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Old Jan 25, 2007, 11:07 AM   #1
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If I were to buy a lens like theNikon 80-200mm f/2.8 should I bother with a 85mm f/1.8 for portraits? Being that the 80-200mm would cover focal lengths between80 and 200mm. Would the two lenses also have different "angles of view"?
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Old Jan 25, 2007, 3:39 PM   #2
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The f/1.8 lens is more than twice as bright as the f/2.8 lens. Basically, in a light situation where the f/2.8 lens would shoot at 1/15 sec, the f/1.8 could shoot at 1/40. This gives the lens a huge advantage when shooting a moving subject as it will reduce blur from subject movement and camera shake, and it will allow for good exposures in less light so your pictures may come out more well exposed and less noisy.

Check this site out to compare the difference in f-stops: http://www.robert-barrett.com/photo/...alculator.html

Generally speaking, prime lenses (non-zoom lenses) take sharper pictures than zoom lenses. This is because they are specifically designed for that one focal length where a zoom lens has a bunch of moving parts to change the way the different lenses interact. Zoom lenses are also more prone to chromatic aberration (coloring along contrasting edges, usually purple), vignetting at wide angle, and image distortion at either extreme zoom.

Finally, with a wider aperture like f/1.8, you get a shallower depth of field, which means for a blurrier background at that focal length which is usually preferable for portrait photography.

I hope you enjoyed the lesson. It took me about 2 years to learn all that :?.
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Old Jan 25, 2007, 5:12 PM   #3
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Corpsy wrote:
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The f/1.8 lens is more than twice as bright as the f/2.8 lens. Basically, in a light situation where the f/2.8 lens would shoot at 1/15 sec, the f/1.8 could shoot at 1/40. This gives the lens a huge advantage when shooting a moving subject as it will reduce blur from subject movement and camera shake, and it will allow for good exposures in less light so your pictures may come out more well exposed and less noisy.

Check this site out to compare the difference in f-stops: http://www.robert-barrett.com/photo/...alculator.html

Generally speaking, prime lenses (non-zoom lenses) take sharper pictures than zoom lenses. This is because they are specifically designed for that one focal length where a zoom lens has a bunch of moving parts to change the way the different lenses interact. Zoom lenses are also more prone to chromatic aberration (coloring along contrasting edges, usually purple), vignetting at wide angle, and image distortion at either extreme zoom.

Finally, with a wider aperture like f/1.8, you get a shallower depth of field, which means for a blurrier background at that focal length which is usually preferable for portrait photography.

I hope you enjoyed the lesson. It took me about 2 years to learn all that :?.
Hello Corpsy,

Thanks for the post. You bring up some good points. And a URL I bookmarked. But most of what you said was a reminder more so than a "lesson". But they are definitely worth considering.

Though, when you're comparing maximum apertures...while what you said was true...I don't think most users would be using either lens wide-open most of the time. As every lens has a sweet-spot. I personally would stop-down one aperture value at least depending on the intent of my shot.

As for prime lens vs. zooms...or in this case an 85mm vs an 80-200mm...in terms of sharpenss...I suppose if you didn't want to bother with PP then I suppose the 85mm would be a better bet. Though, the 80-200m is also a pretty nice lens for the money. Also, I'd venture to bet that if you step down an aperture or two the sharpness would be comparable. And being that most of us do run our photos through some PP software I guess the degree of sharpness isnt really that important. I mean when comparing the two lenses.

The 80-200mm is said to do good quality bokeh. As would the 85mm.

Btw this would be one of my first lenses bought for my first DSLR. Maybe I should have mentioned that at the beginning. :-)

Maybe what I'll do to start is buy the 80-200mm f/2.8 and a wide-zoom like the Tamron 18-35mm f/2.8 (budget combo). Or the 70-200 f/2.8 VR and a 12-14mm f/4G if I'm willing to fork over a little more coin. This way I'd have a lens for wide shots (landscape, cityscapes, architecture) and some head-to-toe portraits (35mm with the Tamron). And use the 80-200 (or 70-200mm) for everything else shooting at a distance. And if I'm reall good maybe the superb 28-70mm f/2.8. Sounds like a good trio to me.
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