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03-05-2014, 07:24 AM   #1
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maximizing bokeh of DA50mm 1.8 on K30

Question:
I'm buying the DA50mm 1.8 at the end of March. My goal is to get the maximum bokeh quality from the lens.
My question is... The minimum focusing distance on my 50mm is about 19".
If I use spot focus will that give me a better isolation of close up flower shots and give me more bokeh.
Any input will be greatly appreciated. Freddy

03-05-2014, 07:28 AM   #2
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Well, get in close, shoot wide open, and watch your background (distance, makeup, etc). That's all I can say!
03-05-2014, 07:40 AM   #3
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QuoteOriginally posted by fevbusch Quote
If I use spot focus will that give me a better isolation of close up flower shots and give me more bokeh.
Any input will be greatly appreciated. Freddy
I'm a little confused by the intent of your question - when you say spot focus, do you mean as opposed to multi-area focus that would focus on other places besides the flower?

Bokeh is as filoxophy says - shooting a subject up close and wide open and positioning the subject as far from the background as possible will generate the smoothest backgrounds.
03-05-2014, 07:52 AM   #4
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maximizing bokeh of DA50mm 1.8 on K30

Yes, I do mean spot focus as opposed to multi-focused. Looking forward to your reply. Thank you, Freddy

03-05-2014, 07:56 AM   #5
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Well in general, spot focusing is the most accurate focusing method for non-moving objects. In consideration, multi-area focusing can still be used if the flower you are aiming at is the dominant subject in the frame.
03-05-2014, 08:34 AM   #6
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Fifty Bokeh?

Hi Freddy,
I've had the DA 50 f/1.8 for over a year now, and really like it, especially the bokeh and rendering. But, it can be tricky as a close-up lens. Above f/5.6 or so it doesn't get exactly jagged or harsh, but slightly harder around the edges of background objects. More well-defined blurring, so to speak.
The absolute best range I've found for this lens is f/4.0 to f/5.6. Bear in mind, I'm using it for street candids, semi-macro, selective-focus work. Not so much scenic, true Macro or great depth-of-field subjects. A good, lightweight short telephoto.
Here's a few photos to illustrate; The first flower shot was done using a K10D and fill flash. No flash on # 2 and 3. The rendering of this sensor will be different from any later CMOS sensor, but the Bokeh should have a similar look. The flash allowed me to use a higher f/stop, helping the DOF and isolation, but not the Bokeh.
In the third photo, notice how shallow the DOF is. The shoulder straps of her dress are both out-of-focus. For candids, f/4.0 rocks!
In order, the F/stops are f/8.0, f/5.6, f/4.0. Of course, it's not the same subject and setting, but will hopefully provide some visual information.
If you intend to use the fifty as a Macro or candid portrait lens, I'd suggest a fill reflector (white and gold, or 5-color 60cm disc) and hot-shoe flash with 'softbox' diffuser as accessories. And, a tripod w/remote release.
I do use spot metering for close-up, but pick your spot well! DOF preview, LV, chimping and bracketing (by focus and f/stop) help considerably.
Good luck!
Ron
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Last edited by rbefly; 03-05-2014 at 08:43 AM.
03-05-2014, 08:58 AM   #7
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All focusing is "spot focusing." There's a certain number of autofocus points the camera can choose. It seems to do so randomly (there's a recent thread about this somewhere on the forum), so using autoselect is a poor idea when you shoot at large apertures. You don't have the DoF to cover for when the point is off from your intended target like when shooting at, say, f/8.

One suggestion is to set the AF to the center point and recompose as necessary. The center AF point is the most sensitive, down to f/2.8, while the others aren't as high. In my experience, they seem to work just fine (even the linear types on the sides), so you can use focus point select and avoid having to recompose. That's what I do with a 50 f/1.7. It gives great results wide open and at f/2.0 for me.

There is spot METERING, which is different. Multisegment (or matrix) metering basically takes an average over the whole frame. Autofocus does not work like this; it picks a single point from the 11 (for K-5) or 24 (for K-3) predefined regions and focuses there. Matrix metering is great if you care about everything, but when you want to isolate subjects, you want the target to be properly exposed and forget the background. There's two solutions:
1) Use center spot metering with the center AF point and recompose
2) Set the camera to tie autoexposure to the autofocus point

Otherwise, it's what people say: shoot at large apertures and focus as close as you can!
03-05-2014, 11:20 AM - 1 Like   #8
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fevbusch...

I think you're actually asking a simpler question than the answers we've given you so far. Spot focusing does not affect bokeh at all. Bokeh only has to do with your aperture and subject distance (and the lens). The method that you use to focus only determines *what* is in focus, not the quality of the bokeh. You could, for example, use spot focusing or many-point focusing (or even manual focusing) and still obtain exactly the same photo.

Good luck!

03-05-2014, 01:09 PM   #9
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QuoteOriginally posted by ofer4 Quote
fevbusch...

I think you're actually asking a simpler question than the answers we've given you so far. Spot focusing does not affect bokeh at all. Bokeh only has to do with your aperture and subject distance (and the lens). The method that you use to focus only determines *what* is in focus, not the quality of the bokeh. You could, for example, use spot focusing or many-point focusing (or even manual focusing) and still obtain exactly the same photo.

Good luck!
What he said. I would add that with this lens to achieve the best balance between sharp focus "pop" of your subject, and a creamy defocus bokeh background, I'd stop down to just shy of wide open rather than all the way to f/1.8. I'd land it in the 2.0 to 2.5 range if you're looking for super slim depth of field focus and crazy swirly colors.
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