constant 2.8

bjake · 12-08-2011, 12:30 PM

Looking to replace a da 18-55 with something with a constant 2.8 with equal to or better quality than the da.Could get by with one at 28mm on the short end,price is important and will probably buy used.
Thanks,
Jake

ross · 12-08-2011, 12:43 PM

Just be careful with getting a zoom lens in the 18-55mm range at f2.8.
I have a Tamaron 17-50mm constant f2.8 and I think it's very soft and blurry at f2.8 but very sharp at f5.6 and above, it might be a faulty lens but if you do decide on getting a zoom lens at least try it out first before you buy and try taking a few photos at f2.8 and see if it's not too soft for you.

JinDesu · 12-08-2011, 12:46 PM

Sigma's 17-50 2.8 is the sharpest in that range, afaik. However it's also the most expensive. Tamron's 17-50 has great reviews, but is softer and louder. Pentax's 16-50 is more expensive, not as sharp, but is WR and also has SDM.

Sigma's 24-70 2.8 is sharper than the 17-50, but also more expensive. Tamron's 28-75 is as sharp, quite a LOT cheaper, but doesn't have that ultrasonic motor. Pentax's FA 24-70? is supposed to be as good as anything else, but is expensive and I don't know how often you see those on market.

rob1234 · 12-08-2011, 01:03 PM

Just for a different point of view... I'd massivley disagree with that. My Tamron 17-50/2.8 is sharp (in the centre at least) wide open, and from f/4 onwards is pretty much indistinguishable from a prime, although it is slightly worse at the long end than the short.

See full-size images at Tamron 17-50mm f/2.8 - a set on Flickr

Originally posted by ross

Just be careful with getting a zoom lens in the 18-55mm range at f2.8.
I have a Tamaron 17-50mm constant f2.8 and I think it's very soft and blurry at f2.8 but very sharp at f5.6 and above, it might be a faulty lens but if you do decide on getting a zoom lens at least try it out first before you buy and try taking a few photos at f2.8 and see if it's not too soft for you.

Docrwm · 12-08-2011, 01:59 PM

Why is SDM put forth as desirable when it has reliability problems and emerging evidence is that it is not necessarily faster to focus?

JinDesu · 12-08-2011, 02:06 PM

It's quiet. If it doesn't break down, it's nicer to work with than the screw drive. So hope for a good copy of the lens.

Adam · 12-08-2011, 02:17 PM

DA* 16-50mm vs. Sigma and Tamron 17-50mm Comparison - Introduction

Adam
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psychdoc · 12-08-2011, 04:13 PM

Originally posted by bjake

Could get by with one at 28mm on the short end,price is important and will probably buy used.

Tamron 28-75 maybe it:
28mm on the short end-yup
price-yup
And its sharp. And not too heavy.

K57XR · 12-08-2011, 04:26 PM

Originally posted by bjake

Looking to replace a da 18-55 with something with a constant 2.8 with equal to or better quality than the da.Could get by with one at 28mm on the short end,price is important and will probably buy used.
Thanks,
Jake

I had both the Tamron 17-50 f2.8 and the 28-75 f2.8 at one point. IMO, IQ for either lens is on a league of their own with the latter edging the former. The 17-50 tends to underexpose, at least on my K-x. Unfortunately, my experiences with Tamron quality have been less than perfect. The 28-75 had incorrect FL on exif where it showed either 35mm or 55mm throughout entire FL range regardless. The 17-50, I went through two copies before finally deciding against a third. The first one was contaminated while the second/replacement had severe de-centering issue. My suggestion is to make sure to buy from a source with a return or exchange policy.

I do have my eye on the Sigma 24-70 f2.8. It's just a little off my budget at this point.

mlatour · 12-08-2011, 06:44 PM

OP mentionned looking for a used lens/not too expensive:

my choices would either be:

Tamron 17-50mm f2.8
(look to buy from a knowledgeable photographer who's tested and picked a good copy)

or a Sigma 18-50mm f2.8 EX DC Macro (non-HSM)

perhaps even a Sigma 24-70mm f2.8 EX DG Macro (non-HSM) also but in my experience
it tends to flare more than above lenses, is huge and takes expensive 82mm filters.

The Tamron 28-75mm f2.8, sounds like a great lens but 28mm (for me) is just not wide enough.

I used a Sigma 24-70mm f2.8 for a while last summer and sold it, went back to a 17-50mm for my main lens.
Really missed the 18 to 24mm range at the wide end, something to consider if you are used to shooting with your DA 18-55mm

steve1307 · 12-09-2011, 04:20 AM

Originally posted by Docrwm

Why is SDM put forth as desirable when it has reliability problems and emerging evidence is that it is not necessarily faster to focus?

Originally posted by JinDesu

It's quiet. If it doesn't break down, it's nicer to work with than the screw drive. So hope for a good copy of the lens.

Its extremely quiet if it DOES break down.

Originally posted by Adam

DA* 16-50mm vs. Sigma and Tamron 17-50mm Comparison - Introduction

As reviews go on these lenses this is a good read, very thorough, as far as you can practically get with a single copy of each.

I don't want any of these 3 lenses but if I was to pick one it would be the Tamron and buy it from somewhere like B&H or Adorama which allows 7 day return after checking it out.
Just as good as the the other 2 in therms of IQ, Its the lightest, cheapest and takes the cheapest filters unless you've already got 77's

12-08-2011, 12:30 PM	#1
bjake Veteran Member Join Date: Mar 2011 Location: Eastern Kentucky Posts: 416	constant 2.8 Looking to replace a da 18-55 with something with a constant 2.8 with equal to or better quality than the da.Could get by with one at 28mm on the short end,price is important and will probably buy used. Thanks, Jake

12-08-2011, 06:44 PM	#10
mlatour Senior Member Join Date: May 2010 Location: Montreal Posts: 197	OP mentionned looking for a used lens/not too expensive: my choices would either be: Tamron 17-50mm f2.8 (look to buy from a knowledgeable photographer who's tested and picked a good copy) or a Sigma 18-50mm f2.8 EX DC Macro (non-HSM) perhaps even a Sigma 24-70mm f2.8 EX DG Macro (non-HSM) also but in my experience it tends to flare more than above lenses, is huge and takes expensive 82mm filters. The Tamron 28-75mm f2.8, sounds like a great lens but 28mm (for me) is just not wide enough. I used a Sigma 24-70mm f2.8 for a while last summer and sold it, went back to a 17-50mm for my main lens. Really missed the 18 to 24mm range at the wide end, something to consider if you are used to shooting with your DA 18-55mm Last edited by mlatour; 12-08-2011 at 10:29 PM.

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12-08-2011, 12:43 PM	#2
ross Junior Member Join Date: Apr 2008 Location: hobart Posts: 40	Just be careful with getting a zoom lens in the 18-55mm range at f2.8. I have a Tamaron 17-50mm constant f2.8 and I think it's very soft and blurry at f2.8 but very sharp at f5.6 and above, it might be a faulty lens but if you do decide on getting a zoom lens at least try it out first before you buy and try taking a few photos at f2.8 and see if it's not too soft for you.

12-08-2011, 12:46 PM	#3
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Sigma's 17-50 2.8 is the sharpest in that range, afaik. However it's also the most expensive. Tamron's 17-50 has great reviews, but is softer and louder. Pentax's 16-50 is more expensive, not as sharp, but is WR and also has SDM. Sigma's 24-70 2.8 is sharper than the 17-50, but also more expensive. Tamron's 28-75 is as sharp, quite a LOT cheaper, but doesn't have that ultrasonic motor. Pentax's FA 24-70? is supposed to be as good as anything else, but is expensive and I don't know how often you see those on market.

12-08-2011, 01:03 PM	#4
rob1234 Veteran Member Join Date: Apr 2010 Location: Wiltshire/Hampshire Photos: Albums Posts: 1,760	Just for a different point of view... I'd massivley disagree with that. My Tamron 17-50/2.8 is sharp (in the centre at least) wide open, and from f/4 onwards is pretty much indistinguishable from a prime, although it is slightly worse at the long end than the short. See full-size images at Tamron 17-50mm f/2.8 - a set on Flickr Originally posted by ross Just be careful with getting a zoom lens in the 18-55mm range at f2.8. I have a Tamaron 17-50mm constant f2.8 and I think it's very soft and blurry at f2.8 but very sharp at f5.6 and above, it might be a faulty lens but if you do decide on getting a zoom lens at least try it out first before you buy and try taking a few photos at f2.8 and see if it's not too soft for you.

12-08-2011, 01:59 PM	#5
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Why is SDM put forth as desirable when it has reliability problems and emerging evidence is that it is not necessarily faster to focus?

12-08-2011, 02:06 PM	#6
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	It's quiet. If it doesn't break down, it's nicer to work with than the screw drive. So hope for a good copy of the lens.

12-08-2011, 02:17 PM	#7
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,597	DA* 16-50mm vs. Sigma and Tamron 17-50mm Comparison - Introduction 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:

12-08-2011, 04:13 PM	#8
psychdoc Veteran Member Join Date: Jul 2010 Location: Bham Photos: Gallery \| Albums Posts: 949	Originally posted by bjake Could get by with one at 28mm on the short end,price is important and will probably buy used. Tamron 28-75 maybe it: 28mm on the short end-yup price-yup And its sharp. And not too heavy.

12-08-2011, 04:26 PM	#9
K57XR Veteran Member Join Date: Feb 2011 Location: Colorado, USA Posts: 830	Originally posted by bjake Looking to replace a da 18-55 with something with a constant 2.8 with equal to or better quality than the da.Could get by with one at 28mm on the short end,price is important and will probably buy used. Thanks, Jake I had both the Tamron 17-50 f2.8 and the 28-75 f2.8 at one point. IMO, IQ for either lens is on a league of their own with the latter edging the former. The 17-50 tends to underexpose, at least on my K-x. Unfortunately, my experiences with Tamron quality have been less than perfect. The 28-75 had incorrect FL on exif where it showed either 35mm or 55mm throughout entire FL range regardless. The 17-50, I went through two copies before finally deciding against a third. The first one was contaminated while the second/replacement had severe de-centering issue. My suggestion is to make sure to buy from a source with a return or exchange policy. I do have my eye on the Sigma 24-70 f2.8. It's just a little off my budget at this point.

12-09-2011, 04:20 AM	#11
steve1307 Veteran Member Join Date: Mar 2010 Location: Sydney Photos: Gallery \| Albums Posts: 1,130	Originally posted by Docrwm Why is SDM put forth as desirable when it has reliability problems and emerging evidence is that it is not necessarily faster to focus? Originally posted by JinDesu It's quiet. If it doesn't break down, it's nicer to work with than the screw drive. So hope for a good copy of the lens. Its extremely quiet if it DOES break down. Originally posted by Adam DA* 16-50mm vs. Sigma and Tamron 17-50mm Comparison - Introduction As reviews go on these lenses this is a good read, very thorough, as far as you can practically get with a single copy of each. I don't want any of these 3 lenses but if I was to pick one it would be the Tamron and buy it from somewhere like B&H or Adorama which allows 7 day return after checking it out. Just as good as the the other 2 in therms of IQ, Its the lightest, cheapest and takes the cheapest filters unless you've already got 77's