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02-03-2010, 11:54 AM   #1
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Any K-x user experience with M42 lens (Gus, please help)

I used two of my M42 lens today with my K-x. I found the Av metering to be way off by a big margin needing +1.7Ev to +2.0Ev. I will later mount the same lens to my K20D. And I find this odd as in K20D, I can use my m42 lens quite reliably in Av mode.

Thanks,
Hin

02-03-2010, 01:02 PM   #2
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I have the same thing going on with my Kx as well. It's just something we have to live with. Either adjust with the EV adjust or within the Custom Image settings for High/Low Key.
I have no such problem with my K20D. I find that with the Kx it all depends on the lens. the two 50mm Russian lenses I have need less adjustment than the 400mm Lentar which in-turn needs slightly more than the 200mm Tak. Maybe it has to do with focal length???
02-03-2010, 01:16 PM   #3
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QuoteOriginally posted by fccwpe Quote
I have the same thing going on with my Kx as well. It's just something we have to live with. Either adjust with the EV adjust or within the Custom Image settings for High/Low Key.
I have no such problem with my K20D. I find that with the Kx it all depends on the lens. the two 50mm Russian lenses I have need less adjustment than the 400mm Lentar which in-turn needs slightly more than the 200mm Tak. Maybe it has to do with focal length???
Much thanks for the report. I will later go back and check out the same M42 lens on my K20D. I don't recall any M2 lens that I have used with K20D that need a big adjustment to Ev. The most with K20D is usually in a +0.3 to +0.7 adjustment when aperture is wide open. So far my observations to K-x with both M lens and M42 lens are pretty much in the negative sides. Here are the run down of observations:
  • With M42 lens, Av mode need large +2 Ev adjustment, may vary with lens. I will confirm more later on but so far I am very unsettled in using K-x with M42 lens.
  • With M lens without A aperture in K mount, M mode + green button works well in metering but it goes with mysterious extra mirror flipping in the stop-down. It is NOT a biggie issue but I am concerned on the extra mirror slap with noise in every green button press.

Thanks,
Hin

Last edited by hinman; 02-03-2010 at 01:29 PM.
02-03-2010, 01:20 PM   #4
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Try to short data pin.

02-03-2010, 01:23 PM   #5
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QuoteOriginally posted by jerrymouse Quote
Try to short data pin.
You mean with foil. I will give that a try. Even if that works, it will be inconvenient to use K-x with M42 lens. I wonder if there is problem with center-weighed metering with M42 lens.

Hin
02-03-2010, 01:24 PM   #6
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Use M mode. It way more accurate with green button.
02-03-2010, 01:45 PM   #7
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QuoteOriginally posted by hinman Quote
You mean with foil. I will give that a try. Even if that works, it will be inconvenient to use K-x with M42 lens. I wonder if there is problem with center-weighed metering with M42 lens.

Hin
Yes. It was like that on K-m, so I suppose it'll work with K-x too. Actually it does - I just tested with Helios 58mm/2:
No foil - 1/60, ISO 1000, underexposed
With foil - 1/15, ISO 1000, spot on

I guess it's because it's not suppost do work in a first place (in Av). I think it's a coincidence that it works on K10D/K20D. Shortening data pin forces the camera to think that M lenses are mounted and it meters wide open (it's all just my guess!).
02-03-2010, 01:48 PM   #8
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QuoteOriginally posted by hinman Quote
I used two of my M42 lens today with my K-x. I found the Av metering to be way off by a big margin needing +1.7Ev to +2.0Ev. I will later mount the same lens to my K20D. And I find this odd as in K20D, I can use my m42 lens quite reliably in Av mode.

Thanks,
Hin

Hi Hin, I have never really been a Av user on the M42's on my K100 or K20 as it always needed a little ev comp, and the amount of ev comp changed as you change the aperture. So I always shot M and green button.
So when I got the kx I continued using M green button...

But I did check Av mode early on with the m42's and I found the same thing you are seeing. +1.5 to +2 ev comp was needed. However I did see that at least with my helios and my nikkor 105, that the comp worked thru the full aperture range of the lens. I dont know why the kx needs such ev comp to start off with but once it was dialed it worked better than the ever changing comp needed on my K20 thru the ap range.

Does that make sense?

See if once you set the 1.7 comp if it meters the same thru the range.


Also in live view, I do use Av with 0 ev comp and it works well. Thru the entire aperture range.

02-03-2010, 01:50 PM   #9
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Hey Jerry

QuoteOriginally posted by jerrymouse Quote
Yes. It was like that on K-m, so I suppose it'll work with K-x too. Actually it does - I just tested with Helios 58mm/2:
No foil - 1/60, ISO 1000, underexposed
With foil - 1/15, ISO 1000, spot on

I guess it's because it's not suppost do work in a first place (in Av). I think it's a coincidence that it works on K10D/K20D. Shortening data pin forces the camera to think that M lenses are mounted and it meters wide open (it's all just my guess!).
When you have the foil shorted... does it work well at all the aperture settings?
02-03-2010, 02:10 PM   #10
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QuoteOriginally posted by Igilligan Quote
When you have the foil shorted... does it work well at all the aperture settings?
The histogram was the same at all apertures (at least with Helios 58/2). I got almost the same image in Lv (with or without DATA pin shortened).
02-03-2010, 07:36 PM   #11
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Thank you for all the help with useful replies. I will report more later when I can find the time to check the metering with foil. So far my impressions has been on constant application of Ev in Av mode.

Gus and other members with K-x:
when you have a K mount manual focus lens, do you guys find mirror flipping upon green button press? I find it annoying and I can't figure out the reason. With the M42 lens, there is no closing of the blades as the blades are already closed down subject to the aperture chosen on aperture ring. And green button will be quiet without the mysterious mirror flipping. But on a K mount M lenses, I always get a mirror flipping right after (or about the same time) that the blades close down. I find that odd and I have asked a few time in other threads with no response.

Thanks,
Hin
02-03-2010, 09:42 PM   #12
Igilligan
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I have noticed that too

Hin I hear the mirror flip too... I also do not like that it does that. I can't for the life of me figure out why it has to flip the mirror to meter the M lenses.


Almost all of my lenses are M42's so it has not bothered me much... But on the two M lenses I have used, I dont care for it.
02-03-2010, 10:32 PM   #13
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QuoteOriginally posted by hinman Quote
Thank you for all the help with useful replies. I will report more later when I can find the time to check the metering with foil. So far my impressions has been on constant application of Ev in Av mode.

Gus and other members with K-x:
when you have a K mount manual focus lens, do you guys find mirror flipping upon green button press? I find it annoying and I can't figure out the reason. With the M42 lens, there is no closing of the blades as the blades are already closed down subject to the aperture chosen on aperture ring. And green button will be quiet without the mysterious mirror flipping. But on a K mount M lenses, I always get a mirror flipping right after (or about the same time) that the blades close down. I find that odd and I have asked a few time in other threads with no response.

Thanks,
Hin
I hear the mirror flip as well on my K-x with the manual lenses I have. I have read that it's just part of the design of the mirror and nothing to be concerned about. I don't think it's a huge deal, but sometimes people will think I'm taking a shot when really I'm just metering
02-04-2010, 01:59 AM   #14
Damn Brit
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Perhaps the Metering on Green Button and Liveview functions are connected in some way for whatever reason (cost cutting?).






QuoteOriginally posted by hinman Quote
Thank you for all the help with useful replies. I will report more later when I can find the time to check the metering with foil. So far my impressions has been on constant application of Ev in Av mode.

Gus and other members with K-x:
when you have a K mount manual focus lens, do you guys find mirror flipping upon green button press? I find it annoying and I can't figure out the reason. With the M42 lens, there is no closing of the blades as the blades are already closed down subject to the aperture chosen on aperture ring. And green button will be quiet without the mysterious mirror flipping. But on a K mount M lenses, I always get a mirror flipping right after (or about the same time) that the blades close down. I find that odd and I have asked a few time in other threads with no response.

Thanks,
Hin
QuoteOriginally posted by Igilligan Quote
Hin I hear the mirror flip too... I also do not like that it does that. I can't for the life of me figure out why it has to flip the mirror to meter the M lenses.


Almost all of my lenses are M42's so it has not bothered me much... But on the two M lenses I have used, I dont care for it.
QuoteOriginally posted by wshi Quote
I hear the mirror flip as well on my K-x with the manual lenses I have. I have read that it's just part of the design of the mirror and nothing to be concerned about. I don't think it's a huge deal, but sometimes people will think I'm taking a shot when really I'm just metering
02-04-2010, 10:05 AM   #15
Igilligan
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I bet video-Live view functionality and cost cutting has something to do with it. Gary does your k2000 have Live view? If so does it do the same thing?
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