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I don't understand this lens topic. I watched so many videos and now i have more questions. I have a Canon M200 for streaming. I want nice bokeh effect for my background and silence auto focus. Default lens can focus silently but aperture is not enough for bokeh.

Camera to subject distance is 85 cm. Subject to background distance is 165cm.

I found some lenses but they have noisy auto focus. Thanks for your suggestions!

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  • when you say that you want bokeh, do you mean that you just want the background to be blurred, when you are 85 cm from the camera, and the background is 165 cm behind you? – osullic Jan 19 at 15:11
  • what is the background? how much blur do you want? – osullic Jan 19 at 15:11
  • @osullic Yes i want some blurred background. There is some led lights on my background and i want them look good with some blur. Here i found a sample look : prntscr.com/x81idk – user497657 Jan 19 at 15:28
  • You are misusing the term bokeh. Bokeh isn't how much blur, but the quality of the blur. Yes, some blur is prettier than other blur. Google it. – Mattman944 Jan 20 at 0:21
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More blur == larger aperture, if other factors remain fixed.

From 85cm you'll need a 35mm lens to get head & shoulders in shot, possibly a 50mm if you can drop the camera back a way.
You can get a f/1.8 for a reasonable price or a f/1.4 for a lot more. $£€100 1.8 to $£€ 500 for a 1.4.

The shorter your lens, the larger aperture you will need to blur the background.

Examples… (ignore the quality, these were lit by the computer screen & one room light & the ISO ramped up to max - not exactly ideal lighting)
Bear at 85cm, centre of flowers test print on wall another 165cm

50mm 1.4

enter image description here

35mm 1.8

enter image description here

This is on an APC-C with a 1.5 crop, the Canon is a 1.6 crop so your framing would be tighter.

Personally, I'd always go for the 50 & try to gain some distance rather than the 35 which can get a bit 'pointy' for me - big nose, little ears.

If you don't want to hear the autofocus motor, don't use the built-in mic.
Pulling focus to follow a talking head at 65cm on either a 35 or 50 is going to be pretty distracting. You will probably have to choose between razor-thin DoF & not making your audience dizzy by sacrificing some of your blur.

Late edit
Another idea, if you want to "outcool the other kidz" is a fake anamorphic lens (or a real one if you can afford it, but they're expensive ;)
This is a 52mm lens (a Helios 44M) I got from a Russian lens mod company, for $55 USD. It has a 'fake' iris inside which gives the impression of an anamorphic effect on bokeh. It is totally manual, so no more follow-focus issues to worry about. Look at the light I put in the scene, which is a single LED point-light. It gives it a vertical oval shaped bokeh, characteristic of anamorphic lenses. It's actually only an f/2, but it feels much wider because of the distortion in the out of focus areas. Crop to a more movie-style 16:9 or even tighter & there's your fake cool lens effect…

enter image description here

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    Thank you so much for detailed info and reference pictures. I will probably take the camera back 30cm more with a new tripod. I will go for 50mm with your suggestion. – user497657 Jan 19 at 16:10
  • I added another idea - this one was v cheap. The lens is manual only, so no focus-follow issues to worry about ;) – Tetsujin Jan 19 at 17:46
  • Thanks for the cheaper alternative. I did some research and field of view is a big problem for me. There is no much space even if i want to. I made some test with 15-45mm stock lens. For example if i put stock lens to 30mm is this FOV equals to 30mm f/1.4 lens? I'm looking this lens from canon : Canon EF-M 32mm f/1.4 STM Lens it's looking pretty good on reviews. Only problem is FOV i guess. It's really complicated for me. Thanks again! – user497657 Jan 19 at 19:10
  • Wider FoV needs wider aperture to achieve the same out-of-focus blur. Any zoom lens set to the same length as a prime will give similar results at the same aperture. If you're limited for space, then you'll have to go shorter & wider, no alternative. For great bokeh there's no real substitute for distance, I'm afraid. – Tetsujin Jan 19 at 19:17
  • Looking at the vertical bar in the background, the modified Helios seems to be giving a bit of the (usually disliked) double-line Bokeh effect. – Jerry Coffin Jan 19 at 21:02

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