Pentax 18-55mm kit lens or Sigma?

Driline · 01-23-2013, 12:41 PM

I recently purchased a K5 (my first DSLR) and bought the 18-55mm DA L Kit lens with it. I really like the focal length of this lens and use it quite a bit.

My question is should I invest in a better lens like the Sigma 17-50mm F2.8 EX DC OS HSM lens? As an amateur will I really notice the difference between these lenses especially in sharpness?

If not then I'll invest the Pentax 15mm Prime instead.

thanks.....

Adam · 01-23-2013, 12:55 PM - **1 Like**

Originally posted by Driline

I recently purchased a K5 (my first DSLR) and bought the 18-55mm DA L Kit lens with it. I really like the focal length of this lens and use it quite a bit.

My question is should I invest in a better lens like the Sigma 17-50mm F2.8 EX DC OS HSM lens? As an amateur will I really notice the difference between these lenses especially in sharpness?

If not then I'll invest the Pentax 15mm Prime instead.

thanks.....

Yes, you will be able to notice a difference. The Sigma lens will give you less distortion, better sharpness, and not as much vignetting. Don't miss our review of it!

JinDesu · 01-23-2013, 01:00 PM - **1 Like**

Also, at F2.8 on the long end vs the 5.6 of the kit lens, you'll really appreciate the Sigma when shooting indoor shots when there is not much light available. It could mean the difference between a shutter speed of 1/30 vs 1/125 or a ISO of 1600 vs 6400.

Ikarus · 01-23-2013, 01:10 PM

It depends on what you use it for. If you can afford shooting at or around f/8 most of the time, you'll have to look really hard for it to see an improvement in sharpness. If you use it under less than ideal lighting conditions or want better subject/background separation, being able to go to f/2.8 will make a world of difference. However, I would say that if you really want to push the envelope on that front, f/2.8 is still a bit slow and you would be better served with a fast prime.

Obligatory DA 18-55 shot:

Franky2step · 01-23-2013, 01:15 PM

You will definitely notice a difference with the Sigma. In fact, you will immediately notice how much brighter your viewfinder is with the Sigma.

Driline · 01-23-2013, 01:27 PM

Originally posted by JinDesu

Also, at F2.8 on the long end vs the 5.6 of the kit lens, you'll really appreciate the Sigma when shooting indoor shots when there is not much light available. It could mean the difference between a shutter speed of 1/30 vs 1/125 or a ISO of 1600 vs 6400.

Wow that is a huge difference. Although a prime would be nice, I'd rather throw my money toward a lens I would use everyday. The 15mm prime will have to wait.

Tanzer · 01-23-2013, 01:37 PM

You have to be careful how you ask your questions here on the lens forum -- the answer to a yes/no question is always going to be "yes" ...

You will almost certainly be able to tell the difference between an image taken with the kit lens and an upgraded lens, just by expanding both of them to your full computer screen and comparing them directly.

However, the kit lens is still considered to be pretty decent and can produce some really good images (search for the kit lens sub-forum). If I were you, I would not immediately spend your money on the Sigma. Use the kit lens for a while to see if you might want something different than what the 17-50 offers you, like a wider zoom range, or some primes, or a super wide zoom.

I may pick one up a lens like the 17-50 for indoor use someday, but I elected to go with the 18-135 WR (and a bunch of primes) and am very happy with my setup, even for indoor use.

Last edited by Tanzer; 01-23-2013 at 05:38 PM.

causey · 01-23-2013, 01:54 PM

It depends on what you want/ need.
By all accounts, the Sigma 17-50mm is an excellent normal fast zoom. ("Fast" refers to the f2.8 max. aperture.) However, 15mm is very different from 17mm, and the DA 15mm is said to have lots of 'pixie dust'. The kit lens is best between 22mm and 45mm, especially around f8, and it's a very light little zoom. I find it extremely useful in good light. I used the kit lens and my Samyang 14mm f2.8 (a superb ultra wide angle, but heavy: about 500 grams) on my 2 week trip in Spain, in December. I wouldn't use the kit lens without DxO Optics, a great piece of software which automatically improves sharpness, corrects distortions and aberrations, etc...
So here's an alternative: keep the kit lens, get a cheap 50mm 1.7 prime (around 50 or less, faster and likely better than the Sigma at 50mm), buy the DA 15mm or the Samyang 14mm, and perhaps get the DxO when on sale (for about $100).

Here are two Spain shots I quickly processed in DxO (and then Lightroom):

**kiwi_jono** · 01-23-2013, 02:04 PM

Pretty sound advice mentioned already.
After using the 18-55 for about 9 months I went for a Sigma 17-70. While the 17-70 did help me move forward (better IQ, reach and a bit faster), I now wish I had gone for a 17-50 (Tammy or Siggy 18-50 at the time). In fact I'm thinking about buying a f2.8 in that range now. I still worry about the quality (including SDM) of the DA* 16-50 and certainly the price is somewhat above my price range currently.
But maybe this is all just a symptom of LBA.

The point is, while the 18-55 is certainly capable of great photos, sometimes (perhaps after working with the kit lens for a while) it can help to go on a bit of a lens journey to help you develop better skills. The reason (for me anyway) is that with a new lens comes new fun capabilities to experiment with and in doing so you are getting more practice. I even find that I quite enjoy playing with old lenses (comparing / benchmarking in tests and in the field) and in the process I am learning new things.

Driline · 01-23-2013, 02:38 PM

If pixie dust is fairy poop then no thank you on the 15 mm lens.

Na Horuk · 01-23-2013, 02:56 PM

The 18-55mm kit lens is mostly good if you have the WR version and a WR body. In terms of quality, it might be slightly better than some other brand (or some older) kit lenses, but its not really that great in terms of IQ

Driline · 01-23-2013, 02:59 PM

Originally posted by Na Horuk

The 18-55mm kit lens is mostly good if you have the WR version and a WR body. In terms of quality, it might be slightly better than some other brand (or some older) kit lenses, but its not really that great in terms of IQ

I don't have the WR version. It's just the el cheapo plastic mount DA L version.

causey · 01-23-2013, 03:04 PM

Originally posted by Driline

If pixie dust is fairy poop then no thank you on the 15 mm lens.

What made you think it would be fairy poop?

https://www.pentaxforums.com/forums/lens-clubs/86234-15mm-limited-controls-my-mind-club.html

Ikarus · 01-23-2013, 04:37 PM

Originally posted by Driline

I don't have the WR version. It's just the el cheapo plastic mount DA L version.

Same difference as far as IQ is concerned. You should ask yourself, what exactly is it that you find lacking with the 18-55? I have a hard time believing it is sharpness. Also, what other lenses do you own already? Frankly, if I weren't yet covered on the uwa, portrait, tele, macro and low-light front, replacing the kit would be the last of my priorities. I'd get a Sigma 10-20, for instance, or a DA-35/2.4, or a 55/1.4, or the 55-300.

Driline · 01-23-2013, 05:30 PM

Originally posted by causey

What made you think it would be fairy poop?

https://www.pentaxforums.com/forums/lens-clubs/86234-15mm-limited-controls-my-mind-club.html

Its common knowledge pixie dust is fairy poop.

01-23-2013, 12:41 PM	#1
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,695	Pentax 18-55mm kit lens or Sigma? I recently purchased a K5 (my first DSLR) and bought the 18-55mm DA L Kit lens with it. I really like the focal length of this lens and use it quite a bit. My question is should I invest in a better lens like the Sigma 17-50mm F2.8 EX DC OS HSM lens? As an amateur will I really notice the difference between these lenses especially in sharpness? If not then I'll invest the Pentax 15mm Prime instead. thanks.....

01-23-2013, 12:55 PM - 1 Like	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,594	Originally posted by Driline I recently purchased a K5 (my first DSLR) and bought the 18-55mm DA L Kit lens with it. I really like the focal length of this lens and use it quite a bit. My question is should I invest in a better lens like the Sigma 17-50mm F2.8 EX DC OS HSM lens? As an amateur will I really notice the difference between these lenses especially in sharpness? If not then I'll invest the Pentax 15mm Prime instead. thanks..... Yes, you will be able to notice a difference. The Sigma lens will give you less distortion, better sharpness, and not as much vignetting. Don't miss our review of it! Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-23-2013, 01:54 PM	#8
causey Veteran Member Join Date: Feb 2009 Location: Arlington, VA Photos: Albums Posts: 3,757	It depends on what you want/ need. By all accounts, the Sigma 17-50mm is an excellent normal fast zoom. ("Fast" refers to the f2.8 max. aperture.) However, 15mm is very different from 17mm, and the DA 15mm is said to have lots of 'pixie dust'. The kit lens is best between 22mm and 45mm, especially around f8, and it's a very light little zoom. I find it extremely useful in good light. I used the kit lens and my Samyang 14mm f2.8 (a superb ultra wide angle, but heavy: about 500 grams) on my 2 week trip in Spain, in December. I wouldn't use the kit lens without DxO Optics, a great piece of software which automatically improves sharpness, corrects distortions and aberrations, etc... So here's an alternative: keep the kit lens, get a cheap 50mm 1.7 prime (around 50 or less, faster and likely better than the Sigma at 50mm), buy the DA 15mm or the Samyang 14mm, and perhaps get the DxO when on sale (for about $100). Here are two Spain shots I quickly processed in DxO (and then Lightroom): Last edited by causey; 01-23-2013 at 02:03 PM.

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01-23-2013, 01:00 PM - 1 Like	#3
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Also, at F2.8 on the long end vs the 5.6 of the kit lens, you'll really appreciate the Sigma when shooting indoor shots when there is not much light available. It could mean the difference between a shutter speed of 1/30 vs 1/125 or a ISO of 1600 vs 6400.

01-23-2013, 01:10 PM	#4
Ikarus Veteran Member Join Date: Apr 2010 Location: California Photos: Albums Posts: 484	It depends on what you use it for. If you can afford shooting at or around f/8 most of the time, you'll have to look really hard for it to see an improvement in sharpness. If you use it under less than ideal lighting conditions or want better subject/background separation, being able to go to f/2.8 will make a world of difference. However, I would say that if you really want to push the envelope on that front, f/2.8 is still a bit slow and you would be better served with a fast prime. Obligatory DA 18-55 shot:

01-23-2013, 01:15 PM	#5
Franky2step Veteran Member Join Date: Aug 2011 Location: Niagara Photos: Gallery \| Albums Posts: 793	You will definitely notice a difference with the Sigma. In fact, you will immediately notice how much brighter your viewfinder is with the Sigma.

01-23-2013, 01:27 PM	#6
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,695 Original Poster	Originally posted by JinDesu Also, at F2.8 on the long end vs the 5.6 of the kit lens, you'll really appreciate the Sigma when shooting indoor shots when there is not much light available. It could mean the difference between a shutter speed of 1/30 vs 1/125 or a ISO of 1600 vs 6400. Wow that is a huge difference. Although a prime would be nice, I'd rather throw my money toward a lens I would use everyday. The 15mm prime will have to wait.

01-23-2013, 01:37 PM	#7
Tanzer Veteran Member Join Date: Mar 2012 Location: Perrineville, NJ Posts: 1,375	You have to be careful how you ask your questions here on the lens forum -- the answer to a yes/no question is always going to be "yes" ... You will almost certainly be able to tell the difference between an image taken with the kit lens and an upgraded lens, just by expanding both of them to your full computer screen and comparing them directly. However, the kit lens is still considered to be pretty decent and can produce some really good images (search for the kit lens sub-forum). If I were you, I would not immediately spend your money on the Sigma. Use the kit lens for a while to see if you might want something different than what the 17-50 offers you, like a wider zoom range, or some primes, or a super wide zoom. I may pick one up a lens like the 17-50 for indoor use someday, but I elected to go with the 18-135 WR (and a bunch of primes) and am very happy with my setup, even for indoor use. Last edited by Tanzer; 01-23-2013 at 05:38 PM.

01-23-2013, 02:04 PM	#9
kiwi_jono Loyal Site Supporter Join Date: Dec 2009 Location: Christchurch, New Zealand Photos: Gallery \| Albums Posts: 2,437	Pretty sound advice mentioned already. After using the 18-55 for about 9 months I went for a Sigma 17-70. While the 17-70 did help me move forward (better IQ, reach and a bit faster), I now wish I had gone for a 17-50 (Tammy or Siggy 18-50 at the time). In fact I'm thinking about buying a f2.8 in that range now. I still worry about the quality (including SDM) of the DA* 16-50 and certainly the price is somewhat above my price range currently. But maybe this is all just a symptom of LBA. The point is, while the 18-55 is certainly capable of great photos, sometimes (perhaps after working with the kit lens for a while) it can help to go on a bit of a lens journey to help you develop better skills. The reason (for me anyway) is that with a new lens comes new fun capabilities to experiment with and in doing so you are getting more practice. I even find that I quite enjoy playing with old lenses (comparing / benchmarking in tests and in the field) and in the process I am learning new things.

01-23-2013, 02:38 PM	#10
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,695 Original Poster	If pixie dust is fairy poop then no thank you on the 15 mm lens.

01-23-2013, 02:56 PM	#11
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	The 18-55mm kit lens is mostly good if you have the WR version and a WR body. In terms of quality, it might be slightly better than some other brand (or some older) kit lenses, but its not really that great in terms of IQ

01-23-2013, 02:59 PM	#12
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,695 Original Poster	Originally posted by Na Horuk The 18-55mm kit lens is mostly good if you have the WR version and a WR body. In terms of quality, it might be slightly better than some other brand (or some older) kit lenses, but its not really that great in terms of IQ I don't have the WR version. It's just the el cheapo plastic mount DA L version.

01-23-2013, 03:04 PM	#13
causey Veteran Member Join Date: Feb 2009 Location: Arlington, VA Photos: Albums Posts: 3,757	Originally posted by Driline If pixie dust is fairy poop then no thank you on the 15 mm lens. What made you think it would be fairy poop? https://www.pentaxforums.com/forums/lens-clubs/86234-15mm-limited-controls-my-mind-club.html

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01-23-2013, 04:37 PM	#14
Ikarus Veteran Member Join Date: Apr 2010 Location: California Photos: Albums Posts: 484	Originally posted by Driline I don't have the WR version. It's just the el cheapo plastic mount DA L version. Same difference as far as IQ is concerned. You should ask yourself, what exactly is it that you find lacking with the 18-55? I have a hard time believing it is sharpness. Also, what other lenses do you own already? Frankly, if I weren't yet covered on the uwa, portrait, tele, macro and low-light front, replacing the kit would be the last of my priorities. I'd get a Sigma 10-20, for instance, or a DA-35/2.4, or a 55/1.4, or the 55-300.

01-23-2013, 05:30 PM	#15
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,695 Original Poster	Originally posted by causey What made you think it would be fairy poop? https://www.pentaxforums.com/forums/lens-clubs/86234-15mm-limited-controls-my-mind-club.html Its common knowledge pixie dust is fairy poop.