Servicing for Pentax cameras


mattie

Link Posted 15/10/2020 - 09:51
Hi all

My local camera shop doesn't service/repair Pentax cameras, suggesting I go direct to Pentax. Are there any local alternatives, or is going through Pentax/Ricoh the only option?

I was hoping to get some help with a few focus issues, which I wonder may be down to the mirror assembly needing a good service and the focus adjust needing a competent hand to sort, but I'm not likely to get the latter from a mail-in service centre.

I'm in Edinburgh, just for context, but keen just to know if it's a general thing or not.

pschlute

Link Posted 15/10/2020 - 11:02
mattie wrote:
Hi all

My local camera shop doesn't service/repair Pentax cameras, suggesting I go direct to Pentax. Are there any local alternatives, or is going through Pentax/Ricoh the only option?

I was hoping to get some help with a few focus issues, which I wonder may be down to the mirror assembly needing a good service and the focus adjust needing a competent hand to sort, but I'm not likely to get the latter from a mail-in service centre.

I'm in Edinburgh, just for context, but keen just to know if it's a general thing or not.

The official Pentax repair agents in the UK are John Pye Technical https://www.johnpye.co.uk/john-pye-technical-services/

But before you ask for a quote, what camera and lens is it and what focus issues are you having ? The mirror will only affect manual focus generally, although if there is a serious problem with it that can affect the AF module too.

The AF Fine Adjust menu can usually sort out minor Front or Back focus issues but needs a methodical approach to get it right.

Let us know the actual problems.
Peter



My Flickr page
Last Edited by pschlute on 15/10/2020 - 11:03

mattie

Link Posted 15/10/2020 - 11:27
Thanks Peter

The camera needs a service in general, it looks like I've been hammering nails in a swamp with it, but the focus issue is a bit vexing.

Basically, the image can look perfectly focused through the viewfinder, I've lined up the AF sensor exactly over the (for example) eyes of the subject, and yet once closely inspected the point of focus is either ahead of or behind the intended. This is a classic use case for the focus adjust, but I still seem to suffer these problems - it might be that I'm not following the correct procedure, I usually try to take a photo of something with lot of contrast at wide aperture, and then increment the adjust until I get a sharp image. The problem is, this doesn't always seem to translate to sharp images when out and about. Is there a more 'scientific' way of doing this? I was wondering if a good service would help, as something may be out of alignment.

I'll contact John Pye Technical re a service as it's long overdue anyway, but any advice on getting better critical focus would be greatly appreciated. Losing what could be good images as the subject isn't quite sharp is infuriating!

pschlute

Link Posted 15/10/2020 - 14:17
OK this is what I would advise.

1. Buy a hammer for your next swamp visit, don't use the camera.

2. Adjust the dioptre on the camera to make sure it is still at the optimal setting.

3. Use a rocket blower inside the mirror box in Sensor cleaning mode. The aim of this is to get rid of any dust that may have settled on the AF sensor. You need to have the mirror up to do this.

4. If the camera has Live view....get it on a tripod, focus on a high contrast unequivocal subject (like a focus chart) using first the OVF not LV. Make the lens work to focus by starting it off at either closest focus distance or infinity. Once focus is acquired, turn off AF switch and switch to LV. Use the OK button to zoom to 100%. Is it in sharp focus ? You should repeat this test a number of times, each time making the lens work as described above. If the PDAF (optical viewfinder) is not getting the focus right when you look at the result in LV then to what degree is it getting it wrong.... eg consistent backfocus/frontfocus can be dealt with in the AF/FA menu but you need to do about 10 tests to get a reliable indication.
It is also worth seeing if the lens focusses differently when made to work from close focus distance compared to working from infinity. Some do !
When making AF/FA adjustments try and use natural light. Artificial light can produce different results. If using say a 50mm lens I would test from about two metres away. Camera on a tripod.

5. Independent to the AF/FA also check if the optical viewfinder is accurate. Use LV zoomed 100% to focus. Then turn off LV and look through the VF. Repeat the test the other way round. If the viewfinder is not agreeing with the LV then you may have issues with the mirror or focus screen.

Here is a decent test chart http://www.kscameraclub.org/docs/pdfs/focus_test_chart_edited.pdf
Peter



My Flickr page
Last Edited by pschlute on 15/10/2020 - 14:22

mattie

Link Posted 15/10/2020 - 21:54
Many thanks, I'll give that a go!

pschlute

Link Posted 15/10/2020 - 23:01
Forgot to mention....single centre autofocus point only
Peter



My Flickr page
Add a Comment
You must be registered or logged-in to comment.