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06-29-2007, 06:36 AM   #31
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QuoteOriginally posted by Ian Quote
It seems to me that this whole issue of metering with the older lenses could be solved very easily by a small firmware fix.
The existing focus screen works just fine for metering, provided that the camera has information about the actual aperture settings so that it can meter through a wide-open lens and make the necessary calculations about the exposure required when the lens stops down.

What is the difference between an A-series lens and an older K or M series lens? Or between an A series lens on and off the ´A´ position? As far as I can see the only difference is that in the case of the older lenses (or the A lenses in manual mode) the camera does not know what the wide-open apature is, or to what aperture the lens will go to when taking the photo. It can obviously stop down the aperture to the selected value with the green button, or the optical preview, but this is evidently not a satisfactory solution for metering with the hardware in the k10.

The fix to this problem is to give the computer in the camera the information it has when using A series and later lenses. This is 1. the wide open aperture and 2. the aperture to which the lens will go to when the shutter is open.

The wide-open apeture could be entered in the menus in the same way as the focal length is, and perhaps one of the e-dials could be used to tell the camera where the manual apeture ring was set to. This would give the camera the same information that it has available to it when using an A series lens, and would probably enable multi-segment metering with any of the old lenses as well.

Pentax need to be persuaded to implement this in a firmware upgrade. It would be very easy for them to do - no new actual features, just an extra entry in one of the menus. Probably the place to put it would be in with the ´use aperture ring´ selection.

Ian
After a few people suggested a firmware fix I thought that a bit of contemplating on a workflow scenario. First you could pre-program all your manual lenses and include the wide open f stop (BTW this would instantly fail for lenses w/ smaller tha f4 aperatures ie mirror lenses and some on 2x teleconverters) (ANOTHER note: even "A" lenses w/ "A" teleconverters should fail if the effective f stop goes above f8, which may happen in larger,slow zooms. Something to check on). Now you could choose your lens in a menu.
Then meter w/ the green button at wide open (see notes above).
Then tell the camera what f stop you want to use (camera will decide on speed based on the above)and
then take the picture if you have a speed/aperature combination to your liking.
Unfortunately this only works for aperature priority (which is what you set it for basically)
Seems to me dropping a DS screen in is much quicker, permanet, global and doen't screw anything else up too badly.
And shoot, check histogram, reshoot is at least as fast. And you can choose either to change shutter speeds or aperature........ No the software fix is too cumbersome for me.
If this was an easily solveable issue by Pentax, it would be solved. My guess is this is just a minor way of pushing new glass, short of the Canon way of just ditching the mount all together.
Since the old screens weren't "broken" and there is not a ton of praise for the new screens (adds really nothing AFAICT), it just seems like an out and out mistake in engineering logic.........probably made a lot of sense in marketing, bean counting logic though. Pentax HAD to know the implications of the new screen on manual focus lenses or they are all brain dead there in R/D.........

06-29-2007, 07:26 AM   #32
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I got the *ist LL-60 screen from B&H, Best $40 i've spent - works great and I would have liked it for the grid lines alone (previously M lenses would overexpose and I had to adjust for every shot almost- tough with birds) YMMV. It would be interesting to see if the few K10d's that expose correctly out of the box had a *ist screen installed from the factory.
06-29-2007, 10:03 AM   #33
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QuoteOriginally posted by jeffkrol Quote
Since the old screens weren't "broken" and there is not a ton of praise for the new screens (adds really nothing AFAICT), it just seems like an out and out mistake in engineering logic.........probably made a lot of sense in marketing, bean counting logic though. Pentax HAD to know the implications of the new screen on manual focus lenses or they are all brain dead there in R/D.........
Agreed that anything short of a mechanical aperture coupling won't work.

Since other cameras (like the Minolta 7D) have this identical issue as well, my guess is that Pentax went with a cheaper or more abundant source.
06-29-2007, 10:12 AM   #34
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QuoteOriginally posted by borno Quote
I got the *ist LL-60 screen from B&H, Best $40 i've spent - works great and I would have liked it for the grid lines alone (previously M lenses would overexpose and I had to adjust for every shot almost- tough with birds) YMMV. It would be interesting to see if the few K10d's that expose correctly out of the box had a *ist screen installed from the factory.
I seriously doubt ANY expose correct at f8 and above without user intervention.
Of course a random lucky error could occur. Anyone saying it works has yet to post ANY concrete proof.................ie white wall test shot, straight default setting ect..

06-29-2007, 09:14 PM   #35
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I wonder if the massive underexposure problems the AF-540FGZ has with many people's K10D units could be related to the manual lens underexposure problems.

I'm very tempted to order the LL-60 this weekend. I use manual lenses a lot (although haven't yet had much of a chance to see if there are any REALLY wonky exposure regions yet), I also like the extra lines, and if it can improve the exposure of my P-TTL flash that would be an incredible benefit.
06-29-2007, 10:47 PM   #36
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After reading about using the DS screen on another thread, I ordered one. My camera was more than a full stop off most of the time - more like 2 full stops. Before it came in, I talked to a Pentax rep, who said that he thought that wasn't a good idea and gave me the phone number of someone else in Pentax to talk to. They also told me that I should send it in the camera for repair - it shouldn't meter so badly with manual lenses. I dithered about it, decided to send it in, but the focusing mirror had already been shipped, so I thought, "why not try it, I've bought it. I can always take it back out." It worked for me and I can't figure out why - it makes no sense to me. I probably should send it in for repair, to see if they can make it work, but I really like the divided LL-60 screen, my lenses work and I'm happy.
06-30-2007, 12:23 AM   #37
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QuoteOriginally posted by jeffkrol Quote
I seriously doubt ANY expose correct at f8 and above without user intervention.
Of course a random lucky error could occur. Anyone saying it works has yet to post ANY concrete proof.................ie white wall test shot, straight default setting ect..
Well, here it is.

Taken at f22



Taken at f 8



SMC A 50 f 1.7, on Manual f setting, M mode, green button. DS focusing screen. The camera was unable to meter correctly with the original focusing screen or with a KatzEye one.
06-30-2007, 05:50 AM   #38
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Yeah pentax service in colorado told me the ds screen wouldn't fix the problem (they did say problem) but it did for me

06-30-2007, 06:11 AM   #39
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QuoteOriginally posted by ben-pentax Quote
Well, here it is.

Taken at f22



Taken at f 8



SMC A 50 f 1.7, on Manual f setting, M mode, green button. DS focusing screen. The camera was unable to meter correctly with the original focusing screen or with a KatzEye one.
Thanks but I was referring to people w/ the original screen who say "it's perfect". I can only imagine how burnt out the shot would be at f22
06-30-2007, 06:12 AM   #40
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QuoteOriginally posted by borno Quote
Yeah pentax service in colorado told me the ds screen wouldn't fix the problem (they did say problem) but it did for me
Somebody should send them some "before and after" shots.....
06-30-2007, 07:54 AM   #41
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QuoteOriginally posted by jeffkrol Quote
Thanks but I was referring to people w/ the original screen who say "it's perfect". I can only imagine how burnt out the shot would be at f22
Oops .. got you the wrong way .... I don't have to imagine how burnt out the shot would be - I can still remember.
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