is not optically perfect may produce interesting effects.

Cling film is another possibility.

In other words, if we are deliberately destroying the resolution of our lenses it is possible to use a wide variety of ordinary items to see what happens.

The most expensive option is the Zeiss Softar 1 and Zeiss Softar 2, but that's probably in fantasy land for most of us....

From years ago, a pair of ( Ladies ) stockings make a good soft focus filter,

Have to ask, how does the K5's built-in "Soft" filter stack up compared to the lenses?

I can second the comment about using nylons as a soft focus filter, and the "Cokin type" filters ( I use a now defunct competitor's filters ) which are nothing more than a plastic sheet with a half inch diameter hole in the middle. The plastic is closer to translucent than transparent so the surround gives that glow to the sharp image transmitted through the central aperture.

Changing the f/stop on the lens controls the amount of glow transmitted to the film/sensor. Smaller f/stops restrict the lens' field of view to the hole, wider ones allow more of the glow from the translucent area to overlay the sharp image. The vaseline trick simply uses a clear filter to become only centrally clear with a glowy (?) surround, similar to the cokin type.

A soft focus lens such as the Pentax 85 has a number of smaller holes in a pattern that is exposed to varying degrees by the aperture, and thus changing the amount of glow added to the sharp image.

The stocking trick is not quite as good, although the effect can be similar, because there is no perfectly clear image area. I suppose one could cut a small hole in the centre of the stocking to increase the effect.

Thank you for all your good advice. I will take notice and try a few things.

Regards, Horst