What makes Bokeh "better" on FX format cameras?

"Bokeh" - meaning blurred background.

On any camera, but easier on a camera which uses a largish sensor and thus longish lenses, e.g. full-frame or crop frame DSLRs.

Three factors come into play:

1] Use longish focal length, thus ideally 100mm or greater on FX.

2] Use wide-open aperture, thus f1.8, f2.8, f3.5, or whatever lowest number is on your lens (not f8, f11, etc)

3] Keep main subject well forward of the background that you want to blur.

Some lenses give nicer-looking blur than others, so you need to check a few by personal trial if you intend to buy specifically for blur. Note that different people have different ideas of what looks nice in blur.

"Bokeh" is actually a Japanese word. The effect you are looking for, in simple terms, is "shallow depth of field".

The amount of "bokeh" you get are affected by the following:

1) aperture size

2) focal length

3) subject to lens distance

4) size of image (ie. sensor size, film size, etc)

This is very difficult to explain without drawing it out. Let's imagine you have a subject, lens, and the image plane (sensor) of a given size. Let's assume, your subject fills the sensor. Here, you have a certain amount of DOF established. That is, there is a zone that appear to be clearly in focus.

Cropped sensor basically is portion of that image. Draw the size of new sensor on this image plane. Now, you don't have the whole subject So you'll have to use a shorter focal length lens to attain the whole subject in the now smaller sensor. This is what happens with cropped sensor cameras. You'll have to use shorter focal length to take the same image. You already know, wider angle lens will give you deeper DOF.

Therefore, smaller the sensor size, deeper DOF. Use something like an iPhone with tiny sensor and you get almost infinite DOF.

Boke is the quality of the out of focus regions. Has nothing to do with the body of the camera. It is part of the lens design that controls how the out of focus regions look.

I'm guessing you mean how you get narrow depth of field (selective focus). Yes, a full frame camera is a bit easier to get selective focus. Using a medium format camera is even better. However, with a crop sensor body, you should be able to do pretty good.

You need to use a wide aperture (small f-stop number). Something f/2.8 or wider (like f/1.8).

You need to be aware of subject versus background distance ratios. Shooting along the length of the car will make the distance ratio favorable.

It's not an effect. And it's not called "bokeh".

It's called shallow depth of field.

You need to read this: understanding depth of field: http://www.cambridgeincolour.com/tutorials/depth-o...

Camera vs camera = the larger the sensor the more shallow the depth of field. It is part of optics and physics.

It's the lens , not the camera body.