Old chestnut:- K10D and adaptall 2

I am hoping fellow K10d users can provide me with some assistance. I have some adaptall 2 lenses and k mount that I wish to use, but am growing increasingly confused regarding the metering issues associated with the K10D. The more I read, the muddier the water becomes. Much of the info available seems to make sense, but in practice doesn’t add up.
‘Green button’ metering not working on old M lenses is supposedly due to the non linear function of the aperture lever. Ok, sounds logical, but aren’t adaptall 2 supposed to function as A lenses and operate with a linear function? If so, stop down should work, but doesn’t.

I have heard reports of changing focusing screen to improve stop down metering, is this true and if so, is any advantage offset by adverse effects on metering for other lenses in other modes?
Do I opt for an expensive Pka mount, which again is variously reported as unreliable or fixable (scraping/cleaning mount contacts, bending/adjusting wiper contacts internally within the mount).

My main lens interest is my treasured sp90. I often use this wide open and this is one solution. My alternative work around is to meter wide open, count the number of stops I shut down to and adjust shutter speed a corresponding number of steps..
I cut my teeth with a manual approach to everything and I am not too concerned if I have to continue this way. However, if there is a better way to more reliable metering it would be good. However, from all the mixed messages out there, it is unclear (to me at least) what level of reliable metering is actually possible.
I understand there may not be definitive answers, but so far I have found the unreliability of information more frustrating than the difficulties of camera and lens.


neville

In general I have found that the easiest way to work with old manual lenses is to make sure the preview image you get when you take a shot is overlain with the histogram, and then to adjust the exposure on the basis of that. I have found that "green button" metering on the K10D or the K20D to be very unreliable, and did not get any better with the replacement of the standard screen with a Katzeye screen.

Often I'll take a few images of the grass or a worn tarmac surface to get the lens into a ballpark exposure. These days I usually have my external meter with me for use with my other old cameras that have no meter and so I'll use that to get into about the right area. Often with digital I'll under-expose a bit (compared to film) to ensure I do not blow the highlights.

I haven't used an Adaptall 2 lens, but having the PK/A adaptor will mean you can change the aperture from the body rather than the lens. Whether it will improve the metering or not I cannot say.

Hope this helps. Kris.

Kris, thanks for the input. I do use the histogram on occasions and find it useful. Although I have to say that initially it was a tool I tended to forget I had available. Didn't have those 'back in the day'.
Also, like you, will set ballpark exposure in readiness. I can work this way and am happy to do so. My quandary is whether this is all I should expect or is reliable metering and/or predictable 'A' lens behaviour achievable? In theory a PKA mount should solve things, but does it? £50-60 for a PKA mount is a lot if all I get is the ability to set aperture from the body but still have very unpredictable metering.

The rumour regarding focusing screens suggests using an older ( and darker) screen as in the ist (LL60 screen). Theory has it that the K10D green button metering is calibrated to this screen!??? I guess if there is any merit in this the katzeye would not help. It does sound strange, but it is equally as strange that pentax failed to get stop down metering right for the K10D, when it was successful in it's predecessors.

I may be incorrect, but I feel I am facing two issues. Firstly the camera metering problems that are well known and secondly the
the idiosyncrasies adaptall 2 lens and mounts. I therefore suspect that the specific advice I need will come from those who use both the same camera and lenses.

Mike is an adaptall fan and so I guess better advice should be forth-coming.

As to the histogram, I use it all the time no-matter what lens is attached to the camera. Although the DR of digital sensors is improving all the time, I find the need to ensure that the highlights are not blown much more critical with digital than I do with film, especially black and white (which I have been using extensively of late).

Rumour has it that the K7/K5 are much better at metering with older lenses. I have only had the K10D (now with Andrew) and the K20D and although fantastic in many ways the metering with older glass is close to useless...

Good luck with trying to find reliable information!

Best wishes, Kris.

One advantage if the PK/A mount is that it can be used with multi-segment metering, whereas only spot metering is supported for PK mount lenses, as I understand it. It's debatable whether this is an advantage worth the additional £30-40 over a PK mount, but it may help make the metering with your K10D more consistent.

I briefly had a Samsung GX-10 (sister to the K10D) with the intention of using it with my old MF lenses (including a few Adaptalls) but found it easier to get good results with my K-m, both in terms of consistent metering and also in-camera JPEG processing.

If it's any consolation, I tend to check the metering using the histogram, as Kris described above, with my K-5 when using PK mount lenses, as it is quite often a couple of stops out from where I'd like.

All thoughts and comments are appreciated. I would stress that I can live with the situation as it is. Being forced to think before you shoot is no bad thing.
Stumbling around on the net one comes across tales of 'cures', fixes and improvements that others have achieved. It wets the appetite, but with so many remedies suggested one wonders if they are 'fools gold' or the real McCoy. I am sure everyone will identify with the desire to have your kit working to it's full capabilities. If what I have is the limitation of my tools, then fair enough, but if it can be sensibly improved i'd like to know more.