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12-28-2009, 07:27 AM   #1
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bokeh/ 3d rendering

I have been reading the posts on the forum and saw a post with taken with a Pentax smc 135mm f2.5 and was extremely impressed with the sharpness, bokeh, 3d effect. So looked around the second hand stores and came across a Pentax smc m135mm f3.5. Can anyone say if this will this give similar results.

I also looked at the thread about different lenses for different effects of bokeh which lead me to Rice Highs blog where he states that he thinks the DA lens do not give the same 3d effect that old pentax lenses give. The obvious ones being the ltds. I have a 70mm ltd 2.4 and I'm a little disappointed at the lack of the 3d effect but then that could be more to do with my technique - than the lens itself.

I would be interested of any of you think the same as he does regarding the 3d effect.

12-28-2009, 07:43 AM   #2
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QuoteOriginally posted by kiwao Quote
I have been reading the posts on the forum and saw a post with taken with a Pentax smc 135mm f2.5 and was extremely impressed with the sharpness, bokeh, 3d effect. So looked around the second hand stores and came across a Pentax smc m135mm f3.5. Can anyone say if this will this give similar results.

I also looked at the thread about different lenses for different effects of bokeh which lead me to Rice Highs blog where he states that he thinks the DA lens do not give the same 3d effect that old pentax lenses give. The obvious ones being the ltds. I have a 70mm ltd 2.4 and I'm a little disappointed at the lack of the 3d effect but then that could be more to do with my technique - than the lens itself.

I would be interested of any of you think the same as he does regarding the 3d effect.
Are you disappointed with the "lack of 3D effect" because of what you've seen with your photos, or because of what RiceHigh says about the lens? The DA 70 is a very capable lens, and I think it offers great color rendition, relatively fast AF, a very usable image wide open, and pleasant enough bokeh in an extremely small, yet well-constructed package. The FA 77mm ltd. certainly has a bit of magic to it's bokeh, but I really don't think any owner of a DA ltd. should be worried about his or her lens. You have a nice piece of glass.

As far as the 135mm question, I think the biggest issue between the two is not the bokeh, but rather the contrast difference between the two. I'm not sure the f/3.5 version has SMC, so it might offer lower contrast on your images. Also, you need to determine if you want the extra speed of the 2.5 lens. If anyone know more about this, please correct me.
12-28-2009, 07:46 AM   #3
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The "3D Effect" is nothing more than a visual manifestation of the mathematical combination of aperture size and how the lens renders out-of-focus details, and possibly how close you are to the subject. Any company can make a lens that gives a good "3D Effect", and its importance and appearance largely has to do with justifying how much money a person has spent on their lens ("I got this $2000 lens because of its amazing 3D effect no other lens can produce").

The 70mm ltd is "lacking in 3d effect" because f/2.4 is not a very large aperture. It's not much more than a placebo effect that you're experiencing. Any other 70mm f/2.4 lens or lens with similar specs will give roughly the same result, though if you spent a lot more on it you will be inclined to praise its 3D effect, even if it's no different.

The 135/3.5 will not be close to the 135/2.5 in "3D effect" because the maximum aperture is significantly smaller.

If you want "more 3D effect", get a lens with a larger maximum aperture and rounder aperture blades. Those two factors alone make up for about 80% of what the "3D effect" is.
12-28-2009, 08:26 PM   #4
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135mm f3.5 macro are predominantly sharing same optical formulae hence its rendering is not specific to pentax brand alone. Though sharp at f3.5 but just as sharp as any of modern macro lenses at the same aperture.

Da limited produced less 'popping' look comparing to Fa limited in a number of circumstances but Da limited lenses shine just like Fa limited.

12-29-2009, 08:18 PM   #5
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Thanks for the comments every one. I was interested in Rice Highs comments regarding older lenses having more oof, pop 3d effect than the da lenses and wondered if others agreed.
If so is this extra oof only confined to the FA Ltds or are there some older k mount or m lenses out there that have the same oof. The FA Ltds are out of my price range, thats why I bought the DA70 ltd instead of the 77ltd, but if there are used k or m lenses with the 'oof' quality then I can scour the many used camera shops in my area for one. I mentioned the 135mm f3.5 m because on Stans Pentax site it was said to be sharp wide open close to the 135mm f2.5 and have the 3d effect but the reviews on this site not so good. I can pick one up here for $80. I also found a 100mm fa2.8 macro which they rave about on Stans site? but they wanted $500 seems a bit steep?
An comments would be much appreciated.
12-29-2009, 08:32 PM   #6
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"3d effect" is hard to qualify, but I will say that in *my opinion* Zuiko glass on a large sensor tends to produce it with higher frequency than anything else I've used.

12-29-2009, 08:42 PM   #7
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Pingflood, My god that's amazing oof.

What's the major factor number elements, number of and shape of blades, speed of lens?
12-29-2009, 09:24 PM   #8
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To be honest, in my experience it's neither. Zeiss lenses and Zuiko (Olympus) lenses seem to make this magic happen, but nobody can quite explain the optical reason for it.

12-29-2009, 09:34 PM   #9
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I think a 3-d effect is acheived with a couple criteria:

1. Sharp and contrasty areas that are in focus. This really brings attention to what is in focus and "pops" out at the viewer.
2. Buttery smooth bokeh that still retains a lot of contrast. The smoothness of the bokeh allows potentially distracting background elements to be smoothed away and allows the in focus areas to "pop" even more. Good contrast even in the bokeh prevents the entire image from looking washed out and flat.

I have noticed this with several lenses I have, and I will note that you don't necessarily need ultra-large apertures to acheive a "3d" effect. With ultra-large apertures (in combination with short subject distances), the background can be too out-of-focus and isolates the subject too much, almost removing the subject from the scene. IMO there is a perfect balance to the relative blur amount of the OOF areas that creates a wonderful 3d image. Larger aperture lenses just allow you to create the 3d effect in more shooting situations, and often have more aperture blades (because they are more expensive lenses) and thereby render the OOF areas much smoother than cheaper, smaller aperture lenses.

I have an SMC 135/2.5 and it produces good images not only at f/2.5, but also at f/4 and up. Don't let people fool you into thinking that you need to shoot with lenses wide open to get great shots. An SMC-M 135/3.5 won't produce quite as smooth of background blur, and may not have quite as much contrast, so it may be slightly more difficult to get that 3d effect. But it is still capable of taking nice images, and would be a good introduction to the 135mm focal length before you drop more money on the f2.5 lens.

that's all i've got.
12-30-2009, 03:20 AM   #10
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QuoteOriginally posted by pingflood Quote
To be honest, in my experience it's neither. Zeiss lenses and Zuiko (Olympus) lenses seem to make this magic happen, but nobody can quite explain the optical reason for it.
Here are my 2 cents: Zeiss lenses tend to be sharp and have good color contrast wide open. So there is a clear demarcation between what is in focus and what is not.

Also, since you didn't take two photos of the same composition with two different lenses at the same aperture setting, your post is nothing but the perpetuation of mythology.
12-30-2009, 07:44 AM   #11
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QuoteOriginally posted by pingflood Quote
"3d effect" is hard to qualify, but I will say that in *my opinion* Zuiko glass on a large sensor tends to produce it with higher frequency than anything else I've used.
Great shot Pingflood! Looking at it, I'm in agreement with a lot of what arpaagent says. I think your photo achieves the 3d effect due to:

1 - sharp focus of the subject
2 - blurriness, but not excessive blurriness of the background
3 - brighter exposure of subject (did you use fill flash?)

I'm not yet convinced that certain lenses have special pixie dust that gives them magical 3d powers. Yes, the number of aperture blades may make a subtle difference, and faster lenses maybe create more opportunities to separate the subject from the background "just right", but I think the 3d effect is more dependent upon the situation and the skill of the photographer.

Here, for evaluation, I submit a photo taken with the K-x and a kit lens. Not nearly as nice as yours, but it demonstrates that you can achieve a 3d effect with a kit lens:



Exposure: 0.013 sec (1/80)
Aperture: f/5.0
Focal Length: 30.6 mm
ISO Speed: 3200

One of the neat things about the high ISO capabilities of the K-x is that you have more latitude in selecting an aperture in low light situations - you don't have to worry about noise at smaller apertures/higher ISOs. If I were taking this shot with my K20d, I would have had to worry about high ISO noise more and probably opened up the aperture a couple of stops (F2.8 or F3.2) in order to keep the ISO somewhere around 800. I would have gotten the shot but might have lost some of the 3d effect in the process due to excessive blurring of the background.

I suggest others submit other 3d photos for evaluation as well. This is an interesting subject.
12-30-2009, 07:58 AM   #12
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I know this is very subjective, but "typically(if one can say that)" the 3D effect talked of in photography is a very destinguished and striking phenomenon. Having said that, I'm not really feeling it in the samples provided to date.


Image by - brainiac - Contax 35 f1.4 - posted on Fred Miranda's forums

There are many said recipes for this type of output, though proven methodology remains quite rare. My take on it, is that it may very well happen under such a number of criteria that a working recipe is simply to hard to grasp.

Whatever the case... it never ceases to amaze me when I see it.

Here are a few highlights I've gleaned from various sources on the subject.

QuoteQuote:
I first encountered a 3D effect when I began using a 5D. The camera needed to be able to record the high contrast that the lens was transmitting which seemed less visible with crop bodies due to the higher per-image photon noise.
QuoteQuote:
I believe the 3D effect is dependent on lighting and background. And since some lenses capitalize on those conditions so contributors maybe contrast, acuity, and resolution; the base camera requirements
QuoteQuote:
And contrast in my experience is best achieved from glass and sensor(imaging engine) followed by resolution too provides the basis for acuity to engage the substance of the image
QuoteQuote:
Microcontrast, tonal separation, color separation, linearity, good OOF rendition. I am of the opinion that there are "no secret ingredients, only fresh ones". For instance, the Pentax A* 135/1.8 I used to own was very three-dimensional, but the other Pentaxes I own lack those qualities except the last and look pretty 2D.
  • good sharpness and microcontrast on in-focus areas
  • use of lighting to bring out textures on the subject
  • use of DOF
  • use of perspective
  • use of color
  • use of framing

Textural 3-dimensionality.
This is the sense that you're looking at something physical, that you can reach out and touch. This comes from resolution of fine textural details (which in the case of a wide angle landscape shot can actually be very large real life objects -- think of tiny trees blanketing a hillside). Actuance, i.e. microcontrast, plays its role here, hence the performance of great lenses. Resolution of fine details does as well. And directionality of lighting is paramount to giving little textures both a luminous and a shaded side -- a very important textural feature.

Depth.
This is the sense that you're looking into a world that you can walk into. Composition plays a role here, with things like leading lines, S-curves, and distinctive foreground-middleground-background relationships giving you a sense that the world is converging into the distance. The simplest example would be plain old perspective convergence, like the railroad tracks that come to a point on the horizon. Lighting, color relationships, and in some cases shallow DOF will evoke depth.

QuoteQuote:
Depth, and that is compositional. Leading lines, perspective convergence, depth cues, and DOF are what suggest depth in a photo. Shadows and lighting are extremely important to this as well.
QuoteQuote:
Textural realism. And lighting and microcontrast are the most important components to this.
QuoteQuote:
I think lighting and contrast(NOT detail) are THE predominant factors that produce a 3D effect when one is there. If the lighting is right, a photo will look like you can reach into it and touch it.

Last edited by JohnBee; 12-30-2009 at 08:10 AM.
12-30-2009, 08:11 AM   #13
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IMHO, 3D effect is created by light and shadow. Shallow DOF only gets you two layers, but light and shadow can give you much more. Here is an example (not taken by me)
Attached Images
View Picture EXIF
NIKON D50  Photo 

Last edited by sbbtim; 12-30-2009 at 08:13 AM. Reason: add an attachment
12-30-2009, 08:23 AM   #14
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Interesting, JohnBee, because while you posted a great shot, it doesn't fit my definition of 3d effect - primarily because the background has been blurred beyond recognition. My definition of 3d effect is that the subject appears to be in a place with definite depth, that they are in a place. In other words, somewhere between the flat "everything-in-focus" effect of small sensor cameras and "background-is-an-abstract-creamy-bokeh-painting" effect of ultra-fast lenses.

Not to be an Internet critic or anything, had the shot you posted been taken with the aperture stopped down just a hair, the figures in the background might have become more legible, and the subject's nose might have been a little sharper. Either way, it's a great shot and one I would have been proud to have taken. But I guess that there is some subjectivity with regards to what 3d effect is, and that's ok...
12-30-2009, 08:28 AM   #15
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And this is why talking about this subject will lead nowhere... everyone has a different opinion on what makes a "3D effect"...
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