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08-13-2013, 01:53 PM   #1
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Why should I buy a prime?

With the good deals on the DA 35 2.4 & DA 50 1.8, I'm considering buying one (or both) of these to use with my K-30. But other than being slightly faster than my 18-55 WR, what's the benefit of buying one of these lenses? I'm more interested in the 35mm and if it was a 1.8, instead of 2.4 or if it was priced like the 50mm I would jump on it and worry about how to use it later. I'm typically the de facto photographer at any family event, indoors & out. In those situations, a zoom can be useful. So why go prime? Thoughts?

08-13-2013, 02:00 PM   #2
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Prime lenses get you (primarily) two things:

1) Faster aperture
2) Better IQ (image quality)

They also do it at a (relatively) affordable price.

Many will also tell you that using a prime will make you a better photographer. (Because you don't have the crutch of zoom to lean on)

There are now several threads about 50/1.8 vs 35/2.4. General consensus is most people should go for the 35mm.
08-13-2013, 02:01 PM   #3
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It's about image quality. If you're satisfied with the images from the kit lens, then look for a prime which can do something the kit lens can't do. That means true macro, if you're interested, or a telephoto if you're interested. Otherwise, if you want more reach, look for one of the 55-300s. There are plenty of users who use zooms almost exclusively - many of which overlap.

The primes are optimized. You might look at your 18-55 photos and decide the DA 35 would suffice for 80% of your shots and have a much nicer IQ. Or you could decide to save your money for the long zoom or a super-wide like a 10-20 or Sigma's 8-16. Some of the zooms rival primes at certain focal lengths.

Which do you think would be more useful for you? I rented a bunch of lenses before deciding to buy. I have Sigma's 28mm f1.8 macro, which I really like indoors and as a close-range lens. It's not as wide but it's really nice. I rented their 8-16 which I really liked, but don't have the money for right now, and really should compare to the 10-20s to make a fair decision.
08-13-2013, 02:05 PM   #4
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The advantage? (These are from the FA 50/1.7 but it is basically the same as the DA)

The kit lens is ok from f/5.6 to f/11 but the 50/1.8 will shine from f/1.8 on...

If I had the funds right now I would jump on the 35/2.4 @ $181.95. It would be even better if Pentax had a 28/2.8...

08-13-2013, 02:05 PM   #5
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Well several things to think about:

First, the 50 1.8 is about 4 stops faster than the 18-55.
The 35 F2.4 is about 1.5 stops faster than the 18-55.

Both of them are much sharper wide open than the 18-55 is wide open. At F8, they'll be pretty similar.
Both of them allow you to shoot with thinner DOF than the 18-55, which can render the background smoother and more out-of-focus for subject isolation (especially the DA 50 F1.8)
Both are smaller than your 18-55.
Both have better flare resistance, better microcontrast, and better chromatic aberration control.

So there are many reasons why they are better than the 18-55. What they do not replace is the convenience of the zoom, especially indoors. When you are at a party or a dinner and need to get the 18mm, that 18-55 is invaluable. The prime lenses are meant for photography for photography's sake - where you can step closer or further away from your subject without worrying about walking into people or the street. I actually walk around taking pictures with my Sigma 50 F1.4 a lot - I love that lens. But I will admit that it is very restricting when I want to shoot pictures at friends' events - because it's too tight. Even when I had my DA 35 F2.4, it was a bit tight at dinners.

So - they are lovely lenses for landscape, portraits, some events, walking around, and almost everything. But they won't replace your 18-55 for everything unless you are pretty experienced.
08-13-2013, 02:26 PM   #6
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Many will also tell you that using a prime will make you a better photographer. (Because you don't have the crutch of zoom to lean on)
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 :-(

Last edited by SpecialK; 08-13-2013 at 03:11 PM.
08-13-2013, 02:37 PM   #7
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QuoteOriginally posted by SpecialK Quote
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 thought they are fairly close in FL - and buy some aftermarket hoods. The Pentax ones seem to be $50-60 on their page :-(
For some people, I think the idea is to use primes a bit to learn more about framing and about recognizing photo opportunities (you'll be looking for completely different shots with a 28mm prime vs. a 200mm prime), and then go back to using zooms when their advantages make sense.
08-13-2013, 03:00 PM   #8
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Some good points here already. At those prices, these lenses are an absolute steal.
Now, true, Pentax' primes are generally not super fast (in terms of max f-number), at least their current lineup. But they are very compact and deliver great IQ. Along with the 35mm and 50mm, I would also recommend the 40mm f2.8 (ltd or XS). These lenses will make much better photos than the kit lens. Even at the kit lens' sweet spot (35mm, f8), it still can't beat the primes.
Other than better max aperture (low light performance), faster/quieter AF (usually - depends on the lens), and overall better IQ (less distortion, better sharpness, more detail, better colours, better contrast, better bokeh, less CA, less flare and ghosting,,..), you also have to frame your photos differently. You get used to a focal length and then you can imagine how the frame would look like without putting the camera to your eye. This tends to improve composition of the photos because the photographer is more conscious of how he is positioning himself and where he is pointing the lens.
I would recommend the DA 50mm for portraits and suchlike. 35mm for more all-around photography, because it is wider. I would also suggest you buy a cheap lens hood for these lenses - just make sure its fitting for the focal length and APS-C sensor. A hood is the easiest way to improve IQ of any lens. Tripod being the other accessory that improves photos.

After buying some primes, I only use my zoom lenses when I really need fast focal length changes, like at a live event where I only have a short time to capture many different perspectives. Usually I take the time to use primes and just "zoom with my feet." For family events, I usually use a fast prime, because the events are held indoors with poor light. If you are skeptical, you can buy a prime second-hand at a slightly lower price. But that Pentax rebate.. Im not sure even used lenses go that cheap.

Last edited by Na Horuk; 08-13-2013 at 03:08 PM.
08-13-2013, 03:01 PM   #9
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QuoteOriginally posted by boriscleto Quote

If I had the funds right now I would jump on the 35/2.4 @ $181.95..
It's actually lower than that currently -
08-13-2013, 03:13 PM   #10
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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 ).
08-13-2013, 03:32 PM   #11
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08-13-2013, 03:34 PM   #12
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Yes—it's about image quality and speed.

It's also about consistency and relative simplicity. I have two lenses: an A50mm ƒ/1.4, and an A100mm ƒ/2.8. After having used the 50 for about 6 years now, I know my field of view, how much depth of field I get at each aperture, and so on. Having that kind of consistency means I can quickly set my focus distance to hyperfocal and frame the shot quickly…without having to think too much. I also only have three controls: focus, aperture, and shutter speed. With zoom lenses, everything changes as you zoom in and out: field of view, depth of field, etc. You also have to worry about another control: the zoom control. When I had a zoom lens, I ended up setting my lens to 28mm just so I wouldn't have to think about it.

Of course, all of this depends on your style. I don't use auto anything. I think you'd like a 35mm prime no matter what your style is, though.
08-13-2013, 03:34 PM   #13
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At first, a prime lens will seem frustrating, especially at a party or similar. You will pick up the camera and you'll be too close or too far away and the ideal shot will be gone by the time your framing is right. It will feel like you are missing shots. You may even switch back to the 18-55. But you are already missing shots like Ben's examples. The second and third shots were at f1.7 and high ISO. The 18-55 would have needed flash for both shots. Combined with the increased depth of field you'd get, the shots would not have looked as good. After you get familiar with a prime, you look for subjects within its range and abilities, and can take advantage of its strengths. One focal length, with practice, makes it easy to visualize a shot before you pick up the camera. So you might anticipate a shot happening over there and move into the right position before it happens.

You can decide between the 35mm and 50mm by looking at photos you have taken with the 18-55 and the focal lengths you've used. If your shots are often in the middle, go with the 35.
08-13-2013, 03:40 PM   #14
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Apples + Oranges?

Hello ecruz,
Most new photographers who try a prime or two, (whether new or used) rarely buy another zoom, unless it's a pro-grade f/2.8 constant. Generally speaking, we're looking at a $500 to thousand-dollar zoom.
Why do you think that is?
Because they are spoiled. They've seen the difference, using the same camera and skill level they had with the zoom.
Lighter, faster, smaller, sharper, better bokeh, higher resolution, cleaner rendering, less abberations and distortion.
Ads for high-end zooms often describe their lens as 'prime-like quality'.
Have you ever seen an ad for a prime that says 'As good as any zoom'?
The first lens most aspiring photographers buy after the kit zoom(s) will be a prime. Their skill level is improving and they want better equipment to match.
Zooms are versatile, no doubt. If that's the most important quality needed, take a zoom.
Otherwise, take primes.
There is an arc of development in photographic skill when image quality becomes more necessary than convenience.
Only you can say if you've reached that point.
08-13-2013, 03:49 PM   #15
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At certain focal lengths my DA * 50 - 135mm f2.8 is as good as my fa *43 1.9 (except speed, of course)

Good luck with your search



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