Glow vs soft vs blur

[daveleo]

This is not a joke or sarcastic.

I am struggling to explain to myself the differences between "glow", "soft" and "blur"

I like not-razor-sharp images that have a modest "glow" to them. They seem to have no sharp edges, Warmish highlights. But, I don't like blurred images.

I also don't know when an image is "soft" versus "blurred" (I am not talking about motion blur).

As an example. Images from a Zeiss softar filter look wonderful. Soft, glowy but not blurred. Images from some other soft filters just look blurry.

So, if anyone can point me toward understanding the differences . . . . ?

 

[Jamie123]

Soft filters have a diffusing effect which tends to make highlights "bleed out" beyond the edges (glow) while not affecting shadows to the same extent. A soft lens (as in not very sharp) will just give you less resolution than a sharper lens but not make anything glow. Blurred (when not relating to motion blur) usually means out of focus so even a sharp lens can give you blurry pictures. You probably would refer to the out of focus areas in a picture as blurred, not soft.
However, I'm not quoting any dictionary definitions here, just giving a few ideas how these concepts could be seperated. A lot of the time people use soft and blurry interchangeably.

 

[Dwig]

The Softar's magic comes from the fact that it delivers a mix of sharp, unaffected image and blured, out-of-focus image, something most "soft focus filters" fail to do. Softars simulate the similar characteristics of the classic soft-focus lenses such as the Imagon. You get soft images with a weak, but never the less present, sharp edges at the point(s) of best focus.

 

[Gumby]

Check out the B+W filter manual (Schneider web site). I think they show the difference between softar and duto. I actually prefer duto more than softar. Also check out the Hoya filter manual... that shows and describes the effect of their various soft focus products.

 

[charjohncarter]

I don't know what I talking about but thinking about it: I don't understand glow, soft is produced by lens, filters or software, and blur (they way you are thinking of it) is; out of focus. I have many soft lenses some that I've made for screwmounts and some for my Pentax 6x7. I also have an old Japanese folder that has a soft lens, and it is great.

 

[Roger Hicks]

Who cares?

Either you like the images, or you don't.

My favourite lenses are the pre-aspheric 1,4/35 Summilux, the 1,5/50 C-Sonnar, the 75/2 Summilux and the 90/2,2 Thambar. WHO CARES how you describe "glow", "soft" and "blur"?

Cheers,

R,

 

[Bob Michaels]

............. WHO CARES how you describe "glow", "soft" and "blur"? ............

I believe those who try to use simple one word labels always have the implicit assumption "anyway, you know what I mean" No, we don't know what they mean.

 

[Rob-F]

My $0.02: Softness is caused by lens aberrations, such as (and importantly) spherical aberration. I think "glow" is caused by an (over)abundance of same; for example, the 50mm Summar. Blur can be caused by the image being out of focus, or by motion blur or camera shake. Softness, I think, can often be used effectively, while glow is to be used sparingly (IMHO). Blur is very good in the out of focus areas, and seems to contribute to 3D "pop."

 

[EdwardKaraa]

Well, there is out of focus blur, and there is lens blur, and motion blur. Lens blur is caused by poor optics, and not related to lens softness ( which is caused by spherical aberrations as pointed out by Rob above ).

 

[biomed]

Dave,
This is how I understand the terms. I believe that "soft focus" and "glow" are basically the same.

sharp focus

blur

softfocus/glow

I bet that there examples on the web that would better illustrate the differences.

 

[fstops]

Thanks to photoshop I can offer an example using my trusty test image.


Glow!

Blur...

Soft.

 

[daveleo]

I am wresting with all this helpful input, and reading internet descriptions.
Clearly, if I may be funny, the personal "definitions" are a little blurry !

I will comment on a few things at this point (may be right, may be wrong) . . .

I read that the Zeiss softar filter is a series of very small, widely spaced "hemispheres" on the flat glass . . . so it sounds to me like they induce a modest amount of spherical aberration to get "soft but sharp" effect. (?)

The Hoya Duto filter (as described by the BHPhoto item description) softens only the outer edges, leaving the center untouched.

Diffusion filters smear everything. Soft effect filters leave edges sharper than diffusion smear.

"Glow" (I think!) . . . is when the highlights spill ever so lightly over the edges. Probably the same thing as "soft focus" but a little more or less so?

"Blur" is loss of edge detail.

Why ask the question? . . . curiosity . . . trying to understand why people like "glow" and "soft focus" but hate "blur" and "soft / unsharp" images. Trying to understand how to get these effects (in small amounts) on a computer without just pushing a monkey button. Trying to understand how filters and lenses do what they do.

I do appreciate all the input, and hope to read more as time goes by.