# Diffusion Filter



## klschaney08 (Dec 15, 2010)

*So, I just got a Canon Rebel T2i, and Im trying to figure out why when I take Portrait photos with the diffusion filter it is so blurry, I know that it's meant to soften the photo but it just does not look right, Can anyone give me a suggestion on what to try. Thanks!*


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## dxqcanada (Dec 15, 2010)

What kind of diffusion filter is this ? Make/Model

Have an example ?


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## klschaney08 (Dec 15, 2010)

It's rocketfish Diffusion Filter for 58mm lens.


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## Garbz (Dec 16, 2010)

Sorry to derail, but isn't a diffusion filter mostly irrelevant? This is an effect that can be easily mimicked, even automated in post processing.

One thing I was glad to stop using was the old diffusion filter from my film days. The effect was very non customisable and often the diffusion effect which was dependant on focal length and aperture was not what I wanted but I was compositionally stuck with those settings on the lens. 

Can you post an example image? Have you tried playing around with the aperture?


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## MarkF48 (Dec 16, 2010)

Agree with Garbz that diffusion is something that can be added later in post processing and you'll have more control of how the results look.

As far as looking blurry and not right with the filter attached, I wonder if it is somehow messing with the Auto Focus and throwing something off.

If you are using Windows and Photoshop, the plugin Beautifier free from Redpaw Media is a decent method to soften portraits. the other plugins are good also. There other ways to do it as well.

Red Paw Media - Plugins and Filters for Adobe Photoshop


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## Derrel (Dec 16, 2010)

Garbz said:


> Sorry to derail, but isn't a diffusion filter mostly irrelevant? This is an effect that can be easily mimicked, even automated in post processing.



THat is a fairly common misconception. No, the effects of in-camera diffusion can not be easily mimicked...the effects of in-camera, lens-based diffusion and Photoshop re-arrangement of pixels are lost on the uninitiated. Older, more experienced workers will be aware of the differences between using diffusion UNDER the ENLARGER's lens (ie-post-capture),and in-camera diffusion.

The difference between in-camera diffusion and re-arranging the pixels later are profound. In-camera diffusion causes light scatter from the highlights into the shadow areas, and in that way actually, physically changes the contrast ratio of the scene that is recorded by the film or sensor. This is a PHYSICAL, "actual change" to the light that goes through the lens. The effects of some of the better modern diffusion filters like the Tiffen Black Net series are a secret that only some of the top wedding and portrait shooters will let you in on. We're not talking about heavy-handed, clownish, hairspray-coated UV filters here...we're talking about subtle altering of the light that is going to be imaged by the lens...not clumsy after the fact pixel re-arranging attempts.


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## MarkF48 (Dec 16, 2010)

Derrel said:


> The effects of some of the better modern diffusion filters like the Tiffen Black Net series are a secret that only some of the top wedding and portrait shooters will let you in on. We're not talking about heavy-handed, clownish, hairspray-coated UV filters here...we're talking about subtle altering of the light that is going to be imaged by the lens...not clumsy after the fact pixel re-arranging attempts.


Somehow I get the feeling you used to play with nylon stockings for effect. I always liked the look of black nylons and shooting through a tear made for a nice vignette effect :mrgreen:


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## klschaney08 (Dec 16, 2010)

I want to focus more on portait pictures, so im trying to get softer pictures with the diffusion filter. The pictures without a soft filter are kind of too sharp, when you want portait pictures to be alittle softer than just a normal picture.


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## KmH (Dec 16, 2010)

That's what Vasoline on the lens is for.


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## MarkF48 (Dec 16, 2010)

klschaney08 said:


> I want to focus more on portait pictures, so im trying to get softer pictures with the diffusion filter. The pictures without a soft filter are kind of too sharp, when you want portait pictures to be alittle softer than just a normal picture.


Is the "diffusion" filter the camera's built in blur effect or are you using an actual diffusion filter on the front of the lens?

Few things to try....

- Decrease the in camera sharpness setting so images aren't as sharp

- Apply a diffusion or soft effect in your post processing. This way you can always go back to the original and try something else.

- If using the camera's built in effect try a diffusion filter that mounts to front of the lens instead. These can be bought in different diffusion strengths to vary the effect. Once the image is shot this way you can't "un-diffuse" it. Derrel mentioned one in his post above which if I remember correctly was/is the magic bullet for a lot of older film wedding and portrait shooters.

- Canon made a 135mm Soft Focus lens that the degree of softness can be varied. I have this lens and I like what it can do. Canon EF 135mm f/2.8 Soft Focus Lens Sample Photos and Specifications

- Experiment with different materials in front of the lens such as nylon stockings/pantyhose, window screening, sandblasted piece of glass, Vaseline rubbed on an old filter or piece of glass(not the lens itself)


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## klschaney08 (Dec 16, 2010)

I use a filter that i attach to the lens.


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## Josh66 (Dec 16, 2010)

MarkF48 said:


> - Canon made a 135mm Soft Focus lens that the degree of softness can be varied. I have this lens and I like what it can do. Canon EF 135mm f/2.8 Soft Focus Lens Sample Photos and Specifications


I have it too.  (I do need to actually use it more...  It's probably my least used lens.  I do like the soft focus under the right conditions, and it's still fairly sharp if you don't want that.)

I've always kinda wondered exactly how the diffusion filters work...  I don't think they work the same as a soft focus lens.  On the lens, you basically dial in spherical aberration.  I don't think a filter can do that, so I don't think the effect would be exactly the same.


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## Garbz (Dec 17, 2010)

MarkF48 said:


> Diffusion, soft-focus and lack of sharpness are all separate things. You can still user a diffusion filter and extract tac sharp details from a picture. Turning down sharpness is not the right way to go about getting that effect.
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