Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-31-2015, 05:24 AM   #1
New Member
kroal's Avatar

Join Date: Jun 2011
Location: Poltava
Photos: Albums
Posts: 18
Using Pentax-F on K10D

Hi guys. Few days ago I became a happy owner of Pentax -F 50/1.7. But yesterday I found few issues that I've never met before. It was a sunny day so I started using built-in flash in slow sync mode. The general mode of using camera was Av (lens in Auto position). After few shots with aperture set to 2 I found a huge exposure miss. Almost the same situation taking a shots without flash with very light background. While using kit lense (18-55) gives normal results. What is my mistake? It is my first time of using F-lenses. Here under you can find to images made by kit and 50mm lens with slow sync flash.

Attached Images
View Picture EXIF
PENTAX K10D  Photo 
View Picture EXIF
PENTAX K10D  Photo 
08-31-2015, 05:59 AM - 1 Like   #2
Site Supporter




Join Date: Oct 2012
Location: North-East England
Posts: 73
The aperture in the second image is open more, even though the exif info reads the same. Look at the Eiffel tower in the background for the clue in this. I've not got any F lenses to try. Did you try the shot in manual as well? I reckon the lens was at f1.7 as the picture looks about 2 stops and a bit over exposed.
08-31-2015, 06:13 AM   #3
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,723
Flash can be tricky with close subjects and large ( open ) apertures. Post some of the non flash misses.

On the shots posted, it looks like the flash shoot was taken from closer than the other, is that true? That could account for the differences in depth of field.

If you dismount the lens and manually flip the aperture control arm mouth the ring is set to A does the lens stop down evenly and rapidly?
08-31-2015, 06:17 AM   #4
New Member
kroal's Avatar

Join Date: Jun 2011
Location: Poltava
Photos: Albums
Posts: 18
Original Poster
QuoteOriginally posted by eonb Quote
The aperture in the second image is open more, even though the exif info reads the same. Look at the Eiffel tower in the background for the clue in this. I've not got any F lenses to try. Did you try the shot in manual as well? I reckon the lens was at f1.7 as the picture looks about 2 stops and a bit over exposed.
No. I didn't try manual mode because shutter speed couldn't be above than 1/90 (while using built-in flash). So I couldn't shot in this mode with small apertures. To the point - this is the open question for me when I use manual settings.

08-31-2015, 06:52 AM   #5
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,723
QuoteOriginally posted by kroal Quote
No. I didn't try manual mode because shutter speed couldn't be above than 1/90 (while using built-in flash). So I couldn't shot in this mode with small apertures. To the point - this is the open question for me when I use manual settings.
So which mode were you in?
08-31-2015, 07:21 AM   #6
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,838
The EXIF says spot metering was used. The camera would have to be using the exact same "spot" for these shots to meter the same. I think that's at least a contributor.
08-31-2015, 08:27 AM   #7
New Member
kroal's Avatar

Join Date: Jun 2011
Location: Poltava
Photos: Albums
Posts: 18
Original Poster
QuoteOriginally posted by UncleVanya Quote
Flash can be tricky with close subjects and large ( open ) apertures. Post some of the non flash misses.

On the shots posted, it looks like the flash shoot was taken from closer than the other, is that true? That could account for the differences in depth of field.

If you dismount the lens and manually flip the aperture control arm mouth the ring is set to A does the lens stop down evenly and rapidly?
OMG. You were right. There is some issue with aperture blades. They stuck at 1.7 and works a bit tight. So aperture was always 1.7. Do anyone has exp. in repairing such problem?
08-31-2015, 08:35 AM   #8
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,723
QuoteOriginally posted by kroal Quote
OMG. You were right. There is some issue with aperture blades. They stuck at 1.7 and works a bit tight. So aperture was always 1.7. Do anyone has exp. in repairing such problem?
Dcshooter

08-31-2015, 10:39 AM   #9
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,030
I don't think shipping from Ukraine to Dcshooter is going to be all that inexpensive.
08-31-2015, 10:50 AM   #10
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,723
QuoteOriginally posted by Not a Number Quote
I don't think shipping from Ukraine to Dcshooter is going to be all that inexpensive.
True - but he may be willing to share some wisdom on how to approach fixing it.
08-31-2015, 10:51 AM   #11
New Member
kroal's Avatar

Join Date: Jun 2011
Location: Poltava
Photos: Albums
Posts: 18
Original Poster
QuoteOriginally posted by Not a Number Quote
I don't think shipping from Ukraine to Dcshooter is going to be all that inexpensive.
Yeah. Definitely. So, repairing is a new challenge for me. That is why I just need an advice (materials, manuals, etc...).
08-31-2015, 12:48 PM   #12
Veteran Member




Join Date: Jan 2011
Location: Corinth, NY
Photos: Albums
Posts: 385
how mechanical are you?

I've taken my F 50 apart a couple times, and it works fine now. But i would not recommend someone doing it unless you have mechanical skills, and patience. The Correct screwdrivers and fine tweezers are a must.
08-31-2015, 02:44 PM   #13
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,483
QuoteOriginally posted by link81 Quote
Correct screwdrivers and fine tweezers are a must.
Add very good eyesight and/or a workbench magnifier.


Steve
08-31-2015, 06:17 PM   #14
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,030
QuoteOriginally posted by stevebrot Quote
Add very good eyesight and/or a workbench magnifier.


Steve
An infinite amount of patience helps enormously too.
09-03-2015, 02:51 PM   #15
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,838
I have seen some of these for sale with oil on the aperture blades which would be consistent with the symptoms. You can access the aperture blades by unscrewing the beveled trim ring around the front element. Some kind of friction tool, like a sink drain stopper, should grip the thing well enough. Then you'll see a brass colored ring with three tiny screws in it. My Moody's JIS #000 fits these. They were a bit tight. The ring holds on the front lens group so don't tip the lens to let the screws fall out without holding the group in. Once the group is removed you can see the top side of the aperture blades. I have had reasonable luck carefully wiping them down with mineral spirits or naptha, then drying them off, several times, using the aperture lever to move them and distribute the solvent. The blades are thin metal so you can't press on them. When the solvent is dry, try the aperture lever again and see if the blades snap closed properly. You should check the inner lens surfaces of rear and front groups to see if either has oil or solvent on them, and clean that before reassembly.

Sometimes I have to remove the rear lens group to clean the other side of the blades. The oil migrates everywhere so the ideal repair is to remove the blades, wash them and the area in solvent and reassemble. That usually means a lot of disassembly since the aperture mechanism is right at the heart of the lens.
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, flash, kit, lens, mode, pentax help, photography, shots, sync, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Exposure Meter on K10D when using SMC-M 50mm 1.7? RiverKayaker Pentax DSLR Discussion 13 04-08-2014 03:36 PM
Getting a flashing F when I try using an SMC Pentax-M 1.7 lens with my K10D altrace Pentax DSLR Discussion 5 12-30-2010 10:34 PM
Using M42 lenses on K10D Matamanoa Pentax DSLR Discussion 6 11-19-2008 10:50 AM
Using a SMC PENTAX-A LENS on the K10D GRIZZLY GULCH Pentax DSLR Discussion 4 01-31-2008 12:11 PM
Using M lenses on K10D Olrocker Pentax DSLR Discussion 4 06-22-2007 07:44 AM



All times are GMT -7. The time now is 02:00 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