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01-04-2014, 01:35 PM   #1
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Pentax LX question.

I've just acquired and LX with the sports viewfinder and will be learning to use the camera. One thing I've noticed before loading any film that with my two M 50 lenses focussing at infinity the lines I'm viewing in the distance don't quite align in the split prism viewfinder.

Any thoughts, advice would be most welcome.

Many thanks,

James

01-04-2014, 01:47 PM   #2
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Indicated focus off at infinity is common on an old LX, and shows that the mirror stop which positions the mirror has softened or taken a "compression set" and lets the mirror come down too far, so its angle is off. That happened to mine after 30 years, along with the mirror hesitation when tripping the shutter, which means the mirror stop had also gotten sticky, and the mirror had to unstick in order to raise. (This is a unique sticky mirror LX syndrome not related to the upper bumper like most SLRs.)
So I sent it to Eric for a full CLA, and it has been fine since.
01-04-2014, 01:52 PM   #3
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It could also be that the focusing screen hasn't been installed correctly (or clicked into place properly).
01-04-2014, 02:53 PM   #4
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Thanks, Guys!

01-04-2014, 04:47 PM   #5
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Further LX inquiries

QuoteOriginally posted by johnha Quote
It could also be that the focusing screen hasn't been installed correctly (or clicked into place properly).
QuoteOriginally posted by TomB_tx Quote
Indicated focus off at infinity is common on an old LX, and shows that the mirror stop which positions the mirror has softened or taken a "compression set" and lets the mirror come down too far, so its angle is off. That happened to mine after 30 years, along with the mirror hesitation when tripping the shutter, which means the mirror stop had also gotten sticky, and the mirror had to unstick in order to raise. (This is a unique sticky mirror LX syndrome not related to the upper bumper like most SLRs.)
So I sent it to Eric for a full CLA, and it has been fine since.
Johna and TomB-tx (or anyone else),

Wonder if I could ask you to weigh in again. I've been in touch with the seller who said that it is normal for the eyepiece he provided to be off in this way (the FB-1 and the action eye piece). He recommended consulting the manual, but I can't find any reference to this in the main manual for the LX body or in the one brochure describing the interchangeable eye pieces. (I may have left a more specific manual on the viewfinder in my office, where I can consult it on Monday). This may be my fault, but I found his reply to my query opaque: "the eyepieces I provided produces incorrect picture ( -2 d) please read the manuals". Do you think this means - 2 degrees? Is this true & if it is and the image in the viewfinder is systematically off, what's the recommended technique for focussing? Should one expect lines to align for everything less than infinity?

I had hoped to avoid sending it off for servicing right away (in view of the description and the price), but will do so if I need to.

Any advice would be much appreciated

James

Last edited by jva59; 01-04-2014 at 04:56 PM.
01-04-2014, 05:36 PM   #6
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There is a relativly easy way to check if the focus screen / mirror are in correct alignment if you have 2 cameras. If you are 100% sure lens collimation (infinity focus) is correct on both lenses you can skip test 1 but I would do both.
Test 1:
Open back of camera, open shutter and lock mirror up. Using bulb setting and locking cable release is best. Place a small piece of glass / transparent rigid plastic hard up against the film rail. This can be held in place with a few rubber bands and spacer blocks. This is the one time when dust can be usefull. You can either scratch a line on the front of it, draw on it with a marker, place a hair on it or collect some dust on the front of the glass. This is what you will focus on. Mount lenses on both cameras and set focus to infinity. Place both lenses facing each other and parrellel to each other. I use a cobbled together reverse adapter made from reverse adapters and step up / down adapters and actually attach the lenses to each other which assure they are paralell but just aligning them sitting together will work. When you look through the viewfinder of the test camera the dust or whatever on glass test screen should be in focus. This test is used to confirm camera flange focal distance and lens collimation. The chances of focal distance being incorrect is very slim so if it does not pass one of both lenses collimation is off.

Test 2:
Mirror in the down position. Use the same setup as above (minus the glass screen) with the cameras facing each other. When you look through the viewfinder of the test camera the focus screen of the camera being tested should be in focus. If it is not then either the mirror is out of alignment or the focus screen is not installed correctly. I would double check focus screen is installed correctly and if so no doubt the mirror is the problem.
01-04-2014, 05:36 PM   #7
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Hi James.

He probably means -2 diopters. Some of the finders are adjustable to compensate for the users eyesight (-2D is for short-sighted users), however I have the FB-1 & FC-1 combination and they don't offer this adjustment. My camera manual doesn't mention anything about the FB-1 finder, presumably there's a separate manual for the finders? As long as you can see the split-image focus aid itself sharply, this adjustment is set correctly but either way it shouldn't affect the split-image at infinity.

It should reach infinity, but does it focus 'past' infinity (i.e. the split-image starts on one side, meets and crosses to the other)? I've had an intermittent problem with an MX with a similar problem which seemed to go away. Either I used a different lens or popped open and re-latched the focusing screen and it seemed to go away.

My LX is unserviceable at the moment (sticky mirror), but I'll try and test infinity focus with the FB-1 & FC-1 tomorrow. I presume you've tried removing and re-attaching the finder (can't see how that would make a difference though) and checked the sport finder is attached to the base correctly (again unlikely to cause the problem)?

John.
01-04-2014, 07:01 PM   #8
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I tested my FB1+FC1 then replaced the FC1 with my FD1 to verify proper focus and yes the viewfinder should be in focus at infinity with any prism on the LX provided everything is as it should be. Of course with a viewfinder magnification of only .55 for greater eyerelief, the FB1+FC1 is hard to critically focus.

01-04-2014, 07:26 PM   #9
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QuoteOriginally posted by johnha Quote
Hi James.

He probably means -2 diopters. ...

John.
QuoteOriginally posted by LesDMess Quote
I tested my FB1+FC1 then replaced the FC1 with my FD1 to verify proper focus and yes the viewfinder should be in focus at infinity with any prism ....

QuoteOriginally posted by Tool_Horder Quote
There is a relativly easy way to check if the focus screen / mirror are in correct alignment if you have 2 cameras. If you are 100% sure lens collimation (infinity focus) is correct on both lenses you can skip test 1 but I would do both.
Test 1:

Test 2:
Johna, Tool-horder and LesDmess,

Many, many thanks for the taking the trouble to pen these helpful and illuminating replies.

I've also been in touch with Eric Hendrickson, to whom I'll be sending the LX. He says that the focus should line up all the way to infinity. I take that to be authoritative.

I am a now a trifle peeved with the seller, less for the presence of the problem itself, which it wouldn't be hard to miss if one didn't use the camera much oneself, than for the opaque and misleading replies to my queries.

Thanks again,

James

Last edited by jva59; 01-04-2014 at 07:32 PM.
01-05-2014, 08:18 AM   #10
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An LX serviced by Eric . . . what more could one ask for! Please post pictures of it - as well as results from it, when you get a chance.
01-05-2014, 09:52 AM   #11
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QuoteOriginally posted by LesDMess Quote
An LX serviced by Eric . . . what more could one ask for! Please post pictures of it - as well as results from it, when you get a chance.

LesDMess,

I think that's the way to think about it! Though I'll end up having spent a good deal more than I originally envisaged (I got carried away bidding for it on ebay, sometheing I'm usually careful not to do), with a bit of luck, in the fullness of time I'll have a fine looking, smooth functioning LX. Meanwhile I heard from the seller again, citing information about the fixed diopter setting (Pentax Interchangeable Viewfinders) as a reason why lines don't align at infinity. But I think this is wrong for the reasons you, Johna and Eric H. give. The diopter adjustment should affect how the focussing screen looks to the camera operator, but not lines seen through it.

Thanks again,

James
01-05-2014, 10:59 AM   #12
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FWIW RE: your immediate prior post, my FB-1/FC-1 combination has no discernible effect on the alignment of the split-image focusing screen at any focusing distance, including infinity. The principal benefit and compromise of that particular VF is the method of use - held slightly away from the eye and looked INTO rather than through. In this way I think it is similar to a spotting scope or rifle scope - a different technique, but useful in its place o with eyeglasses.
01-05-2014, 12:03 PM   #13
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QuoteOriginally posted by monochrome Quote
FWIW RE: your immediate prior post, my FB-1/FC-1 combination has no discernible effect on the alignment of the split-image focusing screen at any focusing distance, including infinity. The principal benefit and compromise of that particular VF is the method of use - held slightly away from the eye and looked INTO rather than through. In this way I think it is similar to a spotting scope or rifle scope - a different technique, but useful in its place o with eyeglasses.

Thanks Monochrome! Wish I'd been able to convince you to part with your LX when we were in contact about it earlier. (The benefits of buying from a forum member who knows what he's talking about!) But I'll get there.
01-05-2014, 12:21 PM   #14
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A small victory for the preservationists ;)

QuoteOriginally posted by jva59 Quote
convince you to part with your LX
My wife claims I am a compulsive hoarder. This way there will be another LX renovated to as-intended operating condition for the general aesthetic good of society.

One unintended beneficial consequence of my hobby these last 15 years, which has been to buy, have Eric repair, use for a while and then sell every Pentax camera I've ever wanted in the past, has been that all those cameras are still operating in the hands of users somewhere rather than sitting on a shelf or buried in a landfill. I know of a case in which a member's prized Pentax body and kit lens was destroyed in a natural disaster. I had had my time with that model combination and offered to send it to him for what he was able to pay. There's something fulfilling in that, I think, that goes beyond just getting my money back and moving on to the next one.

it's all good.
01-10-2014, 02:13 PM   #15
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Welcome to LX ownership!

QuoteOriginally posted by jva59 Quote
Johna and TomB-tx (or anyone else),

Wonder if I could ask you to weigh in again. I've been in touch with the seller who said that it is normal for the eyepiece he provided to be off in this way (the FB-1 and the action eye piece). He recommended consulting the manual, but I can't find any reference to this in the main manual for the LX body or in the one brochure describing the interchangeable eye pieces. (I may have left a more specific manual on the viewfinder in my office, where I can consult it on Monday). This may be my fault, but I found his reply to my query opaque: "the eyepieces I provided produces incorrect picture ( -2 d) please read the manuals". Do you think this means - 2 degrees? Is this true & if it is and the image in the viewfinder is systematically off, what's the recommended technique for focussing? Should one expect lines to align for everything less than infinity?

I had hoped to avoid sending it off for servicing right away (in view of the description and the price), but will do so if I need to.

Any advice would be much appreciated

James
This doesn't sound reasonable from the seller. Since the viewing screen is in the body I can't see how various finders could affect the rangefinder alignment. I've never noticed any misalignment on my LXs between the "standard" pentaprism, the magnifying eyepiece, or the FB 1 and action eyepiece. I'd imagine that either the screen is improperly installed, or that the mirror's rest position is incorrect, as suggested by TomB_tx.

You'll love the LX. Watch for the winder, it integrates well with the camera and offers power rewind! Wowzer!
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