Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-06-2008, 04:34 AM   #1
Inactive Account




Join Date: Jan 2008
Posts: 6
Lens advice

Hi all

I bought my K10D with the Pentax 18-55, and I find it a little soft. Compared to my manual focus f1.7 50mm the results seem, well, soft.

What comparable lens would you recommend?

I heard the 16-45 is better, which I guess is why it was a lot more expensive!

I'm considering the Sigma 24-135mm F2.8-4.5 Aspherical IF Lens and the equivalent Tamron.

Any thoughts on those from anyone?

I'm looking for a 24mm minimum focal length because on digital I'd rather have the extra little bit of wide angle compared to a 28mm. Otherwise I then have to look at lenses made for digital such as 18-55 or 16-45 which are then a little short at the long end.

I suppose what I really want is to replace the 18-55 with something a little longer but still wide at the short end, and sharper, so that I don't have to take the 18-55 with me at all.

I love my old 50mm PKA but on digital it's a little bit too long for general use.

Pete

01-06-2008, 06:25 AM   #2
Veteran Member




Join Date: Sep 2006
Location: Virginia Beach VA USA
Photos: Gallery
Posts: 1,364
Welcome to the forums Pete.

Try stopping the kit lens down to around f8.0. You will be surprised how good it can get. But, I understand how limiting that can be.

A couple of things to keep in mind. the 24-135 will not give you a wide angler fov on your K10, because of the 1.5x crop factor. If you want a 24mm fov you will need something in the 16mm range.

That leaves you with 2 Pentax lenses and 2 Sigmas to choose from.

Pentax: DA 16-45 f4.0 and the DA* 16-50 f2.8
Sigma 18-50 EX DC Macro f2.8 and 17-70 f2.8-f4.5 DC

There are also The Tamron 18-250 f3.5-f6.3 super zoom and the Pentax rebadged version DA18-250 f3.5-f6.3, if you prefer a one lens solution.
01-06-2008, 06:34 AM   #3
Inactive Account




Join Date: Jan 2008
Posts: 6
Original Poster
Thanks Alan

I'll certainly give it a try on f8 and see how it compares.

I understand the difference in frame size, I think I would find it more useful having more length than width (!) so the 24-135 appeals because it would be roughly equivalent to a 36-200 whereas the 18-55 would be a 27-80 or thereabouts, which is a bit short for what I like.

So sorry when I said 24-135 I knew that would be a 36-200 in old money.

Pete

Last edited by peterfreeth; 01-06-2008 at 06:35 AM. Reason: typo
01-06-2008, 06:49 AM   #4
Veteran Member




Join Date: Sep 2006
Location: Virginia Beach VA USA
Photos: Gallery
Posts: 1,364
I understand. My kit replacement is the Tamron 28-75mm f2.8 XR DI. I don't go wide often, and I've got the10-17 FE and a FA20 f2.8 when I want to. I found that at shoot 20% of my shots in the 50-70mm range.

This Tamron is an outstanding lens. It's IQ rivals any First party lens, and for the price, it is a bargain. Definitely worth your taking a look.

01-06-2008, 07:01 AM   #5
Inactive Account




Join Date: Jan 2008
Posts: 6
Original Poster
I'll take a look - thanks for your advice

I just tried the Pentax 18-55 on f4.5, f8, f11 and f22. To be honest, the image got grainier as the aperture got smaller but I could see no difference in clarity. The ASA went from 200 to 400 on auto, but the noise increased quite a bit.


Pete

Last edited by peterfreeth; 01-06-2008 at 07:25 AM. Reason: update
01-06-2008, 08:35 AM   #6
Veteran Member
Finn's Avatar

Join Date: Feb 2007
Location: Phoenix
Photos: Gallery
Posts: 1,056
Welcome to the forum.

For starters, you will probably never find a lens sharper than the 50/1.7, period. That thing is a gem.

The 16-45 is a fantastic zoom, and I can't recommend it highly enough. Sigma makes a 17-70, but I haven't used it and can't attest to its qualities. A lot of folks around here seem to like that Tamron 28-75 as well, as mentioned above. Alternately, if you like primes you could pick up a DA 21mm, which would get you the wide end. That's also a great little metal-bodied lens.
01-06-2008, 08:40 AM   #7
Veteran Member
Finn's Avatar

Join Date: Feb 2007
Location: Phoenix
Photos: Gallery
Posts: 1,056
QuoteOriginally posted by peterfreeth Quote
I just tried the Pentax 18-55 on f4.5, f8, f11 and f22. To be honest, the image got grainier as the aperture got smaller but I could see no difference in clarity. The ASA went from 200 to 400 on auto, but the noise increased quite a bit.
It is kind of a rule of thumb (who makes these "rules" anyway?) that peak sharpness is from around two stops from wide open, down to around f/8 or f/11. I would expect that at f/22, you are experiencing not only diffraction effects, but also noise incurred from long exposure times. Also, if you are using a tripod, turning off SR can help increase sharpness.

Please forgive me if this is old news to you.
01-06-2008, 08:56 AM   #8
Veteran Member




Join Date: Mar 2007
Location: U.K.
Posts: 685
QuoteOriginally posted by peterfreeth Quote
Hi all

I bought my K10D with the Pentax 18-55, and I find it a little soft. Compared to my manual focus f1.7 50mm the results seem, well, soft.

What comparable lens would you recommend?
Pete
A lot of people won't believe you about the kit lens because they get very good results with it. I do though, as mine was, well, very soft at any setting and I quickly gave up on it.

My Sigma 17-70 is in a totally different league and approaches prime quality in the 24-60 region at f5.6 and is quite usable throughout its full range wide open or slightly stopped down if being fussy. It's quick to AF as well and works quite well in poor light. Only drawbacks are no quick-shift and occasionally it misses focus a little because it thinks it's already in focus but that's probably the K100D partly. Bad samples do crop up though, I think Tamron are more consistent but there's no 17-70 equivalent sadly.

01-06-2008, 09:57 AM   #9
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,144
QuoteOriginally posted by Finn Quote
It is kind of a rule of thumb (who makes these "rules" anyway?) that peak sharpness is from around two stops from wide open, down to around f/8 or f/11. I would expect that at f/22, you are experiencing not only diffraction effects, but also noise incurred from long exposure times. Also, if you are using a tripod, turning off SR can help increase sharpness.

Please forgive me if this is old news to you.
Hey, guys, we are using Pentaxes here! Set your program line to MTF when you are using Pentax lenses if you are trying for the super sharp shots. FYI, my k10d will hang onto f/4 for dear life with the DA* 16-50. One stop down. Annoying when shooting scenery, let me tell you. But then I can just swing that little edial and fix it.
01-06-2008, 01:52 PM   #10
Inactive Account




Join Date: Jan 2008
Posts: 6
Original Poster
I agree that comparing it to the 50mm f1.7 is a little unfair, however from the start the images it produced were soft and the colours were muted, and only by comparing it to the 50mm did I see how much more was possible with the K10D. Actually now I think of it, that's the root of the problem. The 50mm f1.7 shows me what the body is capable of and I feel the 18-55 is too much of a compromise.

Some great suggestions here which I will look into though. Thank you all.

Feel free to suggest more for my shopping list, I appreciate your experience!

Pete
01-06-2008, 02:04 PM   #11
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,679
I've bitten the bullet myself to upgrade from the kit lens, and after doing some homework, the DA 16-45 won out. I'm not too fussed about going to 70mm with my walkaround lens, but sharpness is certainly better with the 16-45 and 17-70 (not from experience, but from that of many others...)
Cost is similar between the 2 lenses, and I don't think you can go wrong with either.
Let us know how you go.
01-07-2008, 04:01 PM   #12
Inactive Account




Join Date: Jan 2008
Posts: 6
Original Poster
Well. just to update you all I've been looking at the Sigma 17-70, looks nice. Today I have discovered the long term consequences of the Internet on the High St, which is that noone has any stock of anything any more!

I got excited when Jessops had one in their Pentax cupboard but it turned out to be a weird fit, some foreign name like 'Nokin'. And the guy said that he couldn't order one in for me to try out unless I bought one first..

So I had a look at the one they had and it seems like a nice lens, nicely built, nicely weighted, zoom ring worked smoothly.

The best price I've found online is £213 which includes delivery but that's a 28 day lead time!

Can anyone suggest a good store to try? i.e. good price and availability!! I'm thinking of popping into Cameraworld next time I'm in London.

Pete
01-08-2008, 12:31 AM   #13
Inactive Account




Join Date: Jan 2008
Posts: 10
QuoteOriginally posted by peterfreeth Quote
Hi all

I bought my K10D with the Pentax 18-55, and I find it a little soft. Compared to my manual focus f1.7 50mm the results seem, well, soft.

What comparable lens would you recommend?

I heard the 16-45 is better, which I guess is why it was a lot more expensive!

I'm considering the Sigma 24-135mm F2.8-4.5 Aspherical IF Lens and the equivalent Tamron.

Any thoughts on those from anyone?

I'm looking for a 24mm minimum focal length because on digital I'd rather have the extra little bit of wide angle compared to a 28mm. Otherwise I then have to look at lenses made for digital such as 18-55 or 16-45 which are then a little short at the long end.

I suppose what I really want is to replace the 18-55 with something a little longer but still wide at the short end, and sharper, so that I don't have to take the 18-55 with me at all.

I love my old 50mm PKA but on digital it's a little bit too long for general use.

Pete
Have 18-55 lens too.
Do you know how to set JPG quality in K10D?
if increase sharper and contrast to 3 and 2, the photo will be sharper.

Or take raw and use pentax softare to conver to Jpg, photo will be sharper

If you still not satisify with this lens, DA 16-45 still not the best choice I think.

DA 21,Fa35 FA31 FA43 DA 40 and so on are good choice
01-08-2008, 07:08 AM   #14
Pentaxian




Join Date: Apr 2007
Location: Sweden
Posts: 1,887
I bought the sigma 17-70 and while (my copy) is better on many levels than the kit-lens, (vinjetting, color, speed and range) it isnít sharper. Then again my kit-lens is fairly sharp. So does that mean that the Sigma is a lemon, or that the kit-lens is a gem?
01-08-2008, 07:25 AM   #15
Veteran Member
Tom M's Avatar

Join Date: Aug 2007
Location: Lincoln Park, NJ
Photos: Gallery
Posts: 782
Another vote for the DA 16-45 lens here.. I love it!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
50mm, bit, k-mount, lens, pentax lens, slr lens, soft
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lens advice SebastianP Pentax SLR Lens Discussion 6 10-20-2010 10:44 AM
Advice for lens please fekish Troubleshooting and Beginner Help 9 09-12-2010 08:44 AM
lens advice bsod Troubleshooting and Beginner Help 19 06-05-2009 09:08 AM
Lens advice benjaminmichael Troubleshooting and Beginner Help 15 05-20-2009 08:56 PM
Need advice on a lens robcap13 Troubleshooting and Beginner Help 11 03-04-2009 06:33 AM



All times are GMT -7. The time now is 12:35 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top