[miltona580]

There's also some things you just cannot do with a zoom. For example, you are not likely to want to do astrophotography because the coma aberrations that most zooms have will stop you. A good prime just doesn't have that kind of problem, usually.

[normhead]

There's also some things you just cannot do with a zoom. For example, you are not likely to want to do astrophotography because the coma aberrations that most zooms have will stop you. A good prime just doesn't have that kind of problem, usually.

You're comparing most zooms to a good prime…
How about a good zoom to most primes…
If you have a sigma 8-16, you'll have a hard time finding a prime with as low CA values.

[savoche]

There's also things you just can't do with a prime.

But as Norm says, putting lenses into two categories being zooms or primes isn't very helpful. There are many other and more important attributes that decide whether a lens is good for a particular type of job or not.

That said, I enjoy shooting with primes more, and that is reason enough for me. Also the good zooms tend to be big, and I don't like that.

Umm, and I shoot purely for fun. Had I been a pro I suspect zooms would be more sensible. Maybe.

[normhead]

I actually don't have a zoom I'd use instead of our Tamron 90 macro, our Sigma 70 macro, or FA 50, 1.7, but it's hard to have a prime for every focal length you might need. And it's way to more expensive to do primes. I'd love a 31 ltd, but will I ever actually lay out that kind of money for a lens that covers that focal length? Its an issue.

[miltona580]

You're comparing most zooms to a good prime…
How about a good zoom to most primes…
If you have a sigma 8-16, you'll have a hard time finding a prime with as low CA values.

Even good zooms have coma aberrations, which is not the same thing as CA. That usually stands for chromatic aberrations. A coma aberration will make a star look like a blob. And yes, even the Sigma 8-16 is pretty nasty with coma aberration except in the center (source: Sigma 8-16 mm f/4.5-5.6 DC HSM review - Coma and astigmatism - Lenstip.com. I am not saying it's a bad lens - far from it. Just you probably wouldn't use it for Astrophotography unless you're doing star fields with many stacked images.

[sanjeevdas]

Primes lenses make me *think* about photography. With a zoom I might be content with me zooming to find the best focal length from that spot, it makes me lazy. A prime, on the other hand, does not afford me that luxury. That forces me to move to find alternate angles and positions. I generally find that the original position was not that great and that there are superior alternatives. Primes also force me to think about what lens I need for the task at hand. Because changing lenses is such a PITA, I need to choose carefully, helping me to learn a lot more about focal length, perspective and photography in general. Of course, primes are also smaller, lighter and generally have better quality than zooms.

[lytrytyr]

Of course, primes are also smaller, lighter . . . than zooms.

Not necessarily:

Zeiss ZK 21/2.8 --- 87 x 110 mm, 620 gm
Tamron 17-50/2.8 --- 82 x 74 mm. 434 gm

(comparing two options for a Pentax DSLR).

In fact, there is a clear current trend towards big primes (Zeiss, Samyang, et al.),
now that manufacturers think zooms have accustomed us to big lenses generally.

[lytrytyr]

And it's way to more expensive to do primes.

It depends.

When I was looking for moderate tele coverage on my K-x a couple of years ago,
I started contemplating a DA* 50-135 zoom,
but ended up with 58/1.4 and 90/3.5 Voigtlaenders instead,
for about the same money.

Sure, the Voigtlaenders are MF,
but so is the DA* 50-135 once the SDM goes out!

[enoxatnep]

When I started with Pentax I bought a couple of primes due to all the hype. But then I got lazy and tired of switching lenses CONSTANTLY (because I'm a wide-angle junkie one second and super-zoom the next), plus I wasn't so poor anymore, so I started buying my DA* lenses. Now I'm perfectly content, and my primes make nice paperweights.

[normhead]

I use primes when I know exactly where I'm going and what I'm shooting. When those things can not be predetermined I take a zoom. The 18-135 and 60-250 cover a huge range with acceptable weight. and then the Sigma 8-16 for ultra wide, to the Pentax 10-17 fisheye, and the Sigma 70 for macro, and … and … and… there's body builders that don't lift as much at the gym as I do on a hike.

[DeadJohn]

Saying that primes have better IQ than zooms is a little old.
Zooms can be very fast and have similar or even better IQ than prime! Look at Sigma 18-35mm f/1.8.

The only real advantage of a prime is the size. You can never fit a zoom in your pocket (Q doesn't count ).

The OP was asking about primes compared to the 18-55. The 35 and 50 primes will generally provide "better" (sharper, more bokeh if desired, etc) images than the 18-55. More expensive zooms like the Sigma 18-35 will also give better images.

[formercanuck]

I would say typically, you'd expect primes to have less vignetting, and better sharpness across the whole frame, along with low distortion (barrel/pincussion)
Eg. My Sigma 18-200 DC is 'ok' for what I typically want - albeit a little 'slow' (if I could get this to be an 18-200 f/2.8-4 or 5.6 vs. 18-200mm 3.5-6.3, it would be better for those indoor / moving shots.
If I was taking a lot more indoor/close up shots, I'd either get a prime, or a short/fast zoom.

Reasons for a prime comes down (for me) to:

1. Sharpness (primes are only 1 focal range - but sharp at range) - even at borders/corners.
2. Fast (great for bokeh / thin DoF)
3. Clean image - negligible pincushion/barrel distortion, low vingetting
4. Relatively inexpensive (or can be) compared to a zoom.
5. Light/compact.

Main reasons I don't have a prime (besides my Rokinon 85mm f/1.4):

1. I shoot a lot of moving targets - need the zoom - and many are candid.
2. If I was shooting landscapes - I'd probably have one by now at 10-28mm range.
3. Rokinon was free (for me).
4. I'm looking into the Sigma 17-70mm f/2.8-4

[jimr-pdx]

All the reasons for primes are already here, and stated well. Optimizing a lens for a single focal length pays off in many ways.

As to your choices - I've owned the DA35/2.4 and liked it a lot, but zooms were in the way at the time so it went elsewhere. I've recently sold my DA16-45 and picked up the new 50/1.8 and it's quite impressive, and it has 7 aperture blades for nice focus transitions. I also found a good deal on the DA21 Limited here in the Market. I now can carry 21, 50 and DA50-200WR - one lens on the camera, two in rather large pockets - and I'm ready for most anything I'd expect to see. If I don't need WR or tele, out with the zoom and the DA70 or Sigma 105mm macro can come along!

[reeftool]

When I started in photography, every camera came with a fast 50 or 55 mm lens. The zoom lenses of the day were mediocre and the few good ones were incredibly expensive. Since my generation grew quite accustomed to swapping lenses, we don't think much of it. Modern zooms are pretty good and even the 18-55 kit zooms are very good most of the time. I use my primes for the shots that my zooms don't do well or the primes do much better. Those fast 50's are excellent portrait lenses and give you nice bokeh the kit lens won't. My old prime kit of a 28/3.5, 55/1.8, and a 135/3.5 can easily be replaced by the DA 18-135 as the AF will probably produce more keepers with less hassle on a day's shooting. That said, I'm not getting rid of my old primes and am considering the new DA 50/1.8 for the AF. I will use this lens quite a bit and the price is very reasonable.

I don't think anybody should go buy primes if they are satisfied with the results they get with a zoom. However, primes will get some results you can never get with a zoom providing your photography takes you in that direction.

[waterfall]

Not me. A fixed focal length can be frustrating if your subjects are not at the relatively same distance, or you have to move around a lot, or swap lenses.

I've always felt zooms allow you to match what your eye sees, rather than be locked in to some arbitrary rectangle.

But, I'd get both of those lenses though they are fairly close in FL - and buy some aftermarket hoods. The Pentax ones seem to be $50-60 on their page :-(

I love the way the 50mm f/1.4 mirrors my own eyes. I have the Pentax 18-135 and 50-300 but only use them for hiking. When I know the shot I want, a Prime is my choice. I have the 15mm Ltd, 35mm Ltd, Sigma 50 f/1.4, Pentax DA 18-135 and Pentax 55-300. Primes rule for color and sharpness, IMHO. My favorite lens is the Pentax 35 Ltd because of the color rendition and incredible sharpness.

I forgot what this thread was about. Time for some Chilton white cheddar.

Dick