80->200mm f2.8 vs 85mm 1.8D, both at 85mm f2.8

Have any of you folks compared the image quality of a Nikkor 80-

>200mm f2.8 zoom set at 85mm/f2.8, with a 85mm f1.8D lens set at f2.8?

Thanks

The trembling of may hands, when hand holding the larger lens, negates the theoretical performance of the larger and heavier zoom.

Of course, mounted on a tripod, well, that's a different story.

But if you have steady hands, and can hand hold the lenses, the difference isn't worth talking about.

The smaller prime will have 2 1/3 times as bright in the viewfinder.

DJ:

"The trembling of may hands, when hand holding the larger lens, negates the theoretical performance of the larger and heavier zoom."

The natural frequency of spring-mass systems lowers as the mass goes up. My hands being "sprung" to my body through muscles in fact shake LESS with a heavier lens in them. I workout regularly and am large in build, so fortunately I have never tired with that big zoom in my hands, and I can hold it quite still. Obviously, people's mileage will vary on this point due to different fatigue points. . Once muscle fatigue sets in, spasmodic action of the muscles would inject shaking.

"But if you have steady hands, and can hand hold the lenses, the difference isn't worth talking about."

I was hoping for a more quantified answer than this. Like, "using film x, with the photo enlarge to size Y, you may see a resolution difference". Presumably, the barrel distortion is less with the prime, and its contrast is higher. Will I notice the difference? I doubt it. My gut feeling is that you are right.

If you only have the f/2.8 zoom in this range, then you'll be forced to carry it everywhere. If you mainly take portraits, a small prime such as the 85 or a 105 is nice to have in addition to the zoom for those cases where you don't need the flexibility.

The 85/1.8 is sharper than the 80-200 but the zoom may be slightly more contrasty. How much? I haven't done a formal comparison, I have no use for it. Enough to notice, but not enough to be a big deal. I think that the images from primes (incl. the 85) look 'cleaner', but I'm not able to say why. And if you ever want to take indoor portraits in available light, the primes are the only way to go there.

Ilkka wrote:

"If you only have the f/2.8 zoom in this range, then you'll be forced to carry it everywhere. If you mainly take portraits, a small prime such as the 85 or a 105 is nice to have in addition to the zoom for those cases where you don't need the flexibility."

It's a fact I have been getting very tired hauling around my large Lowe-Pro "Trim Trekker" bag just to port that big zoom, other lenses, and accessories. Traveling lighter when I know I'll be only portrait shooting would be nice. However, it is usually the case that if I don't bring certain equipment with me, I'll be sorry later as unexpected photo opportunities tend to pop up.

Besides convenience, I was after even a slight quality edge by using that 85mm, as portraits are my favorite kind of shooting.

Dufus,

how about the "quality edge" of less intimidation with an 85/1/8 when taking portraits rather than with the 70-200/2.8?

Makes subjects more relaxed when you do not completely disappear behind that 80mm front element + 100mm hood ... of a glass cannon.