Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-06-2009, 06:58 PM   #31
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
ranters,

pardon me for being skeptic about you. it is just that it has not been a good day here as well. K-7 has just recently came out and there are a few party crashers trolling around. plus your thread title about the lens is really incitive, bashing it on it's very own niche.

but anyway, all is good. if you could provide some pics here, some of the guys might be able to help you out. cheers mate.

07-06-2009, 07:28 PM   #32
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,947
I would definitely use Av mode. If you can shoot at f5.6 to f8, you'll have a lot more in focus photos (assuming you can keep your shutter speed up). The other thing is to use center point focus. If you use the green mode for focus, it will choose whatever the maximum contrast point closest to the camera -- often this is not what you want.

The other thing is to shoot a focus test and see if there is something wrong with your focus -- personally I doubt that is the issue, if there are two different lenses involved, but certainly if there is, Pentax will fix them.
07-06-2009, 07:29 PM   #33
Veteran Member
RawheaD's Avatar

Join Date: Dec 2008
Location: MA, USA
Photos: Gallery
Posts: 831
QuoteOriginally posted by ranters Quote
Then i could isolate if it it is lens or camera
You're forgetting the third possibility. I just got my K-7 today, and put on the DA*60-250 and the DA*16-50 I'd got about a week ago in anticipation of the K-7, and took both lenses out for a very brief spin. I'll have to conduct some in-depth tests to check for various issues, but, regarding focus, both did A-OK. Of course, these are slow lenses (F2.8 and F4) so I won't have to be as anal as I would be with my faster lenses (F1.2-1.8).

Of course all companies have QA issues, and Pentax/Hoya has been slammed for the 16-50mm, so you can't rule that out, but I doubt both your star lenses could be at fault, especially if they're giving you similar faulty results.


So, if it's not the camera's fault (AF sensor having backfocus), well, mate, the only other explanation is the third possibility.


And, I'm sorry to say, taking hundreds of pictures a week, and even getting paid for them末i.e., making you a "pro" in that sense of the word末doesn't make you an expert. I know of plenty of "pro" photographers who are less knowledgable about their gear than I am, someone who just started shooting DSLRs exactly one year ago. You may not be a troll, and I'm sorry for calling you one if that's the case, but the attitude you come in with末that the problem must lie with the star lenses and maybe the camera, but no way can it be your fault... well, let's just say, it doesn't gain respect from me.
07-06-2009, 09:19 PM   #34
New Member




Join Date: Jul 2009
Location: Victoria
Photos: Gallery
Posts: 15
Original Poster
yep got your point. I didnt say i was expert but had to say that i do take loads of pics and there r about 40,000 people on a weekly basis that view my pics and all i know is that i have a rather large following for my action pics compared with others. Whats happening is that the the 2 new lenses dont seem to perform with as much clarity and depth of field as i had with some older lenses. the reason i use pentax cameras is that i found they r the best for action shots where there is no time for adjustments. I do understand about the third possibility but in my case i didnt do anything different, just got 2 new cameras with lenses and noticed a difference. But i have done another test today as people suggested so i will post the results.
QuoteOriginally posted by RawheaD Quote
You're forgetting the third possibility. I just got my K-7 today, and put on the DA*60-250 and the DA*16-50 I'd got about a week ago in anticipation of the K-7, and took both lenses out for a very brief spin. I'll have to conduct some in-depth tests to check for various issues, but, regarding focus, both did A-OK. Of course, these are slow lenses (F2.8 and F4) so I won't have to be as anal as I would be with my faster lenses (F1.2-1.8).

Of course all companies have QA issues, and Pentax/Hoya has been slammed for the 16-50mm, so you can't rule that out, but I doubt both your star lenses could be at fault, especially if they're giving you similar faulty results.


So, if it's not the camera's fault (AF sensor having backfocus), well, mate, the only other explanation is the third possibility.


And, I'm sorry to say, taking hundreds of pictures a week, and even getting paid for them末i.e., making you a "pro" in that sense of the word末doesn't make you an expert. I know of plenty of "pro" photographers who are less knowledgable about their gear than I am, someone who just started shooting DSLRs exactly one year ago. You may not be a troll, and I'm sorry for calling you one if that's the case, but the attitude you come in with末that the problem must lie with the star lenses and maybe the camera, but no way can it be your fault... well, let's just say, it doesn't gain respect from me.


07-06-2009, 10:23 PM   #35
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
It's still not really clear what complaints you are raising...

If backfocusing is the issue - that needs adjusting.

If the lenses don't give much 'clarity & DOF' compared with your 'older' lenses (whatever that's supposed to mean), then there are a host of other variables that you have not mentioned that makes a big difference in results: focal length, aperture and distance between subject & background for starters.

If these are all a given to you, more info with photo examples are needed to help you out...
07-07-2009, 03:43 AM   #36
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,862
QuoteOriginally posted by ranters Quote
As i have said i have taken 1000s of pics . What i will do is swap lens onto another body to see if i get different results. Then i could isolate if it it is lens or camera
ranters. Let me assume that you want your problem to be fixed.

May I then propose that you change your attitude? Nobody here is forced to help you. We are not Pentax ... The hardest part in helping you will still remain on your side

The first thing I was wondering (and you are now confirming) is that you have 5 bodies and 5 lenses and you seem to keep body/lenses attached. And your bodies have very different capabilities in autofocus.

And the answer to your "question", "(are) da* lens rubbish"?: No. They focus perfectly.

An answer as good as possible, given your question.
07-07-2009, 05:39 AM   #37
Veteran Member
robjmitchell's Avatar

Join Date: Oct 2007
Location: Melbourne Aus
Posts: 1,144
Well looking at the photos you posted it looks like your shutter speed was too slow. The objects are in focus, they just moved. You clearly have the lenses stopped down to far. The whole point of fast lenses is to blur the out of focus areas, not keep everything in focus. Are you shooting in MTF program line, put it is speed or aperture priority program(I'm Assuming the k200d has a program line?) To get better action shots you need to balance the aperture to get maximum light but with enough depth of field to get the subject in focus. Try f4 for starters. Also boost your ISO to 400 or above. As high as you can go but still have acceptable noise.
Cheers
07-07-2009, 06:27 AM   #38
Pentaxian
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,862
Just a general comment about "pros" vs. "experts" ...

And I don't mean ranters!


Office secretaries certainly are pros when it comes to using M$ Word. Because they earn their money this way. Still, I haven't seen many experts among them.

Best I've ever seen was a secretary with tears in her eyes after the fourth miniscule required change to a letter snivelling "Oh no, don't let me type the letter again"

07-07-2009, 06:57 AM   #39
Veteran Member




Join Date: Dec 2008
Location: NYC
Posts: 944
since you have no problem focusing on far away objects, and only have a problem with close ups.

I have no doubt that its DOF issue.

Fast lenses require practice and knowledge... you need to remember that when shooting closeup on f/2.8 especially with a long lens , most likely you will get a picture with a very very small DOF, if any

and you are right you wil not have this "problem" with a slow lens
07-07-2009, 07:22 AM   #40
Veteran Member
kristoffon's Avatar

Join Date: Aug 2008
Location: Brazil
Posts: 532
You guys shoudln't pay attention to an obvious troll
07-07-2009, 07:52 AM   #41
Site Supporter
GeneV's Avatar

Join Date: Oct 2008
Location: Albuquerque NM
Photos: Albums
Posts: 9,761
QuoteOriginally posted by robjmitchell Quote
Well looking at the photos you posted it looks like your shutter speed was too slow. The objects are in focus, they just moved. You clearly have the lenses stopped down to far. The whole point of fast lenses is to blur the out of focus areas, not keep everything in focus. Are you shooting in MTF program line, put it is speed or aperture priority program(I'm Assuming the k200d has a program line?) To get better action shots you need to balance the aperture to get maximum light but with enough depth of field to get the subject in focus. Try f4 for starters. Also boost your ISO to 400 or above. As high as you can go but still have acceptable noise.
Cheers
The EXIF on the photo says it was taken at 1/2000 F/4, and at ISO 1600 with the DA* 16-50 set at 45mm. I don't think the problem is the shutter speed. There may be some back focus problems, but it is hard for me to find any area of this photo that is really tack sharp, or as sharp as a properly focussed photo on my DA 17-70 would be at that FL and aperture. This may be a crop, so the point of focus may be somewhere else entirely.
07-07-2009, 09:23 AM   #42
Senior Member
superfuzzy's Avatar

Join Date: Dec 2006
Location: NJ, USA (close to NYC)
Photos: Gallery | Albums
Posts: 278
DA* 16-50 - that may explain it! The current production might be OK but there are a ton of bad copies out there. I personally would never buy that lens.

I don't think Ranters is a troll, just a little brusk in his comments. It would have been more effective to state the models o f * lenses that you have and problem with in the very first post.

Good luck and welcome to Pentax Forums
07-07-2009, 08:48 PM   #43
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,189
QuoteOriginally posted by ranters Quote
yea its a beaut frost here this morning just been for a walk
i have both those lenses
dont know anyone with a k20
i have stuck with k200 as they work great for action shots but i would have expected less out of focus shots with sdm lens than ordinary but this is not the case. its the close up shots that r the problem. i have posted 2 shots on the nature part of the forum that might help
This may sound strange, but the SDM lenses are neither much faster to focus nor is the focus more accurate.

I have a few theories about what is happening, but can't confirm unless you are willing to actually do some test shots in a controlled environment. First a reality check:
  • DOF is shallow at f/2.8-f/4
  • Pentax AF is very accurate, but relatively slow
  • The shutter will fire even if focus is not attained if in AF-C mode
  • AF-C mode sucks for following any object moving at more than a walking pace
  • The red dot does not mean focus has been attained
  • The green hexagon means focus has been attained
  • With a moving object, the AF system will often lock focus on a stationary background in preference to your subject. This particularly true if you have a mob of moving subjects.
  • Front/back focus issues are not unknown, but generally do not cause the severe symptoms shown in your 'roo example (usually only a few centimeters one way or another)
  • AF may be overridden using the quick-shift feature and this can happen accidently
  • Finally...AF must be turned on in order for the camera to focus itself
Ok...reality check over. Want to hear my opinion? I suspect you may have been shooting if AF-C mode and exposing before focus had been acquired. To be honest, the bike shots look about as good as you can expect unless you do a lot of that kind of thing. The kangaroo photo is definitely soft and at 1/2000s there is nothing to blame except poor focus or a defective lens.

That is why I suggested doing a controlled test to see if the lens will deliver sharp pictures of a stationary object using both AF and MF. If it fails using manual focus, there is an optical issue. If only AF is affected, it may be the camera and/or lens AF mechanism. Now if doing this kind of testing does not appeal to you. I would suggest contacting your dealer or Pentax Australia for warranty replacement/repair. They can do a thorough evaluation of your lens on an optical bench and make sure that your purchase is providing the excellent performance it was designed for.

Steve

Last edited by stevebrot; 07-07-2009 at 08:55 PM.
07-07-2009, 09:19 PM   #44
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
QuoteOriginally posted by superfuzzy Quote
DA* 16-50 - that may explain it! The current production might be OK but there are a ton of bad copies out there. I personally would never buy that lens.

I don't think Ranters is a troll, just a little brusk in his comments. It would have been more effective to state the models o f * lenses that you have and problem with in the very first post.

Good luck and welcome to Pentax Forums
As said repeatedly in many threads here, there may be a number of 16-50s that have clear decentering and other QC issues, but these problems were largely sorted out in the second wave of production of the lens. Saying that there are a ton of bad copies is a gross exaggeration.

Whether or not you would buy it, the 16-50 is an excellent lens in every way, and I (as well as many other users) have a plethora of examples where this lens outshines any other in its focal range.
07-07-2009, 10:36 PM   #45
Veteran Member
GLXLR's Avatar

Join Date: Feb 2009
Location: Sugar Land, TX
Photos: Gallery
Posts: 686
I definitely think it is front or back focusing issues. Google out how to adjust it on your K200D. Sadly my GX-10 doesn't feature this. I looked at the bike pics and I can see that the background is in focus rather than the biker himself. This could also be that once you locked focus you pressed the shutter button just a tenth of a second to slow, allowing the biker to literally "move" out of focus and then you fired the shot. Hope it all gets resolved and welcome to the forums despite some hostile replies.
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!
da*, da* lens, focus, k-mount, lenses, pentax lens, sigma, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
These shots are rubbish Damn Brit Post Your Photos! 30 08-06-2009 12:16 AM



All times are GMT -7. The time now is 05:50 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