What makes a "good" lens

[creatip123]

I'm having a difficult time achieving what I want because im using a lens that isnt allowing me to get me whole subject in frame and still give me the desired results. It has nothing to do with my lack of knowlage on how it works.

When I got the 35mm yes there was a lack of knowledge since I had never shot before trying to get a bokeh effect because my 18-105 was just to wide, but I do have time with the lens, I get how it works. Cars are simply to wide of a subject though to get all in frame+get close enough to get bokeh with that lens, unless I get REALLY creative with the positioning of the car, or I limit myself to front on shots.

But ya its why I am given the role of the 35mm as upclose detail shots.

 

What he's saying is about understanding the basic concept and rules of lens and bokeh (which is where your problem lies). It's good to view it in the physical aspect (as in applied physics). 

 

What determines the amount (not quality) of bokeh is what technically called 'circle of confusion'. There are a lot of articles on the net, but in a nutshell, it's something like this: If you have 2 dots on a paper, 1mm apart from each other, and you view it from 10m away, you'd only see 1 dot, right? Your eyes can't distinguish that 1mm space between them from that far away. That's basically the reason why it's a lot harder to get bokeh from wide lenses, compared to tele lenses, because of the wide field of view. You can test this if you want. Use a tripod, use your 105mm lens, and shoot something that's stationary, with widest aperture. Mark the spot/object that's blurred, let's just call it 'point A'. Now change to 35mm, and shoot from the same spot + same aperture. Point A won't be as blurred as with the 105mm, right? Now load the picture to photoshop, and magnify it by 3x or 300% (105 divided by 35), you'll see the amount of bokeh will be pretty much the same. 

 

Now back to your problem. one of the key factor of bokeh is the ratio of distance between the lens to the object vs the object to the background. The bigger the ratio, the blurrier the background will be. You can still get bokeh background with wide lens, if you manipulate the ratio. Of course the wider the lens, the bigger the ratio needs to be to get the result, due to the circle of confusion mentioned above. 

 

This is an example of a wide lens with bokeh background (from google):

 

 

The ratio of distance between the lens to the car vs the car to the mountain is very big, thus the mountain is blurred (even though the lens used is a wide lens).

 

Once you understand the basic principle, you'll automatically know what can and can't be done with the existing gears.