Visit MPB Visit MPB Visit MPB

Back-Focus or my Eyes ? !!

Peter Elgar
Posted 29/11/2017 - 16:50 Link
Using my 2007 bought K10D again after a 'lapse' I tried my 50mm f1.4 SMC Pentax-M at full aperture, manual focus and every shot I took of the Brentwood Lights was back-focussed. I went out again an d did some tests, focusing forward a few feet and got better results. My Wife says I am too OLD now at 80 to spend any more money on camera repairs but I'm sure it was not my 'Eyes' !!
First one -- the bricks behind about 30 feet are sharper than tree lights
Comment Image

Second try --
Comment Image

Third Try ---
Comment Image
Been a member of Pentax Club since the Ron Spillman era! Got COMPUTERISED at last - DIGITISED?
Taken the PLUNGE - BUT FILM STILL RULES !!!
pgweber
Posted 29/11/2017 - 17:08 Link
Could you have accidentally moved the viewfinder dioptre adjustment slider?
Peter

Pentax K5
Pentax DA 18-55 Mk1, 50-200 (Samsung), 16-45, 55-300 Mk1, 35 f/2.4
Pentax MZ6 + FA28-90, FA50 f/1.4, M 50 f/1.7
Tamron 80-210mm & 28mm
Edited by pgweber: 29/11/2017 - 17:10
pschlute
Posted 29/11/2017 - 18:13 Link
Peter, the only true way to test this is on a tripod with a fixed subject (focus chart) in good light.

However the K10 has no "official" way to change the AF adjustment (which would re-align on out of position sensor). There is a firmware hack if you want to look into it. Can you do some tests with an AF lens to see how that performs?
JAK
Posted 29/11/2017 - 18:38 Link
They discussed this at the other place: link
May or may not help but a few more ideas about it.
John K
Algernon
Posted 29/11/2017 - 19:24 Link
Peter the first thing you need is a magnifying eyepiece. I use the Pentax one...
https://www.amazon.co.uk/Pentax-Magnifying-Camera-Eyepiece-1-2x/dp/B000R90IM4

Cheaper but I've not used it, although they usually work OK .....

https://www.amazon.co.uk/DSLRKIT-1-08x-1-60x-viewfinder-eyepiece-magnifier/dp/B0...

The DOF is actually seen as an f/2.4 lens with a standard screen so more looks in focus than actually is.

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Peter Elgar
Posted 03/12/2017 - 10:38 Link
I find my AF SMC Pentax -DA 18-55mm f3.4-5.6 'kit' lens cannot be relied on accuracy as many 'press photos' suffered in the past and one time I attached my 35mm f2 Super-Takumar with the adapter in a Gym photographing the Mayor and athletes and the wall about 25 feet behind was sharp and Mayor was out !
Funnily enough I was GIVEN by a Camera Club member a 'Film' lens SMC Pentax-F 35-80mm f4-5.6 and it WORKS on 'auto focus' well so I use that most of the time now when i can according to subject. I n o longer get any 'Press' work, all Freelancers gone broke here.
Been a member of Pentax Club since the Ron Spillman era! Got COMPUTERISED at last - DIGITISED?
Taken the PLUNGE - BUT FILM STILL RULES !!!
pschlute
Posted 03/12/2017 - 13:02 Link
Sounds like time for a new camera Peter
Peter Elgar
Posted 03/12/2017 - 14:06 Link
Sorry to mention BUT I have been GIVEN by an Old Gent 89 years old a lot of gear including an Olympus E-500 4/3rds Digital 12 years old hardly ever used as he didn't understand it, with 2 lenses and it has no back-focus issues.
Been a member of Pentax Club since the Ron Spillman era! Got COMPUTERISED at last - DIGITISED?
Taken the PLUNGE - BUT FILM STILL RULES !!!

Add Comment

To leave a comment - Log in to Pentax User or create a new account.