Why get a 50mm prime if a 17-55 AFS F/2.8 is almost as sharp?

<p >I was wondering if I have a 17-55 AFS F/2.8 and it is almost as sharp as a prime, why would I get a 50mm prime lens? I know the aperture on the 17-55 is sometimes not fast enough and the extra speed is handy when the available light is not good and I don't want to use flash. Are there other reasons? Would it be a bad idea to get the 50mm 1.4 (for portraits)? </p>

<p > </p>

<p >thanks.</p>

<p>It really depends on how you work, if you need zooming then take the zoom but if you like to work with a small and fast lens then the primes is good. My understanding is that the 17-55 flares easily and geometric distortion is probably larger than in a prime. IF lenses also tend to get shorter when focusing close. But if these are not big issues then it's really about working methods.</p>

<p>Depending on the distances between you, your subject, and the background, a 50/1.4 can give you a very different look (in terms of deliberately shallow depth of field) than can an f/2.8 zoom used at 50mm.<br /><br />And no question that a fast 50 is going to give you a brighter viewfinder in marginal light, and give the camera's AF system more to work with when you're in dim circumstances. When composing/focusing, the lens is wide open... and an f/1.4 lens is gathering more than twice the light as an f/2.8 lens. Very helpful when working. <br /><br />But... if you had to send me out the door with one or the other? I'd take the 17-55! It's great to have both, but that 17-55 is a <em>very</em> good bread and butter lens.</p>

<p>I really like the 17-55. On a side note, I haven't noticed any flare though and I read so much about it. Can someone tell me when exactly I would see flare? Is it only if I'm shooting into the sun? What about backlit subjects?</p>

<p>I have discovered that my fast primes are only needed, even with the "soft" 18-200, when I have to shoot in real low light. I love my 35mm f1.8, and my 50mm f1.8, but rarely "need" them.</p>

<p>That said, I really enjoy shooting with a prime. It's purely a "fun" thing... Don't know why.</p>

<p> Leila, every lens has its own optical signature, the sum total of its flaws and strengths. Each one has a kind of personality, and you should use one that aids and abets your own vision. Primes, in general, are quite different from zooms. MTF charts and pixels are abstractions. Look at a print with your own two eyes. Slavishness to ideals, as one often sees here, leads to numbing sameness (among other things).</p>

<p> Want to see flare? Go outside at night, put camera on tripod, and focus on a streetlight with a night sky background. You will see flare. Make a short bracket. Move the framing so the light is in a corner. Flare, more exposures. Now, stop down and use the DOF button, how does the flare change? Get to know your lenses.</p>

<p> </p>

50/1.8 = 150g,

50/1.4 = 225g,

17-55 = 750g

<p>If I owned both, the zoom would sit at home gathering dust because this just isn't a useful focal length for me. I would always carry the prime because it weighs nothing and takes up no space in my bag.</p>

<p>A one stop or more advantage in speed can make the difference between acceptable and excessive noise levels with my D2H. I've often switched to the 50/1.8D AF instead of an f/2.8 zoom that covers the 50mm focal length just to be able to shoot at ISO 400-800, since the D2H is very noisy at 1600.</p>

<p>A 50mm prime tends to be the single best value in any lens maker's lineup. Not only sharp and fast, but typically very well corrected to minimize all optical flaws: chromatic aberration, coma, barrel or pincushion distortion, etc. It can make the difference between pinpoints of light that look like lights and oddly shaped, elongated teardrop shaped smears of light with smudged halos. These are often minor flaws unless the subject of the photo is a display of lights at nighttime or in a darkened building. Think holiday lighting displays, carnivals, etc., where you want the most accurate possible rendering of the lights. Even some very good midrange zooms don't handle these details as well as a modest 50mm prime.</p>

<p>You are trading speed and size for weight and versatility. Price is also very different. Only you can decide which is more important for your application. I have yet to find a zoom I really like on all counts. The 17-55mm reads as a very good lense.</p>

<p>You could just buy the lens, play with it and see if it works for you. If not, send it back to them. I believe B&H, Adorama have 2 week return policy (don't remember the details). Plus you might get fre S&H so if you don't like it, the only thing you'll spend your $ on will be shipping it back to them.<br>

good luck<br>

Adam</p>

<p>Hi Leila,<br>

I too believe there is little point in a prime when you have an excellent zoom, the 50 f/1.4 is generally not that sharp wide open in order to gain sharpness you need to stop down to f/2.8 any way. My 24-70 doubles for me as a 50 prime and it is sharper than any 50 at f/2.8. But you can create some special effects with the thin dof of the 50 at f/1.4, but you need to battle the fringes. </p>

<p>Gotta love the primes for several reasons.</p>

<p>1) Often possess optical purity, ( Little CA, Flare, Ghosting, almost zero distortion.<br>

2) Weight..very light.</p>

<p>Main drawback?..I might miss "The Shot" and changing often I risk dust & dirt on the sensor. </p>

<p>I own a prime in every zooms focal length range I own. As pointed out above, they are always faster...or at least are available in faster apertures....and that extra stop is definitely worth while if you do a lot of low light photography like I do. Another reason is that in almost every case, the prime is smaller and lighter than the zoom in the same focal length range. Almost....there may be an exception or two but if you're talking f/2.8 zooms and fast primes, it never happens as far as I know.</p>

<p>Smaller, lighter, and faster.....always a winning combination if you're carrying photography equipment for long periods of time. If we're talking studio work.....out of focus highlights is about the only advantage of a fast prime over a 2.8 zoom.</p>

<p>This all assumes your original question....."if the sharpness is almost the same".</p>

<p>If your current lens does everything you need, and you are happy with the results, no need to spend more money. However, if the points made by other posters ring a bell with you, and you want to see what works best for your particular circumstances, little is lost in trying out a direct comparison between the lenses.</p>

<p>good question. 1.4 will make a difference in extreme low-light or with certain bodies, but that money might be better spent elsewhere. you might want to consider the 50/1.8 as its smaller and lighter and less expensive. not my favorite portrait lens, though. if you want a portrait lens, get something outside the range you already have covered with the 17-55, like an 85.</p>

<p>Instead of considering the 50, how about the new AFS Micro 60mm f/2.8G ED which will give you a prime lens that has macro capabilities and if you are using a DX camera, 90mm focal length which would probaly be better for portarits. </p>

<p>Shooting with prime lenses is just a different experience. When you have a zoom lens mounted on your camera, you're constantly zooming from one focal length to another. When you have a prime lens mounted on your camera, you're constantly moving the camera to find angles where the prime's focal length works best.</p>

<p>A zoom lens is like a person who's good at doing many things. He's very versatile and flexible. A prime lens is like a person who is REALLY GOOD at doing ONE THING. He can be versatile, too, but you'll need to think creatively if you're going to get the most out of his talents.</p>

<p>Another advantage of smaller, lighter prime lenses is that they're more discreet in their appearance. Fast zooms (f/2.8) are always large and conspicuous.</p>

 

<p>Depth of field is probably the biggest. I have never used the 17-55 but I own the 50mm 1.4D. I can't imagine a zoom being as sharp as my prime. The 50 is the sharpest lens I have ever owned, and it's DOF is incredible on the D700. It rarely leaves my camera.</p>

<p>The difference between f2.8 and f1.8/1.4 is huge for both shutter speed and DOF. It's funny that the 50mm, the cheapest lense Nikon makes, is just that good.</p>

<p>"and an f/1.4 lens is gathering more than twice the light as an f/2.8 lens" - exactly four times more light is certainly more than twice.</p>

<p>Weight, size, and one less ring to move...after shooting events i noticed the metadata using the 17-55 indicated that the lens was usually right around 50mm for a majority of shots</p>

<p>The Nikon 17-55 is quite soft at the long end; the 50/1.8 is far sharper in my experience, though you might find the 17-55 "good enough" depending. I liked the 17-55 very much - it's a great lens for people photography/events at the wide angle end and a good portrait lens at 55mm but there are a bunch of issues with it also. 1) soft at 55mm, 2) ghosts like crazy if point light sources are the main source of light and are included in the frame, 3) strong field curvature at 17mm can cause weird edge softness problems at long distances in landscape photography, 4) truly sharp aperture range very narrow (f/4-f/5.6). But it has very little CA and a very pleasant rendition of people's skin and is quite compact for the aperture and zoom range. I sold mine when I went FX. The 24-70 is 1) sharper at f/2.8, 2) rarely ghosts, and of course renders the whole FX frame, but on the downside it's more expensive and heavier + bigger than the DX zoom. I wouldn't want to be without a 50mm prime whichever zoom you have.</p>

<p>Sharpness isn't the only criteria. If you want to do any shallow depth-of-field work you can open up the 50mm prime lens to <em>f</em> 1.8 or even <em>f</em> 1.4.</p>

<p>You just can't do this with the 17-55mm even if the 'sharpness' is acceptable.</p>

Because it won't let you zoom out or in? Because it fosters your creativity by making you think how you could take the picture, although you have the wrong focal length for the immediate solution? Because it is light and small?

 

And: the Sigma 50/1.4 IS a good lens to have, though it is neither light nor small :)