Thanks.

I will stick with my K10D for a while longer then. There certainly are no problems using A series lenses, and there is a reasonable work around for the few M series lenses that I like using. Its a shame that they couldnt fix the metering problem on the K20D though, particularly as there seems to be no such issue with the earlier digital SLR's - I suppose that there must be a fairly significant technical issue here.

Hi

Can anyone tell me if the exposure problems experienced when using manual M series lenses on the k10D have been cured on the k20D ? (Thinking of upgrading..!)

thanks

Hi. I have used a film scanner for about 10yrs. First an Epson and more recently a Microtek Filmscan 3600 budled with Lasersoft's Silverfast scanning suite. Results from slides (esp with Silverfast) have been great - but it is a time consuming process. I must confess that I now "cheat" and send my undeveloped films off for E6 process and scanning at the same time. Its a lot quicker and less hassle!

No worries - actually, this granny's memory isn't as good as it was!!

I re-ran the tests using the plastic cover, and the measured exposure values were the same through the viewfinder and on the top LCD......(unsurprisingly!) I am surprised that it made such a big difference (up to 2 stops) - I have never found my film cameras this sensitive before.

I also ran extensive tests over the w/end with various manual lenses and subjects to get some idea of the scope of the exposure problem. In all cases, the results were the same: Exposure OK when aperture fully open, but starts to overexpose at about f8 getting progressively worse...the problem seems to be worse in low light.

There is a tendancy to underexpose sometimes when fully stopped down, but this does not appear to be evident when the viewfinder is completely covered. I supect that this could be an issue on a bright day or in low light conditions if you do not get your eye close enough to the viewfinder (eg: if' like me you are wearing spectacles) and thus the ratio of light entering via the viewfinder vs light entering via the lens is sufficiently skewed to cause the problem. (Not noticable unless stopped down metering is used - which is always is for manual lenses)

Anyway - I have now returned the camera for exchange together with all my test results and CDR of images clearly documenting the problem. (something for Pentax engineers to think about!) It will be interesting to see if the replacement body exhibits the same tendancies...will keep you posted!

Thanks Chris - I was covering it with my hand - but will re-run the test over the weekend using the little plastic cover just to be sure. Am returning the camera for an exchange on Monday anway...will be interesting to see if the next one has the same DOF exposure problem.

Another interesting phenomenon that I have just noticed:

When using DOF (Optical) preview in Hyper Manual, the EV meter in the viewfinder is 1-2 stops different from the meter on the top LCD. Invariably ONE of them is showing correctly...but it seems to vary as to which one. This happens when using DA AND M series lenses.

Using the green button tends to select one of these two at full aperture and the wrong one at fully stopped down

Am I doing something really stupid? Or is this just weird?

Hi Pete

No - you are not missing anything. It seems that this problem is unique to the K10D - hence my whinge!

K10D users essentially have the same 3 choices that you do, but it would appear that only (a) (Aperture wide open) works correctly. Stopped down metering using the "green button" (similar to AE lock) or manual DOF metering is not reliable and throws up some wild results.
It seems (from the various posts on this site and others) as though this issue varies between individual cameras and different light intensities.

In short though - your K100D appears to function a lot better on this point....want to swap?

Unfortunately, it is not that straightforward as the metering problem is so variable. I accept that there have to be restrictions but it would be good to understand what exectly they are -and to have been clear on this BEFORE I bought the camera. If I could guarantee that I always got an accurate exposure using just DOF preview at just one aperture setting then I could compensate for this, but the problem seems to vary with the light intensity. In low light, I seem to get an underexposure above f8 with accurate exposure in the f4-f8 range. This morning, I am getting an over exposure in the range f2.8 - f8.

If Pentax were clear on these "restrictions" and exposure problems and explained that TTL metering does not work reliably with M and K series lenses, then those of us to whom this is important could have taken an informed decision: Basically we either chose a 6MP Pentax Digital or accept that we carry a light-meter/make adjustments in our heads.

The situation is far from clear:

i) Is this a problem with all K10D cameras? (If not, then an exchange should be offered)

ii) If it is a problem with then all, can it be resolved by a future firmware fix? (in which case we might decide to hang on) or is it a hardware fix? (in which case we might just as well get a refund and either buy a 6MP model or wait for a revised K10D)

iii) If it can't be resolved, are Pentax committed to addressing the issue on a future camera, or have they accepted that this is as far as compatability goes? (If so, again, we can make an informed decision.)

Pentax Europe, although helpful on the phone, are clearly very vague as to the exact nature of the problem and the type of exposure errors that may occur. I am left with the feeling that they have released a beta version of the camera which has an unresolved issue - the question is, how are they going to resolve it if at all?

As far as new lenses go - I accept that they are the future, and will invest in them as I already have. It would be nice to be able to use some of the older superb optics on a compatible DSLR - but maybe we will have to accept that the K10 is not actually compatible......contrary to what we were told.

Oh dear - I wish I had read this site properly a couple of weeks ago......

After waiting a long time for Pentax to bring out a digital camera even half as good as the LX I was delighted to see the recent very positive reviews of the K10D in Amateur Photographer & What Digital Camera. Here at last was a digital SLR worthy of the Pentax name offering 10 MP and the option of using my old M series lenses. Digital need no longer mean Extachrome and a slide scanner!

No mention in the press of the "known issue" of exposure problems with M series lenses. Oh yes, Pentax mentioned "restrictions", but these were described in terms of limiting the full functionality - ie a manual lens is clearly never going to be able to work in full program mode or autofocus. And of course, with the previous experience of ist DS users singing the praises of the easy use of M lenses who would have thought that there would be a problem?

All well & good until you read the instruction manual..and its tales of "exposure error" - what exactly does this mean I thought. And of course, it means exactly what ChrisA has described. In my case, accurate exposure (measured against performance with the "digital" lens and against my lightmeter and against my LX) is acheived at f5.6 and f8 with wild underexposure in low light conditions occuring at f16 and f22.

The result is EXACTLY the same whether you use the green button or use DOF preview and manual adjustment - the fact is that the lightmeter is off.

So - 30 years after I was the proud owner of my first SLR, a Praktica with stop down TTL metering, I find that Pentax have managed to produce a camera on which the lightmeter does not work in the most basic of modes. Quite simply; it is unable to measure accurately the amount of light coming through the hole!

It is not a matter of "changing technology" and incompatability with older lenses - the fact is that M lenses were compatible in this mode with the *istD series cameras and there is no real reason why they should not be able to work on the K10D. This camera has clearly been released onto the market before this issue was resolved (otherwise why acknowledge the fault in the manual) in the hope that either very few people will notice OR that we will put up with it.

Question is what are people doing about it? I am now very tempted to send the camera back from whence it came and shoot off a stiff letter to the MD of Pentax in Japan, suggesting that he take a long hard look at an LX, MX, ME super, Spotmatic or even an old Praktica or Zenith and find out how they managed to acheive this minor miracle 40 years ago!

Is it just a few of us (in which case they should replace ours with one that works) or does everyone really have this issue and just not care about it?
I have grown rather attached to my M series 15mm f3.5 rectilinear, 20mm f4, 200mm f2.5 and 300mm M* f4 lenses...amongst others, and may just revert back to the LX, Ektachrome & the slide scanner!