Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-24-2010, 10:11 PM   #16
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
QuoteOriginally posted by stevebrot Quote
I have two 28mm lenses (Tamron 28/2.5 and Vivitar 28/2.8 CF). Here are my thoughts:
  • My kit lens (v. I) at 28mm is a notch off either prime, but not by much
  • A 28/2.8 will provide narrower DOF and needs less light than the kit
  • The best use of 28mm on an APS-C dSLR is as a "short normal"
  • Some designs are very compact
  • Both my 28s are quite capable on my K10D, but really shine as a wide-angles on 35mm full-frame
I have the FA 35/2. As a result, I mostly use 28s as wide-angles with the film cameras.

Steve
Steve, I saw your test results of the 3 lenses. I was just wondering if you did something similar but at a much farther distance like mid-range or infinity?

when I did my individual tests, the kit lens is good to very good up close but seems to falter at longer focus range. it loses significant sharpness.

02-25-2010, 08:46 AM   #17
Veteran Member




Join Date: Oct 2008
Location: Sweden
Posts: 359
QuoteOriginally posted by Marc Sabatella Quote
Lars, you posted that before, but now I'm wondering, is that a 100% crop? Because that's *much* worse than anything I've seen even from the kit lens (although as I recall, yours ithe version I).

Basically, the reasons to use a 28 instead of the kit lens (version II) are either:

- you need the extra stop or so of speed
- you need the extra sharpness you get up to about f/8, after which the differences are negligible
- you're just a prime kind of person
It's not a 100% crop. However, the framing was exactly the same for both lenses. Like you I was also amazed at the huge difference so I did more comparisons at F5.6 and F8. Well, the result is the same, the K 28 is definitely sharper at F5.6, no doubt about it. At F8 the K 28 is a bit sharper but the difference is not huge. I don't know if I have a very good copy of the K 28 or a very bad kit lens.... perhaps both.

Kind regards
.lars
02-25-2010, 11:35 AM   #18
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
It's heresy time.

I'll say the unthinkable: you don't need a 28mm. Or at least, *I* don't. On APS-C, it's 'normal' (the sensor's diagonal is 30mm). I tired of 'normal' shooting long ago. Oh, I sometimes carry a manual-focus Access 28/2.8 macro, for convenience, but it doesn't get much use. I have a batch of 35-37mm lenses (equivalent to 52-55mm in full-frame) that mostly don't get used either, except a close-manual-focusing Isco Westron 35/2.8, almost Leica-like in its sharpness.

I'll carry a manual Vivitar 24/2 (broken so it's always wide open) and a manual Vivitar 21/3.5 (stopped-down to f/5.6-8 for street shooting) and of course the DA 10-17, DA 18-250, FA 50/1.4. But except for fixed-lens folders, I just don't find 'normal' to be interesting any more. I'll put a 135 cart in a 6x9 folder for that sprocket-hole pano effect. I'll put fisheyes and wides and long teles on 135 film bodies. But 'normal' is boring. Been there, seen that.
02-25-2010, 11:46 AM   #19
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,202
QuoteOriginally posted by Pentaxor Quote
Steve, I saw your test results of the 3 lenses. I was just wondering if you did something similar but at a much farther distance like mid-range or infinity?

when I did my individual tests, the kit lens is good to very good up close but seems to falter at longer focus range. it loses significant sharpness.
I did not do any other direct comparisons with the kit. I did the one shot on a whim. The camera was on the tripod and the lens was sitting there and I said...I wonder? My experience has been that it is a dangerous thing to compare a competent zoom to even your better primes.

Steve

02-25-2010, 01:13 PM   #20
tux
Forum Member




Join Date: Dec 2009
Posts: 82
I own a pentax M 28mm f2.8 & a Makinon 28mm f2.8. I love using both these lenses as they are very sharp & easy to focus.
02-25-2010, 01:15 PM   #21
Site Supporter
grey goat's Avatar

Join Date: Dec 2009
Location: Spring Green, WI
Photos: Gallery | Albums
Posts: 320
QuoteOriginally posted by RioRico Quote
I'll say the unthinkable: you don't need a 28mm. Or at least, *I* don't. On APS-C, it's 'normal' (the sensor's diagonal is 30mm). I tired of 'normal' shooting long ago.
[ . . . ]
But 'normal' is boring. Been there, seen that.
I see your point, RioRico, but to my eye, a 28mm on an APS-C is a wide normal, which changes things for me. I might feel the same way about a 35mm on the K-7, except I know what folks say about the DA 35.

But to me, it's not all about focal length. Sometimes to get what I see in a particular light, I need a certain lens. I know a good zoom would work, too, but . . . well, right now, anyway, I'd rather carry my 17, 28, 70 and 135. The kit lens, too, but I'd rather shoot primes.

But I think the right light trumps focal length almost every time. To me, that's what keeps things from being "normal."

Still, we've all got different eyes, and different ways of seeing. And that's a good thing, isn't it?
02-25-2010, 01:21 PM   #22
Forum Member




Join Date: Dec 2008
Location: Fishtown, Philly PA
Photos: Albums
Posts: 55
I kind of felt the same way, I have the sigma 28mm f1.8 and was not using it.

I even put it up for sale here.

But then I started using it for nightclub/bar low-light shooting and found that it was really a good lens for that.

You don't have to get too far away or too close to frame the people in your shots.

Now I use that lens a lot when I am out and about at night and would never think of getting rid of it...

I like it better than the kit lens because it seems to have an easier time focusing in the low light situations...

also, in clubs I use the off camera flash and thus my other hand is full and I would not be able to use the adjust for the zoom on the kit lens anyway...

I do wish the Sigma was smaller, so I think I would find an "A" series lens even more to my liking...
02-25-2010, 01:29 PM   #23
Veteran Member
pasipasi's Avatar

Join Date: Feb 2008
Location: Oulu
Photos: Gallery
Posts: 533
I've got a Kiron 28/2 and a Pentax-A 28/2.8 and when I still had a digital Pentax dslr these lenses only got mounted on my film bodies. 28mm just isn't very exciting focal lenght on crop digital. The equivalent focal lenght on film is much more interesting due to shorter dof and better viewfinder (I found manual focusing to be quite difficult with wide and normal focal lenghts), and the 28/2 has seen quite a lot of use during the dark winter time.

02-25-2010, 01:57 PM   #24
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Pentaxor Quote
Marc, I have the 18-55 WR and basing from the shot comparisons that I made against it and the K28/3.5, FA35, and FA50/1.7, the resolution of the WR kitlens seems to suffer more with the 18-55 as you shoot longer at midrange to infinity, irregardless if you stop down or not. I did shoot at 3 varying stops from f4, f5.6 and f8 at 28mm, 35mm, and 50mm.
Interesting. I've done similar comparisons with my M28/2.8 and found the 18-55II closed the gap *hugely* by f/8 or f/11, even at longer shooting distances. But I suppose that could be a matter of the M28/2.8 not sharpening up as dramatically between f/4 and f/8 as the K28/3.5. That's not really what Yoshihiko's resolution test results suggest, though. So there could also be sample variation involved, testing methodology variation, or just differences in our perception of the magnitude of differences we see.

But even so, that still doesn't really explain Lars' comparison, which appears to be shot at pretty close range, unless that is indeed a 100% crop. Like I said, I've never seen *either* version of the kit lens produce anything so soft.
02-25-2010, 03:02 PM   #25
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
Here are some generalities that apply to any lens discussion:

* We like what we like, what we're used to, unless we're bored by it -- same as politics or art or any other theology. Maybe we're so familiar with a certain mode (like shooting short/long normal, or ultra-wide/long) that all else seems perverse.

* Technical items (like photo gear) may get high tech-test ratings and still either 1) generate many user complaints, or 2) just provide sucky results to our quirky eyes, or 3) be forever beyond our financial means, without robbing liquor stores.

* A lens is a tool. "It's a poor worker who blames their tools." Some tools are specialized, some more general. All are useless until we know how to use them.

* Except for collectors, lenses aren't the goal, images are. But where do the images go? How many digital image files are actually printed, or displayed, anywhere near their full size, if at all? Do we gain masturbatory satisfaction by producing images that will never be seen in their full glory? Are Polaroids better?

* The best lens (or camera) is that which you use.
* An imperfect picture is better than none at all.
* Almost any picture looks good if it's small enough.
* Almost anything can be fixed in post-processing.
* Rule of street/photo/journalism: f/8 and be there.

* Every lens contains design compromises. Every lens purchase contains desire / reality compromises. Every photo contains vision / reality compromises. We all must muddle through the best we can. The only perfection is in death. Eek.
02-25-2010, 03:18 PM   #26
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
QuoteOriginally posted by stevebrot Quote
I did not do any other direct comparisons with the kit. I did the one shot on a whim. The camera was on the tripod and the lens was sitting there and I said...I wonder? My experience has been that it is a dangerous thing to compare a competent zoom to even your better primes.

Steve
true. as of the moment, a prime in general is still superior to a zoom. also, there are a few exceptions as well.
02-25-2010, 03:38 PM   #27
Site Supporter
grey goat's Avatar

Join Date: Dec 2009
Location: Spring Green, WI
Photos: Gallery | Albums
Posts: 320
I like those generalities, RioRico, especially these:
QuoteOriginally posted by RioRico Quote
* Except for collectors, lenses aren't the goal, images are.

* The best lens (or camera) is that which you use.

* An imperfect picture is better than none at all.

* Rule of street/photo/journalism: f/8 and be there.

* Every lens contains design compromises. Every lens purchase contains desire / reality compromises. Every photo contains vision / reality compromises. We all must muddle through the best we can. The only perfection is in death. Eek.
Heck, I may pin those up on the wall somewhere around here.

"f/8 and be there." I like it. Especially the "be there" part. . . .
02-25-2010, 03:49 PM   #28
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
some may find the 28mm of little use. but for me, I find it very useful for walkarounds. given the FOV it shows on an APS-C cam, it is an ideal focal length for anything with significant background at an ideal distance. I do find the 50mm quite longer than I may have wanted it. even a 35mm is still longer for close table shots.

that's also why I'm in need of a full-frame dslr that should do what a 50mm suppose to do.
02-25-2010, 04:50 PM   #29
Veteran Member




Join Date: Oct 2008
Location: Sweden
Posts: 359
QuoteOriginally posted by Marc Sabatella Quote
Interesting. I've done similar comparisons with my M28/2.8 and found the 18-55II closed the gap *hugely* by f/8 or f/11, even at longer shooting distances. But I suppose that could be a matter of the M28/2.8 not sharpening up as dramatically between f/4 and f/8 as the K28/3.5. That's not really what Yoshihiko's resolution test results suggest, though. So there could also be sample variation involved, testing methodology variation, or just differences in our perception of the magnitude of differences we see.

But even so, that still doesn't really explain Lars' comparison, which appears to be shot at pretty close range, unless that is indeed a 100% crop. Like I said, I've never seen *either* version of the kit lens produce anything so soft.
Ok, I just did a new comparison including the DA 40 F2.8 Ltd.
At F5.6 the DA 40mm Ltd is slightly sharper than the K 28mm K3.5, but it is very difficult to see the difference.
At F8.0 the K 28mm F3.5 is sharper than the DA 40 F2.8 Ltd.

The kit lens is softer at both F5.6 and F8.

Kind regards
.lars
02-25-2010, 06:29 PM   #30
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
QuoteOriginally posted by Recercare Quote
Ok, I just did a new comparison including the DA 40 F2.8 Ltd.
At F5.6 the DA 40mm Ltd is slightly sharper than the K 28mm K3.5, but it is very difficult to see the difference.
At F8.0 the K 28mm F3.5 is sharper than the DA 40 F2.8 Ltd.

The kit lens is softer at both F5.6 and F8.

Kind regards
.lars
lars, did you do the test at minimum focusing distance as for comparison or did you also do a series of tests at varying focusing distance as well?
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!
28mm, k-mount, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cityscape Crossed purpose? raymeedc Post Your Photos! 4 04-20-2010 12:38 AM
How many tripods do you own and what lenses/purpose do you use them for? gofour3 Pentax Camera and Field Accessories 17 04-09-2010 03:08 AM
Looking for an all-purpose lens wedge Pentax SLR Lens Discussion 12 04-08-2010 06:17 AM
What is the purpose of LightRoom? photolady95 Digital Processing, Software, and Printing 58 06-02-2009 01:29 PM
How to take photos for printing purpose? marius Digital Processing, Software, and Printing 2 08-05-2008 05:43 AM



All times are GMT -7. The time now is 05:52 AM. | 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