Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-16-2011, 09:50 AM   #1
Junior Member




Join Date: Aug 2011
Location: Los Angeles
Photos: Gallery | Albums
Posts: 33
Tuning your glass

Greetings.

Just got the DA* 60-250mm in the mail from B&H. Needless to say, I'm pretty excited.

I was reading the review of the glass elsewhere on this site when I came across this...

"Make sure to tune your glass for AF adjustment. Ours needed +4. Once it was tuned, it went from mediocre pictures wide open to impressive pictures from a zoom."

I have never done this with any of my previous glass and now I'm wondering what I'm missing. Can anyone point me to where in the manual or an online resource to instruct me on how to do this?

I appreciate it.

Best,
Chuck P.

12-16-2011, 10:10 AM   #2
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
Can O worms time. You are going to get all sorts of advice regarding downloadable test targets, moire patterns off a computer monitor, and probably a few other Rube Goldberg type ideas.
While the computer monitor idea isn't bad, I just use something that is at a bit of distance that has some fine detail. Perhaps a power wire or some such for a telephoto, or a clock face across the room for a shorter lens.
Without knowing which camera you are using, look in the index of your owners manual for AF Adjustment (or similar wording) for instructions on how to dial in a lens.

Edit: My method is to use a target, and take a picture of it with the adjust at 0, then one at +5 and -5. I put those images on the computer and see which is sharpest. I then use that setting as the basis and shoot images plus or minus 3 from that setting and see which is sharpest. I then use that setting and take pictures at plus and minus 2, then again at plus and minus 1.
That gives me a good dial in.
12-16-2011, 10:11 AM   #3
Loyal Site Supporter
eddie1960's Avatar

Join Date: Aug 2010
Location: Toronto
Photos: Gallery | Albums
Posts: 12,165
I think they meant adjust the camera for back or front focus with that lens.

you need to test the focus using a chart and adjust until it is accurate

this is a pretty good one it's free (well you have to print it) and has decent instructions

Jeffrey Friedl's Blog Jeffrey’s Autofocus Test Chart
12-16-2011, 10:41 AM   #4
Pentaxian
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
Lots of folks seem to have their own ways of doing this. I think its important not to make it so tedious that it doesn't get done.

I string out 3 magnetic signs in a line across my refrigerator, stand back from 5 to 10 feet, at an angle of 45deg and dial in the adjustment for maybe the 3 lenses i expect to use that day. I do this before each major shoot at the theatre i volunteer at just to make sure everything is working fine.

12-16-2011, 11:24 AM   #5
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by philbaum Quote
Lots of folks seem to have their own ways of doing this. I think its important not to make it so tedious that it doesn't get done.

I string out 3 magnetic signs in a line across my refrigerator, stand back from 5 to 10 feet, at an angle of 45deg and dial in the adjustment for maybe the 3 lenses i expect to use that day. I do this before each major shoot at the theatre i volunteer at just to make sure everything is working fine.
That is pretty much how I do it; keep it simple.

FWIW, it can get a little trickier with a zoom lens as the amount of adjustment needed can change throughout the focal length range. Since you can only enter a single AF adjustment value, you may have to use a value that gives you the best results overall or decide to use a value that gives you the best focus at the FL you intended to use most often.
12-16-2011, 01:14 PM   #6
Veteran Member
mysticcowboy's Avatar

Join Date: Apr 2009
Location: port townsend, wa
Photos: Albums
Posts: 968
Front and back focus adjustments are very handy for fixed focal length lenses. I've had to adjust my FA100 macro and it works well. However, with such a long zoom range, you may find that the back/front focus of your lens changes at different focal lengths. Considering the price of your lens, I'd test it for focus and if it's off at all, exchange it. B&H is good about that. It may take a return or two, but having a zoom lens set right at the factory is better than adjusting your camera.
12-16-2011, 04:06 PM   #7
Veteran Member




Join Date: Jul 2010
Location: Flushing NY
Photos: Albums
Posts: 409
Before doing any AF adjustments, I would suggest updating your firmware, if there's a chance you were going to update it anyway, since I assume new firmware would wipeout any adjustments you made, and the amount of adjustment needed might be different with new firmware.
12-16-2011, 05:19 PM   #8
Junior Member




Join Date: Aug 2011
Location: Los Angeles
Photos: Gallery | Albums
Posts: 33
Original Poster
Excellent suggestions here folks. I thank ya for them.

Finally cracked open the box and put the MASSIVE lens on my K5. Amazing. One thing I noticed tho...

When I zoom the lens out, it moves fairly fluidly and consistent until 200... then from 200-250 it seems like it's barely moving. It looks like it's barely moving through the viewfinder as well. I know this thread isn't about the 60-250, but I thought I would mention it in hopes of getting some feedback from people who have this lens. So far, the pics look pretty sharp, but I'm going to try testing it at different focal lengths this weekend to see how it performs.

Cheers,
Chuck P.

12-16-2011, 05:32 PM   #9
Veteran Member
dgaies's Avatar

Join Date: Oct 2009
Location: Maryland / Washington DC
Posts: 3,917
QuoteOriginally posted by chuckp8 Quote
Excellent suggestions here folks. I thank ya for them.

Finally cracked open the box and put the MASSIVE lens on my K5. Amazing. One thing I noticed tho...

When I zoom the lens out, it moves fairly fluidly and consistent until 200... then from 200-250 it seems like it's barely moving. It looks like it's barely moving through the viewfinder as well. I know this thread isn't about the 60-250, but I thought I would mention it in hopes of getting some feedback from people who have this lens. So far, the pics look pretty sharp, but I'm going to try testing it at different focal lengths this weekend to see how it performs.

Cheers,
Chuck P.
What you're seeing if the effect of focus breathing. The 60-250 can go out to 250mm at infinity focus. At intermediate distances, the maximum focal length is closer to 200-220mm. At the MFD, the focal length is quite a bit under 200mm. So what you're seeing is normal, especially at close to intermediate focusing distances.
12-16-2011, 06:59 PM   #10
Veteran Member
Raybo's Avatar

Join Date: Dec 2007
Posts: 871
QuoteOriginally posted by chuckp8 Quote
Excellent suggestions here folks. I thank ya for them.

Finally cracked open the box and put the MASSIVE lens on my K5. Amazing. One thing I noticed tho...

When I zoom the lens out, it moves fairly fluidly and consistent until 200... then from 200-250 it seems like it's barely moving. It looks like it's barely moving through the viewfinder as well. I know this thread isn't about the 60-250, but I thought I would mention it in hopes of getting some feedback from people who have this lens. So far, the pics look pretty sharp, but I'm going to try testing it at different focal lengths this weekend to see how it performs.

Cheers,
Chuck P.
Just keep using it a bit more Chuck, the HSM needs to "breath" and then it will be fine (I hope).
12-17-2011, 03:20 AM   #11
Loyal Site Supporter
AdrianM's Avatar

Join Date: Aug 2008
Location: Ipswich, Queensland, Australia
Photos: Gallery | Albums
Posts: 545
QuoteOriginally posted by philbaum Quote
Lots of folks seem to have their own ways of doing this. I think its important not to make it so tedious that it doesn't get done.

I string out 3 magnetic signs in a line across my refrigerator, stand back from 5 to 10 feet, at an angle of 45deg and dial in the adjustment for maybe the 3 lenses i expect to use that day. I do this before each major shoot at the theatre i volunteer at just to make sure everything is working fine.
I like Phil's approach, and also use AA batteries as targets in the 45 degree manner that Phil has suggested but outside in daylight, but for tuning my 500mm, I choose 3 soft drink cans at a distance of about 6 metres as being somewhat representative of shooting birds.
12-17-2011, 04:35 AM   #12
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
I tried using focus charts,and even built a home made version of onew of these



but found they are completely unnecessary.


Now I just aim at a few things at an angle using the widest aperture and snap. And then adjust until it's spot on. objects with print on are pretty good. Cerial packets,etc
12-17-2011, 05:23 AM   #13
Veteran Member




Join Date: Jul 2010
Location: Flushing NY
Photos: Albums
Posts: 409
QuoteOriginally posted by Smeggypants Quote
Cerial packets,etc
Coffee cans for me.
12-17-2011, 05:54 PM   #14
Junior Member




Join Date: Aug 2011
Location: Los Angeles
Photos: Gallery | Albums
Posts: 33
Original Poster
QuoteOriginally posted by dgaies Quote
What you're seeing if the effect of focus breathing. The 60-250 can go out to 250mm at infinity focus. At intermediate distances, the maximum focal length is closer to 200-220mm. At the MFD, the focal length is quite a bit under 200mm. So what you're seeing is normal, especially at close to intermediate focusing distances.
Wow. I'd never heard of this! It seems I never noticed this on the 50-200mm that I have. Maybe it's not quite so pronounced. At any rate, as I use it more I'm sure I'll notice if it's a problem or not. I've got a couple of sporting events I'll be shooting next week, so I'll really put it to the test.

Thanks again for all the great suggestions. If anyone has any more tips on shooting with the 60-250mm, feel free to message me directly, or (if the moderator gods approve) tack them on to this thread.

Best,
Chuck P.
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, glass, k-5, k-5 ii, k-5 iis, k5, pentax k-5, pictures
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K200D autofocus fine tuning. polur101 Pentax DSLR Discussion 30 02-09-2014 02:23 PM
Tuning in from WAIKIKI, West Australia nightjar Welcomes and Introductions 2 10-16-2010 09:40 PM
Will K-7 have AF lens tuning like the K20D? jsherman999 Pentax News and Rumors 17 04-27-2009 04:01 PM
K20D AF tuning with FA*80-200mm dsport Pentax SLR Lens Discussion 9 09-14-2008 11:49 AM
K20D with AF Fine Tuning? blende8 Pentax News and Rumors 12 12-17-2007 06:36 AM



All times are GMT -7. The time now is 10:49 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