Soft focus question

[steveh552]

I think I understand the whole soft focus thing. Basically you shift

it a bit out of focus but not enough to really make it look bad. Now

the question, is there certion F-stop to use for this, or shutter

speed that works better? I have not tried this yet, but am wanting to

give it a try. I have only relied on my cameras AF to do all the work

for me.

Thanks,

Steve

[henk]

Steve,

 

Soft focus is something related to filters and lenses that make your in-focus area look softer. Selective focus is that you focus in a way only the eyes(for example) are sharp. The first is a equip 'thing' the last a technique 'thing'. Although the technique 'thing' will benefit from certain equipment offcourse.

 

I suppose you mean the selective focus so ill try to give you a few tips. The eyes focus is the most easy i think so ill tell something about that. Use a 50mm or small tele wide open and frame head and shoulders as straight as possible. Set the lens at low distance and move the focus plane slowly towards the subject. If you see the eyes come into focus, press the shutter. If you dont use the lens wide open, use the DOF preview button. A shutterspeed of 1/125s works best, you dont want the selective focus to get unsharp also... Fast lenses and bright focus screens are preferable because you can better see what the focus plane is doing, though they are not required.

 

BTW this is a wonderfull exersise to practise your manual focussing or maintain its accuracy and speed.

 

Greetings,<div></div>

[peter nelson]

<I>I think I understand the whole soft focus thing. Basically you shift it a bit out of focus but not enough to really make it look bad. </I><P>

 

<U>NO</U>, soft focus in <B>NOT</B> the same thing as out of focus, or even slightly out of focus. Soft focus is spherical aberration. Visually they look entirely different. There are various lenses or filter attachments you can choose from to achieve soft focus.

[henk]

Peter,

 

"Soft focus is spherical aberration."

 

Spherical aberration is a technical term for bokeh not soft focus.

 

Greetings,

[peter nelson]

<I>"Soft focus is spherical aberration."<P>

 

Spherical aberration is a technical term for bokeh not soft focus.</I><P>

 

Soft focus lenses and soft-focus filters work by introducing controllable spherical aberration. See, for instance, the Mamiya 180mm f/4 VSF lens, or the Pinkham & Smith Visual Quality Series IV soft-focus portrait lens used by 4x5 photogs, the Canon 85mm f/2.8 FD soft-focus lens, or the Minolta 85 f/2.8 varisoft, etc, et cetera, ET CETERA. Deliberately introducting spherical aberration is the correct way to do soft focus. (the poor man's way to do it is to introduce diffusion or fake it in Photoshop).<P>

 

(I'm surprised you don't know this Henk, since you are pretty regular here on PN and this has been discussed here very extensively)

[emaxxman]

I agree with Peter. I've been studying soft focus images lately (I'm pondering getting a soft focus filter, that's why) and there is a definite difference between soft focus and out of focus.

 

Out of focus just looks blurry. I tend to find a portrait where a portion of the subject is out of focus undesireable.

 

In a soft focus image, everything that is intended to be in focus is in focus. The subject is not blurry. Instead, there is slight 'halo'effect around the highlights in the image.

[GerrySiegel]

I try it with a diffused light source and if that fails to get rid of the sharp pores etc etc, I use a softnet filter on the lens. It seems that some lighting contributes the most to "softness" of an image. My 85mm FD Canon 1.8 for instance (has optical aberrations) is way softer at 1.8 than my 50mm 1.4 but not soft enough to be called real soft focus. The Canon FD 85mm 1.2L which I borrowed once could be used for medical specimen work its so knifeedge sharp,too too sharp. I disagree with the idea of shifting anything out of focus,that's not soft focus as I was told. Try a window, one uncleaned for a long time:-) first, or the silk stocking treatment or the vaseline on the filter treatment or if you get a work bonus, the Zeiss softar filters,or not settle for what Tiffen sells much cheaper in various combinations,black softnet,white softnet and so on. Someone recently posted a Photoshop plug in recommdation by Corel that looked most clever. Check Corel web site...GS<div></div>

[henk]

Peter,

 

A soft focus lens increases the occurrance of sferical aberration, sometimes even some chromatic aberration in the optical formulae. However soft filters reduce the correction for sferical aberration of the used lens. This is archieved by simply reducing overall focus sharpness. In the larger(and intenser) OOF area more sferical aberration will occur ofcourse.

 

As sferical aberration occurs in all OOF areas(not limited to soft focus lenses/filters), even in focus areas when using any filters. I though you essentially should have an unusable lens if it were true that the optical formulae 'creates' sferical aberration in the focus area. Soft-focus lens formulae seem a little more complex, there is a focus area(small) which remains relatively free of sferical aberation.

 

The fact that sferical aberration occurs when using soft focus lenses or filters is not a correct base for a definition. Esentially soft-focussing makes the picture unsharp and as a natural effect it increases the occurrance of sferical aberratons.

 

"I'm surprised you don't know this Henk, since you are pretty regular here on PN and this has been discussed here very extensively"

 

Normally i have my own opinion, i value the opinions of others but i dont always believe everything said in here, its stupid iknow ;)P

 

Greetings,

[peter nelson]

<I>The fact that sferical aberration occurs when using soft focus lenses or filters is not a correct base for a definition. Esentially soft-focussing makes the picture unsharp and as a natural effect it increases the occurrance of sferical aberratons. </I><P>

 

Soft focus doesn't <B>just</B> make the picture unsharp - it makes it unsharp in a particular way, and that way is optically described by spherical aberration. If simply making the picture unsharp was an adequate description then you could achieve soft focus by simply defocussing, but has already been noted by others here, that doesn't work.<P>

 

All of my information comes from the manufacturers' own technical data about their lenses. THEY are the ones who specify that they create soft-focus by producing a controlled degree of spherical aberration. They ought to know - it's their optical design. But if you don't believe me do a search on PN or on the web via Google. This is not exactly groundbreaking information.

[henk]

Peter,

 

Dont take it personal, i just want to share some info.....

 

""Soft focus doesn't just make the picture unsharp - it makes it unsharp in a particular way, and that way is optically described by spherical aberration. If simply making the picture unsharp was an adequate description then you could achieve soft focus by simply defocussing, but has already been noted by others here, that doesn't work.""

 

I said exactly the same in the preceeding alinea in my previous post. I didnt say OOF was the same as soft-focus anywhere.

 

""THEY are the ones who specify that they create soft-focus by producing a controlled degree of spherical aberration.""

 

Well this is a fact, i have to admit they are right. However EVERY lens without a fixed aperture gives the user a controlled degree of sferical aberration. Its sales-talk....

 

""But if you don't believe me do a search on PN or on the web via Google.""

 

I think believing or not isnt the issue, anyone has a right to his/her own opinion. Discussing an opinion is another thing. If you want some info on what sferical aberration really is go here:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0033Dq

 

The guy who posted the last post has a pretty clear understanding of how optical design and the ocurrance of sferical aberration are connected.