DOF Canon 28 1.8

Chris Johnston

Chris Johnston

Veteran
I'm looking around in prep to buy another lens and came across this statement on B&H.......

"excellent background blur is possible with fast shutter speeds"

I'm not a camera whiz and don't know about the mechanics of optics but I thought that DOF was an attribute of apature only????? The statement above leads me to believe that shutter speed may have some impact on bokeh or DOF blur......

Is that true or just some misquote/typo kinda thing?
 
DoF in controlled primarily by aperture, focal distance and focal length. Sensor size also plays a huge role in DoF, but remove the sensor size from the equation, assuming you are comparing lenses on the same camera. Example, a 24mm at 2.8 will give a deeper DoF (more of the background in focus) than an 85mm at 2.8.

You can learn more about how aperture, focal distance and focal length affects DoF at this site. They have some handy downloads that you can use on your mobile device.
http://www.dofmaster.com/

I think what they meant by the statement is that at 1.8, you will get a more shallow DoF. When you shoot at a higher shutter speed you need to open up the iris to get the same exposure as shooting at a slower shutter speed, so by having a faster lens (1.8 compared to 2.8) you can shoot at faster shutter speeds and an added benefit is a more shallow DoF.

Generally speaking, photographers who want sharp images want to shoot at faster shutter speeds where we (video/cinema) want to shoot at 1/60th, generally speaking.

Did that answer your question or did I make it worse?
 
No, I understood what you meant, (and I do actually have a rudimentary knowledge of how it works) but I was assuming what they were implying was (same lens, same cam, same focal distance etc) If you shoot at a faster shutter speed, your blur (or possibly DOF) would be different. I'm kinda sure thats not gonna affect anything but.........
 
videohog said:
No, I understood what you meant, (and I do actually have a rudimentary knowledge of how it works) but I was assuming what they were implying was (same lens, same cam, same focal distance etc) If you shoot at a faster shutter speed, your blur (or possibly DOF) would be different. I'm kinda sure thats not gonna affect anything but.........
Click to expand...


If you raise the shutter speed you will create a shallow DOF, I have done this many many times. I was once told this was not true, but when I do it, the camera does it and simply puts out a better quality image imo.


Personally I do not like shooting at 50 shutter speed, to me when I shoot above 200/300 it creates an amazing choppy look which I love.
 
life4eva said:
Personally I do not like shooting at 50 shutter speed, to me when I shoot above 200/300 it creates an amazing choppy look which I love.
Click to expand...

I'm familiar with the choppy bit, but that doesn't have anything to do with DOF. (thats all....... lack of motion blur, No?)
 
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