Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-23-2009, 08:40 AM   #1
Senior Member
deludel's Avatar

Join Date: Jan 2008
Location: Durham, CT
Posts: 196
Why aren't my images sharper???

I really, really need help with focus/sharpness. I did not post this in the "critique" forum, because I think it's due to overall technique.

Attached are three horrid examples which highlight my inability to focus.
My K10 was on "Center Focus" (the right-hand option, where it centers in the middle .. I started using that when I had issues with the auto-option) ... my style is to half-press to lock focus then recompose. This is CLEARLY not working.

First Image:
lens used: Tamron 28-75 /1:2.8
63mm focal length
1/180sec at f/2.8
ISO 200
Pattern Metering
EV 0

Second Image:
lens used: Tamron AD 70-300/1:4-5.6
110mm focal length
1/125 sec at f/4
ISO 200
Pattern
EV 0

Third Image:
lens used: Tamron AD 70-300/1:4-5.6
100mm focal length
1/125 sec at f/4
ISO 200
Pattern
EV 0


Overall, most of my images in all different settings suffer from terrible focus. Who can share insight as to what I can do differently?

Attached Images
     
07-23-2009, 08:44 AM   #2
Veteran Member




Join Date: Jun 2008
Location: Borås, Sweden
Photos: Gallery
Posts: 3,165
Hard to tell from these shots, but it looks like your lens might be front focusing a fair bit.

Try sticking the camera on a tripod, line up a row of batteries or something diagonally, then focus on the middle one with center point and shoot. Post the result. (Do this with the lens at 2.8 -- then you can tell easier if you have problems. If you do the battery you focused on won't be the one in focus but rather those in front or further back...)
07-23-2009, 08:50 AM   #3
Veteran Member




Join Date: Apr 2008
Location: Minnesota
Photos: Gallery
Posts: 1,530
Did you de-couple autofocus from the shutter button? could it be that the camera is refocusing before you take the shot? If you focus and do not recompose does the frame stay in focus on the subject?
07-23-2009, 08:58 AM   #4
Site Supporter
ismaelg's Avatar

Join Date: Apr 2009
Location: Puerto Rico
Photos: Gallery
Posts: 962
Are there any filters in front of the lenses?

07-23-2009, 09:18 AM   #5
Site Supporter




Join Date: Jan 2008
Location: Connecticut, USA
Posts: 874
It's hard to tell by what you posted. Try taking a picture with some items in the foreground as well, so we can tell if it is badly front focusing. Also, if you could take some at a higher shutter speed and see if that helps, we might be able to eliminate camera shake as the cause.
07-23-2009, 09:30 AM   #6
Senior Member
deludel's Avatar

Join Date: Jan 2008
Location: Durham, CT
Posts: 196
Original Poster
QuoteOriginally posted by ismaelg Quote
Did you de-couple autofocus from the shutter button? could it be that the camera is refocusing before you take the shot?
What does "de-couple autofocus" mean? I should tell you that I had it on Single Focus, rather than Continuous.


QuoteOriginally posted by ismaelg Quote
Are there any filters in front of the lenses?
UV filter on both.

QuoteOriginally posted by MrApollinax Quote
If you focus and do not recompose does the frame stay in focus on the subject?
I will have to test this. OK, so tonight I'll test this, plus the battery idea suggested above and get back for more feedback. Thanks, all.
07-23-2009, 09:33 AM   #7
Veteran Member




Join Date: Apr 2008
Location: Minnesota
Photos: Gallery
Posts: 1,530
By default the auto-focus is activated by half-pressing the shutter button. You can change this through a custom setting to make the "OK" button be the button to activate auto-focus. This will make it so you do not accidentally re-focus after recomposing by pressing the shutter button.
07-23-2009, 09:44 AM   #8
Veteran Member
alohadave's Avatar

Join Date: Jan 2008
Location: Quincy, MA
Photos: Gallery | Albums
Posts: 2,024
You shot all three of them at the max aperture. Those lenses are probably soft wide open, like many lenses. Try stopping down a stop or two and see if it improves.

07-23-2009, 09:48 AM   #9
Veteran Member




Join Date: Jun 2008
Location: Borås, Sweden
Photos: Gallery
Posts: 3,165
QuoteOriginally posted by alohadave Quote
You shot all three of them at the max aperture. Those lenses are probably soft wide open, like many lenses. Try stopping down a stop or two and see if it improves.
A lens that soft even wide open is defective unless it's on a Holga.
07-23-2009, 09:51 AM   #10
Veteran Member
foxglove's Avatar

Join Date: Sep 2006
Location: Atlantic Canada
Photos: Gallery
Posts: 1,049
QuoteOriginally posted by deludel Quote
63mm focal length
1/180sec at f/2.8

110mm focal length
1/125 sec at f/4

100mm focal length
1/125 sec at f/4
Two things I see here that might be giving you trouble.
1) Wide apertures - this gives you shallow depth of field. That's particularly challenging if you're using focus-recompose, there's little margin for error.
2) Relatively slow shutter speed. The rule of thumb is a minimum of 1/focal length to hand-hold, depending of course on your degree of steadiness, technique, number of cups of coffee, etc. I've never been entirely convinced that you need to apply the 1.5x crop factor to this rule of thumb, but if you do, you may be pushing the limits of hand-holding, particularly in the last two. 110 mm x 1.5 = 165 mm, you should be using a minimum of 1/180 - unless you're a sniper...

Have you been using SR?

I would certainly try the various tests the others have suggested, but you may also want to check your other photos and see what sorts of apertures and shutter speeds you're using. It also may help to pay very close attention to your shooting technique - I was having trouble a while back and realised that I was being pretty slap-dash. I started making sure I was bracing the camera well, and pressing, not poking, the shutter, and got much better results.

I hope you figure it out soon!

Julie
07-23-2009, 10:02 AM   #11
Veteran Member
falconeye's Avatar

Join Date: Jan 2008
Location: Munich, Alps, Germany
Photos: Gallery
Posts: 6,863
All I can say is that the images are too soft. Unfortunately, the EXIFs are missing and there are plenty of possible reasons.

Starting from defective lenses (if this soft wide open), dirty filters, ..., ending in having the camera-internal soft-effect filter enabled (very exotic possiblity, I agree, but showing that we don't know enough).

It doesn't help ... you have to play little engineer and experiment a bit, changing various parameters (like lenses, manual focus, flash, etc.) to single out the reason.
07-23-2009, 10:04 AM   #12
Veteran Member




Join Date: Jun 2008
Location: Borås, Sweden
Photos: Gallery
Posts: 3,165
To be honest, hand holding is such a personal thing that it's hard to apply any rule of thumb. I know some people who need to shoot at 1/1000 to get sharp shots at 400mm on a crop body while I generally get fine results with 1/200-1/250.

The first shot was 1/180 at 63mm so she'd have to have some pretty shaky hands to get that one so soft. I suppose it's possible if that was the case AND she disabled SR, but I think there's something more to it... look at the images and it seems that some parts are better in focus. The second shot, you can see the jeans on his left leg with better clarity than his face for instance.
07-23-2009, 10:04 AM   #13
Site Supporter
ismaelg's Avatar

Join Date: Apr 2009
Location: Puerto Rico
Photos: Gallery
Posts: 962
QuoteOriginally posted by deludel Quote
UV filter on both.
Try without the filters and see if there is any improvement. This could be a case like most aircraft accidents, where there is no single cause but a combination of causes. Filters can sometimes degrade sharpness, but in this case it seems there is more going on.
All other tests and suggestions are excellent.

Thanks,
07-23-2009, 10:10 AM   #14
Inactive Account




Join Date: Dec 2008
Location: Ames, Iowa, USA
Photos: Albums
Posts: 2,965
QuoteOriginally posted by deludel Quote
What does "de-couple autofocus" mean? I should tell you that I had it on Single Focus, rather than Continuous.

UV filter on both.

I will have to test this. OK, so tonight I'll test this, plus the battery idea suggested above and get back for more feedback. Thanks, all.
Here's a few suggestions that might help you figure out what's wrong.

Remove & replace the filter & when you do repeat test shots of the same subject. Make sure there's some foreground in the photo so you can tell where focus is. A good scheme is to focus on something like a ball lying on a lawn. Then it is really easy to see what's actually in focus.

Put the camera on a tripod or sit it on a stool or something so you are not holding it when a shot is taken - use the 2 or 10 second delay to shoot the photo. This will clarify if your holding technique is an issue.

Make sure the lens is clean.

If no part of a photo of a ball on a lawn is in focus and you are not hand-holding the camera, it is a camera/lens problem.

Dave

Last edited by newarts; 07-23-2009 at 10:52 AM.
07-23-2009, 10:17 AM   #15
Veteran Member
foxglove's Avatar

Join Date: Sep 2006
Location: Atlantic Canada
Photos: Gallery
Posts: 1,049
QuoteOriginally posted by pingflood Quote
To be honest, hand holding is such a personal thing that it's hard to apply any rule of thumb.
That's what rule of thumb means, though, more or less - something that is variable, but can be more or less described by the "rule". It seems a reasonable starting point.

QuoteQuote:
The first shot was 1/180 at 63mm so she'd have to have some pretty shaky hands to get that one so soft. I suppose it's possible if that was the case AND she disabled SR, but I think there's something more to it... look at the images and it seems that some parts are better in focus. The second shot, you can see the jeans on his left leg with better clarity than his face for instance.
I quite agree that (a) shutter speed on the first one should be sufficient and (b) there's more to it that camera shake. The differences in clarity on the second shot could be due to missed focus in the rather shallow dof. Or it could be the filter, back or front focus, or any of the other good suggestions, but you have to identify what could be going wrong to identify what is going wrong. Nobody else had mentioned shallow dof or low shutter speed, and the OP needs to take those into account while trying to sort out what's going wrong. They're also some of the simplest potential sources of trouble, and it makes sense to start simple. Whenever my granny would call up and ask my father to drive 150 km to fix her stereo, he would ask her, "Is it plugged in?" You would not believe how many times it wasn't!
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!
camera, dslr, ev, f/4, focus, image, iso, length, lens, pattern, photography, sec, tamron
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sharper images--auto or manual focus Dimeman Photographic Technique 10 02-05-2010 11:01 AM
OK, Which is Sharper ? wll Pentax SLR Lens Discussion 10 09-06-2009 06:27 PM
Tweaking the K20D for Sharper Images nanhi Pentax DSLR Discussion 58 06-19-2009 12:18 AM
Shouldn't this be sharper? FHPhotographer Pentax SLR Lens Discussion 17 01-17-2009 07:20 PM
What is sharper karq Pentax SLR Lens Discussion 6 10-25-2008 02:17 AM



All times are GMT -7. The time now is 03:06 PM. | See also: NikonForums.com, CanonForums.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