Huge in bokeh difference between f/1.8 and f/2?

Discussion in 'Photography Equipment & Products' started by TonyUSA, Mar 11, 2017.

  1. TonyUSA

    TonyUSA TPF Noob!

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    I have to say Canon 200mm f/2 is my dream lens. I believe the latest one is f/2.

    Wondering, would it be a huge difference in bokeh between f/1.8 and f/2.

    Thank you,

    Edit: I should say, would it be a huge difference in bokeh, depth of the field, pop, and separation between f/1.8 and f/2.
     
    Last edited: Mar 11, 2017
  2. Destin

    Destin No longer a newbie, moving up!

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    Well... DOF is dependent upon a variety of factors, only one of which is aperture. DOF is also affected by focal length, distance to subject, and sensor size.

    I'd say it's not a massive difference in end result.. all things being equal. But they don't make any 200 f/1.8 lenses that I know of. The longest 1.8 I know of is nikon's new 105mm.

    So what lens are you comparing against?

    A 200 f/2 is going to have far more pronounced bokeh than say, an 85 1.8, due to the large increase in focal length.

    Grab a DOF calculator app for your smart phone and put in the different settings to see how they affect your DOF.

    Also keep in mind that quality of bokeh is affected by more than just DOF.. all sorts of optical jibberish can affect it, which is why some lenses are known for their "creamy" bokeh while others have "harsh" bokeh, despite being similar in DOF.

    Edit: disregard much of my post. I didn't realize than canon once made a 200 f/1.8. That's incredible. But probably not a huge difference from 1.8 to 2.
     
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  3. Destin

    Destin No longer a newbie, moving up!

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    Just threw some numbers into my DOF calculator.

    Assuming you're shooting Canon Full Frame, with a subject distance of 20 feet:

    DOF @ 1.8 - 3.78 inches

    DOF @ 2 - 4.25 inches
     
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  4. dasmith232

    dasmith232 TPF Supporters Supporting Member

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    To the OP:

    Depth of field is a technical thing. It measure the depth of field based on focal length, aperture and distance to subject (and the required precision called "circle of confusion").

    Bokeh is an artistic thing. The main factor is depth of field, but also significant are the number and shape of the aperture blades. Destin's description about quality of bokeh is right on, so don't disregard that part! :)
     
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  5. Derrel

    Derrel Mr. Rain Cloud

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    Not a lot of difference. I owned the Nikkor 200mm f/2 AF-S VR for over a decade...I settled on f/2.2 and f/2.5 for almost all of my ultra-shallow DOF shots. At wide-open the DOF is simply so,so narrow at typical closer ranges that one risks having the body out of focus, or the arms out of focus, or the breasts out of focus,etc.,etc..

    The thing is this: there is depth of field, and there is selective focus, and there is a closely related thing called backround blurring. Background blurring is seldom discussed except among the congnescenti. The physically LARGER the lens aperture is, in actual terms, not relative terms, not in f/value, but in HOW LARGE say f/4.5 is, across the hole in the lens, the MORE the background will be blurred. Also, the larger (wider) the lens aperture is in PHYSICAL measurement, the less that diffraction affects sharpness: this is why 4x5 inch film cameras can be shot at f/45 or f/64, and still yield razor-sharp images that do not have diffraction effects.

    Because of the way background blurring works on massive lenses, there is a VERY fast degree of defocusing behind the focused distance with the 200mm f/2 and 300mm f/2.8 and 400mm f/2.8 clkass lenses. It's very difficult on a portrait to spot the differences between f/2 and f/2.2 and f/2.5 (which would be wide-open, 1/3 down, 2/3 stop down from wide open).

    What it comes down to is that f/1.8 and f/2.0 are only one-third of an f/stop apart, and both are very large apertures, and both produce very shallow DOF, and the degree of difference between the "old 200mm f/1.8" and the new 200mm f/2.0 are very minimal. These massive lenses have BIG holes at all the f/stops, and they create very de-focused AND blurred backgrounds.

    Take a VERY careful look at the two photos in this article: one shot with an 85mm lens at f/5.6, the other shot with a 56mm lens at f/5.6. Note that BOTH have the foreground subjects the exact, same size and height in the picture! But notice the diffferent degree of background blurring.

    See: Bokeh and Background Blur Calculator- Bob Atkins Photography

    and see also Bokeh and Background Blur - Bob Atkins Photography for yet another excellent example of how a longer lens, with a physically BIGGER aperture value, creates more background blurring. All three shots of the camera box were done at f/2.8; using 50mm, 85mm,and 135mm lenses.
     
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  6. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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  7. TonyUSA

    TonyUSA TPF Noob!

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    Thank you very much everyone. :1219::1219::1219:
     
  8. TonyUSA

    TonyUSA TPF Noob!

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    I just love the pop, background, and separation of them. I told myself about 3 times already that "forget about this lens, it is just too expensive" and many times I see the photos from 200 f/2 again and I just want it again and again. :BangHead:

    I just came back from Japan and I was going to get Canon 135mm but someone told me that a new 135mm will come out so I didn't get it. 135mm is one of the lens that I want it too.
     
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  9. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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    I don't think there is a noticeable difference in the quality of the bokeh. There definitely is in price.
     
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  10. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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    I have the 200 f2 because I got it barely used. A lawyer bought one to shoot his daughters tennis competitions when she was in high school and sold it. My 300mm f2.8 I got the same way but it was from a Doctor that bought it to shoot his daughters soccer matches. It is the Sigma version. Both very lightly used, both bought at half the cost new.

    My 400 f2.8 on the other hand was brand spanking new from Canon and cost me months of peanut butter and jelly sandwiches to afford.
     
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  11. fmw

    fmw No longer a newbie, moving up!

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    To correct some terms, bokeh is not depth of field. It is a description of the appearance of out of focus highlights. Depth of field defines the range of the image that is in acceptable focus from front to back. It is not bokeh. the difference in depth of field between f 1/8 and f2 is meaningless. But understand that how meaningless it is depends on the focal length of the lens.
     
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  12. TonyUSA

    TonyUSA TPF Noob!

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    gryphonslair99, Wow, I wish I would be lucky as you to get those lens in such a good deal. I will take a look at some of the photos of 200mm f/2.8.
     

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