What is the difference between sony 50mm and 85mm lense?

I have the sony 50mm portrait lens and im looking at the 85mm lens, now I know that the 85 is a closer lens. I have the 18-200 lens if i put that on around 85 would there be a big difference in using the portrait lens 85mm to the 18-200 lens. What exactly would be the difference?|||A general note, 85mm lenses are good portrait lenses in general because the prime lens is relatively easy to manufacture to a high standard making it very sharp, this coupled with the ease to produce a large aperture you have a very nice portrait lens. However on a APS-C DSLR the crop does make the 85mm lens rather long and not a lens suitable for confined spaces. Great outdoors or in a studio but not so great for indoor events. 35mm and 50mm lenses are more suited for cramped indoor events.





As to how the 18-200 @85mm compares to the 85mm prime. The field of view will be exactly the same, however the overall performance of the 85mm prime will be far superior to the zoom. You will get a sharper image (most primes are sharp wide open, the zoom needs to go to f/8, that gives you over 4 stops advantage with the prime), and less change of artifacts coming up in the image (common problem of big zooms) and you'll also gain the advantage of the shallower depth of field.|||The 85 gives a magnified image compared to the 50. You'd get the same magnification with the zoom at the 85mm setting but the single-length lens would probably give better clarity.





BTW, greater magnification isn't the same as "closer". Moving closer changes perspective where increasing image size does not. That is to say moving closer makes the size of objects in the background smaller in proportion to the subject where magnifying the image does not.|||The field of view would be the same, so by adjusting the 18-200mm to 85mm you'll get an idea what you'll see using the 85mm. You will of course have a wider aperture at 85mm than is achievable on the 18-200mm at 85mm.|||What is the difference between prime lens and zoom lens?


Very nicely summed up in this article;


http://www.slrphotographyguide.com/camer鈥?/a>|||35 mm