Lens calibration shop

Optikos make some very expensive/specialist equipment for
adjusting lenses.......

http://www.lensrentals.com/blog/2014/03/rogers-new-toy-needs-a-name

--

I read that when it was published. Amazing machine. It's for measuring lenses though not adjusting them. I still reckon the mallet shown in the pics is the adjustment tool

its quite a dilemma really since I got the lens used, the body is in mint condition and got it for 370 euros from japan and ended up avoiding another 100+ euros in import charges + VAT (lucky me).its just a matter of whether I can accept the lens, swallow the fact that I will rarely shoot at f/4 since I did get it for landscapes and move on, or I could calibrate it at a shop or the last option would be to return it. and I really need to decide soon

looking at the photo on the left, even though I focused at 0, the numbers 8 and 16 above it look much sharper than the 0. However after the tuning, the 0 I believe is slightly sharper than the 8 above it even though the two 8's arent equally sharp as you said. I dont know if this is the lens or the fact that the lens was almost at minimal focusing distance and that anything closer to the lens will be obviously more blurry.

According to a guide I read, the points above and below the centre dont always need to be equally out of focus.read this,page 9 link

No it's purely for adjusting lenses....
Quote "While this isn’t designed to be a screening or testing tool,
some comparisons are kind of interesting."

A mallet is always handy whatever you are doing

--

The machine doesn't adjust lenses it measures them. The lenses are then adjusted if the machine shows they need adjusting. I understand how the machine works, but I'm interested in how the lenses are actually adjusted and I can't find any info on this.

No they don't need to eb equally OOG, but the proper test is if it's giving acceptable results in the real world.

I don't use test charts any more when calibrating the AF for my lenses, I just take loads pictures of stuff at the widest aperture until I'm satisfied the adjustment is the best for all focal distances and, if a zoom all focal lengths.

The only lenses I've found that lie outside the +/-10 range is some old manual focus lenses.


Also bear in mind that there maybe be a parameter in debug mode that could set the core AF adjustment upon which the +/-10 parameters sits on top of.

The only way to adjust AF on the K10-D was in Debug mode and this was measure in micro metrese rather than an arbitrary dimensionless number

Something like that. With a bit more maths And the output of the correlator also gives you the amount and direction in which to go to focus.

Back to the OP :

How does this lens behave at infinity (how much correction does it need) ?

What is the point of adjusting the phase detect AF correction for manual focus lenses ?

"Capture in focus" - press the shutter release then slowly alter focus and when focus is detected the shutter will release.

after ive adjusted it to +10 ive tried it at infinity with f/8 and f/11 and its sharp and everything is in focus.

and wide open?

is it possible to use PK Tether with the K50? if so that would make a larger adjustment range available

If you want the ultimate in focus peaking and the most
accurate focusing possible..... see this software....

http://lensvid.com/gear/kuuvik-capture-tethered-shooting-the-next-stage/

No Pentax version though!
Big Boys Don't Cry!

--

I'd always found that to be a hit-and-miss affair with manual lenses both on the K-7 and K-5ii. A good focusing screen is much easier.

Focus confirmation.


.